An S- and V-Band Dual-Polarized Antenna Based on Dual-Degenerate-Mode Feeder for Large Frequency Ratio Shared-Aperture Wireless Applications

An S-/V-band dual-polarized antenna is proposed for large frequency ratio shared-aperture wireless applications, which includes a 2.4 GHz patch and a structural-reused 60 GHz substrate integrated waveguide (SIW) parallel-plate orthogonal long-slot array. A dual-degenerate-mode feeder including a circular waveguide and a coaxial cavity is designed to excite the developed S-/V-band shared-aperture dual-polarized antenna. Two degenerate dominant modes of the circular waveguide and a 180 degrees hybrid junction with five ports are used to realize the dual-polarized differential feeding at V-band. By the use of this differential feeding method, the beam direction of the V-band long-slot array antenna is unchanged with the frequency. Two degenerate high-order modes TE1 1,1,0.51 and TE1,1,0.52 of the coaxial cavity are used to realize the dual-polarized feeding at S-band. Two SMA connectors for two orthogonal-polarized feeding are placed at their respective electric field minimum points to increase the isolation between input ports. Finally, the dual-band dual-polarized antenna is fabricated and measured.