A 123 GHz Wideband Patch Antenna with Parasitic Modified Mushroom Structures

A low-profile microstrip-fed wideband patch antenna using BCB substrate is presented in the paper. The antenna is composed of a central patch radiator and two pairs of parasitic modified mushroom structures with different dimensions. Characteristic mode analysis is applied to revealing the mechanism of bandwidth broadening, which shows that the three different modes contribute to the radiation. The simulated −10-dB impedance bandwidth is 20.03% (110.55-135.17 GHz) with a peak gain of 10.5 dBi at 133.5 GHz. In addition, the radiation patterns are stably fixed in the boresight direction and the cross-polarization levels are relatively low over the whole bandwidth.