Dual-Port RHCP Compact Antenna at 868 MHz Using a 120^∘ Hybrid Coupler

This work presents the design of a compact dual-port circularly polarized antenna based on new coupler topology. The can radiate right-hand circular polarization (RHCP) in two opposite directions depending input port. In proposed structure, radiating system has three inverted F antennas connected to 120∘ hybrid coupler. modeling and 5-ports are described experimentally validated. prototype is fabricated using 1.6mm thick low-cost FR4 Epoxy substrates assembled with metal wires, dimension 80mm × 12mm (ka < 0.74). provides realized RHCP gain 2.4 dBic 1.8dBic at 868 MHz for Port 1 2, respectively.