A low-profile microstrip patch array with broadband and wide-angle scanning characteristics

A low-profile broadband patch array antenna with a wide scanning range is presented at X-band. The antenna element consists of the stacked patches, the sheet resistances and the metallic posts with a total thickness of 3.27 mm. The stacked patches are excited by a stripline-fed aperture with four edge patches surrounding the bottom patch. The sheet resistances and the metallic posts provide a solution to ameliorate the matching responses, besides promoting the scanning angle. The simulated active VSWRs are below 2 and 2.6 as scan ranges +/- 60 degrees and +/- 70 degrees, respectively, over a bandwidth of 40%. As an example, a prototype array with 8 x 8 elements was fabricated to verify the method. Its measured active VSWRs are lower than 2.4 and 2.9 with the maximum losses of 1.6 dB in the scan angles above.