An Open Boundary Quad-Ridged Horn Antenna Operating at 1-18 GHz

A dual-polarized open boundary quad-ridged horn antenna operating at 1-18 GHz is presented. The antenna consists of a coaxial-line to ridged-waveguide transition, a conical cavity, and a quad-ridge with an open boundary. By introducing a metal tapered ridge composed of exponential and elliptic sections, a conical cavity, the proposed antenna achieves stable unidirectional radiation and good impedance matching. The simulated results reveal that the impedance bandwidth of VSWR <; 2.2 is from 1 to 18 GHz. The proposed antenna has stable radiation patterns, high isolation, and low cross polarization over the whole frequency band.