Antenna LNA filter for GNSS devices

• US 8,975,967 B2
• Filed: 11/08/2012
• Issued: 03/10/2015
• Est. Priority Date: 11/09/2011
• Status: Active Grant

• Current Assignee: Javad GNSS, Inc.
• Original Assignee: Javad GNSS, Inc.
• Inventors: Ashjaee, Javad, Dubrovsky, Dmitry
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US13/672,329
• Publication Number:
  US 20130113571A1
• Time in Patent Office: 852 Days
• Field of Search: 330/302, 330/306, 330/310
• US Class Current: 330/302
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H

Abstract

A low-noise amplifier (LNA) filter for use with global navigation satellite system (GNSS) devices is disclosed. A first LNA stage, which is configured to connect to an antenna configured to receive GNSS signals, includes an LNA. A second LNA stage, which is connected to the output of the first LNA stage, has a surface acoustic wave (SAW) filter and an LNA. A third LNA stage, which is connected to the output of the second LNA stage, also has a SAW filter and an LNA.

Claims

1. A low-noise amplifier (LNA) filter comprising:

a first LNA stage having a first input and a first output, wherein the first input is configured to electrically connect to an antenna configured to receive global navigation satellite system (GNSS) signals, and wherein the first LNA stage includes a first LNA and a ceramic filter;

a second LNA stage having a second input and a second output, wherein the second input is electrically connected to the first output, and wherein the second LNA stage includes a second LNA and a first surface acoustic wave (SAW) filter; and

a third LNA stage having a third input and third output, wherein the third input is connected to the second output, and wherein the third LNA stage includes a third LNA and a second SAW filter.

2. The LNA filter of claim 1, wherein the second LNA stage includes a third SAW filter and wherein the third LNA stage includes a fourth SAW filter.

3. The LNA filter of claim 2, wherein an output of the first SAW filter is connected to an input of the third SAW filter, and wherein an input of the second LNA is connected to an output of the third SAW filter.

4. The LNA filter of claim 2, wherein the first LNA and the second LNA are implemented with the same circuit topologies.

5. The LNA filter of claim 2, wherein at least one of the first, second, third, or fourth SAW filters have a 3 db bandwidth of less than 60 MHz, a center frequency of 1574-1577 MHz, and an insertion loss of less than 2 db.

6. The LNA filter of claim 2, wherein the first, second, third, and fourth SAW filters have a 3 db bandwidth of less than 60 MHz, a center frequency of 1574-1577 MHz, and an insertion loss of less than 2 db.

7. The LNA filter of claim 2, wherein the first LNA is implemented with a high-electron mobility transistor.

8. The LNA filter of claim 2, wherein a ripple group delay in a GPS band is less than 40 ns.

9. The LNA filter of claim 2, wherein a ripple group delay in a GLONASS band is less than 60 ns.

10. The LNA filter of claim 1, wherein a gain of the LNA filter below frequencies of 1540 MHz and above frequencies of 1640 MHz is less than −

40 dB.

11. The LNA filter of claim 1, wherein a gain of the LNA filter below frequencies of 1540 MHz and above frequencies of 1625 MHz is less than −

40 dB.

12. A global navigation satellite system (GNSS) device comprising:

a radio frequency (RF) front-end comprising;

a first signal path having a first LNA stage comprising a first LNA and a ceramic filter, a second LNA stage comprising a second LNA and a first SAW filter, and a third LNA stage comprising a third LNA and a second SAW filter; and

a second signal path having a fourth LNA and a plurality of filters;

a first antenna coupled to the first signal path and configured to receive GNSS signals; and

a second antenna coupled to the second signal path and configured to receive GNSS signals.

13. The GNSS device of claim 12, wherein the first and second antennas are different antennas.

14. The GNSS device of claim 12, wherein the first and second antennas are the same antenna.

15. The GNSS device of claim 12, wherein the second LNA stage further includes a third SAW filter and the third LNA stage further includes a fourth SAW filter.

16. The GNSS device of claim 12, wherein at least one of the first or second SAW filters have a 3 db bandwidth of less than 60 MHz, a center frequency of 1574-1577 MHz, and an insertion loss of less than 2 db.

17. The GNSS device of claim 12, wherein the first and second SAW filters have a 3 db bandwidth of less than 60 MHz, a center frequency of 1574-1577 MHz, and an insertion loss of less than 2 db.

18. The GNSS device of claim 12, wherein a ripple group delay for the RF front end in the GPS band is less than 40 ns.

19. The GNSS device of claim 12, wherein a ripple group delay for the RF front end in the GLONASS band is less than 60 ns.

20. The GNSS device of claim 12, wherein a gain for the RF front end below frequencies of 1540 MHz and above frequencies of 1640 MHz is less than −

40 dB.

21. The GNSS device of claim 12, wherein a gain for the RF front end below frequencies of 1540 MHz and above frequencies of 1625 MHz have is less than −

40 dB.