Dual‐band, dual‐polarised metallic slot transmitarray antenna

Abstract

A metallic, dual-band, dual polarised slot-based transmitarray antenna is presented. The antenna consists of three thin metallic layers do not use any dielectric substrates, with air gaps in between the layers. The unit cell uses interleaved orthogonal slots, as well as crossed-dipole slot and uniplanar compact photonic bandgap slot elements to provide the lower and upper frequency band resonators, respectively. The frequency separation between the two resonances can be adjusted from closely spaced to far from each other. The antenna provides dual linear polarisation and circular polarisation with the use of the appropriate feed. The fabricated transmitarray antenna provides two independent frequency bands with a band ratio of 1.13 and low mutual coupling. The measurement of a 14 × 14 element transmitarray antenna at 11 GHz shows a maximum gain of 23.74 dB with -1 dB gain bandwidth of 6.8% and aperture efficiency of 38%; at 12.5 GHz, a maximum gain of 24.45 dB is obtained with -1 dB gain bandwidth of 5.4% and aperture efficiency of 34.6%. The antenna is simulated by using the CST software; the ADS package is used for equivalent circuit simulation.