Circuits, devices and methods related to fine phase shifters

1. A phase shifter comprising:

a first node and a second node; and

a first transmission line element having an inductance and a variable capacitance on each side of the inductance, the variable capacitance configured to provide a plurality of capacitance values to provide corresponding phase shift values based on an increment having a magnitude that is less than 90 degrees, the variable capacitance provided by a switchable circuit having a plurality of capacitive paths arranged in parallel, each capacitive path including at least one capacitor in series with a switch, the switchable circuit including four capacitive paths to provide 4-bit variable capacitance values over a range of at least 90 degrees.

2. The phase shifter of claim 1 further comprising a second transmission line element in series with the first transmission line element, the second transmission line element having an inductance and a variable capacitance on each side of the inductance configured to extend an overall phase shift range provided by the phase shifter.

3. The phase shifter of claim 2 wherein the capacitive path includes a first capacitor and a second capacitor arranged such that the switch is between the first and second capacitors.

4. The phase shifter of claim 3 wherein the series arrangement of the first capacitor, the switch, and the second capacitor is configured to provide DC blocking functionality.

5. The phase shifter of claim 3 wherein the first and second capacitors have substantially same capacitance values.

6. The phase shifter of claim 5 wherein the series arrangement of the first capacitor, the switch, and the second capacitor is configured to provide a substantially symmetric capacitance for the capacitive path.

7. The phase shifter of claim 5 wherein the switch includes a field-effect transistor (FET) such that a source and a drain of the field-effect transistor are connected to the first and second capacitors.

8. The phase shifter of claim 7 wherein the field-effect transistor is biased such that its channel and gate are biased to opposite potentials.

9. The phase shifter of claim 2 further comprising a quadrant phase shifter coupled to one of the first and second nodes, the quadrant phase shifter configured to provide a bypass state, a single first-handed quarter-wave state, a double first-handed quarter-wave state, or a single second-handed quarter-wave state utilizing two or less inductors.

10. The phase shifter of claim 9 wherein the quadrant phase shifter includes two inductors, such that the phase shifter includes four inductors.

11. The phase shifter of claim 10 wherein the four states of the quadrant phase shifter are achieved by a 2-bit control signal over the four quadrants.

12. The phase shifter of claim 10 wherein the phase shifter has a 6-bit phase shift resolution over a range of at least 360 degrees.

13. An electronic module comprising:

a packaging substrate configured to receive one or more components; and

a die mounted on the packaging substrate, the die including a phase shifting circuit having a first node and a second node, the phase shifting circuit further including a first transmission line element having an inductance and a variable capacitance on each side of the inductance, the variable capacitance configured to provide a plurality of capacitance values to provide corresponding phase shift values based on an increment having a magnitude that is less than 90 degrees, the variable capacitance provided by a switchable circuit having a plurality of capacitive paths arranged in parallel, each capacitive path including at least one capacitor in series with a switch, the switchable circuit including four capacitive paths to provide 4-bit variable capacitance values over a range of at least 90 degrees.

14. The electronic module of claim 13 wherein the phase shifting circuit further includes a second transmission line element in series with the first transmission line element, the second transmission line element having an inductance and a variable capacitance on each side of the inductance configured to extend an overall phase shift range provided by the phase shifter.

15. The electronic module of claim 14 further comprising a quadrant phase shifter coupled to one of the first and second nodes, the quadrant phase shifter configured to provide a bypass state, a single first-handed quarter-wave state, a double first-handed quarter-wave state, or a single second-handed quarter-wave state utilizing two or less inductors.

16. The electronic module of claim 15 wherein the inductances associated with the first and second transmission lines and the two or less inductors of the quadrant phase shifter include corresponding inductors implemented on the die.

17. A wireless device comprising:

a processor configured facilitate processing of a signal; and

a phase shifting circuit having a first node and a second node, the phase shifting circuit further including a first transmission line element having an inductance and a variable capacitance on each side of the inductance, the variable capacitance configured to provide a plurality of capacitance values to provide corresponding phase shift values based on an increment having a magnitude that is less than 90 degrees, the variable capacitance provided by a switchable circuit having a plurality of capacitive paths arranged in parallel, each capacitive path including at least one capacitor in series with a switch, the switchable circuit including four capacitive paths to provide 4-bit variable capacitance values over a range of at least 90 degrees.

18. The wireless device of claim 17 further including a quadrant phase shifter coupled to one of the first and second nodes, the quadrant phase shifter configured to provide a bypass state, a single first-handed quarter-wave state, a double first-handed quarter-wave state, or a single second-handed quarter-wave state utilizing two or less inductors.