US Patent 7636025 Low-rise duplexer

A duplexer that includes an input filter (Rx filter), an output filter (Tx filter), and one or more of an isolation line and a delay line is disclosed. The Rx and Tx filters are microwave (MW) resonators and include continuous, internally metallized holes in a ceramic body. The ceramic body includes a metal coating substantially covering the external surfaces of the ceramic body except for an end face and one or more recesses on a bottom side of the ceramic body. An output of the Rx filter on the bottom side of the ceramic body is electrically connected to a balun. The ceramic body has a first height in an area of the Tx filter and a second height in an area of the Rx filter, the second height being less than the first height.