Mutual Coupling Reduction between elements of Dual-polarization Phased Array Antenna for Weather Radars

In this paper, a novel uni-planar EBG structure is proposed for improving isolation between two adjacent, aperture coupled stacked microstrip antenna elements that are dual linearly polarized and are designed to work in the frequency range of 2.75 to 3.12 GHz. The EBG is used to reduce surface wave coupling and is characterized using waveguide-based direct transmission method and dispersion analysis to determine the band gap frequency. The characterization of EBG also involves the simulated surface current on adjacent elements before and after using EBG to determine its effectiveness. The simulations show that the antenna elements along with the EBG result in mutual coupling suppression of 8 dB and 4 dB for V and H-polarizations, respectively while keeping the cross-polarization level for V- and H-polarization below −47dB. This design when used in a phased array antenna results in an increase in the scan angle range of 5-12
^o
. The increase in scan angle is determined using the active reflection coefficient.