Systems and methods for frequency equalization and temperature compensation in radio frequency devices

Abstract

A frequency equalizer is provided. The frequency equalizer includes a coupler including a main segment extending between a first port and a second port and a coupled segment disposed in a coupling relationship with the main segment and extending between a third port and a fourth port. The frequency equalizer further includes a first thermistor electrically coupled in series between the first port and an input line, a second thermistor electrically coupled in series between the second port and an output line, and a first shunt resistor coupled across the third port. The frequency equalizer simultaneously provides frequency equalization and temperature compensation for signals transmitted through the frequency equalizer.

What is claimed is: 
     
         1 . A frequency equalizer comprising:
 a coupler comprising:
 a main segment extending between a first port and a second port; and 
 a coupled segment disposed in a coupling relationship with said main segment and extending between a third port and a fourth port; 
   a first thermistor electrically coupled in series between the first port and an input line;   a second thermistor electrically coupled in series between the second port and an output line; and   a first shunt resistor coupled across the third port, wherein said frequency equalizer simultaneously provides frequency equalization and temperature compensation for signals transmitted through said frequency equalizer.   
     
     
         2 . The frequency equalizer of  claim 1 , further comprising a second shunt resistor coupled across the fourth port. 
     
     
         3 . The frequency equalizer of  claim 1 , wherein said main segment and said coupled segment have different widths. 
     
     
         4 . The frequency equalizer of  claim 1 , wherein said coupler further comprises a second coupled segment disposed in a second coupling relationship with the main segment and extending between a fifth port and a sixth port, and wherein said frequency equalizer further comprises:
 a third shunt resistor and electrically coupled across the fifth port; and   a fourth shunt resistor and electrically coupled across the sixth port.   
     
     
         5 . The frequency equalizer of  claim 1 , wherein said coupler further comprises a shunt line extending between said main segment and said coupled segment. 
     
     
         6 . The frequency equalizer of  claim 1 , wherein a length of the main segment is greater than a quarter wavelength of an input signal for said frequency equalizer. 
     
     
         7 . The frequency equalizer of  claim 1 , further comprising a first inductor electrically coupled in parallel with said first thermistor and a second inductor electrically coupled in parallel with said second thermistor. 
     
     
         8 . The frequency equalizer of  claim 1 , wherein at least one of said first thermistor and said second thermistor comprises a thermistor paste. 
     
     
         9 . The frequency equalizer of  claim 1 , further comprising at least one impedance tuning structure electrically coupled across at least one of the input line, the output line, the first port, and the second port. 
     
     
         10 . An electronics package for a frequency equalizer comprising:
 a substrate having a first surface and a second surface;   a ground plane disposed on the second surface;   a coupler comprising:
 a main segment defined by a main strip disposed on the first surface and by said ground plane, said main segment extending between a first port and a second port; and 
 a coupled segment defined by a coupled strip disposed on the second surface and by said ground plane, said coupled segment disposed in a coupling relationship with said main segment and extending between a third port and a fourth port; 
   a first thermistor disposed on the first surface and electrically coupled in series between the first port and an input line;   a second thermistor disposed on the first surface and electrically coupled in series between the second port and an output line; and   a first shunt resistor disposed on the first surface and electrically coupled across the third port, wherein said electronics package simultaneously provides frequency equalization and temperature compensation for signals transmitted through said electronics package.   
     
     
         11 . The electronics package of  claim 10 , further comprising a second shunt resistor disposed on the first surface and electrically coupled across the fourth port. 
     
     
         12 . The electronics package of  claim 10 , wherein said main strip and said coupled strip have different widths. 
     
     
         13 . The electronics package of  claim 10 , wherein said coupler further comprises a second coupled segment defined by a second coupled strip disposed on the first surface and by said ground plane, said second coupled segment disposed in a second coupling relationship with the main segment and extending between a fifth port and a sixth port, and wherein the frequency equalizer further comprises:
 a third shunt resistor disposed on the first surface and electrically coupled across the fifth port; and   a fourth shunt resistor disposed on the first surface and electrically coupled across the sixth port.   
     
     
         14 . The electronics package of  claim 10 , wherein said coupler further comprises a shunt line extending between said main segment and said coupled segment. 
     
     
         15 . The electronics package of  claim 10 , wherein a length of the main segment is greater than a quarter wavelength for an input signal of the frequency equalizer. 
     
     
         16 . The electronics package of  claim 10 , further comprising a first inductor electrically coupled in parallel with said first thermistor and a second inductor electrically coupled in parallel with said second thermistor. 
     
     
         17 . The electronics package of  claim 10 , wherein at least one of said first thermistor and said second thermistor comprise a thermistor paste disposed on the first surface. 
     
     
         18 . The electronics package of  claim 10 , further comprising at least one impedance tuning structure electrically coupled across at least one of the input line or the output line. 
     
     
         19 . A method of manufacturing a frequency equalizer, said method comprising:
 forming a coupler including a main segment extending between a first port and a second port and a coupled segment disposed in a coupling relationship with the main segment and extending between a third port and a fourth port;   electrically coupling a first thermistor in series between the first port and an input line;   electrically coupling a second thermistor in series between the second port and an output line; and   electrically coupling a first shunt resistor across the third port, wherein the frequency equalizer simultaneously provides frequency equalization and temperature compensation for signals transmitted through the frequency equalizer.   
     
     
         20 . The method of  claim 19 , further comprising electrically coupling a second shunt resistor across the fourth port.