Advances in the development of gyrotrons and related high power millimeter wave sources, combined with advances in quasi-optical techniques can shape the future ground based or ship based radars and fusion machines. Heating by electron cyclotron resonance (ECRH), plasma diagnostics and current drives are practical objectives.

The far infrared is an important region for the study ofgalaxies. These infrared wavelengths easily penetrate the clouds ofdust and molecules found in many galaxies which tend to hide their intaiors. In addition, the temperatures and densities ofgalacticmolecular clouds fall in a gieral range which easily excites far infrared spectra, but which do not produce much radiation at short wavelengths. Hence spectroscopic measuremaits in this region are of great value in providing measures of temperature, density and velocity. Howeva, it is only within the last ten or fifteen years that much galactic spectroscopy has been done in this region partly because technology for sensitive detectors and for some of the other opticai components has only recently been developed. In addition, the opacity of our atmosphere requires special platforms, generally above most ofthe atmosphere, for astronomical observations at these wavelengths. Fig. 1 shows the transparency ofour atmosphere at various wavelengths in the visible and infrared from the ground, from the height of the observatories on Mauna Kea, and from the height of NASA's aircraft observatory, the Kuiper Observatory, which generally operates at 40,00045,000 feet. Clearly, between about 40 and 300 microns wavelength, essentially no signals are transmitted to the top ofMauna Kea, while thae is substantial transmission to the high flying Kuiper Observatoiy, a C141 four engine aircraft carrying a 36 inch telescope. The telescope is gyrostabihzed and at altitude looks out ofthe side ofthe aircraft with no obstructing windows. Fig. 2 shows a somewhat more detailed picture ofthis transmission. Even at 14 kilometas transmission is by no means perfect the are many regions where spectral lines are well transmitted but also other regions whe radiation is absorbed by atmospheric spectral lines, particularly those ofwater vapor. From the point of view of transmission, an ideal base from which to observe the far infrared is a spacecraft or satellite, such as the Infrared Astronomical Satellite (IRAS), which flew a 60 inch cooled telescope for several years in orbit. However, its function was primarily to obtain systanatic information ofa broad-band nature in the infrared, which it did well, ratha than spectra. Up to the present, most ofthe spectral work done in the far infrared has been carried out in the Kuipa Observatory already mentioned. There is also the possibility ofdoing useful far infrared work from the South Pole. The land mass at the South Pole is actually below sea level, but a pile of about 10,000 feet of snow and ice on top of it gives the structures built atthe South Pole an altitude of about 9,300 feet. This altitude, combined with vy low temperatures which freeze out wat vapor, provide enough transparency in certain localized frequency regions that the South Pole can also be quite useful for particular spectral lines which fall in these atmospheric windows.1 Balloon borne telescopes, which fly considerably higher than the Kuiper Observatoiy, can also be useful. However, they do not carry human attendants to adjust or modil3r the equipment, whereas the airplane can take a sizable crew of passengers who work with the telescopes and spectrometers while observing. The plane also characteristically lands 'and takes offagain for further observations with a turnaround lime ofabout two days, and hence with it the experimental apparatus can be tried, modified and repaired, and flown again rather efficiently. There are three rather different types of spectrometers presently in use for astronomical measurements in the far infrared. The first is a grating systan constructed by Erickson and his associates at the NASA-Ames Research Center, which is shown in Fig. 3 . Ituses a linear array ofdctectors, with three different types ofdetectors for various wavelength ranges and as many as 13 detectors responding at any one frequency. It has excellent sensitivity and a resolving powerof about 5,000. A second type of spectrometer involves the use of Fabry-Perots, and is shown schematically in Fig. 4. Such a Fabiy-Perot system has the advantage that it can examine spectral lines in a number of geometric positions at once. The system shown in Fig. 4, which has been built jointly by groups at the University of California at Berkeley and at the Max Planck Institute in Garching, Gennany, has a 5 x 5 array of detectors and hence maps spectral lines over sizable regions rather rapidly. With three Fabiy-Perots in series, it has a resolving power as high as about 100,000. Its NEP approaches i0 waUs/sec'. The third type of spectrometer, shown in Fig. 5, uses heterodyne detection, with far infrared gas lasers as local oscillators. At infrared wavelengths as long as 300 run, harmonics ofGunn diodes have also been used for a heterodyne detection spectrometa. Hetaodyne detection can achieve exceedingly high spectral resolution and thus resolve any spectral line. For a narrow spectral region it has somewhat higher sensitivity than direct detection, but it is somewhat less saisitive for rather broad lines. The heterodyne system shown was built by Betz3, who is now at the University of Colorado.

A high performance and stabilized U-band microstrip GaAs Gunn Oscillator on duroid 6002 is reported. It is stabilized using a dielectric resonator and a block (stub) circuit resonator in a unique hybrid configuration. Frequency stability of +/- 1.2 ppm/ degree(s)C is achieved over 10 to 60 degree(s)C temperature range. A highest 102 mW of cw output power at 44.6 GHz is obtained from a 108 mW diode.

The generation of monochromatic current modulation of an intense relativistic electron beam for producing high power millimeter wave is studied theoretically. The frequency mismatch, gap electric breakdown and electromagnetic isolation of the cavities are investigated by particle simulation for various beam parameter and geometric configuration.

A well established selective etching technology for GaAs IMPATT diodes was employed to fabricate GaAs TUNNETT diodes on diamond heat sinks. The improved heat dissipation led to significantly higher dc to RF conversion efficiencies and doubled the available RF output power of diodes on diamond heat sinks compared to diodes from the same MBE-grown material on integral heat sinks. An RF output power of more than 80 mW with a corresponding dc to RF conversion efficiency of 5.25% was measured at 106.9 GHz. To the authors' knowledge, this is the first successful demonstration of GaAs TUNNETT diodes on diamond heat sinks, and the dc to RF conversion efficiencies and RF power levels are the highest reported to date from any single device made of group III-V materials (GaAs, InP, etc.) at this frequency. A free-running TUNNETT diode oscillator at 107.7 GHz showed an excellent phase noise of less than -94 dBc/Hz, measured at a frequency off-carrier of 500 kHz and an RF power of 40 mW. Phase-locking of TUNNETT diode oscillators has been demonstrated in a setup with a EIP 578 frequency counter and external down-conversion.

Design and results of solid-state oscillator investigation in the millimeter and submillimeter ranges with the oscillation system in a form of open quasioptical metal-dielectrical resonator (QMDR) are presented in this article. The conditions of the excitement and the methods of the experimental investigations of the azimuthal oscillations with the EH- and HE- poliarization in the resonator are shown. Electrodynamical properties of this system are demonstrated. The investigation results of Gunn oscillator generation with the single diode are presented. The results of the oscillations mutual synchronization and power summing up of a few diodes are demonstrated too.

