Compact Three-Port Integrated-Antenna-Filter Modules

In this letter, two novel three-port integrated-antenna-filter (IAF) modules are proposed. The idea of the IAF is elucidated with two configurations that consist of different combinations of narrow- and wideband microstrip/slot resonators. The return loss, mutual coupling, input impedance, radiation pattern, and insertion loss of the proposed configurations are analyzed. It was found that the mutual coupling between the antenna and filter parts of the IAF is very small; therefore, the two parts can be designed almost independently. As the three-port IAF module is compact and cost-effective, it should be useful for miniaturizing the circuit size of system-on-package (SOP) devices.