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- 摘要
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Ocean Wind Retrieval Models for RADARSAT Constellation Mission Compact Polarimetry SAR
摘要： We propose two new ocean wind retrieval models for right circular-vertical (RV) and right circular-horizontal (RH) polarizations respectively from the compact-polarimetry (CP) mode of the RADARSAT Constellation Mission (RCM), which is scheduled to be launched in 2019. For compact RV-polarization (right circular transmit and vertical receive), we build the wind retrieval model (denoted CoVe-Pol model) by employing the geophysical model function (GMF) framework and a sensitivity analysis. For compact RH polarization (right circular transmit and horizontal receive), we build the wind retrieval model (denoted the CoHo-Pol model) by using a quadratic function to describe the relationship between wind speed and RH-polarized normalized radar cross-sections (NRCSs) along with radar incidence angles. The parameters of the two retrieval models are derived from a database including wind vectors measured by in situ National Data Buoy Center (NDBC) buoys and simulated RV- and RH-polarized NRCSs and incidence angles. The RV- and RH-polarized NRCSs are generated by a RCM simulator using C-band RADARSAT-2 quad-polarized synthetic aperture radar (SAR) images. Our results show that the two new RCM CP models, CoVe-Pol and CoHo-POL, can provide efficient methodologies for wind retrieval.
关键词： CoVe-Pol and CoHo-Pol models,compact polarization (CP),RADARSAT Constellation Mission (RCM),right circular horizontal polarization model,right circular vertical polarization model,wind retrieval,geophysical model function (GMF)
更新于2025-09-09 09:28:46
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Study of Horizontally Polarized Omnidirectional Microstrip Antenna Arrays
摘要： This paper presents two microstrip antenna arrays for horizontally polarized (HP) omnidirectional application, namely rectangular patch antenna array and H-shaped patch antenna array. There are eight patch elements placed with back-to-back structure, four patch elements on each side. Antenna arrays are fed by a split eight power divider. The H-shaped patch antenna array has better omnidirectional performance than rectangular patch antenna array. The H-shaped antenna array is fabricated and measured. Both simulated and measured results show that the bandwidth of the designed H-shaped antenna array is 36 MHz with a center frequency 2.35 GHz. Horizontally polarized gains are greater than 7 dBi over the resonant band (S11 < ?10 dB), while the cross-polarization level is less than ?25 dB. The proposed H-shaped antenna array has high directivity (half-power beam-width is only 20 deg) and good omnidirectional performance (gain variation less than 1.5 dBi) at the center frequency.
关键词： horizontal polarization,omnidirectional radiation pattern,microstrip antenna,Antenna array
更新于2025-09-09 09:28:46