The effects of planar transmission line dispersion, as well as dielectric and ground plane losses, on the propagation of pico-second electric pulses are investigated. For this purpose, the Spectral Domain Approach (SDA) and Fast Fourier Transform (FFT) are used, to operate in the frequency and time domain, respectively. It is observed that the transmission line dispersion is the main cause for distortion of the pulses, while the material losses are mainly responsible for signal attenuation. It is also observed that the dispersive nature of the transmission line can be used with advantage, through careful choice of the line geometry and composition, to reshape asymmetrical pulses, and to compress wide electrical pulses. The results of this study find applications on quasi-optical circuits and short optical pulse generation.

Devices based on dielectric strip waveguides made of low loss ferrites and semiconductors have been created. Circuit elements, such as attenuators, phase shifters, switches, dividers, couplers, in particular with optical and electrical control, nonreciprocal devices, were applied to some millimeter wave systems, including communication systems.

Dielectric constant of sand-powders sampled from desert area have been measured at W band by means of waveguide method. The algorithm about equivalent dielectric constant of analogical sandstorm have been discussed. It is very useful to test the sand-powders of the desert sample at laboratory, to make analogical analysis of sandstorm and to research the effects of sandstorm in desert area upon electric wave propagations.

The methods of the spectral theory of operator-valued functions (OVF) are applied as universal technique for solving the problems of normal waves (NV) and fundamental frequencies (FF) of open slotted cylindrical structures with layered dielectric filling. Analytical formulas for FF are obtained suitable for engineering calculations.

Tapered rectangular transmission lines are widely used in electromagnetic compatibility (EMC) and microwave integrated circuits (MIC). Electromagnetic wave propagation in this kind of transmission line is discussed. A coordinate transformation for analyzing the transmission line is presented. The derived wave equation is a second-order nonlinear partial differential equation which is solved by using Galerkin method. An application of this method is also given, good agreement is seen between the computed and measured results.

Embedding impedance of an axially oriented whisker in a rectangular waveguide is investigated and reported in this paper. The modeling formulation is based on the method of moments and verified by scaled model measurements. The simulation results show that the differences on the embedding impedances between an axially oriented whisker and an transversally oriented whisker are not significant.

In this paper, a compound high power millimeter wave waveguide Y-junction circulator, which has good performance, have been analyzed and developed. Its enduring power attains 60 W CW-power and the temperature of the waveguide surface does not exceed 25 degrees Centigrade under natureal coolness.

A spherical rotating joint operating at millimeter wavelength is proposed here. Unlike the traditional rotating joints, this is made of two half spheres in which the spherical hybrid mode HE11 operated. The coupling effect of the capacitances due to the gap between two half spheres maintains electrical continuity. The measurements indicate that the constant output is achieved while the joint being rotating over 0-- 40 solid angle range, the V.S.W.R. are less than 1.5 and the insertion loss are lower than 1.0 dB from 34.5 GHz to 35.5 GHz.

The use of a molecular beam epitaxy (MBE) engineered III-V semiconductor to quasioptically modulate a millimeter wave Gaussian beam is presented. The effect is based on the generation of excess carrier densities under photonic excitation of the material. Low light power densities are required due to the high recombination lifetime achieved in the used material. A modulation depth of more than 15 dB and a dark insertion loss of less that 0.5 dB has been obtained at 100 GHz.

The results of numerical and experimental analysis of frequency selective properties of periodic gratings, consisting of bare or metallized dielectric (semiconductor) rods of rectangular cross-section are presented. The emphasis is put on optical and electrical control of gratings' frequency selective properties.

A branch-line hybrid-ring is composed of four quarter-wavelength transmission lines, and hence occupies a large area on printed circuit boards because of its loop structure. For this reason, reduced-size hybrid rings using multilayer meander-like transmission lines or lumped capacitors have been proposed. In this paper, a branch-line hybrid-ring which includes microwave C-type sections (C-section) is proposed for size reduction. The perfect input match and isolation can be attained at a center frequency as in a normal hybrid-ring. No practical differences are found in the frequency characteristics between the normal network and the proposed one.

A single-stage high gain wide band amplifier and an MMIC oscillator at V-band have been successfully fabricated based on a 0.15 micrometers T-shaped gate AlGaAs/InGaAs/AlGaAs heterojunction FET (HJFET) technology. The MMIC amplifier exhibits 7.2 dB +/- 1.0 dB gain over 49 approximately equals 61 GHz band and 15.3 dBm output power at 57.9 GHz. The MMIC oscillator shows 51 GHz oscillation with 2.8 dBm output power. These MMICs are promising for realizing compact personal communication terminals.

Design and performance of monolythic waveguide dielectric filters are discussed. To obtain high accuracy of synthesis technique the analytical approach and non-linear optimization have been done successfully. Some results of practical realization of given filters on the basis of integrated waveguide technology are presented.

The output characteristics of a strip distributed microwave (MW) power amplifier tuned by voltage in a wide frequency range analyzed. New energy collector designs are proposed to be employed in the amplifier in the form of a periodically nonuniform strip line and electron optical system comprising an electron gun with the multi-edge field emitter array current modulator. Their electrodynamic and current parameters have been calculated by rigorous methods. The analysis of the output amplitude-frequency characteristics of the amplifier was performed. It is shown that, unlike the previously reported amplifier design, it can allow for a higher gain in the short-wavelength region of centimeter band, including the millimeter band, or operate at substantially lower beam currents.

Using advanced epitaxy and process technologies, we fabricated a planar-doped AlGaAs/GaAs HEMT with gates 0.1 micrometers long. At 12 GHz, the device had a noise figure (NF), including the package loss, of 0.50 dB with an associated gain (Gas) of 13.0 dB. This is, to our knowledge, the lowest NF at 12 GHz reported for AlGaAs/GaAs HEMTs. For GaAs-based InGaP/InGaAs HEMTs, we obtained a NF, including the package loss, of 0.41 dB at 12 GHz with a Gas of 13.0 dB, and a NF of 1.2 dB at 50 GHz with a Gas of 5.8 dB. These high-performance GaAs- based HEMTs are widely used at microwave frequencies. Millimeter wave applications also require low-cost high-performance HEMTs.

Recent advances in pseudomorphic HEMT (PHEMT) MMIC technology have made it the preferred candidate for high performance millimeter-wave components for phased array applications. This paper will describe the development of V-band PHEMT MMIC components including power amplifiers and phase shifters. For the single-stage MMIC power amplifier employing a 200 micrometers PHEMT, we achieved 151.4 mW output power (757.0 mW/mm) with 26.4% power-added efficiency at 60 GHz. A three-stage MMIC amplifier utilizing the same devices demonstrated 80 mW output power, 20.5% power-added efficiency, and 17 dB associated gain at 57 GHz. And, for the phase shifter, a four-bit phase shifter with less than 8 dB insertion loss from 61 to 63 GHz has been achieved.

