A Broadband Coaxial Ridged Horn Antenna

The bandwidth of a circular ora rectangular waveguide can he enhanced by introducing ridges into the waveguide. In this work, ridges are introduced into the coaxial waveguide with the same intention. Simple formulae are given to calculate the cut-off frequencies of the coaxial ridge waveguide. Several set of curves are presented for the cut-off frequencies. Also, a coaxial ridge horn antenna is designed and the measured results are presented. By a multi-coaxial feed of the horn antenna dual polarization or circular polarization can be obtained without significant1y affecting the bandwidth of the antenna. The advantange of this anttenna over conventional circular or rectangular quadruple ridged antenna is that the feed points being in the same plane without any crossing, the ridge gaps can be decreased to enhance the bandwidth. Also thee power handling capability is expected in be better.