DIVERSITY ANTENNA SYSTEM AND METHOD UTILIZING A THRESHOLD VALUE

• US 20100317306A1
• Filed: 06/15/2010
• Published: 12/16/2010
• Est. Priority Date: 06/15/2009
• Status: Active Grant

• Current Assignee: AGC Automotive Americas R&D, Inc (AGC, Inc.)
• Original Assignee: AGC Automotive Americas R&D, Inc (AGC, Inc.)
• Inventors: LEE, Kwan-ho, LEE, Ming, VILLARROEL, Wladimiro, HORIKI, Yasutaka
• Granted Patent: US 8,385,868 B2
• Time in Patent Office: Days
• US Class Current: 455/205
• CPC Class Codes: H01Q 1/1271 for mounting on windscreens
• CPC Class Codes: H01Q 1/325 characterised by the location of the antenna on the vehicle
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/34 by electrical means active lenses or reflecting arrays H01Q3/46
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/002 Reducing depolarization effects
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

An antenna system for receiving an RF signal from a first antenna and a second antenna includes a phase shift circuit. The phase shift circuit shifts a phase of the RF signal from the second antenna by one of a plurality of possible phase shifts to produce a phase shifted signal. A combiner combines the RF signal from the first antenna and the phase shifted signal to produce a combined signal. A comparator circuit compares a signal quality of the combined signal with a minimum threshold value to determine if the signal quality of the combined signal is equal to or greater than the threshold value. The comparator circuit is in communicative control of the phase shift circuit and maintains the phase shift of the RF signal received by the second antenna in response to the signal quality of the combined signal being equal to or greater than the threshold value.

Claims

1. An antenna system for receiving a radio frequency (RF) signal from a first antenna and a second antenna and providing a combined signal to a receiver, said system comprising:

a phase shift circuit electrically connectable to the second antenna for shifting a phase of the RF signal by one of a plurality of possible phase shifts to produce a phase shifted signal;

a combiner electrically connectable to the first antenna and electrically connected to said phase shift circuit for combining the RF signal and the phase shifted signal to produce a combined signal; and

a comparator circuit electrically connected to said combiner for receiving the combined signal and comparing a signal quality of the combined signal with a minimum threshold value to determine if the signal quality of the combined signal is equal to or greater than the threshold value; and

wherein said comparator circuit is in communicative control of said phase shift circuit for maintaining the phase shift of the RF signal received by the second antenna in response to the signal quality of the combined signal being equal to or greater than the threshold value.

2. An antenna as set forth in claim 1 wherein said comparator circuit changes the phase shift implemented by said phase shift circuit in response to the signal quality being less than the minimum threshold value.

3. An antenna as set forth in claim 1 wherein said comparator circuit changes the phase shift implemented by said phase shift circuit only in response to the signal quality being less than the minimum threshold value.

4. An antenna system as set forth in claim 1 further comprising a counter in communication with said phase shift circuit for implementing one of the plurality of possible phase shifts to shift the phase of the RF signal from the second antenna to produce the phase shifted signal.

5. An antenna system as set forth in claim 1 further comprising an analog-to-digital converter (ADC) electrically connected to said combiner for receiving the combined signal to produce digital data corresponding to a signal strength of the combined signal.

6. An antenna system as set forth in claim 5 wherein signal quality is further defined as signal strength.

7. An antenna system for receiving a radio frequency (RF) signal and providing a combined signal to a receiver, said system comprising:

a first antenna for receiving the RF signal and a second antenna for receiving the RF signal;

a phase shift circuit electrically connectable to said second antenna for shifting a phase of the RF signal from the second antenna by one of a plurality of possible phase shifts to produce a phase shifted signal;

a combiner electrically connectable to the first antenna and electrically connected to said phase shift circuit for combining the first RF signal and the phase shifted signal to produce a combined signal; and

a comparator circuit electrically connected to said combiner for receiving the combined signal and comparing a signal quality of the combined signal with a minimum threshold value to determine if the signal quality of the combined signal is equal to or greater than the threshold value; and

wherein said comparator circuit is in communicative control of said phase shift circuit for maintaining the phase shift of the RF signal received by the second antenna in response to the signal quality of the combined signal being equal to or greater than the threshold value.

8. An antenna as set forth in claim 7 wherein said comparator circuit changes the phase shift implemented by said phase shift circuit only in response to the signal quality being less than the minimum threshold value.

9. An antenna as set forth in claim 7 wherein said comparator circuit automatically changes the phase shift implemented by said phase shift circuit in response to the signal quality being less than then minimum threshold value.

10. An antenna system as set forth in claim 7 further comprising a counter in communication with said phase shift circuit for implementing one of the plurality of possible phase shifts to shift the phase of the RF signal from the second antenna to produce the phase shifted signal.

11. An antenna system as set forth in claim 7 further comprising an analog-to-digital converter (ADC) electrically connected to said combiner for receiving the combined signal to produce digital data corresponding to a signal strength of the combined signal.

12. An antenna system as set forth in claim 11 wherein signal quality is further defined as signal strength.

13. An antenna system as set forth in claim 7 wherein each of said antennas are disposed on a window of a vehicle.

14. An antenna system as set forth in claim 13 wherein said antennas are conformal to each other and/or the vehicle.

15. A method of providing a signal to a receiver using an antenna system, said method comprising the steps of:

receiving a radio frequency (RF) signal with a first antenna;

receiving the RF signal with a second antenna;

phase-shifting the RF signal received by the second antenna to produce a phase shifted signal;

combining the RF signal received from the first antenna and the phase shifted signal to produce a combined signal;

comparing a signal quality of the combined signal with a threshold value;

maintaining the phase shift of the RF signal received by the second antenna in response to the signal quality of the combined signal being equal to or greater than the threshold value; and

providing the combined signal to the receiver.

16. A method as set forth in claim 15 further comprising the step of changing the phase shift of the RF signal received by the second antenna in response to the signal quality of the combined signal being less than the threshold value to change the phase shifted signal.

17. A method as set forth in claim 15 further comprising the step of changing the phase shift implemented by said phase shift circuit only in response to the signal quality being less than the minimum threshold value.

18. A method as set forth in claim 15 wherein signal quality is further defined as signal strength.

19. A method as set forth in claim 15 wherein signal quality is further defined as an inverse of noise signal.

20. A method as set forth in claim 15 wherein signal quality is further defined as signal-to-noise ratio.