A 100-200-400 micrometers pHEMT monolithic amplifier has been developed for Ka-Band operation. This amplifier has achieved the state-of-the-art efficiency of 40% with 235 mW output power and 20.7 dB gain at 31 GHz. Two other circuits with 50-100-200 micrometers and 50-100-250 micrometers gate width have been fabricated in quantity of 100 to 200. This has been made possible by the advance of new fabrication techniques such as RIE dry recess with etch-stop layer which insures uniformity across full three-inch wafers. Amplifiers of this type are being used in a prototype phased-array antenna.

The performance of receivers incorporating subharmonically pumped mixers is presented over the signal frequency (RF) range of 585 GHz to 2.1 Thz. The mixers employ whisker contacted Schottky barrier diodes in corner cubes. Free standing resonant metal mesh bandpass filters are used to suppress fundamental mode mixing by blocking signals at f_LO +/- f_IF while allowing second harmonic mixing by passing radiation at 2f_LO +/- f_IF. The spectral performance of the mesh filters is presented and fabrication techniques are briefly discussed. Comparisons are made to similar fundamental mode mixers.

The microwave electric field strength sensor of single powerful radio pulses is described. Dielectric acoustic line of the surface acoustic wave (SAW) is used which has the nonlinear electroacoustic properties and involves two transducers. The first (nonlinear) transducer is affected by the microwave electric field and excits the SAW due to nonlinear effects. Delayed SAW signal, carrying information about the electric field strength, is received by a linear interdigital transducer.

A quasioptical Josephson detector with resistively shunted superconducting tunnel junctions of superconductor-insulator-superconductor (SIS) type and different integrated matching circuits for mm waveband region has been designed, fabricated and experimentally studied. A special quasioptical cryogenic probe has been designed and fabricated for measurements of microwave response of such integrated receiving structures. For low-frequency matching a cold transformer has been used at the output port. Many efforts have been made for reducing the external noise influence on Josephson junction IV curve. Quasioptical beamguide has been optimized and adjusted using Bi bolometers evaporated instead of Josephson junctions in the center of planar antenna. Beampatterns of several types of planar antennas, including self-complementary and non-complementary logarithmic spiral and log-periodic antennas, have been measured using the same technique.

This work presents an implementation procedure for finline band-pass filters. Using empirical formula, a synthesis program was developed to give initial dimension values for a tridimensional TLM (Transmission Line Matrix) simulation. With the obtained response, new specifications are generated and used in the synthesis part, which provides new dimensions. This loop continues until the initial design parameters are met within an acceptable error margin. The simulation difficulties are discussed and the initial and final results are shown.

According to Floquet's Theorem and Brillouin Principle, a two beam radiation antenna based on inverted strip dielectric waveguide (ISDG) with grating structures for both dielectric grating and metallic strip grating is investigated and tested. The radiation characteristics of a 61 GHz dual-beam flat antenna with symmetry in respect to the broadside direction are plotted. The beamwidths of 4.5 degree(s) and 18.5 degree(s) in E-plane and H-plane are observed, respectively. Millimeter Wave dual-beam flat antennas will be of potentially wide applications, such as aircraft, tracking radar, collision avoidance, car navigation system and true ground speed information with a required high accuracy and rejection the measurement error. The FMCW Doppler Systems using single- and dual-beam antenna at 61 and 40 GHz have been constructed with high sensitivity. The millimeter wave integrated front ents are connected with the dual-side-band heterodyne receiver and the Digital Signal Processing (DSP) system of a Fast Fourier Transform (FFT) frequency analyzer and the two sidebands separation circuits. The direction of flying aircraft to be inclined toward can be corrected by dual-beam system. The true ground speed of the vehicle can be measured exactly by it also, when the vehicle has the vertical component of movement speed. The Doppler direction of the target can be discriminated immediately with the single-beam system. For extremely low costs by very simple MMW system using two mixer diodes and a 3 db hybrid at the Doppler frequency, the Doppler direction can be discriminated also.

In this paper, a novel feed circuit called modified T-junction splitter is proposed and a 94 GHz 5 X 9 element microstrip comb line antenna array was designed and experimented with good performances by using the modified T- junction splitter.

The problem of the analysis and design of planar antennas on a dielectric slab loaded with a metal-strip grating is solved. Such antennas are capable of emitting of directional electromagnetic radiation in the millimeter-wave band. The two-dimensional diffraction model of the antennas is proposed. According to the model the radiation and scattering characteristics of the antenna are treated as a result of dielectric slab surface mode diffraction by the grating of finite extent. The analysis is based on the electromotive force technique. Some numerical results concerning the antenna characteristics in the specific case of a finite-periodic grating are given. An effect of an air gap between the slab and a metal ground plane is readily illustrated. Moreover, the problem of the antenna design aimed at the reduction of side lobes is considered. Applying the proposed analysis to the designed antenna, one can determine the deviation of the actual antenna characteristics from the desired ones thus correcting the design procedure if necessary.

Some theoretical and experimental results concerning a millimeter wave narrow beam integrated antenna are presented. A two-dimensional model is proposed to solve the diffraction problem of the surface wave scattering by a finite grating of metal strips placed on the dielectric substrate surface. According to the used model radiation and scattering phenomena in the grating are considered as the result of surface wave diffraction. Radiation and scattering antenna characteristics calculated within such a model are given. A planar exciter including an integrated lens was proposed to feed the antenna. The lens focusing properties were studied experimentally. The computed main beam angles were compared with those ones measured at frequencies 58 divided by 68 GHz. It was shown that the analysis is in a good agreement with experimental observations.

System and devices to be applied in millimeter-wave (MMW) indoor local area networks (LANs) transmitting data of more than 100 Mb/s are studied, a minimum delay-spread communication configuration is proposed to overcome the indoor multiple reflection waves, newly introduced reflection test set is analyzed to measure the radio absorbing materials to be used to the indoor LANs, and some MMICs operating at 60 GHz are described.

This paper extendedly describes the space coupling in the shared transmit- receive multichannel pulse-modulating millimeter-wave system. The signal distortion in the pulse-modulating receiving system is analyzed theoretically and investigated by experiment. The significant experimental results are given.

