Aperture coupled metamaterial patch antenna with broad E-plane beamwidth for millimeter wave application

In this paper, an aperture coupled metamaterial patch antenna having a broad E-plane half power beamwidth (HPBW) for mm-wave application is presented by using a zeroth-order resonance (ZOR) mode and a half wavelength (TM₀₁₀) mode. When the ZOR mode and the TM010 mode operate at the same frequency, the E-plane radiation pattern of two modes are combined. Also, by controlling the injected powers to two modes, the E-plane HPBW of the TM₀₁₀ mode can be broadened. To generate two modes, a patch antenna with an etched hole for TM₀₁₀ mode and a mushroom antenna inside an etched hole for ZOR mode are designed. In addition, an aperture coupled feeding structure is employed to excite two modes and the position of aperture is optimized to obtain the impedance matching and the broader HPBW. The result shows that the E-plane HPBW of the antenna is broadened to be 135°. Moreover, the antenna has a good radiation efficiency of 91%.