A dual-polarised wideband planar array for X-band synthetic aperture radar

This paper describes the design and performance of a wideband planar array panel for use in a dual linear-polarisation antenna for the Australian Defence Science and Technology Organisation (DSTO) Ingara X-band airborne synthetic aperture radar (SAR). The final array aperture is approximately 1200 mm by 200 mm and comprises 192 dual-fed microstrip patch elements divided into three panels, each panel with an integrated microstrip feed network. To accommodate high power operation, a coaxial power distribution network is used to feed the panels. The primary objective of the design was to achieve on-axis cross-polarisation radiation in each polarisation at least 25 dB below the co-polarised radiation over a 600 MHz bandwidth.