MULTIPLE-BAND RADIO FREQUENCY (RF) CIRCUIT AND METHOD FOR A WIRELESS COMMUNICATION DEVICE

• US 20090233642A1
• Filed: 03/13/2008
• Published: 09/17/2009
• Est. Priority Date: 03/13/2008
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: ZHITNITSKY, Gene E.
• Granted Patent: US 7,917,170 B2
• Time in Patent Office: Days
• US Class Current: 455/552.100
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

A multi-band wireless communication device includes a plurality of transmit paths outputting signals to one or more antennas and one or more power amplifiers coupled to the transmit paths. Each of the transmit paths is configured to transmit signals on a specific radio frequency (RF) band. The RF bands can include the Advanced Wireless Services (AWS) band and the Personal Communication Service (PCS) band. Passive filters, such as SAW, BAW or FBAR devices, having out-off-band low return losses are included in the transmit paths. The passive filter and phase shifters on each transmit path can be configured so that RF switching between transmit paths is not necessary and a single power amplifier can be used for the different RF bands. Significant cost, power and space savings can be achieved by reducing the need for RF switches and using a single power amplifier to amplify plural RF bands.

Claims

1. A wireless communication device capable of transmitting on a plurality of radio frequency (RF) bands, comprising:

a plurality of transmit paths, each of the transmit paths configured to transmit signals on a predetermined radio frequency (RF) band; and

a power amplifier, coupled to each of the transmit paths, configured to amplify the signals associated with each of the transmit paths.

2. The wireless communication device of claim 1, wherein one of the transmit paths transmits signals on an Advanced Wireless Services (AWS) band and another of the transmit paths transmits signals on a Personal Communication Service (PCS) band.

3. The wireless communication device of claim 1, further comprising:

a plurality of filters, operatively coupled to an input of the power amplifier, each of the filters configured to filter the signals on a respective one of the transmit paths.

4. The wireless communication device of claim 3, wherein each of the filters has a low out-of-band return loss.

5. The wireless communication device of claim 3, wherein each of the filters is selected from the group consisting of a surface acoustic wave (SAW) filter, a bulk acoustic wave filter (BAW), a FBAR, and any suitable combination of the foregoing filters.

6. The wireless communication device of claim 1, further comprising a directional coupler, operatively coupled to an output of the power amplifier, configured to couple amplified signals associated with each of the transmit paths.

12. The RF circuit of claim 11, further comprising:

a PCS phase shifter and impedance matching circuit coupled to directional coupler.

13. The RF circuit of claim 11, further comprising:

an AWS phase shifter and impedance matching circuit coupled to directional coupler.

7. A radio frequency (RF) circuit, comprising:

a first Advanced Wireless Services (AWS)-path phase shifter receiving an AWS band transmission signal and a PCS band transmission signal;

a first Personal Communication Service (PCS)-path phase shifter receiving the AWS band transmission signal and the PCS band transmission signal;

a first surface acoustic wave (SAW) filter, coupled to the first AWS-path phase shifter, configured to bandpass filter the AWS band transmission signal; and

a second SAW filter, coupled to the first PCS-path phase shifter, configured to bandpass filter the PCS band transmission signal;

a second AWS-path phase shifter coupled to the first SAW filter; and

a second PCS-path phase shifter coupled to the second SAW filter.

8. The RF circuit of claim 7, included in a wireless communication device.

9. The RF circuit of claim 7, wherein the first and second SAW filters each have a low out-of-band return loss.

10. The RF circuit of claim 7, further comprising:

a power amplifier, coupled to the second AWS-path phase shifter and the second PCS-path phase shifter, configured to amplify the AWS band transmission signal and the PCS band transmission signal, whereby outputting amplified AWS band and PCS band transmission signals.

11. The RF circuit of claim 10, further comprising:

a directional coupler, operatively coupled to an output of the power amplifier, configured to couple the amplified AWS band and PCS band transmission signals.

14. The RF circuit of claim 7, wherein the first AWS-path phase shifter is configured to present a predetermined impedance to the PCS band transmission signal.

15. The RF circuit of claim 7, wherein the first PCS-path phase shifter is configured to present a predetermined impedance to the AWS band transmission signal.

17. The method of claim 14, wherein the first predetermined RF band is an Advanced Wireless Services (AWS) band and the second predetermined RF band is a Personal Communication Service (PCS) band.

18. The method of claim 14, further comprising:

bandpass filtering the first transmission signal using a first filter prior to receiving the first transmission signal at the power amplifier; and

bandpass filtering the second transmission signal using a second filter prior to receiving the second transmission signal at the power amplifier.

19. The method claim 14, further comprising:

phase-shifting the first transmission signal using a first phase-shifter; and

phase-shifting the second transmission signal using a second phase-shifter.

20. The method of claim 14, further comprising:

applying the amplified first and second transmission signals to a directional coupler.

16. In a wireless mobile device, a method of amplifying transmission signals, comprising:

receiving at a power amplifier a first transmission signal associated with a first predetermined radio frequency (RF) band;

receiving at the power amplifier a second transmission signal associated with a second predetermined RF band; and

amplifying each of the first and second transmission signals using the power amplifier.