A planar triplexer based on substrate integrated waveguide technology for TD-SCDMA applications

In this paper, a planar triplexer based on the substrate integrated waveguide (SIW) technology for TD-SCDMA applications is proposed. The triplexer consists of three inductive window SIW bandpass filters, operated at bands of 1.88GHz-1.92GHz, 2.01GHz-2.025GHz and 2.3GHz-2.4GHz, respectively, and an optimized matching circuit. Moreover, by introducing a stepped-impedance microstrip lowpass filter, the spurious passbands can be effectively suppressed. The proposed triplexer is fabricated with standard printed circuit (PCB) process. The measured isolation is below -40dB in the designed bands, and moderate insert loss and good return loss are also obtained. All the performances presented in this paper demonstrate the proposed triplexer a promising candidate for TD-SCDMA applications.