Design of Bandpass Filter with Four Transmission Zeros Based on GaAs IPD

To solve problems such as the excessive size and low integration of traditional bandpass filter, this paper proposed a miniaturized bandpass filter. ADS software was used to optimize the filter circuit, and four transmission zeros were added at the stopband to increase the attenuation based on cross coupling. The GaAs-based integrated passive devices (IPD) was utilized to model and simulate the filter structure via HFSS software. The simulation results showed that the center frequency of the proposed filter was 6.6GHz, with an insertion loss of 2.1dB. The relative bandwidth of 3dB was 18%. The stopband attenuation within the range of 0-3.1GHz was greater than 50dB, and the stopband attenuation in 9-15GHz was greater than 25dB. In addition, the overall size was only at 1000μm*1300μm*111.96μm. The return loss in the passband was generally better than 15dB.