Compact shared-aperture antenna for L/S/C-band with dual-band broadband and multi-polarization capability

This paper presents a broadband dual-band multi-polarized shared-aperture antenna for wireless communication systems. The proposed design achieves significant bandwidth enhancement through strategic structural modifications: loading L-shaped microstrip stubs on the low-band dipole (LBA) and embedding crossed microstrip structures combined with parasitic elements in the high-band dipole (HBA). This innovative configuration successfully expands the operational bandwidth from 820 MHz to 1730 MHz in the low-frequency band (representing a 34.8% increase) and from 1600 MHz to 2650 MHz in the high-frequency band (a 22.4% improvement), while simultaneously enhancing overall performance. The simulation results demonstrate excellent impedance matching characteristics with simultaneous improvement in gain stability. The performance of the shared-aperture antenna is analyzed under two different arrangements of the HBA and LBA. A decoupling method is proposed, utilizing an ultra-wideband frequency selective surface (UW-FSS) to reduce cross-band coupling between antennas and restore radiation performance through pattern compensation. Additionally, copper rods are introduced to achieve impedance matching for the shared-aperture antenna. Experimental results demonstrate that the antenna covers 1.42–3.14 GHz (75.4%) and 3.85–6.49 GHz (51.1%), with peak gains of 9.4 dBi and 9 dBi for the LBA and HBA, respectively, while maintaining stable radiation patterns. The proposed antenna effectively operates across the L/S/C bands.