Quasi-TEM H-plane horns with wideband open hard sidewalls

Quasi-TEM H-plane horn is usually designed with hard sidewalls to achieve uniform field distribution, but the hard walls limits its bandwidth. Here, open side walls based on the ridge gap waveguide are used to generate the hard walls. The concept is demonstrated numerically by an initial study on an H-plane sector horn. The horn achieves wider bandwidth than dielectric-loaded hard sector horns and has higher gain than normal smooth metal wall sector horns of the same aperture size and length.