Gain enhancement for low-cost terahertz fresnel zone plate lens antennas

Low-cost terahertz Fresnel zone plate lens (FZPL) antennas have been previously constructed using generic PTFE substrate with simple plated-through-hole and printed-circuit technologies. Equal and symmetric E- and H-plane radiation patterns are then obtained through the use of a complementary source technique applied to an open-ended rectangular waveguide. In this paper, we present our recent efforts in enhancing the antenna gains. By the combination of increasing the number of zones and removing the substrate in the zone regions, the antenna gain can be increased by 3.18 dB. Other gain enhancement can also be achieved by adding re-radiating elements on the rings or modifying the reflecting ground plate with a grating.