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

Abstract

This article presents a novel, compact reflectarray 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 0.28λ × 0.28λ at operating frequency 5 GHz that is much smaller than the conventional periodicity 0.5λ × 0.5λ. The aim of unit cell design is to have a slower slope of the reflection phase graph without sacrificing the phase range of 360° where in general there is a trade-off between these two goals. The maximum slope in reflection phase graph obtained here is 34°/mm. The proposed array is fabricated on a low loss PTFE substrate of thickness 3.175 mm (0.053λ at 5 GHz) and illuminated by a horn antenna. Radiation pattern results show a very precise far-field beam with 3-dB beamwidth of 7° and 7.3° for two principal planes respectively. The gain of the antenna is 26 dBi at 5 GHz.

Modern Reflectarray Antennas: A Review of the Design, State-of-the-Art, and Research Challenges

“…A phase shift of 320˚ is obtained during the FDF, so a spiral dipole is constructed and tuned, and a full phase shift of 360˚ is obtained, resulting in the SDF. In [94], the phase range is obtained by using an element that has two degrees of freedom. The phase range is obtained by varying the length of the square ring and adding a complementary square ring, and by varying the size of the square ring, the necessary phase range is obtained.…”

Wideband reflectarray antenna using logarithmic patch element

“…Furthermore, recently reported some reflectarray antennas using sub‐wavelength unit‐cell, with size less than 0.5λ 0 , to realize more than 50% aperture efficiency. For example, in Reference 26, a reduced sized unit‐cell (0.28λ × 0.28λ) including square ring and its complementary structure is used to design a compact reflectarray with aperture efficiency of 58% at 5 GHz. To describe the performance improvement of the designed RA, based on the proposed element, Table 2 compares the characteristics of the presented RA and some previous works which used PDLs to adjust the phase of element.…”