Radio frequency switch for suppressing intermodulation
View Patent ↗A radio frequency (RF) switch adapted to reduce third order intermodulation (IM3) products generated as RF signals propagate through the RF switch is disclosed. The RF switch includes N semiconductor switch segments, and N−1 phase shift networks, individual ones of the N−1 phase shift networks being coupled between adjacent ones of the N semiconductor switch segments where N is a natural number greater than 1. In operation, when the RF switch is on, IM3 products generated by the RF switch propagating through the N−1 phase shift networks are phase shifted such that the IM3 products are at least partially canceled.
1. A radio frequency (RF) switch adapted to suppress third order intermodulation (IM3) products generated as RF signals propagate through the RF switch comprising:
N and only N semiconductor switch segments; and
N−1 and only (N−1) phase shift networks, individual ones of the N−1 phase shift networks being coupled between and in series with adjacent ones of the N and only N semiconductor switch segments where N is a natural number that is at least 3, and wherein each of the N−1 and only (N−1) phase shift networks provides around 180°/N of phase shift.
2. The RF switch of claim 1 wherein the N and only N semiconductor switch segments comprises groups of series stacked field effect transistors (FETs).
3. The RF switch of claim 1 wherein N=3 and the N−1 and only (N−1) phase shift networks provide around 60° of phase shift.
4. The RF switch of claim 1 wherein the N−1 and only (N−1) phase shift networks each comprise an inductor-capacitor (LC) tee network.
5. The RF switch of claim 4 wherein the LC tee network comprises series capacitors and a shunt inductor.
6. The RF switch of claim 5 wherein the series capacitors are integrated with the RF switch and the shunt inductor is a surface mount device (SMD).
7. A method to suppress IM3 products generated as RF signals propagate through an RF switch, the method comprising:
providing the RF switch with N and only N semiconductor switch segments;
providing N−1 and only (N−1) phase shift networks; and
coupling individual ones of the N−1 and only (N−1) phase shift networks between and in series with adjacent ones of the N and only N semiconductor switch segments where N is a natural number that is at least 3, and wherein each of the N−1 and only (N−1) phase shift networks provides around 180°/N of phase shift.
8. The method of claim 7 wherein the IM3 products are reduced as the RF signals propagate through the RF switch in a same direction.
9. The method of claim 7 wherein the IM3 products are reduced as the RF signals propagate through the RF switch from opposite directions.
10. The method of claim 7 wherein the N and only N semiconductor switch segments comprises groups of series stacked field effect transistors (FETs).
11. The method of claim 7 wherein N=3 and one of the N−1 and only (N−1) phase shift networks provides around 60° of phase shift.
12. The method of claim 7 wherein the N−1 and only (N−1) phase shift networks each comprise an inductor-capacitor (LC) tee network.
13. The method of claim 12 wherein the LC tee network comprises series capacitors and a shunt inductor.
14. The method of claim 13 wherein the series capacitors are integrated with the RF switch and the shunt inductor is a surface mount device (SMD).
15. A mobile terminal comprising:
an antenna;
a receiver front end;
an RF switch having an antenna terminal coupled to the antenna and a terminal coupled to the receiver front end, the RF switch comprising:
N and only N semiconductor switch segments having a control terminal;
N−1 and only (N−1) phase shift networks, individual ones of the N−1 phase shift networks being coupled between and in series with adjacent ones of the N and only N semiconductor switch segments where N is a natural number that is at least 3, wherein each of the N−1 and only (N−1) phase shift networks provides around 180°/N of phase shift; and
a control system communicatively coupled to the control terminal for turning on and turning off the N and only N semiconductor switch segments.
16. The mobile terminal of claim 15 wherein the N and only N semiconductor switch segments comprises groups of series stacked field effect transistors (FETs).
17. The mobile terminal of claim 15 wherein N=3 and the N−1 and only (N−1) phase shift networks provides around 60° of phase shift.
18. The mobile terminal of claim 15 wherein the N−1 and only (N−1) phase shift networks each comprise an inductor-capacitor (LC) tee network.
19. The mobile terminal of claim 18 wherein the LC tee network comprises series capacitors and a shunt inductor.
20. The mobile terminal of claim 19 wherein the series capacitors are integrated with the RF switch and the shunt inductor is an SMD.