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UAVSAR Phased Array ApertureThis paper describes the development of a patch antenna array for an L-band repeat-pass interferometric synthetic aperture radar (InSAR) instrument that is to be flown on an unmanned aerial vehicle (UAV). The antenna operates at a center frequency of 1.2575 GHz and with a bandwidth of 80 MHz, consistent with a number of radar instruments that JPL has previously flown. The antenna is designed to radiate orthogonal linear polarizations in order to facilitate fully-polarimetric measurements. Beam-pointing requirements for repeat-pass SAR interferometry necessitate electronic scanning in azimuth over a range of -20degrees in order to compensate for aircraft yaw. Beam-steering is accomplished by transmit/receive (T/R) modules and a beamforming network implemented in a stripline circuit board. This paper, while providing an overview of phased array architecture, focuses on the electromagnetic design of the antenna tiles and associated interconnects. An important aspect of the design of this antenna is that it has an amplitude taper of 10dB in the elevation direction. This is to reduce multipath reflections from the wing that would otherwise be detrimental to interferometric radar measurements. This taper is provided by coupling networks in the interconnect circuits as opposed to attenuating the output of the T/R modules. Details are given of material choices and fabrication techniques that meet the demanding environmental conditions that the antenna must operate in. Predicted array performance is reported in terms of co-polarized and crosspolarized far-field antenna patterns, and also in terms of active reflection coefficient.
Document ID
20110011534
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other
Authors
Chamberlain, Neil
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Zawadzki, Mark
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Sadowy, Greg
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Oakes, Eric
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Brown, Kyle
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Hodges, Richard
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2009
Subject Category
Communications And Radar
Report/Patent Number
PB2010-104116
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
Unmanned Aerial Vehicle (UAV)

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