A wide bandwidth microstrip subarray for array antenna applications fed using aperture coupling

The authors describe experimental work carried out to develop an array antenna element based on microstrip patches for fixed beam communication link antennas. Three basic criteria had to be met: a minimum 10-dB return loss bandwidth of 10%; a radiation pattern consistent with good array sidelobe performance; and a structure fully compatible with printed circuit board manufacturing techniques, for low cost. The experimental optimization of a single probe-fed five-patch subarray is described, and the advantages of increased pattern and return loss bandwidth and improved directivity are demonstrated over a single probe-fed patch. A further bandwidth increase has been achieved by the use of aperture coupling, which also has significant manufacturing advantages over the use of probes.<>