Design of High-Performance Millimeter Wave and Sub-Millimeter Wave Quasi-Optical Isolators and Circulators

Faraday rotators using permanently magnetized ferrite materials are used to make quasi-optical isolators and circulators at millimeter wave and sub-millimeter wave frequencies that have far higher performance than their waveguide equivalents. This paper demonstrates state-of-the-art performance for four-port quasi-optical circulators with 60-dB isolation, 0.2-dB insertion loss, and better than 80-dB return loss for devices centered at 94 GHz. A method is presented for the accurate characterization of the complex permeability and permittivity of permanently magnetized ferrites via a series of frequency and polarization dependent transmission and reflection measurements. The dielectric and magnetic parameters for the sample are determined by fitting theoretical curves to the measured data. These fitted parameters are then used in a model for a complete quasi-optical Faraday rotator, including matching layers, allowing the accurate design and fabrication of these devices for any specific operational frequency band in the millimeter wave and sub-millimeter wave regime. Examples are given showing typical results and demonstrating how temperature cycling can significantly improve the temperature stability of these devices, while allowing fine tuning of the center frequency. We also indicate the performance possible at higher frequencies to above 1 THz and outline performance of truly planar isolators where lossy polarizer material is built into the Faraday rotator matching structure     

The new technique of harmonic power combination—Millimeter-wave quasi-optical harmonic power combination

In this paper, the new technique of harmonic power combination—millimeter -wave quasi-optical harmonic power combination is presented. In this technique, by compounding several closed resonators with a quasi-optical open resonator, the harmonic powers of active devices are combined, which takes effectively respective advantages of closed cavity power combination and open cavity power combination and improve the combination efficiency of multiple-device harmonic power combiner. The experimental results for W-band are given and shown this combination method is available.     

等离子体诊断用的毫米波准光学系统的设计和测量

准光学方法有效地提高了毫米波接收系统在等离子体诊断中的空间分辨率。本文给出了准光学系统的设计公式、设计步骤以及测量的实验结果。     

毫米波准光功率合成评述

本文对各种毫米波功率合成技术做了简单地回顾,综述了几种当前国际上开展的毫米波准光功率合成方法,最后简单地介绍了作者提出的复合式准光功率合成方法。     

Measuring of the reflection coefficients close to 1 with the help of a quasi-optical reflectometer,based on hollow metal-dielectric waveguides

This paper considers the measurement technique features of large reflection coefficients at millimeter wavelengths and structure and design parameters of the measuring bench, containing a quasi-optical reflectometer, built on the basis of hollow rectangular metal-dielectric waveguides. Measurement results of the reflection coefficients of planar samples with reflection coefficient close to 1 (metallized films, fine-period metal grids) are presented. The results may be of interest in the development of foldable antennas and devices for controlling the backscattering of electromagnetic waves from the objects of complicated geometrical form.     

Quasi-optical ferrite devices for millimeter and submillimeter wave bands

Main features of the development of quasi-optical ferrite devices, using Faraday effect, are considered. Properties of a polarizing divider and a ferrite rotator of a polarization plane are analysed with standpoint of minimum losses. A matching method, based on an utilization of the rotator element in a form of the multilayers ferrite structure, which can be adjusted independently for right-handed and left-handed cyrcularly polarized waves, is suggested. It is shown, that this method allows to obtain a total matching in a quasi-optical transmission line. Results of an investigation of quasi-optical ferrite devices for the oversized round waveguide withH ₁₁ mode are presented.     

新型准光学谐振腔及其在电子学中的应用研究

本文详述刘盛纲教授为首的研究小组对所提出的新型特殊准光腔进行的系统的理论与实验研究。介绍新型准光腔在电子学中的应用，尤其是新型准光腔功率合成，准光学毫米波讯号注入器等。研究表明，新型准光腔在开拓毫米波、亚毫米波频谱、发展大功率毫米波电子学中有重要科学与应用价值，在其它一些领域也可能有应用潜力。     

毫米波准光腔双层介质电介质参数测量新技术

提出了一种利用毫米波准光腔测量双层介质电个质参数的新技术．在８毫米波段，建立了一套准光腔测量系统，并对几种双层介质样品进行了实际测量．     

A Design of Flattop-beam Shaper at Millimeter Wavelengths

Beam shaping technique for generating flattop beam has long been used in optics, and there are many methods to design flattop-beam shapers in optics. Flattop beam is also important in some applications at millimeter wavelengths such as in the quasi-optical power divider, however, there are few design method for the flattop-beam shaper used at millimeter wave frequencies and the design method of optics are not suitable to the beam shaper at millimeter wave frequencies, so a design method for the flattop-beam shaper at millimeter wave frequencies is presented in this paper. Several flattop-beam shapers in the form of diffractive element have been designed and simulation results are presented.     

