Broadband slot arrays with wide H-plane beamwidth

Designs of 1 × 4 vertically polarized arrays with wide beamwidths are described. The array is composed of two pairs of monopole slot antennas, and each pair is excited with a differential feed scheme to reduce cross polarization. In addition, a rectangular metallic box is introduced as a reflector of the array to generate different beamwidths and improve front-to-back ratios. From the simulated results, it is found that by tuning the dimensions of the metallic box, the H-plane half-power beamwidth of the array can be varied between 90° and 180°. For each beamwidth case, the 10dB-return-loss bandwidth (BW) of the array can cover the band from 1.7 to 2.7 GHz; moreover, a cross polarization of lower than −20 dB, a front-to-back ratio of higher than 15 dB, and a beamwidth variation of <10° are also realized within the impedance BW. An experiment is also carried out to validate the simulation.