Design of a novel ultra‐wideband dual‐polarized printed planar antenna

Abstract

A novel antenna, which has a simple one-layer printed planar structure with dual-polarization and ultra-wideband (UWB) properties, is proposed in this article. The proposed antenna consists of a pair of crossed dipoles, two stacked square loops, four meander slots, and a hornlike reflecting cavity. The stacked loops positioned around the crossed dipoles are utilized to introduce a new resonant mode in the lower frequency band, which essentially widens the impedance bandwidth and realizes the miniaturization design. To further enhance the impedance bandwidth, the four meander slots are cut from the crossed dipoles to generate a new resonant mode in the higher frequency band. Therefore, the impedance bandwidth is greatly expanded. A hornlike reflecting cavity is used to enhance the unidirectional radiation pattern over the operating frequency band. A prototype is designed, fabricated, and measured. Measured results show that the proposed antenna achieves a voltage standing wave ratio (VSWR) < 2, impedance bandwidth up to 92% (from 1.05 to 2.85 GHz). The isolation between two linear orthogonal polarizations >25 dB, and stable unidirectional radiation patterns over the entire working frequency band with gain >8 dBi. Furthermore, the proposed antenna has a compact planar size of 0.25 λ L × 0.25 λ L ( λ L is the longest operating wavelength).