A diplexer based on transmission lines, implemented in LTCC

This paper presents a diplexer circuit based on transmission lines. In comparison with other diplexer circuits, the implementation of the proposed diplexer can be easily done on single- as well as multilayer substrates. An implementation example of the presented circuit will be discussed for a global system for mobile communications/digital cellular system (GSM/DCS) application. The diplexer is implemented in a multilayer substrate, using low-temperature cofired ceramics (LTCC) technology. Finally, the simulation results will be compared with the measurements, and it will be shown that they agree excellently. These results and the results out of a sensitivity and yield analysis confirm the excellent behavior of the proposed circuit.