Input matching circuit and related apparatus
An input matching circuit and a related apparatus are provided. The input matching circuit includes an inductive branch, a first resistor, and a field-effect transistor, the inductive branch includes one or more inductors and a second resistor, a first end of the first resistor is connected to a signal input end, and a second end of the first resistor is grounded. The signal input end is configured to provide a signal input for the input matching circuit, an input end of the inductive branch is connected to the signal input end, and an output end of the inductive branch is grounded. An inductance value of an equivalent inductor of the inductive branch between the signal input end and the ground varies with adjustment of a frequency of a signal input by the signal input end.
1 . An input matching circuit, comprising:
an inductive branch;
a first resistor; and
a field-effect transistor;
wherein the inductive branch comprises one or more inductors and a second resistor;
wherein a first end of the first resistor is connected to a signal input end, a second end of the first resistor is grounded, and the signal input end provides a signal input to the input matching circuit;
wherein an input end of the inductive branch is connected to the signal input end, an output end of the inductive branch is grounded, and an inductance value of the inductive branch between the signal input end and a ground varies with adjustment of a frequency of a signal input by the signal input end, wherein a resistance of the first resistor is adjustable to change an inductance of the inductive branch and cause an inductive capacitive (LC) parallel circuit formed by the inductance of the inductive branch and a parasitic capacitance of the field-effect transistor to reach LC parallel resonance; and
wherein a gate of the field-effect transistor is connected to the signal input end, a source of the field-effect transistor is grounded, and the field-effect transistor comprises a drain.
2 . The input matching circuit according to claim 1 , wherein the frequency of the signal input by the signal input end is inversely related to the inductance value of the inductive branch between the signal input end and the ground.
3 . The input matching circuit according to claim 1 , wherein the inductive branch comprises a first inductor and the second resistor, the first inductor and the second resistor are connected in series between the signal input end and a ground point, and the second resistor comprises a variable resistor.
4 . The input matching circuit according to claim 3 , wherein the first resistor comprises a variable resistor.
5 . The input matching circuit according to claim 3 , wherein the inductive branch further comprises a second inductor and the second inductor and the second resistor are connected in parallel.
6 . The input matching circuit according to claim 5 , wherein the first resistor comprises a variable resistor.
7 . The input matching circuit according to claim 1 , further comprising an output circuit connected to the drain of the field-effect transistor.
8 . The input matching circuit according to claim 1 , wherein the frequency of the signal input falls within a frequency range that needs to be met by the input matching circuit.
9 . The input matching circuit according to claim 1 , wherein the inductive branch comprises a plurality of inductors.
10 . A receiver, comprising:
one or more low noise amplifiers; and
a front-end drive amplifier coupled to the one or more low noise amplifiers;
wherein the front-end drive amplifier comprises an input matching circuit, the input matching circuit comprises an inductive branch, a first resistor, and a field-effect transistor, wherein the inductive branch comprises one or more inductors and a second resistor;
wherein a first end of the first resistor is connected to a signal input end, a second end of the first resistor is grounded, and the signal input end provides a signal input to the input matching circuit;
wherein an input end of the inductive branch is connected to the signal input end, an output end of the inductive branch is grounded, and an inductance value of the inductive branch between the signal input end and a ground varies with adjustment of a frequency of a signal input by the signal input end;
wherein a gate of the field-effect transistor is connected to the signal input end, a source of the field-effect transistor is grounded, and the field-effect transistor comprises a drain; and
wherein a resistance of at least one of the first resistor or second resistor is adjustable to change an inductance of the inductive branch and cause an inductive capacitive (LC) parallel circuit formed by the inductance of the inductive branch and a parasitic capacitance of the field-effect transistor to reach LC parallel resonance.
11 . The receiver according to claim 10 , wherein the frequency of the signal input by the signal input end is inversely related to the inductance value of the inductive branch between the signal input end and the ground.
12 . The receiver according to claim 10 , wherein the inductive branch comprises a first inductor and the second resistor, the first inductor and the second resistor are connected in series between the signal input end and a ground point, and the second resistor comprises a variable resistor.
13 . The receiver according to claim 12 , wherein the first resistor comprises a variable resistor.
14 . The receiver according to claim 12 , wherein the inductive branch comprises a second inductor, and the second inductor and the second resistor are connected in parallel.
15 . The receiver according to claim 14 , wherein the first resistor comprises a variable resistor.
16 . The receiver according to claim 10 , further comprising an output circuit connected to the drain of the field-effect transistor.
17 . The receiver according to claim 10 , wherein the receiver comprises a plurality of low noise amplifiers.
18 . The receiver according to claim 10 , wherein the inductive branch comprises a plurality of inductors.