Optimum Design of a Novel Electronically Reconfigurable Reflectarray Antenna for X/Ku Band Applications

The frequency reconfigurable reflectarray (RRA) reported in this paper provides a pencil beam at three frequencies captivating the need for satellite broadcast television at uplink and downlink frequencies in Ku band and X band. To achieve such frequency reconfiguration, a unit cell developed and simulated based on an infinite array approach is used in integration with four PIN diodes to produce a reflection phase variation of 525°, 415°, and 308° at 14.34 GHz for uplink operation, 12.2 GHz for downlink and 11.9 GHz for X-band performance respectively. In this proposed unit cell, the phase variation for uplink is achieved by varying the size of concentric loops, while in the case of downlink and X-band, reconfiguration controlled by pin diodes is achieved by varying the length of the delay line. With the periodicity of 0.49λ0 (10.5 mm), a 15 15 array with 225 elements is constructed using the designed unit cell on square planar geometry. The paper reports a maximum gain of 25.77 dBi, 25.13 dBi, and 22.7 dBi and 40.22%, 26.46%, and 25.36% of aperture efficiency at 14.34 GHz, 12.2 GHz, and 11.9 GHz respectively. A -3dB gain bandwidth of 8.37%, 4.92%, and 12.18% is achieved at the three operating frequencies by simulation. Hence this reconfigurable reflectarray serves as an emulous alternative to parabolic reflectors and phased array antennas in deep space communication and direct broadcast satellite applications satisfying the high gain pencil beam requirements.