Modification of metasurface‐based CP array antenna by using cascade feed network

Abstract

In this work, a unique compact size high gain circularly polarised (CP) array antenna is proposed. The array is considered as a 2 × 2 metasurface-based CP patch antennas which fed by a cascade network. The single element consists of two different layers of substrate that metasurface layer excited by aperture slot on metallic ground layer in middle layer between metasurface cells and microstrip line, meanwhile this layer isolates destructive effects of feed lines on radiation layer. For achieving high gain at a compact size several techniques such as (i) use of broadband feed network, (ii) utilising of adjacent cells with unique structure as mutual coupling reducer, and etc. have been simultaneously applied. In order to validation of simulated parameters the proposed array has been fabricated and measured. The measurement results for the proposed compact size array antenna are the impedance bandwidth (| S 11 | <; -10 dB) of 4.22-7 GHz (49.55%), a 3-dB axial ratio bandwidth of 4.71 to 6.28 GHz (28.5%), and a peak gain of 16.57 dBic at 5.5 GHz.