Wideband Decoupling of Zero Edge Spacing Laminated Resonator Antenna Array

A simple wideband decoupling method for the laminated resonator antenna (LRA) array is proposed in this article. For compactness, the LRA elements are placed right next to each other with zero edge spacing (ES), sharing the same middle via a fence on one side. To neutralize the strong space coupling that existed between the antenna elements, the extra cavity coupling is introduced by disconnecting the middle via the fence with the upper ground. With an appropriate dimension of the middle via fence, the electric field coupled through the cavity path is approximately equal in magnitude to that coupled through the space path, but in the opposite direction. Therefore, the isolation between LRA elements is enhanced substantially. By utilizing different shapes of middle via fence, the coupling in both the E- and H-plane placed LRA arrays is reduced significantly. The entire antenna system is very compact and simple without using additional structure. For verification, the decoupling
$1\times 2$
LRA arrays are fabricated and measured. Wide overlapping bandwidths (S
$_{\mathbf {11}} \lt -10$
dB and S
$_{\mathbf {21}} \lt -25$
dB) in both E- (16%) and H-planes (12%) are achieved. Moreover, the effectiveness of the decoupling method is also successfully validated in the
$1\times 4$
LRA arrays, showing its potential in multiple-input-multiple-output (MIMO) systems.