A Novel Compact Monopulse Patch Antenna Array

In this paper, the authors proposed a new technique to generate the sum-difference pattern using a circularly polarized microstrip patch antenna array. The individual truncated corner elements are left-handed circularly polarized and resonate at 12.5 GHz. To achieve the high gain, the $2\times 1$ array is designed using a uniform power divider. In the proposed 4-port structure, the sum pattern in elevation and azimuth planes can be achieved by exciting the ports. In order to achieve the difference pattern in both planes, left and right side $2\times 1$ arrays are placed in the opposite direction to each other along the x- and y-axis. At 12.5 GHz, the sum and difference patterns gain are 10.20 and 10.40 dBic, respectively, in elevation and azimuth planes. In addition, a low sidelobe level, as well as a null depth of −45 dB for difference patterns, are achieved in both planes. The proposed compact single-layer structure is applicable for monopulse tracking applications.