Enhancement of antenna decoupling bandwidth by utilizing common and differential modes cancellation

Abstract

This paper proposes a decoupling technique with bandwidth enhanced by introducing two transmission zeros based on common mode (CM) and differential mode (DM) cancellation. The mutual coupling between antennas can be thoroughly eliminated if the CM and DM impedances are equal. Two transmission zeros with closely spaced frequencies are created by using a neutralization line and a parasitic element. The neutral line and parasitic unit can change the currents of radiation patches in CM and DM to realize an enhancement of decoupling bandwidth. To demonstrate the feasibility of this method, a reference and proposed arrays are fabricated and measured. In measurement, the port isolation of proposed antenna array is enhanced by 10.3-21.56 dB in the desired frequency band. Besides, the efficiency and gain are improved by 0.5-3 dB and 10.4%-18%, respectively. The pattern diversity/ envelop correlation coefficient (ECC) is also enhanced.