Compact micro strip diplexer based on resonators with adjustable frequencies

A novel small planar micro strip diplexer is presented for Long-Term Evolution (LTE) System at 1.8 GHz and 2.6 GHz. The proposed structure consist ring shaped resonators. Changing the size of the ring resonators relate to change of the resonant frequencies. These resonators and stubs decrease the size of the structures, owing to adding the inductive and capacitive effects of the structure and also used to tune coupling between resonators. The measured results show two near frequency channels (centered at 1.8GHz and 2.6GHz) with isolation more than 25 dB. The simulated and measured results are in good agreement.