Contents I. Introduction
The next generation 5G wireless communication demands the peak data rate of 10Gb/s and above per user. Several technical approaches are being explored to reach such high data rate, such as the beam forming in millimeter-wave frequency [1] and the spatial diversity increase with massive multiple-input and multiple-output (MIMO) technique [2]. While millimeter-wave provides the sufficient radio frequency (RF) bandwidth to achieve very high data rate above 1-Gb/s, a high-gain antenna with high directivity is required to offset increased radiation loss at the millimeter-wave radiation frequency. Although the spatial diversity MIMO technique has been successfully used to increase the data rate at lower frequency, the requirement of the high antenna gain to offset high radiation loss makes the MIMO application almost incompatible in millimeter-wave. Recent advances in high gain beam forming antenna has the strong advantage to direct all the energy to the intended receivers, the reliability of such communication link largely depends on the availability of the line-of-sight propagation without path blockage and multi-path interference.
