Analysis on UHF SAR antenna

To meet the requirements of miniaturization, high gain and wideband for UHF SAR, this paper analyses gain loss produced by reducing back cavity of short back-fire antenna. Based on pottel´s formula, gain loss for the cover of reflecting disc is computed. A new approach is presented, that is H-shaped two-element array antenna replaces short back-fire antenna. This structure can expanded bandwidth and shorten antenna structure. This paper also compares miniature antenna´s structure in the overseas. Our study indicates that making use of wide dipole and microstrip can offer lightweight, small structure, high gain and wide-band UHF SAR antenna on small platforms.