Performance assessment of RF-MEMS-based passive ESA for fully-polarimetric Ka-band SAR

Radars based on an electronically scanned array (ESA) offer important advantages over mechanically scanned designs. Multifunctional RF systems typically suffer from large losses due to use of semi-conductor-based phased shifter at the antenna front-end. RF-MEMS technology is becoming a highly mature technology for cost- and propagation loss reduction in passive ESA mounted on energy-starved UAVs. In this paper we evaluate numerically and by means of simulations the overall performance of RF-MEMS-based phase shifters compared to semi-conductor-based on SAR image reproduction mounted on an energy-starved UAV. Assuming realistic conditions it is shown that RF-MEMS technology can enable acquisition of qualitative SAR images even for the most challenging, yet realistic, scenarios encountered for typical civilian applications. This is, however, not the case for semi-conductor-based phase shifters due to too high losses.