Design of Compact Bandpass Filter Using Transformer-Based Coupled Resonators on Integrated Passive Device Glass Substrate

This paper presents a transformer-based coupled resonator structure for a bandpass filter (BPF) using the integrated passive device technology on a glass substrate. The use of such a transformer-based coupled BPF not only provides the advantage of compact size but also creates extra transmission zeros to enhance the roll-off rate or the desired stopband rejection. The measured results verify the validity of this design methodology and show good agreement with the simulated results. For demonstration purposes, two example filters are designed and implemented. Both good performance and miniaturization are achieved for the proposed filters, and the expected transmission zeros are observed.