Switched directional antenna for automotive radio receivers

• US 6,449,469 B1
• Filed: 03/01/1999
• Issued: 09/10/2002
• Est. Priority Date: 03/01/1999
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Miyahara, Shunji
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Green, Miguel D.
• Application Number:
  US09/260,325
• Time in Patent Office: 1,289 Days
• Field of Search: 455/273, 455/134, 455/137, 455/139, 455/275, 455/276.1, 455/277.1, 455/277.2, 455/278.1, 342/446, 342/417, 342/375, 342/380, 375/347
• US Class Current: 455/273
• CPC Class Codes: H01Q 1/1271 for mounting on windscreens
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

A directional antenna system includes several antenna elements, a phase shift/attenuation circuit, and a switching system. The circuit synthesizes four antenna patterns which are oriented toward the front, back, left, and right sides of a vehicle. The system switches between antenna patterns depending upon received signal strength at any particular moment.

Claims

1. A radio receiver system installed on a vehicle, said vehicle having front, back, left, and right sides, said radio receiver system comprising:

a plurality of antenna elements mounted on said vehicle, each antenna element producing a respective radio-frequency signal;

an antenna combiner coupled to said antenna elements electronically combining said radio-frequency signals according to a selected one of four predetermined phase/amplitude combinations to generate a combined antenna signal, wherein said four predetermined phase/amplitude combinations each provides a respective directivity pattern substantially aligned with said front, back, left, and right sides, respectively, whereby said front and back directivity patterns are aligned with a street upon which said vehicle travels;

a tuner generating a tuner signal in response to said combined antenna signal;

a quality detector generating a detection signal in response to a comparison of a quality of said tuner signal and a predetermined quality; and

a pattern selector coupled to said quality detector and said antenna combiner to change-over said antenna combiner to a different one of said predetermined phase/amplitude combinations in response to said detection signal.

2. The radio receiver system of claim 1 wherein said antenna combiner is comprised of four voltage-controlled phase shifters connected in respective pairs to a respective one of four voltage-controlled attenuators, each of said pairs being connected to a summer which produces said combined antenna signal.

3. The radio receiver system of claim 2 wherein said plurality of antenna elements are comprised of four glass-mounted elements, each element being connected to a respective one of said phase shifter/attenuator pairs.

4. The radio receiver system of claim 1 wherein said antenna combiner is comprised of a digital signal processor including predetermined phase shift and attenuation values stored in memory.

5. The radio receiver system of claim 4 wherein said quality detector and said pattern selector are contained within said digital signal processor.

6. The radio receiver system of claim 1 wherein said tuner signal is an intermediate frequency (IF) signal, and wherein said predetermined quality is a predetermined signal strength of said IF signal.

7. The radio receiver system of claim 1 wherein said tuner signal is an intermediate frequency (IF) signal, and wherein said predetermined quality is a predetermined percent of average signal strength of said IF signal.

8. The radio receiver system of claim 1 wherein said phase/amplitude combinations only shift the phases of respective signal.

9. The radio receiver system of claim 1 wherein transmission lines provide said phase/amplitude combinations.