A Dual Linear Polarization Highly Isolated Crossed Dipole Antenna for MPAR Application

Abstract

The design of a dual-polarization antenna with high isolation between ports has always been a challenge in the antenna community. To overcome this issue, a pair of printed collocated bent dipoles with a unique excitation method, is introduced in this letter. A balun and parallel transmission line are concurrently designed for multifunction phased array radar in the frequency bandwidth of 2.7–3 GHz. To maximize the polarization purity of the antenna and eliminate the parasitic radiation of the balun, the radiating element is isolated from the balun by a set of ground planes. A better than 10-dB return loss and a measured port-to-port isolation of 52 dB over the whole bandwidth are achieved. The cross-polarization pattern remains 40 dB below the copolarization peak in the principal planes. Having a compact geometry, the proposed antenna can readily be extended to form an array.