READER FOR AN ELECTRONIC UHF ACCESS CONTROL SYSTEM

• US 20160232388A1
• Filed: 09/18/2014
• Published: 08/11/2016
• Est. Priority Date: 09/18/2013
• Status: Active Grant

• Current Assignee: N.V. Nederlandsche Apparatenfabriek, N.V. Nederlandsche Apparatenfabriek "Nedap"
• Original Assignee: N.V. Nederlandsche Apparatenfabriek "Nedap"
• Inventors: VAN ZON, Bernardus Clemens Maria
• Granted Patent: US 9,704,005 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: G06K 7/10415 the interrogation device being fixed in its position, such as an access control device for reading wireless access cards, or a wireless ATM banking machines in general G07F19/00
• CPC Class Codes: G07C 9/00896 specially adapted for particular uses
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 21/24 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 Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

Reader for an electronic UHF access control system, wherein the reader in operation cooperates with corresponding UHF tags and is provided with a housing, in which an antenna system for creating an electromagnetic interrogation field is arranged, wherein the antenna system comprises a first antenna for generating an interrogation field with a first polarization direction, and a second antenna for generating an interrogation field with a second polarization direction, wherein the first and the second polarization directions are substantially orthogonal to each other, and wherein the first antenna is a loop antenna with an open central area, and the second antenna is an antenna of the inverted F type (IFA), which is placed in the open central area of the loop antenna.

Claims

1. A reader for an electronic UHF access control system, wherein the reader in operation cooperates with corresponding UHF tags and is provided with a housing, in which an antenna system for creating an electromagnetic interrogation field is arranged, wherein the antenna system comprises a first antenna for generating an interrogation field with a first polarization direction, and a second antenna for generating an interrogation field with a second polarization direction, wherein the first and the second polarization directions are substantially orthogonal to each other, and wherein the first antenna is a loop antenna with an open central area, and the second antenna is an antenna of the inverted F type (IFA), which is placed in the open central area of the loop antenna.

2. The reader according to claim 1, wherein the IFA has an elongate shape and the loop antenna is in a plane which is bent at least transversely to the longitudinal direction of the IFA.

3. The reader according to claim 1, wherein the housing is a housing of elongate shape and wherein the IFA extends in the length direction (L) of the housing, and wherein the loop antenna is in a plane bent at least in the width direction (B) of the housing.

4. The reader according to claim 1, wherein the antennas are so dimensioned that the antenna gain and the bandwidth for the first and second polarization directions have a comparable magnitude.

5. The reader according to claim 4, wherein the IFA has a length of one-fourth of the wavelength λ

of one of the signals within the bandwidth in which the reader operates, and that the loop of the loop antenna has a length of one wavelength λ

of one of the signals within the bandwidth in which the reader operates.

6. The reader according to claim 1, wherein the housing comprises an elongate cap and an elongate base, wherein the loop antenna is at a distance above the base in a tunnel-shaped bent plane, which extends in the length direction (L) of the cap and the base between the longitudinal edges of the base and above the base.

7. The reader according to claim 6, wherein the IFA extends in the same tunnel-shaped plane as the loop antenna and in the area of the tunnel-shaped plane located highest above the base.

8. The reader according to claim 6, wherein the tunnel-shaped plane is defined by at least a part of the inner wall of the cap.

9. The reader according to claim 6, wherein the tunnel-shaped plane is formed by a carrier of thin resilient and flexible printed circuit board material, on which at least the loop antenna is arranged.

10. The reader according to claim 9, wherein the IFA is arranged en the same carrier as the loop antenna.

11. The reader according to claim 9, wherein the carrier is located at least partly against the inner wall of the cap wherein the inner wall of the cap is provided with locking means for fixing the carrier.

12. The reader according to claim 10, wherein on the carrier also strip-shaped connecting leads for the antennas are formed, which have been cut loose along their longitudinal edges and one of their transverse edges from the carrier and in the operating condition are bent out of the plane of the carrier in the direction of the base plate.

13. The reader according to claim 12, wherein the base plate has a central portion raised in the direction of the cap, under which an electronic circuit of the reader is located, wherein the base plate is provided with openings via which the connecting leads of at least one of the antennas are connected with the circuit.

14. The reader according to claim 10, wherein the carrier is provided with a number of openings, on opposite sides of the but within the area enclosed by the loop antenna, which openings facilitate the mounting of the carrier in the bent condition in the cap.

15. The reader according to claim 12, wherein a positioning element for fixing at least one of the strip-shaped connecting lead in the bent position.

16. The reader according to claim 15, wherein the positioning element is manufactured from the same material as the carrier and in operation is arranged in the cap in a position bent oppositely to the carrier, wherein the positioning element has at least one supporting edge for fixing at least one connecting lead in the desired bent position, and wherein the positioning element is furthermore provided on opposite sides with lips which engage in one or more of the openings for fixing the positioning element.

17. An electronic UHF RFID access control system including a reader according to claim 1.