A Wideband Reconfigurable Reflectarray based on Aperture Coupled Delay Line

This paper presents a unitcell configuration for a wideband beam-steering reflectarray (RA). A rectangular patch is designed that is coupled through an H-shape slot to a spiral delay line. The substrate of the delay line is designed with Liquid Crystal (LC) layer. By applying a bias voltage between the delay line and slot-loaded ground plane, the permittivity of LC can be changed, and the concomitant change of electrical length can provide over 300 phase shift in a wide frequency range. The LC layer thickness is also reduced to 0.0042 lambda to improve the beam-steering speed. To overcome the issue of complex basing voltage implementation and still achieve a focused beam, a hybrid phase compensation for 1D beam-steering is proposed. The simulated results show that the main beam of the RA can be steered to +/- 60 and the maximum boresight gain reaches 19.5 dBi with 32% 3-dB gain bandwidth.