Diplexing Millimeter Waves

The paper describes a band-splitting filter or diplexer, which splits the incoming spectrum into the sub-bands 120-139 GHz and 141-158 GHz. This diplexer is intended to separate the electron cyclotron emission of a magnetically confined plasma into two subbands and to feed two independent heterodyne radiometers. The construction principle of this diplexer has been used in the past for broadband communication systems. It is particularly suited to systems incorporating oversized waveguides.     

Broadband Orotron Operation at Millimeter and Submillimeter Waves

Due to high selectivity of open cavity, wider electron beams with higher current can be used in orotron as compared with other Cherenkov devices. It provides important advantages at short millimeter and submillimeter waves. Theory and preliminary experiments in the short part of millimeter and long part of submillimeter wavelength range show that orotron with operating voltage of few kV can generate significantly higher output power than existing BWOs. Combined electronic and mechanical frequency tuning in the band of about of octave has been obtained.     

The Experimental Study of Electromagnetic Waves Scattering of Underlying Terrain in Centimeter and Millimeter Ranges

Journal of Communications Technology and Electronics - The results of sensing in various terrain types at centimeter and millimeter wavelength ranges of waves with horizontal polarization and small...     

High Resolution Millimeter Wave Fabry-Perot Interferometer

The design and operation of a microwave Fabry-Perot interferometer at wavelengths around 6 mm is described. This uses reflectors which are simple, easy to make, and which are capable of scaling for operation at short wavelengths in the ultramicrowave region. With power reflection coefficients around 0.999, very sharp fringes and Q values around 100,000 were obtained on the interferometer. Effects of diffraction in the interferometer are considered, and wavelength measurements with this particular interferometer indicate that accuracies of 0.04 per cent are obtained without any diffraction correction. Advantages of such an interferometer for ultramicrowaves are that the component parts are large compared with the wavelength, the effects of diffraction decrease with the wavelength, and the problem of maintaining a high Q with a single mode of propagation and a structure of adequate size is made much easier. Such an interferometer forms the cavity resonator for ultramicrowaves. It can thus be used for such conventional purposes as wavelength measurements, wavelength spectral analysis, dielectric constant, and loss measurements, or as the cavity resonator for frequency stabilization, or as the cavity resonator for a millimeter- or submillimeter-wavelength maser.     

Birefringent Filter for Millimeter Waves

A scale model (f/sub 0/ =20 GH/sub z/ of a Solc-type birefringent wave filter for millimeter wavelengths is described. The filter consists of five cascaded identical half-wave plates, or crystals, each composed of an artificial anisotropic dielectric medium with its reference axis tilted at some prescribed angle to the plane of the input polarization. The design and analysis of an individual plate, using Collin's second-order theory of the birefringence of artificial anisotropic dielectrics, and the analysis of multielement filters (filters composed of many plates), aided by Evans' matrix method, are discussed. The experimental filter was tested in the range of 18 to 33 GHz, and its measured performance was found to compare well with the theoretical performance over a major portion of the range of frequencies used in the tests. A synthesis procedure for optimum (equal-ripple stopband) response multielement filters is given, together with tables of plate angles for such filters. In this procedure, the Dolph approximation and the Harris synthesis are combined.     

毫米波生物热效应的理论研究

从理论上研究了平面分层均匀组织人体模型在垂直入射毫米波照射下，体内电磁场、吸收功率、比吸收热、温度场及其分布，并对毫米波热疗机理进行了初步探讨。     

Superheterodyne Amplification of Sub Millimeter Electromagnetic Waves in an n-GaAs Film

The superheterodyne amplification of sub-millimeter electromagnetic waves in GasAs due to negative differential mobility is analyzed. The nonlinearity arises from the current and the magnetic field of the electromagnetic waves. The case of interaction of two traveling counter propagating electromagnetic waves and the following space charge wave in an n-GaAs film, placed onto i-GaAs substrate, is considered, under a 2D electron gas model. The simulation of this nonlinear interaction shows a certain amplification of the sub-millimeter electromagnetic wave.     

History of Millimeter and Submillimeter Waves

In this review an attempt is made to identify many of the major events that have occurred in the development of millimeter- and submillimeter-wave technology from its beginnings in the 1890's until the present time. The review is not intended to be the definitive history of the field, but may form the basis for someone to later write a more comprehensive or encyclopedic version. The history conveniently divides into three periods: 1890 through World War II, Post War (1947 to 1965), and Modern Age (after 1965).     

Asymmetric Fin Line and Coupler at Millimeter Waves on PBG Substrate

The photonic band gap (PBG) crystals have been used as a perfectly reflecting substrate for many millimeter wave applications. In this work the fin line directional coupler with PBG substrate is analyzed using the TTL—Transverse Transmission Line method. Compared to odder full wave methods the TTL is an efficient tool to determine the coupler characteristics, making possible a significant algebraic simplification of the equations involved in the process. In order to analyze the structure the effective dielectric constant, the attenuation constant and the coupling were determined. News results obtained for this application and the conclusions are presented.     

