Abstract: A new design of the sharedaperture dual-band dual-polarized (DBDP) mi crostrip antenna array is introduced. The antenna operates in S-band and X-band with dual-linear polarization, suitable for airborne and shipborne synthetic ap e rture radar (SAR) applications. To meet the bandwidth requirements in both bands , a stacked patch configuration is used. This overcomes the difficulty of the pr evious DBDP antennas in obtaining large bandwidth in the lower band. Furthermore , to minimize the influence on the higher band, microstrip dipoles are used in t he lower band, located in the spaces among X-band patches. By using orthogonal d ualpolarized microstrip dipoles as the lower band radiation elements, the dual-band array can be applied for a wider range of frequency ratio. The microstrip power combiner is not integrated in the array. The lower and higher bands use pro ximity coupled feed and probe feed respectively. The array was simulated, fabric ated and measured. Experimental results have verified feasibility of the proposed array.

Key words: dual-band, dual-polarized, shared-aperture, synthetic aperture radar(SAR)
, microstrip antenna array