A Novel Microstrip Grid Array Antenna with Both High-Gain and Wideband Properties

A novel microstrip grid array antenna that is simultaneously high in gain and wide in bandwidth is proposed. To enhance its bandwidth, the antenna adopts elliptically shaped and variably dimensioned radiation elements as well as a linearly tapered ground plane, and is optimized by a parallel genetic algorithm (GA) on a cluster system. A prototype antenna was fabricated and tested. Results of simulation and measurement agree well and show the antenna exhibits encouraging properties, e.g., a maximum gain of approximately tely 15.1 dBi at 5.8 GHz; the || ≤ 10 dB bandwidth and the 3dB gain-drop bandwidth are 25.6% (from 5.03 GHz to 6.51 GHz) and 27.6% (from 5.0 GHz to 6.6 GHz), respectively, of the center frequency, both of which are much wider than that of conventional microstrip grid array antennas. Moreover, the overlap between the antenna's impedance bandwidth and the gain bandwidth results in a wide effective operating frequency bandwidth of 25.6%, which is the largest so far achieved for microstrip grid-array antennas.