Integrated circuit and method for receiving and transmitting signals of different frequency bands

1. An integrated circuit for receiving and transmitting signals of different frequency bands comprising:

a transmit signal path connected to an intersecting node, the transmit signal path being used to transmit outgoing signals of at least one frequency band;

a variable resistance device on the transmit signal path;

a receive signal path connected to the intersecting node, the receive signal path being used to receive incoming signals of at least one frequency band;

a capacitive device on the receive signal path;

a bi-directional signal path connected to the intersecting node and a receive-and-transmit terminal;

a bypass path that circumvents the capacitance device on the receive signal path; and

a switching device on the bypass path to control resistance through the bypass path.

2. The integrated circuit of claim 1 wherein the variable resistance device includes a diode.

3. The integrated circuit of claim 1 wherein the switching device includes a transistor.

4. The integrated circuit of claim 1 wherein the capacitive device includes a capacitor.

5. The integrated circuit of claim 4 further comprising a quarter-wave transmission line connected to the capacitor on the receive signal path.

6. The integrated circuit of claim 5 further comprising a shorted diode connected to the quarter-wave transmission line.

7. The integrated circuit of claim 1 further comprising an amplifier and an output matching network connected in series on the transmit path.

8. The integrated circuit of claim 1 further comprising comprising:

a second transmit signal path connected to a second intersecting node;

a second variable resistance device on the second transmit signal path;

a second receive signal path connected to the second intersecting node;

a second capacitive device on the second receive signal path;

a second common signal path connected to the second intersecting node to the receive-and-transmit terminal;

a second bypass path that circumvents the second capacitance device on the second receive signal path; and

a second switching device on the second bypass path to control resistance through the second bypass path.

9. An integrated circuit for receiving and transmitting signals of different frequency bands comprising:

an amplifier on a first signal path to provide outgoing signals of at least one frequency band;

an output matching network connected in series with the amplifier on the first signal path;

a diode connected in series with the output matching network;

a capacitor on a second signal path connected to the first signal path;

a transmission line connected in series with the capacitor on the second signal path; and

a switching device connected on a third signal path that circumvents the capacitor.

10. The integrated circuit of claim 9 wherein the switching device includes a transistor.

11. The integrated circuit of claim 9 wherein the transmission line is a quarter-wave transmission line.

12. The integrated circuit of claim 9 further comprising a shorted diode connected to the transmission line.

13. The integrated circuit of claim 9 further comprising:

a second amplifier on a fourth signal path to provide second outgoing signals of at least one frequency band;

a second output matching network connected in series with the second amplifier on the fourth signal path;

a second diode connected in series with the second output matching network;

a second capacitor on a fifth signal path connected to the fourth signal path;

a second transmission line connected in series with the second capacitor on the fifth signal path; and

a second switching device connected on a sixth signal path that circumvents the second capacitor.

14. A method for receiving and transmitting signals of different frequency bands, the method comprising:

receiving incoming signals of at least one frequency band;

filtering the incoming signals based on frequency; and

selectively routing the incoming signals through a receive signal path for processing, including circumventing a capacitive device on the receive signal path to conduct current through a variable resistance device on a transmit signal path connected to the receive signal path to prevent the incoming signals from traveling through the transmit signal path.

15. The method of claim 14 wherein the circumventing the capacitive device includes circumventing the capacitive device on the receive signal path to conduct current through a diode.

16. The method of claim 14 further comprising transmitting the incoming signals through a quarter-wave transmission line on the receive signal path.

17. The method of claim 14 wherein the circumventing the capacitive device includes activating a switching device on a bypass path that circumvents the capacitive device on the receive signal path.

18. The method of claim 14 wherein the selectively routing the incoming signals includes conducting current through a shorted variable resistance device connected to the receive signal path.

19. The method of claim 14 further comprising selectively routing outgoing signals of at least one frequency band through the transmit signal path, including stopping conduction of current through the variable resistance device to decrease resistance of the variable resistance device on the transmit signal path to transmit the outgoing signals through the variable resistance device.

20. The method of claim 19 wherein the selectively routing the outgoing signals of at least one frequency band further includes deactivating a switching device on a bypass path that circumvents the capacitive device on the receive signal path.