Antenna apparatus for linearly polarized diversity antenna in RFID reader and method of controlling the antenna apparatus

• US 7,804,455 B2
• Filed: 07/24/2007
• Issued: 09/28/2010
• Est. Priority Date: 12/05/2006
• Status: Expired due to Fees

• Current Assignee: Chungbuk National University Industry Academic Cooperation Foundation (Chungbuk National University), Electronics and Telecommunications Research Institute
• Original Assignee: Chungbuk National University Industry Academic Cooperation Foundation (Chungbuk National University), Electronics and Telecommunications Research Institute
• Inventors: Choi, Ik Guen, Lee, Jong Moon, Kim, Nae-Soo, Pyo, Cheol Sig
• Primary Examiner(s): Phan; Tho G
• Application Number:
  US11/782,195
• Publication Number:
  US 20080129641A1
• Time in Patent Office: 1,162 Days
• Field of Search: 343/700.MS, 343/725, 343/853, 343/876, 340/572.1, 340/572.7
• US Class Current: 343/725
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 21/245 provided with means for varying the polarisation polarising devices H01Q15/24; tracking by comparing linear polarisation compounds G01S3/146; reducing depolarisation effects H04B7/00; polarisation diversity H04B7/10
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

Provided are an antenna apparatus for linearly polarized diversity antennas in a radio frequency identification (RFID) reader, and a method of controlling the antenna apparatus. The antenna apparatus includes: a plurality of linearly polarized diversity antennas disposed to have different directions to one another; a switching unit connecting the linearly polarized diversity antennas to the RFID reader; and a controller controlling the switching unit to selectively activate the linearly polarized diversity antennas.

Claims

1. An antenna apparatus for linearly polarized diversity antennas in an RFID (radio frequency identification) reader, the antenna apparatus comprising:

four linearly polarized diversity antennas disposed to have different directions to one another, wherein the four linearly polarized diversity antennas are disposed at angles of 45°

relative to one another and has a polarization mismatch loss of about 1.38 dB;

a switching unit connecting the linearly polarized diversity antennas to the RFID reader; and

a controller controlling the switching unit to selectively activate the linearly polarized diversity antennas.

2. The antenna apparatus of claim 1, wherein if the number of linearly polarized diversity antennas is two, the linearly polarized diversity antennas are disposed to be perpendicular to each other.

3. The antenna apparatus of claim 1, wherein the linearly polarized diversity antennas have micro-strip shapes.

4. The antenna apparatus of claim 1, wherein the controller controls the switching unit in order to switch on and/or off a current that is supplied to the linearly polarized diversity antennas.

5. The antenna apparatus of claim 4, wherein the switching unit is a pin diode.

6. A method of controlling an antenna apparatus for linearly polarized diversity antennas in an RFID reader, the method comprising:

controlling four linearly polarized diversity antennas in order for the linearly polarized diversity antennas to have different directions to one another, wherein the four linearly polarized diversity antennas are disposed at angles of 45°

relative to one another and has a polarization mismatch loss of about 1.38 dB; and

switching on and/or off a current supplied to the four linearly polarized diversity antennas.

7. The method of claim 6, wherein a pin diode is switched on and/or off to control the current supplied to the four linearly polarized diversity antennas.