Precise Design of Millimeter Wave Quasi-Optical Faraday Rotators

A method of designing high performance millimeter wave quasi-optical Faraday rotators (QOFR) is reported in this paper. First, the dielectric and magnetic parameters for the ferrite sample are determined by fitting theoretical curves to the measured data. These fitted parameters are then used in a precise numerical model to predict the rotation angle and insertion loss of the QOFR. Finally, the parameters of the QOFR are optimized according to the requirements of devices. Examples are given showing the performance of the QOFR with an isolation better than 20 dB and an insertion loss less than 0.6 dB from 75 GHz to 95 GHz.     

On Plane and Quasi-Optical Wave Propagation in Gyromagnetic Media

To promote the development and understanding of microwave magnetic devices, especially in the millimeter and submillimeter range utilizing quasi-optical techniques, a discussion of propagation and polarization of plane waves and narrow rays in gyromagnetic media in an arbitrary direction is considered. It is assumed that the medium can be described by a permeability tensor of the Polder type. The approach is structured after classical crystal optics but yields significantly different results since each of the two permitted rays is elliptically polarized. The ellipticities are derived. The phase surfaces are discussed for the lossless case. There are no optical axes but ranges of forbidden directions exist for one or both rays. D, B, and the wave vector n form an orthogonal set at all times. H is confined to the B, n plane; it gyrates along an ellipse such that the Poynting vector traces in time an elliptical cone which contains the wave vector as one mantle line. Therefore, a narrow ray can be understood to proceed along a helical path.     

Quasi-optical waveguide modeling method and microcompact scatteringrange for the millimeter and submillimeter wave bands

The possibility of using the quasi-optical waveguide modeling (QWM) method in the near millimeter and submillimeter ranges of the electromagnetic spectrum for a study of the backward and forward scattering amplitude and phase characteristics of physical objects or scaled models is discussed in the paper. The method is realized with the aid of a quasi-optical waveguide microcompact range (MCR). The microwave part of MCR is based on the regular section of a hollow dielectric waveguide (HDW) and corresponding quasi-optical components. The results of measurements of backward and forward scattering characteristics for a number of standard objects in the 4-mm wavelength band are presented     

毫米波及太赫兹准光学技术：理论、应用与发展

针对毫米波及太赫兹技术在遥感、天文探测以及成像等领域的应用,讨论了准光技术的基本原理、关键器件、系统构成及其技术优势;探讨了准光技术国内外现状及未来的发展趋势。准光技术是基于高斯波束在自由空间中传播而进行系统设计与分析的一种技术。利用准光技术实现的毫米波及太赫兹系统具有高功率处理能力,具备多极化、低传输损耗以及紧凑性等优点。准光技术在未来的各个领域将会有更加广阔的应用前景。     

毫米波空间功率合成技术及其发展

本文综述了当前国际上开展的毫米波准光功率合成和自由空间波功率合成两项新技术，简单地介绍了作者在以上两类功率合成技术研究方面所得的成果，提出了几个有待解决的研究课题。     

Non-linear quasi-optical cell with polarized nuclear target (PNT) material

A resonance electromagnetic structure (a Fabry-Perot resonator) with a plane-parallel sample of the polarized nuclear target (PNT) material of a paramagnetic complex Na HMBA (Cr^V) is considered under condition of dynamic polarization of nuclear by millimeter waves. Non-linear effects observed at the electron spin resonance (ESR) in such structure have been studied. The results of the experiment with the quasi-optical resonance cell of the radiospectrometer designed for the investigation of the magnetic resonance in the millimeter wavelengths range are given. A hysteresis of the transfer coefficient of the cell in the ESR-line has been found while slow passing the ESR-line by retuning of the static magnetic field. The deformation of the form of non-stationary signals passed through the cell has been found.     

被动毫米波太赫兹人体成像关键技术进展

通过分析被动毫米波太赫兹成像检测人体携带物品的基本原理,讨论了被动毫米波太赫兹成像应用于人体安检领域的优势,并分析了成像系统最佳的工作频率和最适宜的工作环境温度。从分析影响成像质量的各项关键技术的角度对被动毫米波太赫兹人体安检成像的进展进行了介绍。重点分析了基于准光学成像原理的光学系统和扫描机构,被动毫米波太赫兹人体成像中最常用的肖特基二极管探测和超导两种探测方法,以及被动毫米波太赫兹图像的处理及目标智能识别。最后,对未来毫米波太赫兹人体成像技术在安全检查领域的应用前景和未来发展方向提出个人观点。     

毫米波准光功率合成技术的研究进展

总结了毫米波、亚毫米波频段的准光功率合成技术的研究进展,介绍了准光功率合成技术早期的研究成果。重点讨论了近期提出的引入全息技术的准光功率合成技术。全息技术有效地解决了器件小型化和散热间的矛盾,能满足未来更高频率的输出功率和效率的要求。     

Effective excitation of quasi-optical resonator in millimeter wave

It is described effective excitation of quasi-optical resonator (Q. O. R) in millimeter wave (M. M. W) in this article in which some useful results are obtained.     

Theory and Optimization Calculation of 3-Mirror Axisymmetric Quasi-Optical Power Combining

Very efficient power combining of solid-state millimeter wave sources may be obtained through 3-mirror quasi-optical resonators and Source arrays. The location and configuration of the source array are determined by CAD (Computer-aided design) technique.