Proof of Concept Low-Loss Reconfigurable Reflectarray for Beam Steering

This paper presents a low-loss reconfigurable reflectarray (RA) design in the X-Band. It has been observed in the literature that the majority of the reconfigurable RAs are operating at the lower frequency bands (less than 5 GHz). This work is based on stretching the string towards the higher frequency bands and observing the performance of reconfigurable RAs in various aspects. An X-Band low-loss, and compact reconfigurable RA is investigated. A varactor loaded aperture coupled element is used to achieve the phase tuning agility. The element is designed by dividing the transmission line (TL) into two parts, and electronically connecting them through a single surface mount Hyper abrupt varactor diode. The proposed element exhibits 265° dynamic phase tuning ability. The element is a square of length 15.6mm (0.6 × λ at 10.5 GHz). A biasing network is also designed to isolate the RF signal from the DC. An equivalent circuit model is verified with the full-wave analysis. A reconfigurable RA of 3 × 3 elements is designed, and its ability to ±45° dynamic beam steering is evaluated for center-fed and offset feeding method. The proposed RA exhibits good potential in electronically steering the beam within ±40° with a scan loss of 4.5 dBi (from broadside), with both feed method (@ 10.5 GHz).