A Novel Filtering Antenna with Transversal Coupling Topology

A novel structure of filtering antennas, termed as "transversal filtering antenna" (TFA), is introduced in this paper. Different from traditional filtering antennas which employ the ladder filtering structure, TFA employs a transversal coupling topology. Compared to traditional filtering antennas in which only the final stage of the filter antenna is radiating, one important advantage of TFA is that all the resonators in TFA will be radiating simultaneously. By controlling the excitation and radiation behaviors for each radiator, filtering response can be achieved for both S parameters and antenna gain. Flexible control of bandwidth and sharp roll-off of antenna gain can be achieved by using TFA. These novel characteristics bring some very promising possibilities for filtering array antennas designs. To demonstrate the validity of this novel topology, several design examples are presented. One prototype is designed, fabricated, and measured, and the measurement results agree well with the simulations.