An FBAR‐ and LTCC‐based RF front‐end module for Wi‐Fi and WiMAX dual‐mode systems

A compact quad‐band RF front‐end module (FEM) is proposed for Wi‐Fi and WiMAX dual‐mode systems using film bulk acoustic resonator (FBAR) and low temperature co‐fired ceramic (LTCC) technologies. The quad‐band RF FEM consists of three LTCC bandpass filters, two diplexers, one FBAR filter, two single‐pole‐double‐throw switches, and one single‐pole‐four‐throw switch. The diplexers with the bandpass filters for each mode are fully embedded in the LTCC substrate, whereas the FBAR filter and three RF switches are placed on top of the substrate. The measured performance of the embedded diplexers with the bandpass filters is compared to the simulated one, resulting in good agreement between both performances. The implemented quad‐band RF FEM provides relatively low insertion loss with high attenuation at other passband for each mode. The overall size of the module is 6.0 mm × 5.0 mm with a substrate thickness of 0.6 mm.