A wideband array antenna with a novel matching circuit and DGS structure for the sub 6 GHz applications

This paper proposes a novel matching network with a DGS structure to enhance the bandwidth of a two-element array antenna. The array antenna only generates a single resonance with a conventional partial ground plane with poor bandwidth and gain. Several dips are observed when the matching network is loaded between the array elements, but their matching is not good enough. Then, the partial ground is applied with a DGS structure, which improves the low-frequency band's matching. After that, three rectangular parasitic blocks are placed on the ground plane to improve the matching of the high-frequency band. Parametric analysis is done on several parameters to position these two bands close enough, considerably enhancing the bandwidth. The overall dimension of the proposed antenna is 30 mm ×30 mm ×1.6 mm. A prototype of the proposed antenna is fabricated and measured. Experimental results show that the antenna has an operating bandwidth of 70% for |S11| < -10 dB ranging from 3.05 GHz to 6.32 GHz, where a pick gain of 3.07 dBi is realized. The radiation patterns at the two significant dips are stable. The cross-polarization level in the E plan is less than - 16 dB at the low resonant frequency.