Improvement of out-of-passband characteristics for a laminated chip bandpass filter using tapped resonator

This paper presents how a tapped resonator can be used to improve out-of-passband characteristics and as an example, a laminated chip bandpass filter using tapped resonators is designed and fabricated with silver paste and high permittivity multilayer ceramic in the MgTiO/sub 3/ and CaTiO/sub 3/ system. Its size is 2.5 mm/spl times/2.0 mm/spl times/0.95 mm. The measured frequency characteristics of the fabricated filter are presented and compared with the simulated ones. Using the tapped resonator, the filter exhibits excellent out-of-passband performances suitable for wireless LAN and Bluetooth applications.