I. Introduction
The 60 GHz band is very attractive for high data-rate communication applications (up to multi -Gbps) due to the unlicensed 7 GHz spectrum. Due to the high path loss at 60GHz, a high gain antenna is needed to maintain the link budget requirements. Basically, the phased array antenna can achieve a high gain and beam scanning capability with beamforming techniques, which is good for LOS and NLOS communication scenarios. Regarding the phased array antenna element, end-fire antennas, such as Vivaldi and Yagi antenna, have high gain performance [1], [2], but they usually have larger electrical size and decrease the package compactness. Considering the mass-market consumer electronics, the patch antenna is preferred, with which a low-cost light-weight and compact packaging solution can be realized.