This paper describes the results of an analysis of radar backscatter and attenuation data collected during field trials of the MMW Module of the XM56 Large Area Screening Generator. The trials were conducted by Edgewood Research Development and Engineering Center personnel at Dugway Proving Ground in 1989 and 1990, and at Eglin AFB in 1992. The purpose of this analysis was to use inversion techniques, similar to those developed for lidar systems, to translate the radar backscatter data from the XM56 smoke clouds into estimates of cloud concentration, and to compare the resulting concentration estimates with those produces by independent, point sampling nephelometers. Three dimensional cloud concentration profiles have been produced and were found to be consistent with the Pasquill stability category. In addition, the overall correlation between the radar-generated concentration data and those collected using the nephelometers was quite good. Examples of these results are presented for the 1989, long range trials, which allowed characterization of a large volume cloud, and the 1990 and 1992 trials, which were performed over a much shorter range, but provided more useful nephelometer data.

The implementation of a radiometric 94 GHz video rate imager that employs a zoned aplanatic imaging lens, folded optics, diometric comparison switching, and a practical focal plane array will be described. Application will be discussed.

The design, fabrication, and test of a multiple beam millimeter wave airborne imaging system is presented. This radiometric system operates at 81 - 98 GHz and consists of a f/D equals 3 offset parabolic reflector antenna fed by an array of 24 feed/receiver elements. The receivers are built as six, four element modules, each of which can be positioned anywhere on the focal plane plate. Fully populated, the plate can accommodate 48 modules in four rows of twelve (192 elements total). The polarization of all four elements in a module is the same, but each module can be rotated 90 degrees to receive either vertically or horizontally polarized radiation. Progress in the development of MMIC based receivers and improved feed arrays for insertion into this system is also presented.

The status of passive millimeter wave radiometry as a thermal imaging technique will be discussed. Methods will be identified for overcoming the usual difficulties of poor spatial resolution and slow response time. High quality images will be presented to demonstrate the potential of this technology.

A real-time two-dimensional imaging method is presented for active guidance application under strong clutter and short data background. This method used conventional DFT computation for radial range high resolution and strong scatters' neighboring area superresolution processing techniques for cross range superresolution.

Features about target shape, size and physical structure can be extracted from HRR profiles. A sequential reasoning-rule-based pattern recognition method adaptive to target angle variation is proposed for target identification using HRR features. This method is of importance in MMW guidance application.

Microwave receiver with the Gann-diode oscillator and Schottky-diode mixer with frequency 42.5 GHz. Sensitivity is 130 dB. The output parameters ar discussed.

By optical pumping of far-infrared (FIR) superradiance and Raman emissions in CH₃F, CH₃CN, D₂O, NH₃ with 10 micrometers -TEA-CO₂ laser pulses truncated within 10 ps by an IR plasma shutter as well as by first application of a new FIR plasma shutter we have observed new phenomena and generated ultrashort FIR single pulses which are presently applied to investigate the exciting and complicated features of FIR quantum-well detectors and high-T_C superconductors.

This paper reports the divergence study of optically pumped far infrared laser with wave lengths of 118 micrometers , 447 micrometers , and 890 micrometers . A special device of scanning, recording and detecting system is used in order to obtain the laser beam divergence.

In this work, the high resolution infrared (IR) spectrum of C-13 substituted methyl alcohol corresponding to the C-O stretch vibration and far infrared (FIR) spectrum corresponding to the torsional-rotational transitions have been recorded using a Fourier transform spectrometer. The results of the detailed analysis on the spectra have been applied to proposed new assignments of FIR laser lines pumped by the 9P(34) CO₂ laser line. These assignments involve highly interacted first excited C-O stretch vibrational state. The assignments are supported by closed combination loops of accurately measured IR and FIR transitions. The analysis also yielded accurate frequencies for seventeen potential FIR laser lines in C-13 methanol. The spectral data relevant to this work are presented. The FIR absorption spectroscopic study allowed us to evaluate the leading torsional-rotational molecular parameters for ¹³CH₃OH in the vibrational ground state. In addition, comments are also made on the identification of FIR laser lines in ¹³CD₃OH pumped by the 10P(24) CO₂ laser line. The results will be useful for a precise model of the Hamiltonian for excited C-O stretching state.

In this work high resolution Fourier transform infrared (IR) spectra corresponding to the OCD-bending, C-O stretching and CH₂-rocking bands of methyl alcohol-D₁ have been recorded in the range 815-1120 cm^-1, at a resolution of cm^-1. Analysis of the OCD bending mode transitions yielded identification of quantum numbers involved for far Infrared (FIR) laser lines optically pumped by the 10P(34) and 10P(46) CO₂ laser lines. The observed wavenumbers for the OCD bending transitions relevant to the laser assignments are presented. The IR assignments are confirmed by forming close combination loops of observed R, P, and Q branch transitions. The results are in agreement with microwave (MW) analysis.

We generate continuously wavelength-tunable truncated laser pulses with a high-pressure (11 bar) single-mode 10 micrometers CO₂ laser and a plasma shutter and applied them to an optical-free-induction-decay (OFID) system. Single- mode operation is achieved using a 3-mirror resonator with etalon. A detailed analysis of this resonator type is presented.

We have developed all-electronic integrated circuits that generate and detect picosecond pulses. We have used these circuits with integrated antennas in a system capable of free-space spectroscopy in the terahertz (THz) regime. With this system, we have measured magnitude and phase transmission characteristics for a variety of samples in the 200 GHz - 1 THz frequency range.

The longitudinal oscillation in an inhomogeneous (p- and n-regions) semiconductor plasma of a p-n junction have been investigated theoretically. It is shown that in a forward biased p-n junction the instability of oscillations can be arised due to the stimulated coupled plasmon emission by injected electrons. The condition on the parameters of a p-n junction and on external circuit, which lead to the generation of submillimeter range oscillations (coupled plasmons), have been formulated.

A 690 GHz receiver was built up by mounting a 690 GHz mixer element in an existing open structure mixer and by upgrading a solid state oscillator used around 345 GHz previously to the 660 to 700 GHz range. A double sideband noise temperature <500 K was accomplished and verified by a laboratory measurement of the ¹²CO (6-5) molecular line at 691.5 GHz. The mixer is operated at a bath temperature <2.5 K. A particular feature of this receiver is the use of one single SIS contact of submicron dimension. Its production and production and specific merits are addressed.

In the paper there are presented the mathematical description and the results of the numerical analysis of frequency response function (FRF) of a turbulent atmospheric radiochannel over the terrestrial surface in Millimeter-wave (MMW) band. Here it is given the analysis of effect on the FRF of the MMW parameters fluctuations due to atmospheric turbulence and rough irregularities of underlying surface. The conditions of validity and demolition of MMW-field interference structure are presented. There are also presented the measurements date ((lambda) equals 2.2 X 10^-3 m) under natural conditions of amplitude FRF of atmospheric radiochannel, according to the original technique, and results of the atmospheric transmission bandwidths measurement versus the receiver and transmitter antennas position.

