High performance microwave dielectric systems and methods

Abstract

Loss tangents in microwave dielectric materials may be modified (increased and/or reduced), particularly at cryogenic temperatures, via application of external magnetic fields. Exemplary electrical devices, such as resonators, filters, amplifiers, mixers, and photonic detectors, configured with dielectric components having applied magnetic fields may achieve improvements in quality factor and/or modifications in loss tangent exceeding two orders of magnitude.

What is claimed is: 
     
         1 . A method for modifying the loss tangent in an electrical device, the method comprising:
 operating the electrical device having a dielectric component containing a paramagnetic additive, wherein the operating subjects the dielectric component to microwave radiation; and   applying a static magnetic field to the dielectric component to modify the loss tangent in the dielectric component.   
     
     
         2 . The method of  claim 1 , wherein the static magnetic field has a strength exceeding 50 gauss. 
     
     
         3 . The method of  claim 1 , wherein the paramagnetic additive comprises at least one of a transition metal or a rare earth element. 
     
     
         4 . The method of  claim 1 , wherein the dielectric component comprises at least one of:
 Ni- and Zr-alloyed Ba(Zn 1/3 Ta 2/3 )O 3 ,   Co-alloyed Ba(Zn 1/3 Nb 2/3 )O 3 ,   ZrTiO 4 —ZnNb 2 O 6 , or   BaTi 4 O 9 —BaZn 2 Ti 4 O 11 .   
     
     
         5 . The method of  claim 1 , wherein applying the static magnetic field results in modification of the spin loss properties in the dielectric component. 
     
     
         6 . The method of  claim 1 , wherein during the operating, the dielectric component is configured with a temperature lower than 300 Kelvin. 
     
     
         7 . The method of  claim 6 , wherein the loss tangent of the dielectric component is reduced by more than a factor of 2 responsive to application of the static magnetic field. 
     
     
         8 . The method of  claim 6 , wherein the loss tangent of the dielectric component is reduced by at least two orders of magnitude responsive to application of the static magnetic field. 
     
     
         9 . The method of  claim 1 , wherein the applying the static magnetic field to the dielectric component causes paramagnetic ions of the paramagnetic additive to assume a preferential spin alignment. 
     
     
         10 . The method of  claim 1 , wherein the applying the static magnetic field to the dielectric component causes paramagnetic ions of the paramagnetic additive to attain a resonant condition. 
     
     
         11 . The method of  claim 1 , wherein the paramagnetic additive comprises at least one of chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), or nickel (Ni). 
     
     
         12 . The method of  claim 1 , wherein during the operating, the dielectric component is configured with a temperature of about 4.2 Kelvin. 
     
     
         13 . The method of  claim 1 , wherein the dielectric component is an insulator. 
     
     
         14 . The method of  claim 1 , wherein the dielectric component is at least one of an oxide, a nitride, or a fluoride. 
     
     
         15 . The method of  claim 1 , wherein the dielectric component is configured with a perovskite structure. 
     
     
         16 . A method for varying the transfer function of an electrical device, the method comprising:
 operating the electrical device having a dielectric component containing a paramagnetic additive, wherein the operating subjects the dielectric component to microwave radiation;   applying a first static magnetic field to the dielectric component to cause the electrical device to operate according to a first transfer function; and   applying a second static magnetic field to the dielectric component to cause the electrical device to operate according to a second transfer function,   wherein the first static magnetic field and the second static magnetic field have a different strength.   
     
     
         17 . The method of  claim 16 , wherein the electrical device comprises at least one of a microwave filter or a microwave resonator. 
     
     
         18 . A method for modifying loss in a dielectric material, the method comprising:
 determining, for paramagnetic ions in the dielectric material, a preferential spin alignment; and   applying, to the dielectric material, a static magnetic field to cause the paramagnetic ions to assume the preferential spin alignment.   
     
     
         19 . A method for operating a microwave device having a dielectric component containing a paramagnetic additive comprising a transition metal, the method comprising:
 operating, at a cryogenic temperature, the microwave device to subject the dielectric component to microwave radiation and cause a loss process to occur in the dielectric component, wherein the dominant portion of the loss process is resonant spin excitations of unpaired d-electrons of the transition metal.   
     
     
         20 . The method of  claim 19 , wherein the dielectric component is configured with a dopant concentration for the paramagnetic additive of less than or equal to 0.5%, and
 wherein the resonant spin excitations arise primarily within isolated transition metal atoms in the dielectric component.   
     
     
         21 . The method of  claim 19 , wherein the dielectric component is configured with a dopant concentration for the paramagnetic additive of greater than 0.5%, and
 wherein the resonant spin excitations arise primarily within exchange-coupled transition metal clusters in the dielectric component.   
     
     
         22 . The method of  claim 19 , wherein the dielectric component comprises Ni- and Zr-alloyed Ba(Zn 1/3 Ta 2/3 )O 3 . 
     
     
         23 . The method of  claim 19 , wherein the paramagnetic additive comprises at least one of chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), or nickel (Ni).