Dual circularly polarized dual-band antenna combining transmitarray and reflectarray for K/Ka-band uplink and downlink satellite communication

This paper presents a dual-band antenna system utilizing transmitarray (TA) and reflectarray (RA) having dual-circularly polarized (CP) characteristics for K/Ka-band satellite communication. The antenna consists of the TA and RA surfaces operating at 19.5 GHz and 29.7 GHz respectively. The RA is designed on a single substrate layer with element size of $ 0.30 \lambda \times 0.30 \lambda $ 0.30λ×0.30λ (λ corresponding to 30 GHz), whereas the TA is designed on two substrate layers with element size of $ 0.33\lambda \times 0.33\lambda $ 0.33λ×0.33λ (λ corresponding to 20 GHz). The equivalent circuit model (ECM) of the TA and RA elements is extracted to validate the working of the proposed elements. A small window of the size of a patch antenna is cut in both the RA and TA surfaces to accommodate the coaxially-fed illuminating sources. The antenna shows the peak gain of 17 dBiC at 19.5 and 29.7 GHz. The 3 dB axial ratio bandwidths range from 19.3–19.6 GHz (1.55 $ \% $ %) and 29.5–29.9 GHz (1.35 $ \% $ %) in the two frequency bands. The antenna radiates two orthogonally polarized CP waves at two frequency bands which makes the antenna suitable for satellite communication applications.