A Novel LTCC UWB Bandpass Filter Based on DGS and Semi-lumped Structure

In this paper, a novel UWB bandpass filter based on LTCC technology is proposed. The filter combines semi-lumped highpass structure and DGS. Firstly, A highpass filter using semi-lumped structure is implemented, which is the cutoff frequency of 3. 1GHz. Secondly, combined with DGS to produce the stopband in the high-end, the bandpass filter of 3. 1 ~10. 6GHz is designed and the final size is only 3. 2mm′1. 6mm′1. 2mm. The test results of the UWB filter as follows: insertion loss<1. 5dB, return loss<12dB, group delay<0. 8ns, attenuation>15dB (11. 5 ~ 17GHz). Good agreement is achieved between simulation and measurement results. Because the filter has the advantages of small size, low insertion loss, small group delay and simple structure, it is easy to control the bandwidth and center frequency. And the relative bandwidth can be more than 150%, which is particularly suited for the frequency selection of the extremely broadband communication system.