Filtenna array design via a lossy coupled-resonators filter approach

The synthesis of an antenna array with filtering capabilities is approached by developing a model suitable for a coupled-resonators description. A redefinition of the relevant quantities is introduced, leading to enforcing prescribed input admittance and far-field “voltage gain” in the desired direction versus frequency. Synthesis is then carried out by a lossy transversal network, to which conventional coupling-matrix transformations can be applied to alter the topology. Additionally, assuming antennas exhibit a uniform quality factor, a class of synthesizable transfer functions is identified, although with trade-offs among in-band return loss and gain flatness. A 20 GHz simulated patch example validates the technique.