Development of a reflection circulator designed for use in quasi-optical beam systems is reported. Requirements of a millimeter-wave radar motivated the project, but the attractive performance features of the device, including broad bandwidth and high power capability, make it suitable for other applications as well. The discussion includes the underlying principle of nonreciprocity, problems of Faraday rotation, refraction, and polarization- insensitive anti-reflection matching at oblique angles of propagation. Comparisons of experimental measurements with a computational model show excellent agreement.

Homodyne method of measurement of polarization reflection matrix, providing the possibility of simultaneous measurement of all four complex coefficients of polarization reflection matrix in quasi-optical circuits of submillimeter waves in presented. Technical realizability of the method for quasi-optical circuits, formed on the base of waveguides of the class of 'hollow dielectric waveguide' is shown.

There are presented the results of investigation of the Doppler frequency shifter designed for using the quasioptical homodyne submillimeter devices. Its using allows to obtain smaller level of accessary components of the intermediate frequency signal spectrum.

We consider new effects of diffraction of electromagnetic waves at the gratings, such as the full reflection in the direction which differs to the mirror and antimirror ones and the full antimirror reflection from the corrugated boundary of dielectrics. Quasioptical dielectrical eshelette resonator with high selective properties is designed. The results obtained are applied for the design of the resonators for high frequency electron devices.

The optimization of the characteristics of the electrooptic modulators can be carried out by choosing the dimensions and cross-section of the millimeter and optical waveguides. A rigorous method of solving the Maxwell equations for the open waveguides with intricate (arbitrary) cross-sections including metallic, dielectric and anisotropic media is proposed in this paper. The longitudinal components of the electric and magnetic fields in the case of uniaxial anisotropic media contain the logarithmical singularity. This fact leads to the solution of that problem by means of singular integral equations, the method is versatile to the cross-section shape. The method proposed this paper allows to vary the electrodynamic parameters of a media (including the dielectric and anisotropic losses) in the wide range.

In this paper, the main properties of quasioptic elements are present. Some practical system based on the elements are discussed. The diffraction quasioptical elements are also used in microwave antennae. Theory and design are discussed along with some experimental and theoretical results.

State-of-the-art millimeter-wave monolithic power components have been developed for Ka- and W-band sensor system applications. This paper presents the development and performance of Ka- and W-band power MMIC components. At W-band, the integrated power module using U-band MMIC power amplifiers in conjunction with W-band MMIC doubler shows the highest reported power (95 mW) and gain at 94 GHz. At Ka-band, a four-stage power amplifier exhibited 14.6 dB of linear gain and 300 mW saturated output power at 35 GHz. These power modules are highly stable and suitable for the future millimeter-wave sensor system applications, such as PCN and collision avoidance sensors.

Low cost, millimeter wave, forward looking radar sensors for applications in Autonomous Collision Warning and Autonomous Intelligent Cruise Control systems will be described. These safety related systems promise the largest payoff in preventing highway crashes.

Designs are presented for infrared free electron lasers (FELs) with rf wigglers and relatively low voltage electron beams. Both Quasi-optical and cavity gyrotrons are considered as sources for the wiggler. One of the most promising designs is the use of a quasi-optical gyrotron, where the radiation is coupled into a corrugated waveguide. This allows focusing of radiation, and propagation over relatively long paths, so that the FEL can be generated with fairly large wiggler parameter and gain.

We present an Hamiltonian treatment of gyrotrons and CARMs for the cases of resonant electron evolution in a constant electromagnetic field and also where the field evolves self-consistently with a single resonant electron. The electron phase space is characterized for both cases.

The gas filled Orbitron Maser has been fitted with a titanium sputter pump. Thus, the gas pressure can be kept at the optimum value without a portable mechanical pump.

Efficiency of the electron beam interaction with one of the periodic structure (PS ) slow harmonics depends on its amplitude .One possibi e method of the amplitude increase in the region of an electron beam motion may be the difraotional radiation resonance connected with the radIating harmonic birth. The frequanoy f at which this effect is observed,is connected with the PS period 1 and electron velocity Ye by formula: p (2/fl/J! (1 ) JA= 7?3 where n = —1 , -2, —3 , . . . ; = Ye/C , 0 is light speed. In this case the increase of amplitudes of all difractional har— monies of this frequency is observed I I ] . The most interesting case is that , when two harmonics are radiated simul taneuosly and one of them is born and another is radiated at O. angle (two-wave regime ) [2 1 . The parameters of this regime can be found from formula: g -/.; 5,t/2t (coi6, (2) As follows from correlation of (1)—(2), that resonance two—wave regime can be observed at rather litle speeds, which are smaller, than speed of light C. But their use demands a quantitive evaluation of radiation intensity. The many-wave regimes are rather widely used in the relativistic strong-current electronics providing a high—efficient electron—wave interaction. But until now the radiation intensity calculation doesn't take into acount resonances in these regimes. Therefore (as first — step) in this paper an evaluation of radiation intensity in two—wave resonance regime of difractional radiation is carried out experimenta— ly.

A 95 GHz, fourth harmonic gyro oscillator is being investigated at Litton. The design centers around a new type of electron gun, the advanced centerpost (ACP) gun. This gun produces an axis-encircling beam which interacts with the rf fields in an 8-vaned magnetron cavity. Four of the vanes have slots in their outside diameters that couple into a coaxial cavity. Radiation is extracted from the coaxial cavity by a fundamental W-band waveguide.

At higher frequencies it is not easy to find a suitable material for output window applications in a high power gyrotron. The room temperature application of sapphire as a window material at higher frequencies is not feasible since its absorption coefficient increases almost linearly with increasing frequency in the millimeter wavelength region. At cryogenic temperature the absorption coefficient value decreases only by a few factors (factor of 2 to 3) in the 90-200 GHz region. The earlier reported temperature squared dependence (decrease) in the absorption coefficient of the loss tangent value is totally absent in our broad band continuous wave data we are reporting here (at 6.5 K, 35 K, 77 K, and 300 K). We utilize our precision millimeter wave dispersive Fourier transform spectroscopic techniques at room temperature and at cryogenic temperatures. The extra high resistivity single crystal compensated silicon is no doubt the lowest loss material available at room temperature in the entire millimeter wavelength region. At higher millimeter wave frequencies an extra high resistivity silicon window or a window made with extra high resistivity silicon coated with diamond film would certainly make a better candidate in the future. A single free standing synthetic diamond window seems to have higher absorption coefficient values at millimeter wavelength region at this time although it is claimed that it possesses good mechanical strength and higher thermal conductivity characteristics. It certainly does not rule out the use of diamond film on a single crystal high resistivity silicon to improve its mechanical strength and thermal conductivity.

