Wideband Planar Array With Broad Beamwidth and Low Cross Polarization

A design for wideband planar arrays with broad beamwidth and low cross polarization is described. The single element of the array is composed of a coaxial-cable-fed slot antenna, a shorting pin, and a planar reflector. For the single antenna, the effects of the key parameters on H-plane beamwidth and cross polarization are, respectively, studied. An optimum design is given, and both of its measured and simulated results prove that the single antenna has the characteristics of wide beamwidth and low cross polarization within an operating bandwidth of about 50%. Based on the optimum design, a 1 × 4 linear array is developed and constructed. Experimental results demonstrate that the array operating in the range from 1.7 to 2.7 GHz has a return loss of less than 13 dB, a cross polarization level (XPL) of smaller than -20 dB, and a half-power beamwidth of 100°±10° in the H-plane.