Double-Ridge Waveguide for Commercial Airlines Weather Radar Installation

This paper describes the design and development of a double-ridge waveguide designed to propagate both C-band and X-band (5,400 and 9,300 mc) so as to allow for a common waveguide installation in commercial airliners which could use either a C-band or an X-band weather penetration radar. This double-ridge waveguide is capable of propagating over the desired frequency range with single mode operation only; it yields attenuation at C-band which is only slightly higher than that of normal C-band waveguide and has somewhat reduced attenuation at X-band compared to standard 1 X 1/2 rectangular waveguide. This double-ridge guide has been adopted by Aeronautical Radio, Inc. and is specified in their Characteristic No. 529 entitled "5.7 Cm Weather Penetration Airborne Radar." This paper also gives an analysis of the calculated guide wavelength in this double-ridge guide, attenuation, and peak power-handling capabilities; and compares the results of these calculations with measured data. Peak power-handling capability for this double-ridge guide is well within the requirements of this application. The testing procedures used for high-power breakdown measurements are described. This paper also covers the development of double-ridge waveguide flanges, elbows, bends, twists, transitions, and flexible waveguide for use over this extremely broad band.     

蒸发波导对雷达探测的影响

大气波导使雷达电磁波产生异常传播，研究其对雷达探测范围的影响具有重要意义。文中利用抛物方程模式及分步傅里叶算法对电磁波在蒸发波导条件下的传播进行数值模拟，并结合在福建平潭的试验，验证了模式的正确性，并论述了蒸发波导对雷达探测的影响。     

W-band high gain lens antenna for metrology and radar applications

A W-band high gain lens antenna has been realised and measured. A hyperbolic lens made in ECCOSTOCK 0005 is associated to an optimised modified circular horn related to a circular-to-rectangular waveguide transition in order to fit the WR-10 standard waveguide. The antenna provides more than 30 dBi gain between 75 and 110 GHz. It is competitive in several fields of applications: first, obstacle detection radar application (at 77 or 94 GHz), secondly metrology, for example, in order to measure radar cross-sections over the whole W-band with a single antenna.     

脊波导漏壁式滤波器的简化算法

脊波导漏壁式滤波器在雷达和微波通信等领域得到广泛的应用。但是脊波导漏壁式滤波器解析计算困难,近似分析误差较大,直接使用商业软件HFSS仿真很耗时。基于传输线理论和波导裂缝有源阻抗提取方法,提出了一种脊波导漏壁式滤波器的简化算法。根据这种简化算法研制了一个脊波导漏壁式滤波器的样件,计算结果与试验结果具有较好的一致性,证明了该方法的有效性。     

Method for radar cross section measurements in millimeter and submillimeter wave regions

We present a new method for electromagnetic modeling radar scattering processes. In this method we use a quasi-optical waveguide of the type of "hollow dielectric waveguide" as a fundamental component of radar cross section (RCS) instrumentation systems. Such waveguide structure produces required target-illuminating quasiplane wave and suppresses unwanted waves as well as transmits the legitimate signal from test object, mounted inside this waveguide, to the reception zone. Presented method is especially effective one in millimeter and submillimeter wave regions, in particular, for investigation RCS of targets with small reflectivity.     

宽带端馈式同轴矩形波导天线单元的研究

端馈式同轴矩形波导作为同轴波导变换,前人已经作了很详细的分析计算.由于端馈式同轴矩形波导与自由空间匹配困难,它很少用作辐射天线单元.本文用环耦合法和FDTD法对这种三维非均匀天线单元结构的特性进行了深入的研究,不仅减少了计算时间和空间,而且提高了计算精确性,得到这种相控阵天线单元的辐射方向图和驻波特性曲线,并进行了实验验证,解决了端馈式同轴矩形波导与自由空间的匹配问题.研究表明该种相控阵天线单元具有带宽宽、大扫描角的特点,可以广泛的用于地面、机载和星载相控阵雷达或者通信系统.     

West Ford radar and microwave equipment

The ground stations used in the West Ford experiment, one in California and one in Massachusetts, can transmit and receive CW X-band communications signals simultaneously. In addition, each station can be changed within minutes to a radar capable of tracking and measuring the characteristics of the dipole belt and other satellites. The high performance of these stations also permits other scientific experiments. New radio and radar techniques and components such as high-power X-band klystrons, low-noise masers, and high-performance waveguide devices are used at these stations. The operation of the stations and the microwave components and techniques are described in this paper.     

