Patent ID: 8797119

Claim:
A method for tuning a tunable matching network comprising a first variable capacitor comprising a terminal connected to a first node, a second variable capacitor comprising a terminal connected to a second node, and a first inductor and a third variable capacitor connected in parallel between the first and second nodes, the method comprising: (a) comparing a source impedance of a source connected to the first node to a real part of a load impedance of a load connected to the second node; (b) when the source impedance is greater than the real part of the load impedance or when a calculated capacitance of the second variable capacitor is less than a minimum capacitance: (i) setting a capacitance value of the second variable capacitor to be a minimum capacitance of the second variable capacitor; and (ii) determining a capacitance value of the first variable capacitor based on a predetermined relationship between the capacitance of the first variable capacitor, a conductance of the source, and an equivalent conductance of the first inductor and the third variable capacitor; (c) when the source impedance is less than the real part of the load impedance or when a calculated capacitance of the first variable capacitor is less than a minimum capacitance: (i) setting a capacitance value of the first variable capacitor to be a minimum capacitance of the first variable capacitor; and (ii) determining a capacitance value of the second variable capacitor based on a predetermined relationship between the capacitance of the second variable capacitor, a minimum susceptance of the first variable capacitor, an impedance of the source, a conductance of the load, and a susceptance of the load; (d) determining a capacitive value of the third variable capacitor based on a predetermined relationship between the capacitance of the third variable capacitor, an inductance of the first inductor, and an equivalent series inductance of the first inductor and the third variable capacitor; (e) adjusting the capacitance value of one or more of the first variable capacitor, second variable capacitor, or third variable capacitor if the capacitance value is less than a minimum capacitance or greater than a maximum capacitance for the first variable capacitor, second variable capacitor, or third variable capacitor, respectively; and (f) setting the capacitances of the first variable capacitor, the second variable capacitor, and the third variable capacitor to be equal to the respective capacitance values.