Design of a 5 GHz Reflectarray with Reduced Size Unit Cell and Extremely Low Phase Sensitivity

Abstract

This article presents a novel, compact reflectar-ray antenna operating at 5 GHz. The array consists of two types of phasing element - square ring and complementary square ring. The complementary square ring is used for the phase values that are not covered by the single ring element. The grid size of the array is 0.28 lambda x 0.28 lambda at operating frequency 5 GHz that is much smaller than the conventional periodicity 0.5 lambda x 0.5 lambda. The aim of unit cell de sign is to have a slower slope of the reflection phase graph without sacrificing the phase range of 360 degrees where in general there is a trade-off between these two goals. The maximum slope in reflection phase graph obtained here is 34 degrees/mm. The proposed array is fabricated on a low loss PTFE substrate of thickness 3.175 mm (0.053 lambda at 5 GHz) and illuminated by a horn antenna. Radiation pattern results show a very precise far-field beam with 3-dB beam-width of 7 degrees and 7.3 degrees for two principal planes respectively. The gain of the antenna is 26 dBi at 5 GHz