Broadband antennas are described that include a quad-ridge horn inside which two different lenses are inserted creating a broadband horn-lens combination. One of these lenses is a cross-polyrod lens, formed from a pair of polyrods disposed in a crossed arrangement, each polyrod shaped in a predetermined manner. The other one of these lenses is a prolate spheroidal lens. The broadband antennas can produce, at the output thereof, Gaussian-like beams in both principal polarizations from VHF to 20 GHz. As such, the broadband antennas can be used to perform material measurements in a compact admittance tunnel. Simulation results show that directivity of quad-ridge horns can be improved using the combination of lenses of the broadband antennas. Therefore, the broadband antennas can also be of interest for far-field radiation applications.
展开▼
