Electronically tunable LTCC based multi-layer filter for mobile handset application

A novel tunable bandpass filter for mobile handset application is reported. Combline topology has been used for this filter and it has been implemented in LTCC multi-layer technology for small size. The filter can be tuned over DCS, PCS, and UMTS bands used in mobile communication without degrading the response. It has less than 4.3 dB insertion loss over the entire tuning range and has a small foot print. Simulated and measured responses of the filter show good correspondence.