There are presented the results of investigation of the homodyne laser interferometer-polarimeter (lambda) equals 195 micrometers made on the quasioptical element basis and designed for the synchronous determination of the plasma electron density n_e and the poloidal magnetic field B_p in 'TOKAMAK' mountings of the thermonuclear fusion.

This work studies the influence of the electromagnetic radiation of low intensity on the rheological parameters of water and water solutions of biologically active substance (NADH) which plays an important role in energy transforming processes in living organisms. The power spectrum of the thermal fluctuations of the free surface of liquid (capillary waves spectrum) has been measured using optical heterodyning method which makes it possible to detect the changes in frequency of the light scattered by moving liquid surface. The amplitude, the spectrum of spacial and time frequencies of thermal fluctuations (capillary waves) of free surface of water solution were investigated using optical heterodyning method. The viscosity and the surface tensions in the microlayer of water solution were determined from the obtained results. Water solution was dealt with as a low-viscosity Newtonian liquid in this analysis and was modelled by Navier-Stokes equation and incompressibility equation.

Data on water solutions of biomolecules response to quasistatic magnetic fields and low-intensity electromagnetic radiation of mm range (EMR of mm R) are discussed. Time history of some chemical and biochemical processes in water solutions in presence of external fields is studied. Investigation results of low-intensity EMR of mm R influence on the rheological parameters and characteristics of spin-lattice and spin-spin proton interaction for water media modeling bioobject low-molecular liquid homeostasis are analyzed. Data on time and time-spatial dynamics of the metabolic processes in tissues of living objects under local and remote exposure to the low intensity EMR of mm R. A hypothesis about the role of proton subsystem collective states in the bioobjects primary reception of the microwave is discussed.

An influence of low intensity mm-wavelength radiation on spin-spin relaxation time T₂ of protons in oxygen aqueous solutions was studied. Oxygen was brought in the system by the catalytic decomposition of the hydrogen peroxide. An own heterogeneity of the relaxometer was used to observe the dynamics of medium diffusion characteristics. The value of the slow component of the magnetization decreasing of the induced signal was shown to depend in sharp resonance way on the external electromagnetic field frequency under the power density P < 1 (mu) W/cm². While rising up the power density to 5.0 mW/cm² in the same frequency range the increasing of spin-spin relaxation time dispersions observed.

Application of the technique suggested for investigation of patients with heart rhythm disturbances showed that the frequency characteristics of the AF_max were different depending on the disease etiology. Thus the technique suggested by us not only distinguished a healthy person from a sick one, but also differentiated patients among the groups of diseases.

Consideration is being given to the problems of organizing treatment of patients with quantum medicine methods by Prof. S.P. Sit'ko at 660 hospitals of Ukraine and Russia. Analyzed are teaching of doctors and treatment of 250,000 patients for 82 nozologic cases in 1990 through 1993. In the State of Ukraine, the Government has adopted a State Target-oriented Program of Large- scale Promotion of Microwave Resonance Therapy Into Medical Practice as presented by the Ministry of Health care in 1989. According to the Program, it was planned, during the three year period, to provide MRT rooms in 325 medical institutions. The Program was based on a discovery by Prof. S.P. Sit'ko DSc (Physics & Mathematics), of a new non-morphological structure of man, i.e. an electromagnetic framework that is manifested by eigenfrequencies in the millimeter range and disturbance of which results in disease while repair returns the organism to health. This idea was subjected to national and international expert evaluation. This evaluation was done by a panel of 12 universally acknowledged scientists headed by the founder of the theory of superconductivity, professor of the Liverpool University (Great Britain) h. Frohlich and director of the Madrid medical center Prof. Alzina. The USA was represented by Dr. W. Rogers, chief of the Center of Radiation, Institute of Bioinformation Research. The stated that Professor S.P. Sit'ko and his coworkers had established a new line of inquiry in medicine, i.e. microwave resonance therapy. To implement the State Target-oriented Program, the Government chose the Interbranch Scientific and Engineering Center on Physics of the Alive and Microwave Resonance Therapy 'Vidhuk'.

Chronic diseases result from defects in the immune system. Consideration is being given to the recovery of an immunoreaction in patients treated with quantum medicine methods by Prof. S.P. Sit'ko. The methods are evaluated as to outlook. Method of non-medicamentous non-invasive microwave resonance therapy (MRT) worked out by Prof. S.P. Sit'ko on the basis of quantum medicine has new possibilities for treatment and prophylaxis of different diseases.

The investigations show that MRT is a pathogenetic method of treatment of peptic ulcer. Thus the results of our investigations permit to draw the following conclusions. Microwave resonance therapy is a harmless and highly effective method of treatment of peptic ulcer. MRT in comparison with traditional medicamental therapy and other methods provides higher efficacy of the treatment and the remote afteractions results. Healing of the ulcers and normalization of functional disorders takes place more rapid. Period of staying in the hospital grows short. Number of the patients with relapses of diseases decrees of importance is the fact that alterations of the involved organs and systems are of multidimentional character conditioned by their initial state. According to our investigations data risks of MRT application for uncomplicated forms of duodenal ulcer are at a minimum and therapeutic and economic efficiency of the method speaks in favor of its advantages over the other methods of duodenal ulcer treatments.

A behavior of aqueous solutions contained oxygen was studied. These solutions simulated the low-molecular liquid homeostasis of human organism. The environment parameters variations radical influence the nature of physical interaction between oxygen and water molecules in the presence of an O₂ of supercritical concentration was shown. Transformations of the 'free' and 'connected' H₂O fractions were controlled by environment parameters, in particular, by low-intensity millimeter wave (MMW) band electromagnetic radiation (EMR). In spite of strong water absorption of MMW the water medium surface structure variations embraced the whole volume. This phenomenon showed a strong specific nature of the influence factor.

The conceptual basis of Physics of the Alive is the perception of the fact that any independently functioning living system is simultaneously a macroscopic quantum object and maser (laser of the mm-range) whose pumping out is provided by metabolism due to the mechanism called "hierarchy of dissipative strnctures." It is precisely this approach that provides understanding of the macroscopic integrity of organism in accordance with the genetic information (origination due to the coherence of the effective long-range forces) and its diverse differential stability (difference and stability of species and specimens) that is based on the principles of identity and discreteness of quantum mechanics).

Results of study of resonance interaction of low-energy radiation in the interval of 37 - 53 GHz with (beta) -alanine and (alpha) -glycine monocrystals have been presented. The role of form-factor effect was investigated. It was revealed that the MMW irradiation of aminoacid crystal in a process of infrared reflection spectra registration led to considerable intensity redistribution and to bands thin structure manifestation of the deformational vibrations of NH³⁺ and CO^2- groups near 15000 cm^-1. Resonance character of millimeter wave influence was determined. In the action spectra numerous resonances with the halfwidths from 40 to 80 MHz were observed.

