A new circuit configuration to obtain large attenuation with a coupled-resonator band elimination filter using laminated LTCC

A new circuit configurations of Band Elimination Filter (BEF) has been invented to recover the attenuation, which was degraded due to the coupling between resonators. The technique of forming an attenuation pole with the laminated planar filter was applied to suppress the influence of coupling. The simulation and the experimental results show that a large attenuation can be obtained by this new configuration. Thus, the very compact BEF's are realized with laminated Low Temperature Cofired Ceramics (LTCC). They are very suitable for next-generation portable telephones.