Can Millimeter Waves Generate Electroporation?

Analysis of the field distributions in a single biological cell under electromagnetic wave is given. With Debye approximation, the dielectric relaxation of each part of the cell, including the extracellular and cellular media, the cell membrane and the nuclear membrane, was taken into account. Making use of some typical parameters for a cell, the voltage across nuclear and cytoplasma membranes under electromagnetic waves are calculated up to millimeter wave frequency range. The calculated result indicates that it is unlikely to generate electroporation by present available millimeter wave sources.     

Experimental Attenuation of Rectangular Waveguides at Millimeter Wavelengths

The experimental values of attenuation of commercially available rectangular waveguides were determined at frequencies between 25 and 200 GHz with emphasis on high accuracy. They were compared with the theoretical values computed from the dc conductivities, taking into consideration temperature effects, work hardening, size effects, surface roughness, and a room-temperature anomaly of the skin effect. A new way to express the excess attenuation due to these effects was fomulated. Excess ratios of attenuation of coin-silver waveguides were found to be well below the values used in engineering in the past. They can satisfactorily be explained by surface roughness. The normalized excess attenuations of copper guides are higher than those of guides made of silver but lower than cited in the literature.     

Scattering of Millimeter Waves from Acid Rain

A theoretical investigation of scattering characteristics of millimeter waves from acid rain is conducted using the method of vector spherical function expansion. The particles of acid rain are considered as the double-layered spheroid. The method is used to derive an analytical solution to the problem of scattering of millimeter waves by a coated dielectric spheroid. The normalized bistatic cross section versus scattering angle for the acid raindrop is calculated at frequencies of 35 GHz and 94 GHz. This is the first part of our study scattering characteristics of millimeter waves from acid rain.     

毫米波非致命生物效应试验

W 波段毫米波由于波长短且处于大气窗口,因此易于传输微波能量且波束能量容易集中;在足够功率密度下W 波段毫米波可以对皮肤产生强烈烧灼感,所以适合作为非致命系统的毫米波源,用于警用、防爆、反恐方面。但由于高功率W 波段毫米波的产生与传输比较困难,目前仅美国有相关系统的研制、部署的报道,国内的相关研究起步比较晚。中国科学院电子学研究所高功率毫米波回旋管的研制处于国内先进水平,与军事医学科学院合作进行了W 波段毫米波生物效应试验研究。试验对象主要为小白鼠、大鼠、猪皮、狗等专用试验生物,取得了初步进展。     

Nondestructive Material Homogeneity Characterization by Millimeter Waves

Millimeter wave bridge technique for nondestructive material homogeneity characterization is described. The idea of this technique is the local excitation of millimeter waves in testing material and the measurement of the transmitted amplitude and phase in it different places. Some results of the homogeneity measurements for the dielectric substrates are presented.     

毫米波微带偶极子天线阵列

介绍了一种毫米波微带双面偶极子天线线阵。在单元天线设计的基础上，对相邻天线单元互耦的影响进行了仿真分析，然后根据实际测试结果，对相邻天线单元互耦的影响进行了分析。实测结果表明，该天线阵列具有较好的驻波和互耦性能，适合用于相控阵系统。     

Spatial and Temporal CM Equalization for Broadband Wireless Indoor Networks at Millimeter Waves

Based on a new multipath channel model, a spatial-temporal combined CM equalization approach is derived at millimeter waves. Computer simulations are presented to testify the theoretical analysis. It is shown that this method can compensate the signal degradation caused by indoor multipath propagation. The convergence behavior of the spatial-temporal CMA is also analyzed.     

Experimental Study of the W-Band Dielectric-Guide Y-Branch Interferometer

Applicability of a W-band dielectric-guide Y-branch (DGY) interferometer as a modulator, switching element for the millimeter-wave planar dielectric-guide integrated circuits is established, The switching element includes a phase shifter formed by a metal wall proximate to a dielectric guide. The influence of the branches asymmetry on the on/off switching ratio was measured, found to comply with theory. On/off switching ratios of about 25 dB were obtained over a 98-104-GHz frequency range.     

一种毫米波表贴型外壳的微波设计

介绍了一种基于高温共烧陶瓷(HTCC)工艺的表贴型外壳的设计及其测试方法,该外壳可用于封装工作频率直到8mm频段的器件,其射频传输途径采用共面波导-准同轴-共面波导的结构,研究利用HFSS软件对该传输结构模型进行了仿真优化,在8mm频段实现较小的插入损耗与较大的回波损耗。采用一种共面波导传输结构的测试基板,利用GSG探针对外壳样品进行测试,测试结果显示从直流到接近38GHz频带内,插入损耗|S21|小于0.8dB。