A Dual- Linearly polarized Ku/K Band Reflectarray for Broadcast and Fixed Satellite Services

Abstract

A novel single layer, dual polarized dual band reflectarray is constructed by implementing independent control over each band. The downlink element in the Ku-band employs a vertical slot embedded with semi-circular rings, featuring 841 elements, and is complemented by two delay lines attached to the outer ring to ensure orthogonal polarization. The uplink element containing 841 elements is formed by 90° rotation of downlink element to avoid mutual coupling effect. The application of the degree of freedom (DOF ) technique enables the attainment of phase ranges of 720° and 840° within the unit cell for both frequency bands. Thus, the total 1682 elements etched over the Taconic TLx-09 substrate with 0.8mm thick substrate of aperture dimensions of 16.5 × 16.5 mm is designed, simulated, and fabricated for Ku and K band applications. The centre-fed reflectarray upon construction exhibits a measured gain of 26.5dB and 25.7 dB and 1dB gain bandwidth of 26.4% for Ku band and 11.7% for K band respectively. Moreover , the proposed reflectarray demonstrates a maximum aperture efficiency of 30.4 at 12.8 GHz and 19% at 23 GHz. Thus, the proposed dual-polarization reflectarray covers the downlink frequencies for the broadcasting satellite communication services like DTH connectivity and uplink frequencies for earth exploration satellite services like forecast of dangerous weather conditions like drought, heavy rain.