THE USE OF SHORTING POSTS TO IMPROVE THE SCANNING RANGE OF PROBE-FED MICROSTRIP PATCH PHASED-ARRAYS

This paper presents a thorough investigation of the use of shorting po sts to improve the scanning potential of microstrip probe-fed patch ar rays, A rigorous spectral domain integral equation (SDIE) technique is used to analyze the scan impedance and related radiation characterist ics of several proposed shorting post-patch array configurations, It i s shown that by using shorting posts, potential scan blindnesses can h e removed and the useful scanning range of the array carl be significa ntly extended beyond 80 degrees in the plane of interest, Comparisons of the scan performance of several microstrip patch arrays containing up to three shorting posts are presented, Novel hybrid shorting post c onfigurations are also proposed and examined, which provide excellent scanning potential in the three principal planes (E-, H-, and D-planes ). These modified microstrip patches incorporate switching diodes and provide minimal scan impedance variation for scan angles near 80 degre es in all three planes, as well as very low cross-polarization levels.