The influence of low-intensity millimeter wave (MMW) radiation in the frequency range of 53.37-78.33 GHz on immune status of patients was studied. From obtained data it is evident the MMW action at low radiation power of 10^-14 W/cm² results in stimulation of organism immune status which is expressed in rehabilitation of functional state of blood cells.

Analysis of semiclassic theory of radiation interaction is done in respect to the millimeter range wave lengths and water milien of biological objects. General characteristics of electromagnetic limit cicles are analyzed with respect to the peculiarity of human anatomy, the correspondence between these characteristics and laws of classical acupuncture system topography is determined. General condition of multicellular organism's stability on all of development stages are formulated as a space quantum conditions for eigen electromagnetic field's states.

The results of the relaxation process investigations in the nuclear spin- system of the paramagnetic substance are presented in dynamic nuclear polarization regime. High degree of the nuclear polarization is achieved by means of microwave pump of the definite transitions in an electron spin- system. The bistability properties in these paramagnetic substance are discussed.

The contributions of lattice disorder by microscopic charges and interatomic bonds respectively to the one-phonon absorption in nonideal dielectric crystals have been theoretically considered. The latter is of the same order of magnitude or more than the first one.

Specific advantage of millimeter wave aquametry is discussed. Many materials and substances were investigated as a object for aquametry. Some examples of moisture meters are presented (water control in crude oil, alcohol determination in wine, humidity of spirit).

The observability of the recently described helical Cerenkov effect, which exists in the microwave to visible spectrum, is discussed. From the kinematics point of view, we show that microwave radiation with the wavelength of 10^-1 cm could occur in a medium with the index of refraction of 1.4, beam energy of 3 MeV, and the uniform magnetic field of 4 T. In the visible spectrum with the central wavelength of 5 X 10^-5 cm, however, the observability of this effect is achieved with up to 3 MeV in beam energy, silica aerogel as a medium with the index of refraction of 1.075, and uniform magnetic fields from 5 to 10 T. Specifically, for the 10-Tesla magnetic field, it is estimated that, in the 250- to 750-nm visible region, an electron generates a photon through an interaction length of 10 cm. As such, this effect could possibly be used as a detector of radiation by energetic electrons that are trapped in a medium by strong magnetic fields.

Tunable backward-wave oscillators (BWO) covering the frequency range of 180- 370 GHz with an output power below 100 mW are used for the study of wave transmission and reflection in composite layered structures. Techniques for transparent and lossy liquid absorption and refraction measurements (blood plasma, ethanol, water solutions etc.) are presented. Besides of the solid- liquid structures which are applicable in phase shifters and attenuators, semiconductor-metal structures with p-i-n junctions are examined as high-speed modulators.

A measurement chamber for liquid dielectric in range (37-47) GHz is examined. The features of the different waveguide structures are considered.

Low compensation thin layer of antimony doped silicon impurity band photoconductors doped at the level 10¹⁷ - 10¹⁸ cm^-3 are evaluated in moderate background photon flux in the range of 10¹² s^-1 with the goal to approach photon noise limitation operation in spectral ranges near 300 cm^-1. Blocked impurity band photodetectors based on the same active layer geometry and thickness than the photoconductors were also implemented and measured. Spectral features including cut off wavenumbers specific to impurity band effects are investigated as a function of electric field and temperature. Spectroscopic evidence for a giant gain mechanism for photoelectrons excited from residual impurities in the blocking layer of BIB structure is found. Figures of merit of both IB and BIB elements were measured and physical mechanisms underlying the limitation of their performances are outlined.

Measurements and calculations of the scattering-characteristics of stratified lossy dielectric blocks completely filling a waveguide cross section are presented. The method is used for contactless conductivity measurements of MBE-grown II-VI semiconductor layers.

The new types of slow surface polaritons are demonstrated to propagate at the interface of homogeneous semifinite space and the layer-periodical structure (classic superlattice), which is made with layers of semiconductor and dieletric. For modern semiconductor and dielectric materials the phase velocity of this waves is value of order V_ph approximately equals 4 X 10⁷ sm/s under the real parameters. Velocity of the carrier drift is known to be less than 7 X 10⁷ sm/s. It is shown in this paper, that slow surface polaritons can interact efficiently with carriers moving in homogeneous space. Different types of instability are analyzed analytically and numerically. Increments of instability are obtained.

Theoretical proposals concerning submillimeter and far-infrared activity based on shallow acceptors states optical transitions in p-Ge and p-Si semiconductors are discussed. Preliminary experimental investigations will be presented.

Determination of the interstitial oxygen concentration in silicon is one. of important elements of its characterization. In the room temperature interstitial oxygen has an absorption level for the —1 wavelength X=9.05 im Cv = 1106 cm ). This level is very well seen because defectless silicon has low absorption in this range. Thus, mainly used method for interstitial oxygen concentration determination is based on dependence between the absorption coefficient of the oxygen peak as measured and interstitial oxygen concentration N [1, 2, 3]. In measurements of N some difficulties associated with absorption on phonons appear. At low silicon resistivities additional difficulties connected with the absorption on free carriers appear [4, 5] and the measurements at very low temperatures are necessary [6, 7]. For the absorption measurements an external source of infrared radiation (IR) of high stability (e.g. CO2 - laser) and thick samples with very well polished both surfaces [3] are required, which is often impossible in the case of commercial wafers. In this work a new optical method enabling determination of the interstitial oxygen concentration N, as well as its spatial distribution in silicon wafers is described. This method is based on the thermal radiation (TR)[4] measurement of the investigated material in the range of the interstitial oxygen absorption [81. According to the Kirchhoff's law the TR emission depends on the absorption properties of the material which enables in certain conditions to estimate the oxygen concentration. For this method an external source of IR is not necessary, and measurements can be carried out on wafers with metallized or rough back surfaces. Creating conditions enabling the measurement of TR radiation of the wafer is realized by heating or cooling a screen placed behind the wafer. With this method one can measure temperature dependence of interstitial oxygen concentration. The measurements can be carried outwith the use of the spectrophotometer, a scanning IR microscope or a thermovision camera with suitable adjusted spectral range.

