MATCHING UNIT AND MATCHING METHOD

摘要

A matching unit includes a directional coupler for detecting a travelling wave and a reflected wave; a matching circuit including a first variable capacitance capacitor, a second variable capacitance capacitor and an inductance; and a control unit for controlling VC1 and VC2 of the first and the second variable capacitance capacitor by calculating a reflection coefficient based on the travelling wave and the reflected wave. When a distance between the calculated reflection coefficient and a circle described by a trace of the reflection coefficient which passes through a matching point on a Smith chart is greater than a predetermined value, the control unit changes VC2 of the second variable capacitance capacitor and the calculated reflection coefficient to make the distance within the predetermined value. When the distance becomes within the predetermined value, the control unit changes VC1 of the first variable capacitance capacitor and makes the calculated reflection coefficient smaller.

主权项

1. A matching unit comprising:
a directional coupler configured to detect a travelling wave and a reflected wave; a matching circuit including an input terminal, an output terminal, a first variable capacitance capacitor having one end connected to the input terminal through a first transmission line and the other end that is grounded, a second variable capacitance capacitor having one end connected to the output terminal through a second transmission line and the other end that is grounded, and an inductance having one end connected to said one end of the first variable capacitance capacitor and the other end connected to said one end of the second variable capacitance capacitor; and a control unit configured to control a capacitance value of the first variable capacitance capacitor and a capacitance value of the second variable capacitance capacitor based on the travelling wave and the reflected wave detected by the directional coupler, wherein the control unit calculates a reflection coefficient based on the travelling wave and the reflected wave detected by the directional coupler, and wherein when a distance between the calculated reflection coefficient and a circle described by a trace of the reflection coefficient which passes through a matching point on a Smith chart is greater than a predetermined value, the control unit changes the capacitance value of the second variable capacitance capacitor and the calculated reflection coefficient to make the distance equal to or less than the predetermined value, and when the distance becomes equal to or less than the predetermined value, the control unit changes the capacitance value of the first variable capacitance capacitor and makes the calculated reflection coefficient smaller.