Filtering Lens Structure Based on SRRS in the Low THZ Band

A flltering lens for conical horns based on Metamaterials is presented. The paper focuses on a millimeter wave application. The metamaterial structure is composed of a printed layer of Split Ring Resonators (SRRs) on a substrate. The structure is used as a superstrate on the horn aperture. When the SRRs are excited, a fllter performance arises preventing radiation in the desired frequency bands. Besides the flltering property, also a lens behavior is achieved. In this way larger gain can be achieved in both E and H planes, reducing the 3dB beamwidth. A 6% i3dB stop band is achieved from 73.3GHz to 85.7GHz. Symmetrisation of the radiation pattern up to 3dB is accomplished and the focalization efiect is achieved by emulating a hyperbolical-plane lens. Thus, a simplifled system based on a conical horn can be designed by unifying the fllter and lens in one electromagnetic element.