Coaxial rf dual-polarized waveguide filter and method

Abstract

Polarization-preserving microwave RF filters having multiple resonators that are each operable for different Q factors for setting overall bandwidth. A coaxial dual-polarized waveguide filter may include a cable having a hollow circular body with ends formed by copper plates that each includes at least one iris. The irises may control the energy transfer into and out of the cavity and therefore set the Q factor for the body. The shape of the internal diameter of the body and the irises may provide for reception and propagation of differently polarized signals. Multiple segments may be cascaded in series to effect higher order filtering. Also described are methods of transmitting signals using these filters.

1 . A device comprising:
 a cylindrical body having a substantially circular internal cavity, said internal cavity operable as an RF waveguide;   a first end plate having a first iris disposed therein, said first end plate disposed over a first end of the cylindrical body, said iris operable to propagate RF energy into the cavity;   a second end plate having a second iris disposed therein, said second end plate disposed over a second end of the cylindrical body, said second end plate operable to propagate RF out of the cavity.   
     
     
         2 . The device of  claim 1 , wherein the length of the cylindrical body is substantially 10 to 20 centimeters. 
     
     
         3 . The device of  claim 1 , wherein the first and second irises are circular. 
     
     
         4 . The device of  claim 1 , wherein the first and second irises are circular and the diameter of the first iris and the diameter of the second iris are different. 
     
     
         5 . The device of  claim 1 , further including: a second cylindrical body having a substantially circular internal cavity, said internal cavity operable as an RF waveguide and said second cylindrical body electromagnetically coupled to the second end plate. 
     
     
         6 . The device of  claim 1 , wherein the first and second irises are circular and the length of the second cylindrical body is substantially the same as the length of the first cylindrical body. 
     
     
         7 . A device comprising:
 a first resonator, said resonator having a first chamber;   a first iris opening to the first chamber, and a second iris opening to the first chamber,   wherein the irises and the resonator are operable to pass multiple polarity RF signals.   
     
     
         8 . The device of  claim 7 , wherein the first iris and the second iris are circular. 
     
     
         9 . The device of  claim 7 , wherein the first iris and the second iris are circular and the diameter of the first and the diameter of the second iris are different. 
     
     
         10 . The device of  claim 7 , wherein the first resonator is substantially cylindrical. 
     
     
         11 . The device of  claim 7 , wherein the first and second irises are formed from separate material than the resonator. 
     
     
         12 . The device of  claim 7 , further including: a second resonator, said second resonator electromagnetically coupled to the first resonator, said coupling effectuated through one of the irises. 
     
     
         13 . The device of  claim 7 , further including: a second resonator, said second resonator electromagnetically coupled to the first resonator, said coupling effectuated through one of the irises wherein the length of the second resonator is an integer multiple of the length of the first resonator. 
     
     
         14 . The device of  claim 7 , further including: a second resonator, said second resonator electromagnetically coupled to the first resonator, said coupling effectuated through one of the irises wherein the length of the second resonator is substantially cylindrical and is an integer multiple of the length of the first resonator. 
     
     
         15 . A method for effecting a radio frequency (RF) filter comprising:
 coupling an RF signal into a cylindrical body of a filter having a circular internal cavity operable as an RF waveguide, said cylindrical body a length substantially one-half a wavelength of a first radio frequency and a diameter substantially 65 percent of the wavelength of the radio frequency;   transmitting at least a portion of the RF signal through a first iris on a first end of said cylindrical body and into the cylindrical body, and   transmitting at least a portion of the RF signal through a second iris on a second end of said cylindrical body and out of the cylindrical body.   
     
     
         16 . The method of  claim 15 , wherein the first iris and the second iris are substantially circular. 
     
     
         17 . The method of  claim 15 , further including: adjusting a Q factor of the filter by altering the diameter of the first iris and the diameter of the second iris. 
     
     
         18 . The method of  claim 15 , further including: coupling the filter to a second, similarly formed filter. 
     
     
         19 . The method of  claim 15 , further including coupling the filter to a second, similarly formed filter wherein the Q factor of the filter is substantially different from the Q factor of the second filter. 
     
     
         20 . A method for effecting a radio frequency (RF) filter comprising:
 coupling a radio frequency signal to a first iris on a first end of a cylindrical body of an RF filter;   passing at least a portion of the RF signal through the first iris and into the cylindrical body of the RF filter, wherein the cylindrical body has a length substantially one-half a wavelength of a first radio frequency and a diameter substantially 65 percent of the wavelength of said radio frequency; and   passing at least a portion of the RF signal through a second iris on a second end of the cylindrical body of the RF filter.   
     
     
         21 . The method of  claim 20 , wherein the first iris and the second iris are substantially circular. 
     
     
         22 . The method of  claim 20 , further including: adjusting the Q factor of said filter by altering the diameter of the first iris and the diameter of the second iris. 
     
     
         23 . The method of  claim 20 , further including: coupling the filter to a second, similarly formed filter. 
     
     
         24 . The method of  claim 20 , further including coupling the filter to a second, similarly formed filter wherein the Q factor of the filter is substantially different from the Q factor of the second filter.