Mobile wireless communications device with adjustable impedance matching network and associated methods
A mobile device includes an adjustable impedance matching network coupled between a power amplifier and an antenna and has an adjustable impedance element. An impedance sensor is coupled between the power amplifier and adjustable impedance matching network. A processor is configured to a) calculate a corrected antenna load impedance based upon a sensed impedance at inputs of the impedance matching network and a current value of the adjustable impedance element, and b) determine a new value for the adjustable impedance element based upon the corrected antenna load impedance. The processor is also configured to c) set the adjustable impedance element to the new value, and d) sense a new impedance at the inputs and determine if the sensed new impedance is within a threshold value of the power amplifier impedance, and repeat steps a), b), and c) if the sensed new impedance is not within the threshold value.
1. A mobile wireless communications device comprising:
an antenna;
a power amplifier having an amplifier impedance;
an adjustable impedance matching network coupled between said power amplifier and said antenna and comprising at least one adjustable impedance element;
an impedance sensor coupled between said power amplifier and said adjustable impedance matching network;
a processor coupled to said power amplifier, said adjustable impedance matching network and said impedance sensor, said processor configured to
a) calculate a corrected antenna load impedance based upon a sensed impedance at inputs of said impedance matching network and based upon at least one current value of said at least one adjustable impedance element,
b) determine at least one new value for said at least one adjustable impedance element based upon the corrected antenna load impedance,
c) set said at least one adjustable impedance element to the at least one new value, and
d) sense a new impedance at the inputs of said adjustable matching network and determining if the sensed new impedance is within a threshold value of the power amplifier impedance, and repeat steps a), b), and c) if the sensed new impedance is not within the threshold value of the power amplifier impedance.
2. The mobile wireless communications device of claim 1 , wherein said processor is configured to set at least one current value of said at least one adjustable impedance element based upon an initial estimated antenna load impedance, prior to performing step a).
3. The mobile wireless communications device of claim 1 , wherein said impedance sensor senses the antenna load impedance based upon a phase of a current and a voltage at the inputs of said adjustable matching network, and a magnitude of the current and the voltage at the inputs of said matching network.
4. The mobile wireless communication device of claim 1 , wherein said at least one adjustable impedance element comprises at least one adjustable capacitance and at least one adjustable inductance coupled thereto.
5. The mobile wireless communications device of claim 4 , wherein said processor is configured to determine the at least one new value for said at least one adjustable capacitance by:
calculating a capacitive reactance of the calculated input impedance such that a calculated new impedance at the inputs of the adjustable matching network matches the power amplifier impedance; and
calculating a capacitance for the at least one adjustable capacitance based upon the capacitive reactance.
6. The mobile wireless communications device of claim 4 , wherein said processor determines the at least one new value for said at least one adjustable inductance by:
calculating an inductive reactance of the calculated input impedance such that a calculated new impedance at the inputs of the adjustable matching network to matches the power amplifier impedance; and
calculating an inductance for the at least one adjustable capacitance based upon the inductive reactance.
7. The mobile wireless communications device of claim 4 , wherein said at least one adjustable capacitance comprises a binary weighted network of capacitors.
8. The mobile wireless communications device of claim 4 , wherein said at least one adjustable inductance comprises a binary weighted network of inductors.
9. A mobile wireless communications device comprising:
an antenna;
a power amplifier having an amplifier impedance;
an adjustable impedance matching network coupled between said power amplifier and said antenna and comprising at least one adjustable capacitance and at least one adjustable inductance;
an impedance sensor coupled between said power amplifier and said adjustable impedance matching network;
a processor coupled to said power amplifier, said adjustable impedance matching network and said impedance sensor, said processor configured to
a) set at least one current value of said at least one adjustable capacitance and at least one adjustable inductance based upon an initial estimated antenna load impedance,
b) calculate a corrected antenna load impedance based upon a sensed impedance at inputs of said impedance matching network and based upon at least one current value of said at least one adjustable capacitance and said at least one adjustable inductance,
c) determine at least one new value for said at least one adjustable capacitance and said at least one adjustable inductance based upon the corrected antenna load impedance,
d) set said at least one adjustable capacitance and at least one adjustable inductance to the at least one new values, and
d) sense a new impedance at the inputs of said adjustable matching network and determining if the sensed new impedance is within a threshold value of the power amplifier impedance, and repeat steps b), c), and d) if the sensed new impedance is not within the threshold value of the power amplifier impedance.
10. The mobile wireless communications device of claim 9 , wherein said impedance sensor senses the antenna load impedance based upon a phase of a current and a voltage at the inputs of said adjustable matching network, and a magnitude of the current and the voltage at the inputs of said matching network.
11. The mobile wireless communication device of claim 9 , wherein said at least one adjustable impedance element comprises at least one adjustable capacitance and at least one adjustable inductance coupled thereto.
12. The mobile wireless communications device of claim 11 , wherein said processor is configured to determine the at least one new value for said at least one adjustable capacitance by:
calculating a capacitive reactance of the calculated input impedance such that a calculated new impedance at the inputs of the adjustable matching network matches the power amplifier impedance; and
calculating a capacitance for the at least one adjustable capacitance based upon the capacitive reactance.
13. The mobile wireless communications device of claim 11 , wherein said processor determines the at least one new value for said at least one adjustable inductance by:
calculating an inductive reactance of the calculated input impedance such that a calculated new impedance at the inputs of the adjustable matching network to matches the power amplifier impedance; and
calculating an inductance for the at least one adjustable capacitance based upon the inductive reactance.
14. The mobile wireless communications device of claim 11 , wherein said at least one adjustable capacitance comprises a binary weighted network of capacitors.
15. The mobile wireless communications device of claim 11 , wherein said at least one adjustable inductance comprises a binary weighted network of inductors.