RF exposure of biological systems in radial waveguides

Two radial waveguide exposure systems for multiple biological targets are described that were conceived, dimensioned, implemented, measured and dosimetrically analyzed. In the first case, a number of 120 hamsters was exposed with mobile communication signals at 383 and 900 MHz. The variation of the dissipated energy within the animals could be reduced to less than 30% though the objects were not restrained. Whole body specific absorption rates of 80 mW/kg were applied. The other system was used for exposing hamster's pineal glands in culture. The small size of the samples yields an even smaller variation of the exposure of 2.4%. This is a consequence of the excellent uniformity of the electromagnetic field distribution across the exposure region, which was achieved by a good rotational symmetry of the waveguide and a careful design of the feed antenna and the absorber/shortcut combination. The paper reports on the technical aspects of the RF exposure     

碳纤维裂缝波导成型及机加工工艺

波导是雷达天线的重要组成部分,星载天线极高的轻型化要求对裂缝波导的材料及工艺技术提出了新的挑战。通过对碳纤维裂缝波导制造的特点及关键技术的分析,经过大量试验,利用钢、铝芯模实现了碳纤维裂缝波导的制造,解决了零件加工中的精度控制和内腔无毛刺难题,电讯性能和铝裂缝波导基本一致。文中总结了碳纤维裂缝波导的成型工艺及机加工工艺,提出了制造不同长度波导的工艺路线建议,并分析了实际应用的可行性。     

大气波导对舰载电子装备作战性能的影响

大气波导是海洋大气近地层内普遍存在的现象,对海上舰船的电子信息装备作战性能有着非常重要的影响。介绍了大气波导的形成原因、分类和形成波导传播的条件,分析了大气波导对舰载雷达、电子对抗和通信系统的作战性能影响。最后提出了运用大气波导的方法措施。     

Phased-array radiator reflection coefficient extraction fromcomputer waveguide simulator data when grating lobes are present

Commercially available finite-element software that solves Maxwell's equations for arbitrary three-dimensional bounded structures has enabled phase-array radiator designers to perform waveguide simulator modeling of phased-array radiating elements on the computer very efficiently. Published work on waveguide simulator design has concentrated on array performance in the absence of grating lobes, a requirement for many radar applications. For such simulators, the reflection coefficient of each propagating mode at the waveguide simulator port gives the radiator reflection coefficient at a discrete scan angle. However, the design of limited scan arrays can lead to selection of an array element spacing that allows grating lobes in real space. When a waveguide simulator is modeled on the computer, and a grating lobe is present, the two waveguide modes representing the main lobe and the grating lobe will propagate in the waveguide simulator and they will be coupled together. The simulator port-reflection coefficient of either mode is not the true reflection coefficient seen by the radiating element. We describe a method for extracting the reflection coefficient of the radiating element from the waveguide simulator data when one or more grating lobes are present     

Data Processing and Calibration for an Airborne Scatterometer

The ERASME radar system has been designed to be easily mounted on small helicopters or aircraft. As it is used for research investigations on radar remote-sensing applications, it has to be well calibrated in every configuration, both absolutely and relatively for comparisons at different points of the swath. The data processing is described, which allows for antenna pattern correction and for flight parameters correction (pitch, roll, altitude), as an introduction for the calibration procedures: internal calibration, external calibration on corner reflectors for absolute calibration (within 1 dB), and a statistical approach, which uses experimental data itself and analyzes the correlation between processed data and recorded flight parameters. This method provides a way to check or adjust calibration for specific flight configurations, and allows a relative accuracy of better than 0.5 dB for data comparison within the radar swath. Such a method could be used to calibrate any airborne or spaceborne scatterometer when accurate antenna measurement is not feasible.     

Leaky-Wave Slot Array Antenna Fed by a Dual Reflector System

A leaky-wave slot array antenna fed by a dual offset Gregorian reflector system is realized by pins in a parallel plate waveguide. The radiating part of the antenna is composed by parallel slots etched on one side of the same parallel plate waveguide. The dual offset Gregorian reflector system is fed by an arrangement constituted by two vias and a grid, also constituted by pins. Also this feed arrangement realizes a leaky type of radiation, this time inside the parallel plate waveguide. A prototype of the antenna has been designed, manufactured and successfully tested. The low profile, low cost and high efficiency of the antenna render it suited for a variety of radar or telecom applications.     

