The interferometric synthetic aperture microwave imager (IMI) on WCOM is a onedimensional L/S/C tri-frequency microwave radiometer aiming to improve the measurement capability on soil moisture and ocean salinity. An IMI antenna system mainly consists of a parabolic cylinder reflector and a tri-frequency linear patch feed array. At present, an L-band ground prototype with a solid reflector and an 8-element feeds array is completed, with the imaging feasibility being verified by experimental results. In order to improve radiometer performance, this paper presents an improved antenna system, which is dedicated to the next generation of interferometric microwave imager prototype. Improvements made for the antenna system mainly include using deployable mesh reflector and increasing feeds. Simulation results of image reconstruction in viewing a series of near real case ocean brightness temperature maps are used to quantitatively compare and analyze imaging performances of the two L-band IMI prototype antenna systems.
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