For dual-band dual-polarized synthetic aperture radar (SAR) applications a compact low-profile design is investigated. The operating frequencies are at the L and C-bands, centered about 1.275 and 5.3 GHz, respectively. Since the C-band frequency is larger by a factor of four, its array elements and interelement separations are smaller by the same ratio. Thus, to allow similar scan ranges for both bands, the L-band elements are selected as perforated patches to enable the placement of C-band elements within them. Stacked-patch configurations were used to meet the bandwidth requirements, especially in the L-band. The C-band element was designed numerically, but the perforated L-band one required final experimental optimization. Also, in the latter case of L-band, balanced transmission line feed was used to minimize cross polarization. For the C-band elements, slot coupling was used and, to simplify the feed, symmetric parasitic slots were incorporated to minimize cross polarization. No vertical connections were utilized, and electromagnetic couplings resulted in a compact low-profile design, with an electrically and thermally symmetric geometry.

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The scattering properties of a dielectric-coated nonconfocal conducting elliptic cylinder are investigated. The theoretical treatment of such a problem is based on the boundary value solution, which is an exact treatment of the problem. Only the transverse magnetic (TM) case is considered here, while the transverse electric (TE) case can be treated in the same way. It is shown that this solution is much more general than all other solutions given before because it can handle a variety of scattering geometries. Numerical results are presented in graphical form for the echo width pattern of various geometries.