Bandwidth and Gain Enhancement for Single-Fed Compact Microstrip Antenna by Loading With Parasitical Patches

In this paper, a novel single-fed single-layer microstrip antenna with wide impedance bandwidth and high gain property is presented. The bandwidth and gain enhancement is realized by loading with a square circle of square parasitical patches. Parameter analysis is made to investigate the effect of the loading structures. For comparisons, both the unloaded and the loaded microstrip antennas are designed, fabricated and measured. Although the same size for the two antennas, the measured -10dB impedance bandwidth of the one with parasitical patches is 27.8% from 5.8GHz to 7.67GHz, compared with that of the unloaded one, 9.9% from 5.8GHz to 6.41GHz. While the gain enhancement is about 1dB similar to 2.5dB around the operating frequency range and the maximum gain of the loaded type is about 10.1dB. This antenna has potential application in the wireless communications for its compact structure, wide bandwidth and considerable gain property.