Systems and methods for impedance tuning
In electronic devices used in radio-frequency communications, impedance matching may result in desirable operating conditions. However, impedance of the antenna may change over time (e.g., due to frequency of signals being transmitted or received, due to ambient conditions, due to age of antenna or related components). Accordingly, it may be desirable to employ antenna tracking circuitry that may operate as an impedance matching network to dynamically match the antenna impedance. To dynamically match the antenna impedance, the matching network may include tunable components. To provide fast, dynamic, and effective impedance matching, antenna tracking circuitry having an architecture with analytically determinable impedance (e.g., determinable via one or more equations) may be implemented. The antenna tracking circuitry may include a variable resistor and three variable impedances. The three variable impedances may include components capable of tuning capacitor ranges of the three variable impedances, among other characteristics of the antenna tracking circuitry.
1 . An electronic device, comprising:
a plurality of antennas;
a transmitter;
a receiver; and
duplexing circuitry coupled to the transmitter, the receiver, and the plurality of antennas, the duplexing circuitry comprising
a resistance device,
a first impedance device coupled in parallel to the resistance device,
a second impedance device coupled to the first impedance device and the resistance device at a first node, and
a third impedance device coupled to the second impedance device at a second node, and coupled to the first impedance device, the resistance device, and a ground at a third node, wherein the first impedance device, the second impedance device, the third impedance device, and the resistance device are configurable to match an impedance associated with the plurality of antennas, and the first impedance device, the second impedance device, and the third impedance device each comprise at least one capacitor coupled in parallel to at least one inductor.
2 . The electronic device of claim 1 , wherein the first impedance device, the second impedance device, or both, comprise a first capacitor coupled in parallel to a series combination of a second capacitor and an inductor.
3 . The electronic device of claim 1 , comprising measurement circuitry configured to determine the impedance associated with the plurality of antennas.
4 . The electronic device of claim 3 , wherein the measurement circuitry comprises voltage standing wave ratio measurement circuitry.
5 . The electronic device of claim 1 , comprising tuning circuitry configured to determine a tuning state for the first impedance device, the second impedance device, the third impedance device, the resistance device, or any combination thereof.
6 . The electronic device of claim 5 , wherein the tuning circuitry is configured to determine the tuning state based on the impedance, a first frequency associated with the transmitter, and a second frequency associated with the receiver.
7 . The electronic device of claim 1 , wherein the first impedance device, the second impedance device, the third impedance device, and the resistance device are configurable to match the impedance associated with the plurality of antennas based on a frequency of a signal transmitted by the plurality of antennas.
8 . A duplexer comprising:
a resistance device;
a first impedance device coupled in parallel to the resistance device;
a second impedance device coupled to the first impedance device and the resistance device at a first node; and
a third impedance device coupled to the second impedance device at a second node, and coupled to the first impedance device, the resistance device, and a ground at a third node, wherein the first impedance device, the second impedance device, the third impedance device, and the resistance device are configurable to match an impedance associated with a plurality of antennas coupled to the duplexer based on a frequency of a signal transmitted by the plurality of antennas.
9 . The duplexer of claim 8 , wherein the first impedance device or the second impedance device comprises a capacitor coupled in parallel to an inductor.
10 . The duplexer of claim 8 , wherein the first impedance device or the second impedance device comprises a first capacitor coupled in parallel to a series combination of a second capacitor and an inductor.
11 . The duplexer of claim 8 , wherein the duplexer is coupled to measurement circuitry configured to determine the impedance associated with the plurality of antennas.
12 . The duplexer of claim 8 , wherein the duplexer is coupled to tuning circuitry configured to determine a tuning state for the first impedance device, the second impedance device, the third impedance device, or the resistance device.
13 . The duplexer of claim 12 , wherein the tuning circuitry is configured to determine the tuning state based on the impedance, a first frequency associated with a transmitter coupled to the duplexer, and a second frequency associated with a receiver coupled to the duplexer.
14 . A transceiver comprising:
transmitting circuitry;
receiving circuitry;
duplexing circuitry coupled to the transmitting circuitry and the receiving circuitry, the duplexing circuitry comprising
a resistance device,
a first impedance device coupled in parallel to the resistance device,
a second impedance device coupled to the first impedance device and the resistance device at a first node, and
a third impedance device coupled to the second impedance device at a second node, and coupled to the first impedance device, the resistance device, and a ground at a third node; and
tuning circuitry coupled to the duplexing circuitry and configured to adjust the first impedance device, the second impedance device, the third impedance device, and the resistance device to match an impedance associated with a plurality of antennas coupled to the transceiver.
15 . The transceiver of claim 14 , wherein the duplexing circuitry is coupled in series to voltage standing wave ratio measurement circuitry.
16 . The transceiver of claim 14 , wherein the duplexing circuitry is coupled in series to tuning circuitry configured to determine a tuning state for the first impedance device, the second impedance device, the third impedance device, or the resistance device.
17 . The transceiver of claim 14 , wherein the resistance device comprises a variable resistance device.
18 . The transceiver of claim 14 , wherein the first impedance device comprises at least a first capacitor, the second impedance device comprises a second capacitor and the third impedance device comprises a third capacitor.
19 . The transceiver of claim 18 , wherein the tuning circuitry is configured to adjust capacitance values of the first capacitor, the second capacitor, and the third capacitor based on a first frequency associated with the transmitting circuitry and a second frequency associated with the receiving circuitry.
20 . The transceiver of claim 19 , wherein the tuning circuitry is configured to adjust a resistance value of the resistance device based on the capacitance values.