Achieving Continuous Stable Beam Steering with Gain Enhancement Using a Graded-Index Metasurface Lens

Abstract

In this paper, the design of an ultrathin highly transmissive angular graded-index metasurface (AGIMS) lens is proposed, and a beam steerable high-gain low-profile lens antenna is designed using AGIMS lens and microstrip patch antenna (MPA) radiator operating at 10.10 GHz. An ultrathin graded-index metasurface lens is designed using fundamental unit cells and their modulated forms. The direction and gain control of the microwave radiator’s beam, using a designed modulated metasurface lens with doubled-sided double circular ring resonator as a fundamental unit cell, is presented. The uniform radial and linear movement of AGIMS in the step of 12 mm steer the radiated main beam of MPA continuously in a conical plane from −40° to +40° with a maximum measured broadside gain of 13.15 dBi and minimum broadside gain of 11.80 dBi at 10.10 GHz frequency, indicating maximum and minimum gain enhancement of 8.40 and 7.0 dB in −40° and 0° direction, respectively. The angular movement of AGIMS over the MPA radiator at the centre point results in beam steering from −25° to +25° continuously with a maximum gain variation of 2 dB and a maximum measured gain from 10.00 dBi to 12.00 dBi, indicating gain enhancement of 5.25 dB to 7.25 dB. Using AGIMS, the stable broadside radiation characteristic with beam steering and continuous gain enhancement is achieved. The measured and simulated results are in good agreement. © 2022 IETE.