Design of compact six-channel diplexer using crossed resonators

This paper reports a compact six-channel diplexer using crossed resonators. The crossed resonator is theoretically analyzed and proved to be able to resonate at three different frequencies. At the same time, by properly choosing the parameters of the crossed resonators, each frequency of crossed resonator can be controlled easily. Based on this, a six-channel diplexer is easily realized by the connection of two tri-band bandpass filters using crossed resonators. Moreover, because of using crossed resonator, the size of the diplexer is compact. To illustrate the concept, a six-channel has been designed, fabricated and measured. Simulated and measured results are found to be in good agreement with each other.