A Defected Ground Structure for TE and TM Coupling Reduction of Dual-Polarized Antenna Array

In this letter, a palisade-type defected ground structure (DGS) is proposed for decoupling a miniaturized low-profile dual-polarized antenna array. The palisade-type DGS loaded between the array elements can achieve both transverse electric (TE) decoupling and transverse magnetic (TM) decoupling simultaneously. The decoupling mechanism is elucidated via analyzing and calculating the equivalent capacitance and inductance values of the parallel resonant circuit of the palisade-type DGS when the antenna array is under TE coupling as well as TM coupling. For verification, a dual-polarized antenna array loaded with palisade-type DGS is designed, whose profile is 0.006λ
₀
and the center-to-center distance between antenna elements is 0.36λ
₀
at the working frequency of 8.1 GHz. The coupled current analysis of the array loaded with DGS reveals that the palisade-type DGS has the spatial band-stop characteristic, changing the direction of the partially coupled current and thereby reducing coupling. Consequently, the simulated and measured results indicate that TE coupling and TM coupling are reduced by about 11 dB and 33 dB, respectively.