A Novel Single-Layer Unit Structure for Broadband Reflectarray Antenna

• Published in: IEEE antennas and wireless propagation letters Vol. 16; pp. 681 - 684
• Main Authors: Han, Chunhui, Zhang, Yunhua, Yang, Qingshan
• Format: Journal Article
• Language: English
• Published: IEEE 2017
• Subjects: Antenna measurements; Bandwidth; Bandwidth enhancement; Broadband antennas; Broadband communication; Feeds; Gain measurement; phase-delay lines; reflectarray antenna; Reflector antennas; single-layer unit cell
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2016.2598733

A novel X-band single-layer unit-cell structure with enhanced bandwidth for linearly polarized microstrip reflectarray antenna is proposed. The unit-cell structure is composed of two circular rings, each with a pair of gaps that are orthogonally placed, and two identical phase-delay lines attached to the outer circular ring. With this novel structure, a linear phase response ranging about 550° is achieved by varying the length of the phase-delay line. An offset-fed reflectarray antenna composed of 277 elements forming an octagon-shape aperture is designed, fabricated, and measured to verify the broadband characteristic of the proposed unit cell. Measurement results show that 20% 1-dB gain bandwidth is realized. Moreover, the maximum gain at 10 GHz is about 26.38 dBi, which means about 51.3% efficiency is achieved. At the same time, the sidelobe level and cross polarization for E-plane are also measured which are below -17.5 and -26 dB, respectively.