High-Q TE01 mode DR filters for PCS wireless base stationsIEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 46, NO. 12, DECEMBER 1998 2493 High- TE01 Mode DR Filters for PCS Wireless Base Stations Ji-Fuh Liang, Member, IEEE, and William D. Blair, Senior Member, IEEE Abstract― This paper presents the state-of-the-art of highTE01 mode DR cavity lters for PCS wireless base station applications. In order to have TE01 mode lter to be competitive with other high- cavity technologies, employment of nonadjacent coupling to implement advanced lter features and easy lter machining and integration are essential. The quadruplet and trisections are regarded as basic blocks to implement symmetric and asymmetric transmission zeros in lter stop band. The relative alignment of the magnetic mode eld across the coupled adjacent cavities is analyzed to id……