Wide scan phased array patch antenna with mutual coupling reduction

Abstract

A simple technique to reduce the mutual coupling between patch antenna arrays is proposed. Mutual coupling phenomena in patch antenna array are investigated and according to the coupling characteristics, a simple rectangular slot(s) placed in between the patch elements is proposed. An equivalent circuit of the proposed structure is obtained through the reciprocity method. In the proposed technique, the series equivalent circuit of the slot is used to reduce the mutual coupling level without changes to the back lobe as well as cross-polarisation levels compared to conventional arrays. The mutual coupling reduction is >20 dB when compared with the conventional array. Applied to a phased array antenna, the reduction in the mutual coupling results in a wider scan range, up to 75°. A parametric study is carried out for different parameters of the slot that affect the mutual coupling and the scan range. A prototype of the antenna array is fabricated and the measured results are compared to the simulation.