A novel dual‐frequency dual‐polarized stacked patch microstrip array feed for remote sensing reflector antennas

This paper presents the design and implementation of a dual‐frequency dual‐linear polarized stacked patch array feed with a novel probe‐feeding architecture for future spaceborne synthetic aperture radar (SAR) applications. To facilitate measurements of soil moisture from space, a large aperture antenna of 30 m operating in VHF (137.5 MHz) and UHF (435 MHz) frequencies is desirable. An array feed that synthesizes a rectangular effective aperture on the 30‐m reflector is proposed in order to obtain matched beams at the VHF and UHF frequencies. We focus on the layout, design, and prototype performance of the stacked‐patch microstrip array designed for scaled operating frequencies of 1.13 GHz (lower patch) and 3.57 GHz (upper patch). The study is also aimed at analyzing the performance of the array in combination with a 3.65‐m reflector. Our test results demonstrate a good correlation between the measurements and simulations from finite‐difference time domain (FDTD) and reflector analysis codes, thus validating the design for use in SAR for soil‐moisture applications.