Dual-Band CP Metasurface-Array Antenna with Sequential-Phase Feed Network for C-Band Operation

Abstract

This paper presents a four-cluster dual-band circularly polarized (CP) metasurface (MTS)-array antenna integrated with a sequential-phase feed (SPF) network for Cband applications. The antenna is implemented on dual-layer FR-4 substrates, incorporating both big- and small-sized MTSarray elements per cluster, with a tilted square-slot ground plane and microstrip-line feed. The SPF network excites each cluster with equal amplitude and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{9 0}^{\boldsymbol{\circ}}$</tex> phase shifts, significantly enhancing return loss bandwidth (RLBW), axial ratio bandwidth, and realized gain. The simulated results demonstrate RLBW of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3.08-4.51 \text{GHz}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4.94-8 \text{GHz}$</tex>, and ARBWs of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3.08-4.66 \text{GHz}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5.27-6.42 \text{GHz}$</tex> for the lower and higher operating bands, respectively. The corresponding highest RHCP gains are 6.15 dBic at 3.8 GHz and 4 dBic at 6 GHz. The proposed antenna design achieves bi-directional radiation patterns and shows substantial performance improvements over conventional dual-band CP MTS-array antennas.