The Compact Ocean Wind Vector Radiometer ( COWVR ) is a technology demonstration mission , developed at the Jet Propulsion Laboratory ( JPL ) , and scheduled for launch in 2016 . The goal of COWVR is to provide the same windvector retrieval accuracy of other instruments , like WindSat , while reducing the total mass and using less power . In this paper , we present an overview of the COWVR instrument , and a detailed description of the EM ( Electromagnetic ) modeling of the antenna system and the test campaign carried out at JPL to assess its performance . Special emphasis has been placed on assessing the accuracy of the predictions made with the RF ( Radio Frequency ) model . We will show that the predicted radiation patterns are accurate enough so one can use them for orbit radiometer calibration .