The theory of the local optical oscillations near the defects of different types (point, linear, and plane) in semiconductors (SC) with a ionic crystal lattice is built. In the optical frequency range the transverse local oscillations (LO) exist in the crystal with a light defect and the longitudinal LO exist in the crystal with a heavy defect. The conduction electrons don't take part in forming of the frequencies of the LO, but influence their field structure essentially owing to the Coulomb interactions of the electrons with the lattice ions and the defect. Because of the Coulomb's screening of the defect by conduction electrons, the space about the defect divides into two regions: the near zone (r << r_D, r_D is the Debye's radius of screening) and the distant zone (r >> r_D). In the near zone the coordinate dependencies of the LO amplitudes have the same form as in the ionic dielectrical crystals. In the distant zone the LO amplitudes decrease exponentially at the macroscopic distances which have scales of the Debye's radius r_D or the length of the transverse electromagnetic waves in the SC media.

Distinction of lattice and coordinated water molecules in lanthanum sulfate nonahydrate could be made through the study of its librational and translational modes of vibration at low temperatures by FTIR spectroscopy. Potential force constants for different modes have been calculated. Rare earth compounds play important role in high T_C superconductors.

We have measured very low microwave losses in Y-Ba-Cu-O fifth wave ring resonators. We deposited the Y-Ba-Cu-O film on (1012) non-buffered sapphire substrates and patterned microwave circuits. High-Tc microstrip resonators demonstrated best Q-factor greater then 800 at 31 GHz, corresponding to surface resistances less than 3,0 mOhm. Identical copper resonator showed Qs of 500 and surface resistance of 27 mOhm. We show that the losses in the high loss samples can be accounted for by the presence of small fractions of c- axis-aligned grains highly misapplied in the plane of those films. Volume fraction of highly misagned c-axis-oriented grains as 3% lead to losses above 3 mOhm.

High-quality Y-Ba-Cu-O films on non-buffered sapphire substrates was obtained. Microwave devices fabricated from films on non-buffered sapphire have included an K-band modified three-pole. Chebyschev filter have an insertion loss of 1.2 dB at 60 K. The HTS filter was designed to be a 5% bandwidth. Our filters out perform similar copper microstrip filters, indicating that practical levels of HTS performance have been achieved.

It has been reported recently that the diamagnetic response has been found in amorphous carbon films doped with copper, what have shown the superconducting state to be present in the films with a certain amount of copper at temperatures about 77 K. In this work the method of direct measurement of the critical temperature (T_C) has been proposed and the measurements have been carried out at microwave frequencies (37.9 GHz). The method is based on the observation of the interference of direct and reflected waves from the carbon sample. The T_C and (Delta) T_C of the samples were found to be 81.5 K and 1.5 K respectively.

SIN and SIS quasiparticle tunnel junctions on high T_C superconductors (HTS) offer the possibility of low-noise, heterodyne, photon detection in the THz regime. We report progress on the development of such junctions using mechanical point contacts. In general, these contacts display the optimum characteristics that can be obtained from HTS native-surface tunnel barriers. The bismuthate, Ba_1-xK_xBiO₃, (T_C equals 25 K) displays ideal, BCS, quasiparticle characteristics at T equals 4.2 K however, at temperatures T approximately equals T_C/2 there is evidence of strong quasiparticle damping which may inhibit device performance. The cuprates typically display non-ideal quasiparticle characteristics including large sub-gap conductances. Recent data for the new Hg-based cuprates (T_C equals 96 K) are promising in that they exhibit very low and flat sub-gap conductances as expected from a BCS density of states. Proximity effect tunnel junctions on Bi₂Sr₂CaCu₂O₈/Au bilayers have been studied using an In tip. An induced energy gap has been consistently observed in the Au layer and the data can be understood using the McMillan model. A few junctions show much improved sub- gap characteristics compared to ones made directly on the BSCCO surface and indicate that this approach may be suitable for mixer development.

This paper reports the Preliminary results of a high Tc superconductive transition-edge bolometer for millimeter and submillimeter waves outputed from an optically pumped far infrared laser. The bolometer was fabricated by using of a photolithographic YBaCuO thin film on a (100) SrTiO₃ substrate at liquid nitrogen (LN) temperature as the fast sensitive detector.

In this review paper we present the research results which have been obtained in our laboratory in the field of submillimeter-wave electrodynamics of weak- ferromagnetic antiferromagnets.

A new exact analytical dispersion relation for TM p-polarized millimeter nonlinear electromagnetic surface waves propagating along the interface of nonlinear ferromagnet cover and linear magnetic media has been derived theoretically. A nonlinear magnetic permeability of the cover can be considered as a function of the absolute value of the magnetic field of the wave and can be written as (mu) ^nl equals (mu) ₁ + (mu) H, which is contacted with an isotropic linear dielectric substrate. The existence conditions for these waves to be propagated are studied. The power flow expressions versus the wave index have also been obtained. This new behavior could be used in Microwave Electronics and Integrated Circuits (IC) Technology.

The numerical analysis of nonstationary and nonlinear properties of magnetoresonance multilayer structure is presented. It is shown that pulse signal shape is sufficiently distorted after penetrating through such structure. The influence of resonator's parameters and sample on signal shape is observed for the first time. The obtained results may be applied in magnetic resonance radiospectroscopy and high energy physics.

It was obtained, that nonlinear TE electromagnetic waves dispersion curves in films with step dielectric function in the plasma-like surroundings can be closed, and can be lying both above and below linear waves dispersion curves. Nonlinear films can be used in the semiconductor lasers as active areas.

The investigation of radio recombination lines if HI and heavier elements is one of the principal methods of studying the structure within the lower solar atmosphere. Spectral lines at millimeter wavelength may be formed in the solar chromosphere when Rydberg transitions between highly excited levels occur. Theoretical and observational antecedents to radio-frequency lines in the solar spectrum are summarized. Physical mechanisms that affect excited atoms immersed in a plasma are discussed and preliminary calculations of the relative line intensity for hydrogen recombination lines from H5(alpha) (7.46 micrometers ) to H42(alpha) (3.38 mm) are presented.

An implicit finite--difference (IFD) scheme is introduced for solving the parabolic equation representing electromagnetic wave propagation in the troposphere. Using Box method, the fading to the electromagnetic wave is calculated especially when the modified refractivity varies both with the range and the height in the representative atmosphere conditions. The consistency, stability and convergence of the Box method is demonstrated.

The absorption coefficient and refractive index spectra of carbon monoxide gas are presented together for the first time in the range 300-900 GHz. An extra high resolution dispersive Fourier transform spectrometer was constructed for studies of gas molecules particularly pollutants. Line positioned can now be studied much precisely via dispersion data since the dispersion through a sharp rotational absorption line is a straight line rather than an envelope. It is therefore not necessary to interpolate around the turning point to determine the line position accurately. A demonstration of the much better resolved splitting for the J" equals 4 rotational transition line (at wavenumber equals 19.222 cm^-1) is shown. The line position we obtained agrees well with theoretical calculations. Results presented in this paper were obtained at a gas pressure of 250 torr.