SBMO International Microwave Conference/Brazil,最新文献_第7页

The 500-KW CW X-band Goldstone System Radar 500千瓦连续波x波段Goldstone系统雷达

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.589544

A. Bhanji

{"title":"The 500-KW CW X-band Goldstone System Radar","authors":"A. Bhanji","doi":"10.1109/SBMO.1993.589544","DOIUrl":"https://doi.org/10.1109/SBMO.1993.589544","url":null,"abstract":"In recent years the Goldstone Solar System Radar (GSSR) has undergone significant improvements in performance in the areas of increased transmitter power and increased receiver sensitivity. An overview is presented of the radar system and each of these improvements is discussed. Additional plans for future improvements are also described Introduction The Goldstone X-Band (8.51-GHz) Continuous-Wave Solar System Radar (GSSR) is one of the few radar instruments in the world used to study the Solar System. Many observations have been conducted of the planets Mercury, Venus, and Mars, its moon Phobos, the Galilean satellites of Jupiter, the rings of Saturn and its moon Titan, as well as near-Earth asteroids and comets. The Goldstone Solar System Radar is a part of NASA’s Deep Space Network of antennas, which provides 24-hour-a-day communication for unmanned space exploration projects. The network consists of three complexes around the world, one near Madrid, Spain, one near Canberra, Australia, and one in the Mojave Desert at Goldstone, California. The GSSR is installed on the Goldstone 70m Cassegrain antenna (Figure 1). In addition to its primary purpose of tracking spacecraft, the 70m antenna is also used for radio astronomy at L-, S-, Xand Ka-band frequencies and radar astronomy at S and X-band. The 70m antenna is a shaped reflector system featuring an asymmetric subreflecfor that can focus on any of the many feeds at the center of the main reflector (see Figure 1). The focus is changed from one feed to another by rotating the subreflector about its mechanical axis. The operation of the radar requires the subreflector to be moved between the transmit and receiver feeds when switching between the transmit and receive portions of the radar cycle. This movement takes approximately 30 seconds and prohibits observations of near-Earth targets where the round-trip lighttime is short. Recent changes in two elements of the radar have improved its performance by 2.0 dB. The transmitter was upgraded with two new state-of-the-art 250-kW X-bandl klystrons, which increased the radiated power from 360 kW to 460 kW (1.1 dB). The microwave receive system was improved by cryogenically cooling a major portion of the receive feed components, reducing the receiver noise temperature from 18.0 K to 14.7 K (0.9 dB).","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127472024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Advanced Microwave Packaging And Interconnection Techniques 先进的微波封装和互连技术

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.589542

R. Sparks

引用次数: 0

Fiber Simulator For Hybrid Lightwave-microwave Technology 用于光波-微波混合技术的光纤模拟器

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.589367

L. Mullen, P. Herczfeld, V. Contarino, D. Allocca, M. Squicciarini, R. Billmers

引用次数: 1

On The Amplitude Center Of Three Dimensional Sources 三维源振幅中心的研究

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.589371

A.R. Panicali

引用次数: 0

Advanced Long And Short Haul SDH Microwave Radio Systems 先进的长短距离SDH微波无线电系统

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.587229

W. Bourdon, H.-P. Lier

引用次数: 0

Finite Element Modeling Of Optical Guided Wave Devices 光导波器件的有限元建模

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.587212

B. Rahman

{"title":"Finite Element Modeling Of Optical Guided Wave Devices","authors":"B. Rahman","doi":"10.1109/SBMO.1993.587212","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587212","url":null,"abstract":"Results for a wide range of optical waveguides and directional couplers with planar, diffusedl, linear, nonlinear, isotropic, anisotropic, lossy (gain), multiple quantum well, and metal plasmon regions are presented using the accurate vector H-field finite element method. The optimization of the performance of the optical guided wave devices requires knowledge of their propagation characteristics and field distributions, and their dependence on the fabrication parameters. As the range of the guiding structures becomes more intricate, so there is the need for versatile modeling techniques which can be used to characterize accurately a wide range of practical optical guided wave devices with material inhomogeneity, nonlinearity or anisotropy. Analytical moldeling techniques available to analyze and design lightwave devices require many restrictive, and sometimes unrealistic assumptions. Various types of numerical anal-ysis methods for optical waveguides have been developed and for a general discussion on this topic, it is appropriate to refer to two review papers by Sorrentino [l] and Saad [ 2 ] . Among the different numerical approaches possible, the finite element method has established itself a s a powerful method throughout engineering for its flexibility and versatility, being used in complicated structural, thermal, fluid flow, semiconductor, and electromagnetic problems. A review paper by Rahman e t a l . [ 3 ] discusses the application of the finite element method to microwave and optical waveguides. This method is particularly advantageous, because of its applicability to waveguides with arbitrary shape, arbitrary refractive index profile, and anisotropic or nonlinear materials. The finite element method has been widely used during the last two decades in the design of various optical waveguide structures and it is probably the waveguide analysis method that is most generally applicable and most versatile. In the finite element method [4,5], the cross-section of the optical waveguide concerned is first suitably divided into a number of subdomains or elements. Each element can have various shapes, such as triangles or rectangles or even with curved sides, and they can also be of various sizes. Using many elements, a given waveguide cross-section with a complex boundary and with arbitrary permittivity distribution can be accurately approximated. Several different variational formulations have been proposed for use with the finite element method to analyze optical waveguides. Among them, the simplest are the scalar formulations, which consider only one field component and these have been used for solving optical waveguide problems [ 6 ] . The scalar formulations are exact for purely TE or TM modes in the one-dimensional planar guides; but they are inadequate, except as an approximation, for the inherently hybrid modes of two-dimensional optical waveguides. Among the vector formulations, the Ez/Hz [ 7 ] , the vector B field [ 8 ] , vector E fi","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116574913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Simple Microwave Frequency Coiwerter 一个简单的微波频率滤波器

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.589536

Hong Keun Lee, E. Camargo

引用次数: 0

Fiber Brillouin Laser With Two Cascaded Fiber Of Different Brillouin Frequency Shifts 两种不同布里渊频移级联光纤的光纤布里渊激光器

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.587232

C. D. de Oliveira, C. Jen

引用次数: 0

Bistatic Radar - Principles And Practice 双基地雷达-原理与实践

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.587208

H. Griffiths

引用次数: 80

Guided Waves In Dielectric Waveguides With Slanted Gratings 斜光栅介质波导中的导波

SBMO International Microwave Conference/Brazil, Pub Date : 1993-08-02 DOI: 10.1109/SBMO.1993.587215

K. Rokushima, K. Matsumoto

引用次数: 0