Patent ID: 8154363

Claim:
A phase cancellation circuit for a cavity filter comprising: a sampler loop assembly operatively arranged to receive an input signal to said cavity filter; a variable signal insertion loop assembly connected to said sampler loop assembly by a cable, wherein said variable signal insertion loop assembly is operatively arranged to transmit an output signal from said cavity filter; wherein said sampler loop assembly samples a cancellation signal at a desired isolation frequency from said input signal and transmits said cancellation signal to said variable signal insertion loop assembly via said cable; and, wherein said cable has a length, and said length is equal to a multiple of a half-wavelength at said desired isolation frequency, wherein said cancellation signal undergoes a 180° phase shift by traveling through said cable, wherein said variable signal insertion loop assembly combines said cancellation signal with said input signal, wherein said 180° phase shift cancels said input signal at said isolation frequency for creating said output signal, and wherein said output signal substantially resembles said input signal but with a notch at said desired isolation frequency; wherein said sampler loop assembly comprises: a bulkhead connector for receiving said input signal; a connector block secured to said bulkhead connector, wherein said connector block is hollow and includes an aperture for enabling insertion of said cable into said connector block; a loop ring secured to said connector block opposite from said bulkhead connector; and, a loop extending out of said connector block, wherein a first end of said loop is affixed to a center pin of said bulkhead connector and a second end of said loop is grounded to said loop ring.