Dual-Band Open-Ended Waveguide Feeder Antennas With Collinear Feed Design

This communication presents two classes of dual-band open-ended circular waveguide antennas with a compact collinear end-launcher-type feed design. The proposed antennas consist of an open-ended circular waveguide, radial cavities, and resonators. The collinear feed is connected to the body of the circular waveguide, providing a high power-handling capability. The proposed structures can generate a mixed mode close to TE11 on the aperture of the open-ended waveguide in both bands. As a result, stable broadside gains over each band of interest are achieved for both antennas. The proposed antennas are good candidates to be used as feeder elements in several high-gain antennas such as bull's eye antennas, surface-wave antennas, and metasurface antennas.