In this chapter, a novel method of designing a microwave diplexer circuit is presented. This technique involves merging a section of a dual-band bandpass filter (DBF) with a section of two separately designed bandpass filters (BPFs). The chapter covers the step-by-step procedures that informed the successful realization of the diplexer circuit model. The circuit model coupling arrangement, simulation, and results are also covered. The diplexer circuit developed here has been simulated using the Keysight ADS circuit simulator. The results presented show a very good isolation between the transmit and the receive bands of the diplexer circuit.