X波段宽频带波导-同轴铰链的研制

波导-同轴旋转铰链是由矩形波导-同轴波导构成，是雷达系统中的关键元件。本文首先简要介绍了该铰链的基本工作原理，然后对铰链的旋转段、同轴-波导的耦合和激励进行了理论分析与设计，尤其是针对如何实现宽频带匹配问题作了较详细的实验研究。     

X波段双基站多普勒天气雷达系统设计

X波段双基站多普勒天气雷达系统是一种新型气象探测雷达系统，主要用于测量降雨回波的三维风场。根据x波段天气雷达的功能要求及设备组成特点，采用波导缝隙天线及GPS系统解决了空间、相位、时间的三大同步问题，具有结构简单、价格低廉、工作可靠、灵敏度高等特点。还分析了确定系统性能指标的算法，并给出了基于GPs的具体工程实施方法，该系统有很好的推广价值。     

Monolithically integrated transverse-junction-stripe laser with anexternal waveguide in GaAs/AlGaAs

This device consists of a five-layer transverse-junction-stripe laser structure monolithically integrated with an external three-layer waveguide. The transverse p-n junction within the laser cavity permits the use of a vertical p-n junction in the external waveguide for future implementation of a modulator without disturbing the laser operation. As a result, this structure allows for flexibility in the design of the external waveguide/modulator without resorting to complicated regrowth procedures. Design curves for two different types of optical cavities are presented, and the reflectivity and transmission of the etched facet as a function of active layer thickness is modeled in detail using an excitation field approach. Finally, integrated laser/waveguide devices are fabricated based on this design and are compared to the theoretical curves. Most devices had threshold currents between 60 and 80 mA, while laser-to-waveguide transmission coefficients were as high as 38%     

A dual vial waveguide exposure facility for examining microwave effects in vitro

A waveguide exposure system operated between 2 and 4 GHz was assembled in a laboratory incubator in order to study potential temperature-dependent and temperature-independent actions of microwaves. Two vials containing cell cultures were exposed simultaneously in a single waveguide in order to reduce the space required, and to allow concurrent study of autologous cell cultures in two different functional states (resting and stimulated) during exposure. Dosimetry was performed using three techniques with different underlying assumptions, as well as the technique of differential power measurement. Each of the four techniques yielded different results, although differences between the two vials using any single technique were negligible. A significant 'hot spot' occurred at the center of each vial. The ratio between maximum and minimum absorption rate within a single vial was 33-fold using a vial of 1.2-cm diameter and 1.6-cm height. With agitation and exposure at specific absorption rate (SAR) equal to 21 mW/ml, the thermal gradient was less than 0.1 degrees C between these two points. The averaged SAR can be determined by steady-state heating analysis. The exposure system can be calibrated readily by calculation for the measured powers, but not by differential power measurement.     

A novel surface-mountable millimeter-wave bandpass filter

A novel millimeter-wave waveguide bandpass filter structure suitable for surface mounting is introduced. The filter is constructed using a rectangular waveguide formed in MMIC substrate employing recently introduced microstrip-to-waveguide transducer. Input and output of the filter are implemented as microstrip lines. The transitions between the microstrip lines and the rectangular waveguide are implemented by using the microstrip-to-waveguide transition. The waveguide filter structure is surface-mountable as flip-chip and can be manufactured using a MMIC process that makes it extremely accurate. It has potential applications in millimeter-wave systems like local multipoint distribution system (LMDS) and autonomous cruise control (ACC) radar for automobiles     

薄壁钛合金Reggia-Spencer移相器的结构实现

Reggia-Spencer移相器是最早用于相控阵雷达的铁氧体移相器,属于矩形波导互易移相器,在早期的应用中结构较为笨重。文中选择质量轻、强度高又耐腐蚀的钛合金作为波导材料,并与采用铝合金和钛合金合成的波导结构相比,结果证明全钛合金薄壁式波导结构更加满足机载移相器小型轻巧的设计要求,达到了此类移相器目前最优结构设计方法。     

Influence of Photolithography on the Cross-Sectional Shape of Polysiloxane as an Optical Waveguide Material on Printed Circuit Boards

Optical waveguide cross-sectional shapes that deviate from rectangles or squares may cause significant loss of signal. In this study, a photolithography approach was adopted to fabricate waveguides on printed circuit boards, using photo-imageable polysiloxane as a waveguide material. The effects of I-line ultraviolet (UV) lamp exposure, 355-nm Nd:YAG laser direct imaging, and 248-nm excimer laser direct imaging on the cross-sectional shape of waveguides were investigated. For I-line UV lamp exposure, increasing the exposure time could cause changes in the tilt angle of the waveguides from negative (inverted trapezoid) to positive (trapezoid). To obtain rectangular waveguides, the optimum I-line UV lamp exposure time was found to be around 150 s. From the results for 355-nm Nd:YAG laser direct imaging, the width and tilt angle of the waveguides varied with the energy density of the laser beam irradiating the core materials, being controlled by the repetition rate and focus. Lowering the laser energy density could produce waveguides with small widths and tilt angles. Excimer laser direct imaging at 248 nm was found to be unsuitable for waveguide patterning since the core materials could not be cured at this wavelength.