A narrow‐band circularly polarized leaky‐wave antenna with open stopband suppressed

Abstract

In this paper, a narrow-band circularly polarized (CP) microstrip leaky-wave antenna (LWA) with open stopband suppressed is proposed. Coupled meandered slow-wave lines are adopted to realize narrow-band beam scanning. The asymmetric elements are employed as radiators to realize CP and zero-crossing scanning. We modulated the antenna by loading the ground inductance and asymmetric capacitors on the meandered slow-wave transmission line. The antenna consists of ten asymmetrical structural elements connected by coupling, the antenna size of L × W is 170 mm × 25 mm. In the operating band of 8.1 to 8.5 GHz, the measured scanning angel of the fabricated antenna is from −31°to +6°. The antenna axial ratios (ARs) are all below 3 dB at the corresponding beam directions. The gain is above 9.1 dBi and the relative bandwidth is only 4.8%. In the operating band, the radiation efficiency is above 60%. It has potential applications in radar detection and wireless communication systems for its simple and low-profile structure with CP, beam-scanning, and narrow-band performance.