| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a tunable RF filter. <P>SOLUTION: The filter includes: a signal transmission path having an input and an output; a plurality of resonant elements disposed along the single transmission path between the input and the output; and a plurality of nonresonant elements coupling the resonant elements together. The resonant elements are coupled together to form a stopband having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements and at least one sub band in the stopband. The nonresonant elements comprise at least one variable nonresonant element for selectively introducing at least one reflection zero within the stopband to create a passband in one of such sub bands. The variable nonresonant element may be configured for displacing the reflection zero along the stopband to selectively move the passband within the sub band or within selected sub bands. <P>COPYRIGHT: (C)2013,JPO&INPIT |
