Circuit for Impedance Matching

Abstract

A circuit provided for impedance matching includes an input, an output and four impedance elements arranged between them. In this case, two of the impedance elements are connected in series in a main path and form a T configuration with a third component. In addition, a fourth component is connected in parallel with the main path of the circuit. By way of example, the components arranged in the main path are variable capacitances and the further components are inductances.

1 . A circuit for impedance matching comprising:
 an input;   an output;   a first component that has an effective impedance;   a second component that has an effective impedance and series-coupled with the first component in a main path between the input and the output;   a third component that has an effective impedance and forming a T configuration with the first component and the second component; and   a fourth component that has an effective impedance and coupled in parallel with the main path, and   wherein the first component and/or the second component includes an adjustable capacitance value to flexibly match an impedance connected to the output with an impedance connected to the input.   
     
     
         2 . The circuit for impedance matching as claimed in  claim 1 , wherein the adjustable capacitance value is adjustable to at least two different capacitance values between which it is possible to select and switch to and from during operation of the circuit. 
     
     
         3 . The circuit for impedance matching as claimed in  claim 1 , wherein the first component and the second component both include the adjustable capacitance value. 
     
     
         4 . The circuit for impedance matching as claimed in  claim 1 , wherein the adjustable capacitance value for the first component and the second component have identical ranges. 
     
     
         5 . The circuit for impedance matching as claimed in  claim 1 , wherein the first component comprises an inductance, a capacitance or a line, the second component comprises an inductance, a capacitance or a line, the third component comprises an inductance, a capacitance or a line, and the fourth component comprises an inductance, a capacitance or a line. 
     
     
         6 . The circuit for impedance matching as claimed in  claim 1 , wherein the first and second components comprise capacitances and wherein the third and fourth components comprise inductances. 
     
     
         7 . A circuit arrangement for impedance matching comprising:
 an input;   an output;   a first circuit that includes first, second, third and fourth components that each have an effective impedance, wherein the first and second components are coupled in series in a first main path between the input and the output and form a T configuration with the third component, and the fourth component is coupled in parallel with the first main path, wherein the first component and/or the second component includes an adjustable capacitance value to flexibly match an impedance connected to the output with an impedance connected to the input; and   at least a second circuit coupled to the first circuit and including fifth, sixth, seventh and eighth components that each have an effective impedance, wherein the fifth and sixth components are coupled in series in a second main path between the input and the output and form a T configuration with the seventh component, and the eighth component coupled is coupled in parallel with the second main path, wherein the fifth component and/or the sixth component includes an adjustable capacitance value to flexibly match an impedance connected to the output with an impedance connected to the input.   
     
     
         8 . The circuit arrangement for impedance matching as claimed in  claim 7 ,wherein the adjustable capacitance value of the first component and/or the second component is adjustable to at least two different capacitance values between which it is possible to select and switch to and from during operation of the circuit. 
     
     
         9 . The circuit arrangement for impedance matching as claimed in  claim 8 , wherein the adjustable capacitance value of the fifth component and/or the sixth component is adjustable to at least two different capacitance values between which it is possible to select and switch to and from during operation of the circuit. 
     
     
         10 . The circuit arrangement for impedance matching as claimed in  claim 7 , wherein the first component and the second component both include the adjustable capacitance value, and the fifth component and the sixth component both include the adjustable capacitance value. 
     
     
         11 . The circuit arrangement for impedance matching as claimed in  claim 7 , wherein the adjustable capacitance value for the first component and the second component have identical ranges, and the adjustable capacitance value for the fifth component and the sixth component have identical ranges. 
     
     
         12 . The circuit arrangement for impedance matching as claimed in  claim 7 , wherein the first circuit is suitable for impedance matching in a first frequency band and is a passage element for a second frequency band. 
     
     
         13 . The circuit arrangement for impedance matching as claimed in  claim 12 , wherein the second circuit is suitable for impedance matching in the second frequency band and is a passage element for the first frequency band. 
     
     
         14 . The circuit arrangement for impedance matching as claimed in  claim 7 , wherein the first and second circuits are connected in series. 
     
     
         15 . The circuit arrangement for impedance matching as claimed in  claim 7 , wherein the first circuit and the second circuit are connected in parallel with one another. 
     
     
         16 . The circuit arrangement for impedance matching as claimed in  claim 15 ,
 wherein the first circuit is suitable for impedance matching in a first frequency band and is a band rejection filter for a second frequency band, and   wherein the second circuit is suitable for impedance matching in the second frequency band and is a band rejection filter for the first frequency band.   
     
     
         17 . An electrical circuit comprising:
 an input;   an output;   a first component that has an effective impedance;   a second component that has an effective impedance and series-coupled with the first component in a main path between the input and the output;   a third component that has an effective impedance and forming a T configuration with the first component and the second component;   a fourth component that has an effective impedance and coupled in parallel with the main path, wherein the first component and/or the second component includes an adjustable capacitance value to flexibly match an impedance connected to the output with an impedance connected to the input;   a generator coupled to the input; and   a load coupled to the output.   
     
     
         18 . The electrical circuit as claimed in  claim 17 , wherein the adjustable capacitance value is adjustable to at least two different capacitance values between which it is possible to select and switch to and from during operation of the electrical circuit. 
     
     
         19 . The electrical circuit as claimed in  claim 17 , wherein the first component and the second component both include the adjustable capacitance value. 
     
     
         20 . The electrical circuit as claimed in  claim 17 , wherein the adjustable capacitance value for the first component and the second component have identical ranges. 
     
     
         21 . The electrical circuit as claimed in  claim 17 , wherein the first, second, third and fourth components are suitable for impedance matching in a first frequency band and are a passage element for a second frequency band. 
     
     
         22 . The electrical circuit as claimed in  claim 21 , further comprising:
 a fifth component that has an effective impedance;   a sixth component that has an effective impedance, wherein the fifth and sixth components are coupled in series in a second main path between the input and the output;   a seventh component that has an effective impedance, wherein fifth and sixth components form a T configuration with the seventh component; and   an eighth component that has an effective impedance, the eighth component coupled in parallel with the second main path, wherein the fifth, sixth, seventh and eighth components are suitable for impedance matching in the second frequency band and is a passage element for the first frequency band.   
     
     
         23 . The electrical circuit as claimed in  claim 21 ,
 wherein at least one of the first component and/or the second component is a capacitance with an adjustable capacitance value, and   wherein capacitance values of the first and second components are chosen such that in the first frequency band an input impedance of the electrical circuit and the load matches an impedance of the generator.   
     
     
         24 . The electrical circuit as claimed in  claim 23 , wherein in the first frequency band an output reflection factor (R OUT ) is less than −10 dB. 
     
     
         25 . The electrical circuit as claimed in  claim 23 , wherein capacitance values of the first and second components are chosen such that in two frequency bands an input impedance matches an impedance of the generator. 
     
     
         26 . The electrical circuit as claimed in  claim 23 , wherein the electrical circuit is part of a mobile radio and wherein the generator comprises an output of a power amplifier and the load comprises an antenna. 
     
     
         27 . The electrical circuit as claimed in  claim 23 , wherein the electrical circuit is part of a mobile radio and wherein the generator comprises an antenna and the load comprises an input of a receiver.