Parasitic patch antenna with filtering response

A low profile, high gain and wideband parasitic patch antenna with filtering response is investigated in this paper. The parasitic patches are fed by two separated microstrip-coupled slots from the bottom. Good filtering performance in the lower stopband is achieved by the separation between the two slots together with a shorting via, whereas a sharp roll-off rate at upper band edge for the filtering function is produced by the elaborately designed parasitic patches. The parasitic patches also simultaneously work as a high efficient radiator, enhancing the impedance bandwidth and antenna gain of the feeding slots. The prototype with profile of 0.06 λ
₀
has a 10-dB impedance bandwidth of 30.0%, an average gain of 8.9 dBi within passband, and an out-of-band suppression level of more than 22 dB within ~0-3.9 GHz and more than 30 dB within 6.4-9.7 GHz.