Filter assemblies, tuning elements and method of tuning a filter

Abstract

The present invention provides filter assemblies, tuning elements and a method of tuning a filter. A filter assembly includes a housing having a top cover, a bottom cover and at least one sidewall, the top cover, the bottom cover and the at least one sidewall defining an internal cavity, the housing configured to receive first through third radio frequency (“RF”) transmission lines; a top metal sheet mounted within the internal cavity that has a plurality of openings that form a first hole pattern; and a bottom metal sheet mounted within the internal cavity that has a plurality of openings that form a second hole pattern. The top and bottom metal sheets are vertically spaced-apart from each other in a vertically stacked relationship within the internal cavity. The top metal sheet and the bottom metal sheet each include at least one resonator.

That which is claimed is: 
     
       1. A filter assembly comprising:
 a housing having a top cover, a bottom cover, and a frame that has at least one sidewall, wherein the top cover, the bottom cover and the at least one sidewall define an internal cavity, and wherein the housing is configured to receive a plurality of radio frequency (“RF”) transmission lines; and 
 a resonator plate mounted at least partially within the internal cavity of the housing, the resonator plate comprising a first conductive layer comprising at least one resonator, 
 wherein a first type of solder having a first melting point is used to solder attaches the resonator plate to the housing frame, and wherein a second type of solder having a second melting point that is lower than the first melting point is used to solder attaches the top cover and/or the bottom cover to the housing frame. 
 
     
     
       2. The filter assembly of  claim 1 , wherein the resonator plate comprises a printed circuit board. 
     
     
       3. The filter assembly of  claim 2 , wherein the at least one resonator is attached to the printed circuit board. 
     
     
       4. The filter assembly of  claim 1 , wherein the first conductive layer comprises a plurality of openings that form a hole pattern. 
     
     
       5. The filter assembly of  claim 1 , wherein the resonator plate is soldered to the housing via a first continuous solder joint that extends around an internal periphery of the housing. 
     
     
       6. The filter assembly of  claim 1 , wherein the resonator plate is soldered attached to an internal ledge of the frame, the internal ledge extending from the at least one sidewall of the housing frame. 
     
     
       7. The filter assembly of  claim 6 , wherein the resonator plate comprises a metal border on a face of the resonator plate to facilitate soldering the resonator plate to the internal ledge. 
     
     
       8. The filter assembly of  claim 1 , wherein at least one of the top cover or the bottom cover comprises an integral tuning element. 
     
     
       9. The filter assembly of  claim 1 , wherein the resonator plate comprises a second conductive layer on a side of the resonator plate that is opposite the first conductive layer. 
     
     
       10. A filter assembly comprising:
 a housing having a top cover, a bottom cover, and a sidewall, the top cover, the bottom cover and the sidewall defining an internal cavity; and 
 a printed circuit board mounted at least partially within the housing, the printed circuit board comprising a conductive layer that comprises a plurality of resonating elements that form part of a resonant cavity filter, 
 wherein the sidewall comprises a slot, and wherein a portion of the printed circuit board extends through the slot to reside outside the housing, 
 wherein at least one of the top cover or the bottom cover comprises an integral tuning element. 
 
     
     
       11. The filter assembly of  claim 10 , wherein a phase shifter assembly is provided on the printed circuit board. 
     
     
       12. The filter assembly of  claim 11 , wherein the printed circuit board further comprises a plurality of radio frequency (“RF”) transmission lines that extend from outside the housing to inside the housing. 
     
     
       13. A filter assembly comprising:
 a housing having a top cover, a bottom cover, and a frame that includes at least one sidewall, wherein the top cover, the bottom cover and the at least one sidewall define an internal cavity; 
 a plurality of resonators in the internal cavity; and 
 a twistable tuning element that is integral with the top cover, 
 wherein at least one of the plurality of resonators includes a narrow base and a widened distal end, and 
 wherein the plurality of resonators are integral with the frame and aligned in a first plane that is parallel to a plane defined by the top cover. 
 
     
     
       14. The filter assembly of  claim 13 , wherein the bottom cover is integral with the frame. 
     
     
       15. The filter assembly of  claim 13 , wherein the top cover is attached to the frame via a continuous solder joint that extends all the way around a periphery of the frame. 
     
     
       16. The filter assembly of  claim 13 , wherein the twistable tuning element includes a first arm, a second arm and a coupling element, wherein the coupling element is configured to rotate as the coupling element is displaced into the internal cavity. 
     
     
       17. The filter assembly of  claim 16 , wherein the twistable tuning element includes a total of two or three arms. 
     
     
       18. A filter assembly, comprising; :
 a housing that defines an internal cavity, the housing comprising at least one cover and a frame; and 
 a substantially planar metal resonator plate mounted within the internal cavity, the substantially planar metal resonator plate comprising a conductive layer comprising at least one resonator, 
 wherein at least the conductive layer and a size and shape of the internal cavity are configured to achieve a pre-selected filter response, and 
 wherein a first type of solder having a first melting point is used to solder attaches the substantially planar metal resonator plate to the housing frame, and wherein a second type of solder having a second melting point that is lower than the first melting point is used to solder attaches the at least one cover to the housing frame. 
 
     
     
       19. The filter assembly of  claim 18 , wherein the substantially planar metal resonator plate comprises a printed circuit board. 
     
     
       20. The filter assembly of  claim 18 , wherein the substantially planar metal resonator plate is soldered attached to an internal ledge of the frame, the internal ledge extending from a sidewall of the housing frame.