The Design of a High Gain Dual-Polarized Quad-Ridged Circular Horn Antenna for Wideband EMC Test Applications

This paper presents the design of a high gain broadband quadruple-ridged circular horn antenna for Electromagnetic Compatibility (EMC) testing. The proposed antenna contains a wideband feed structure as a transition between coaxial line and quad-ridged circular waveguide behind the conical horn antenna. The wideband matching between impedances at the apertures of the feed and the horn is achieved with a tapering at the flare section along the horn length, which is obtained after a detailed investigation of various tapering profiles. The antenna is designed to operate in horizontal and vertical polarizations (dual linear polarization) simultaneously in EMC tests. This implementation is found to present a return loss greater than 10 dB, isolation level higher than 28 dB, high-gain (minimum 13.6 dBi) and low-gain variation of 4.5 dBi within the frequency range of 1-6.75 GHz (6.75:1 bandwidth) at both polarizations, which is a desired feature in radiated emission and immunity tests.