共查询到10条相似文献,搜索用时 62 毫秒
1.
V. V. Parshin 《International Journal of Infrared and Millimeter Waves》1994,15(2):339-348
The dielectric parameters of materials for gyrotron output windows measured in the range 65–300 GHz are given. The special attention is paid to the spread of values of the refractive index and loss tangent of dielectrics produced by different firms. The refractive index and loss tangent are measured for sapphire at the cryogenic temperatures and for boron nitride and silica glass at the temperatures 300–1000K. 相似文献
2.
K. Niki T. Idehara T. Tatsukawa I. Ogawa Y. Yoshisato 《International Journal of Infrared and Millimeter Waves》1995,16(6):1025-1036
A quasioptical technique with a hemispherical-type Fabry-Perot resonator for measuring characteristics of millimeter wave detection using a YBCO-BiO composite superconductor has been successfully developed. This Fabry-Perot resonator consists of a spherical mirror and a plane mirror mounted on the cold head of the refrigerator, under a controlled temperature of 40 to 300 K. The method offers the advantages of estimating irradiation power, easily controlling the sample temperature, analyzing the mode of the irradiated millimeter waves and easily extending to higher frequencies. The superconducting millimeter wave detector has been measured with this technique, with measured sensitivities of 46.5 V/W (70 K) to 160 V/W (35 K) at 50 GHz. These results are close to the theoretical values calculated numerically from the characteristics of the detector. It was confirmed that the millimeter wave detection system using the Fabry-Perot resonator is suitable for estimating the sensitivity of the high-Tc superconducting millimeter wave detector. 相似文献
3.
Hongwei Chen Chuanren Yang Chunlin Fu Dayu Zhou 《International Journal of Infrared and Millimeter Waves》2005,26(2):307-313
The microwave dielectric properties and microstructures of Ba(Mg1/3Ta2/3)O3 (BMT) ceramics were investigated. In order to reduce the evaporation of MgO at high temperature, burying in MgO powders sintered BMT ceramics. The relationship between the composition and Q value of BMT ceramics was discussed. Dielectric resonators using in millimeter wave band have been designed and fabricated. Their attenuations at central resonation frequency (f) are less than 35dB. Temperature coefficients of resonant frequency are adjustable and less than 2 ppm/°C. 相似文献
4.
Friedrich Kremer Jerald R. Izatt 《International Journal of Infrared and Millimeter Waves》1981,2(4):675-694
Millimeter wave absorption measurements are usually complicated by scattering from the sample and by standing waves resulting from internal reflections. These problems can be largely overcome by using an untuned cavity resonator. The dielectric properties of the sample are determined from a measurement of the change in cavity Q produced by introduction of the sample into the cavity. For lamellar samples, Maxwell's equations can be used to find an explicit relationship between the change in cavity Q and the samples complex refractive index. Several measuring techniques based on the use of lamellar samples are presented, and their characteristics are illustrated both analytically and by laboratory measurements at 70 GHz on PTFE, polyethylene and plexiglas.On leave from Département de Physique et Laboratoire de recherche en optique et laser, Université Laval, Québec, Qué., Canada, G1K 7P4 相似文献
5.
N. T. Cherpak E. V. Izhyk A. Ya. Kirichenko M. B. Kosmyna A. V. Velichko 《International Journal of Infrared and Millimeter Waves》1996,17(5):819-831
A possibility of the dielectric constant measurement for substrates with permittivity=+i without an essential restriction on their area has been shown experimentally. The method uses frequency measurement of quasioptical dielectric resonator (QDR) with two slots oriented along the QDR radius with a dielectric substrate in one of them. Taking QDR of teflon in 8mm waveband as an example it is found that measurable values of can ran up 15
q
, where
q
is the QDR material permittivity. Absolute error of the measurements is determined by an accuracy with which the permittivity of calibrated (standard) samples is known. The relative measuring error is determined by the accuracy of the QDR frequency measurement and can be quite a small. As an example the method is demonstrated forLaAlO
3 single crystals. 相似文献
6.
研究了嵌入Fabry-Perot谐振腔的高温超导双晶约瑟夫森结阵列毫米波相干辐射的实验结果.相干辐射是通过约瑟夫森结阵列与基片(作为一个介质谐振器)和Fabry-Perot(FP)谐振器的共同作用实现的.由166个高温超导双晶约瑟夫森结串联阵列在77 K温度下产生的相干辐射,辐射峰的中心频率为75.84 GHz,功率大约为10 pW.
关键词:
高温超导薄膜
Fabry-Perot谐振腔
约瑟夫森结
毫米波辐射 相似文献
7.
S. I. Tarapov F. Yldz Yu. A. Tuchkin 《International Journal of Infrared and Millimeter Waves》2002,23(5):745-754
Electrodynamical features of rectangular cavity resonators as experimental cells of Electron Spin Resonance spectrometer for the millimeter frequency band have been investigated. Measurements and analytical estimations of features of three types of resonators (film-wall type, diffraction grating-wall type, double-wall type) are presented. The advantages and imperfections of each design as well as recommendations for their applications in millimeter wave magnetospectroscopy are given. 相似文献
8.
S. I. Tarapov H. Bayrakdar M. Okutan B. Akta 《International Journal of Infrared and Millimeter Waves》2002,23(8):1215-1225
Investigation of key electrodynamical properties of open resonator intended for operating in millimeter and submillimeter wavelength range Electron Spin Resonance (ESR) spectroscopy are represented. The resonator is designed for study of specimens cooled up to cryogenic temperatures. Methodical features of physical experiment for such non-cooled resonator together with continuous flow cryostat are discussed. Results of test ESR-measurement demonstrating virtues of the resonator structure are given. 相似文献
9.
A dielectric rod resonator excited by a nonradiative dielectric waveguide is used for measuring complex permittivity of low loss dielectric materials. The complex permittivties of single crystal sapphire, polycrystalline Ba (Mg1/2 W1/2) O3 and Mg2 Al4 Si5 O18 (cordierite) have been obtained at 60 and 77 GHz by the new apparatus. The first time the measurement results of complex permittivity of brain grey and white matters from 15 to 50GHz utilizing a two-port microstrip test fixture is presented. S-parameters of Test fixture are simulated employing the finite-element method. A new spectrometer for the precision measurement of dielectric permittivity and loss tangent, which is capable of providing high resolution data for the first time over an extended W-band (68-118 GHz) frequency for specimens with a large range of absorption values, including highly absorbing specimens that otherwise would not be possible. 相似文献
10.
Richard A. Stern Richard W. Babbitt John Borowick Gerald Mikucki William Bayha 《International Journal of Infrared and Millimeter Waves》1985,6(10):999-1016
This paper describes the theoretical and experimental results of a novel leaky-wave antenna incorporating a homogeneous dielectric transmission line and radiating aperture into a single structure. The primary objective of this investigation is to demonstrate the ability to control aperture radiation by simply cutting slots into a metal-free dielectric transmission line. Experimental line source antennas with identical periodic slots were designed to operate in the 35 GHz frequency region. The successful performance of these antennas resulted in the design of a dielectric line source antenna with a symmetrical amplitude taper which provided a lower sidelobe level. The design represents a significant breakthrough in achieving affordable, low-loss, lightweight antennas in the millimeter wave region. The most significant applications for this type of antenna include radar surveillance and tactical missile-seeker terminal guidance. 相似文献