Contents I. Introduction
With the rapid development of modern wireless communication systems, larger communication capacity is urgently demanded [1]. Based on the 3GPP standard protocol, 800 MHz bandwidth allocation in the millimeter-wave (mmWave) frequency band can easily achieve the peak throughput rate of Gbps level. In the mmWave frequency band, signal fading, atmospheric absorptions, and attenuation are several beamforming technologies, and are an effective way to mitigate the signal attenuation and blocking problems. Multibeam antennas include reflector antennas [2], dielectric lens antennas [3], and phased array antennas based on the active devicies, especially the highly integrated beamformer chips. Active phased arrays are widely researched and used based on the high integration and high-gain characteristies [4], [5], [6], [7], [8], [9], [10]. In addition, mmWave dual-polarized (DP) antennas are increasingly being used in mobile devices and base stations for high-capacity communications or high signal to noise ratio [11], [12], [13], [14], [15], [16], [17]. In the light of above facts, it is highly desirable to design DP phased array antennas with low cost and wide-angle scanning characteristics.
