A Dual-Polarized 2-D Monopulse Antenna Array for Conical Conformal Applications

A dual-polarized 2-D monopulse conical conformal antenna is proposed in this article. First, a method for implementing dual-polarized monopulse beams is presented. A novel array arrangement and a dual-polarized monopulse comparator suitable for conformal arrays are developed. Then, a wideband endfire element based on the double rhombic dipole is designed with directors and a reflector to obtain a stable high-gain endfire radiation. A conformal feeding network consisting of four rat-race couplers is employed to excite four conformal elements. The sum and difference beams of horizontal and vertical polarizations are realized on the azimuth and elevation planes. To verify the design concept, a prototype of the antenna array was designed, fabricated, and measured. The experimental results show that the proposed monopulse array achieves a shared bandwidth of 22.2% from 8.96 to 11.2 GHz on four ports, with the sum-beam gain of 9-11 dBi, the difference-beam gain of 5.8-7.7 dBi, and the null-depth of around -25 dB. To the best knowledge of the authors, the design concept of combining dual-polarized 2-D monopulse array with conical conformal antenna is proposed for the first time, which is a promising candidate as target detection and tracking antennas for various aircraft applications.