Hybrid waveguide/coaxial feeder for dual-pol Fabry-Perot cavity antennas radiating omnidirectional TM/TE waves
A hybrid waveguide/coaxial transverse magnetic (TM)/transverse electric (TE) launcher is proposed as a feeder for planar Fabry-Perot (FP) cavity antennas radiating omnidirectional beams. The structure is based on a pair of nested coaxial cables. The inner coax (TM launcher) operates on the standard TEM mode and feeds a vertical probe protruding into the antenna cavity through the ground plane. The outer coax (TE launcher) operates on the TE01 mode excited by an aperture-coupled rectangular-waveguide feeding network.