RFID antenna system with multi-axis polarization for field installation and beam steering operations

Patent metadata

Field	Value
Publication number	US-9716323-B2
Application number	US-201514645984-A
Country	US
Kind code	B2
Filing date	Mar 12, 2015
Priority date	Mar 12, 2015
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

Antenna system includes a fixture having a first portion and a second portion joined along an alignment axis. A first planar antenna element having a first polarization direction is aligned with a first plane, and secured to the first portion of the antenna fixture. A second planar antenna element has a second polarization direction aligned with a second plane. The second planar antenna element is secured to the second portion of the antenna fixture so that the second plane is transverse to the first plane and the first and second planes intersect along a line parallel to the alignment axis. At least one tuned element mitigates near-field interference as between the first planar antenna element and the second planar antenna element. Signals applied to the antenna feed port will result in three-polarization radiation.

First claim

What is claimed is:

1. A field installation optimized radio frequency identification (RFID) antenna system, comprising:
an antenna fixture having a first portion and a second portion joined along an alignment axis;
a first planar antenna element having a first polarization direction aligned with a first plane, and secured to the first portion of the antenna fixture;
a second planar antenna element having a second polarization direction aligned with a second plane, the second planar antenna element secured to the second portion of the antenna fixture so that the second plane is transverse to the first plane and the first and second planes intersect along a line parallel to the alignment axis;
an antenna feed port secured to the fixture directly coupled to at least one of the first and second planar antenna elements;
a passive element comprising at least one of a capacitor, an inductor and a resistor, and having a plurality of manually variable settings that are selectable by an installation technician in a field setting to predictably conform the RFID antenna system to an angle determined by the first and second planes; and
at least one tuned element which mitigates near-field interference between the first planar antenna element and the second planar antenna element when the first and second planar antenna elements are mounted in the antenna fixture;
wherein a plurality of optimal settings for the at least one tuned element is predetermined at a design time to correspond to a plurality of angular positions defining the angle; and
wherein the first polarization direction is transverse to the second polarization direction whereby signals applied to the antenna feed port will result in three-polarization radiation.

2. The field-installation optimized RFID antenna system according to claim 1 , wherein the first and second polarization directions each form an oblique angle with respect to the alignment axis.

3. The field installation optimized RFID antenna system according to claim 1 , wherein the first and second planes are orthogonal.

4. The field installation optimized RFID antenna system according to 1 , wherein the at least one tuned element is integrated into at least one of the first and second planar antenna elements.

5. The field installation optimized RFID antenna system according to 1 , wherein the antenna fixture is rotatably adjustable along the alignment axis to selectively vary an angle between the first and second plane in accordance with an installation requirement.

6. The field installation optimized RFID antenna system according to claim 1 , further comprising
a third planar antenna element disposed in alignment with the first plane and having a third polarization direction parallel to the first polarization direction, the third planar antenna element secured to the first portion of the antenna fixture; and
a fourth planar antenna element disposed in alignment with the second plane and having a fourth polarization direction parallel to the second polarization direction, the fourth planar antenna element secured to the second portion of the antenna fixture; and
wherein the antenna feed port is directly coupled to at least one of the third and fourth planar antenna elements.

7. The field installation optimized RFID antenna system according to claim 6 , wherein the first and second planes are orthogonal.

8. The field installation optimized RFID antenna system according to 6 , wherein the at least one tuned element is integrated into at least one of the first, second, third and fourth planar antenna elements.

9. The field installation optimized RFID antenna system according to claim 6 , further comprising at least one dynamic phase control element which is responsive to a control signal to dynamically shift a phase of a signal applied to the first and second planar antenna element relative to the phase of signals applied to the third and fourth planar antenna elements for steering a direction of an antenna pattern having three-polarization radiation.

10. The field installation optimized RFID antenna system according to 9 , wherein the antenna fixture is rotatably adjustable along the alignment axis to selectively vary an angle between the first and second plane in accordance with an installation requirement.

11. A field installation optimized radio frequency identification (RFID) antenna system, comprising:
an antenna fixture having a first portion and a second portion joined along an alignment axis;
a first planar antenna element having a first polarization direction aligned with a first plane and oblique to the alignment axis, the first planar antenna element secured to the first portion of the antenna fixture;
a second planar antenna element having a second polarization direction aligned with a second plane and oblique to the alignment axis, the second planar antenna element secured to the second portion of the antenna fixture so that the second plane is transverse to the first plane and the first and second planes intersect along a line parallel to the alignment axis;
an antenna feed port secured to the fixture directly coupled to at least one of the first and second planar antenna elements;
a passive element comprising at least one of a capacitor, an inductor and a resistor, and having a plurality of manually variable settings that are selectable by an installation technician in a field setting to predictably conform the RFID antenna system to an angle determined by the first and second planes; and
at least one tuned element which mitigates near-field interference between the first planar antenna element and the second planar antenna element when the first and second planar antenna elements are mounted in the antenna fixture;
wherein a plurality of optimal settings for the at least one tuned element is predetermined at a design time to correspond to a plurality of angular positions defining the angle; and
wherein the first polarization direction is transverse to second polarization direction whereby signals applied to the antenna feed port will result in three-polarization radiation.

12. The field installation optimized RFID antenna system according to claim 11 , wherein the first and second planes are orthogonal.

13. The field installation optimized RFID antenna system according to 11 , wherein the at least one tuned element is integrated into at least one of the first and second planar antenna elements.

14. The field installation optimized RFID antenna system according to 11 , wherein the antenna fixture is rotatably adjustable along the alignment axis to selectively vary an angle between the first and second plane in accordance with an installation requirement.

15. The field installation optimized RFID antenna system according to claim 11 , further comprising
a third planar antenna element disposed in alignment with the first plane and having a third polarization direction parallel to the first polarization direction, the third planar antenna element secured to the first portion of the antenna fixture; and
a fourth planar antenna element disposed in alignment with the second plane and having a fourth polarization direction parallel to the second polarization direction, the fourth planar antenna element secured to the second portion of the antenna fixture; and
wherein the antenna feed port is directly coupled to at least one of the third and fourth planar antenna elements.

16. The field installation optimized RFID antenna system according to claim 15 , further comprising at least one dynamic phase control element which is responsive to a control signal to dynamic

Assignees

• Hosseini Alister
• Trivelpiece Steve E
• Tyco Fire & Security Gmbh

Inventors

• Hosseini Alister
• Trivelpiece Steve E

Classifications

• G06K7/10356

  using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas · CPC title

• H01Q21/24 Primary

  Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction {(circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001)} · CPC title

• H01Q1/523

  between antennas of an array · CPC title

• G06K7/0008

  General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer · CPC title

• H01Q1/2216

  used in interrogator/reader equipment · CPC title