Inverted F antenna with coplanar feed and RFID device having same

• US 8,228,236 B2
• Filed: 08/29/2007
• Issued: 07/24/2012
• Est. Priority Date: 08/29/2007
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Birnbaum, Thomas, Ramisetti, Sireesha, Sardariani, Edmond
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): Hu, Jennifer F
• Application Number:
  US11/847,152
• Publication Number:
  US 20090058656A1
• Time in Patent Office: 1,791 Days
• Field of Search: 340/572.7, 343/700.MS, 343/702, 343/845, 343/846, 343/866
• US Class Current: 343/700.MS
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

An RFID device according to one embodiment includes an inverted F antenna having an active portion, a ground plane spaced from the active portion, and a feed coupled to and coplanar with the active portion; and an RFID controller coupled to the feed. An inverted F antenna according to another embodiment includes a substrate for an RFID device; an active portion coupled to the substrate; a ground plane spaced from the active portion; and a feed coupled to and coplanar with the active portion. An inverted F antenna according to yet another embodiment includes an active portion coupled to the substrate; a ground plane spaced from the active portion; a feed coupled to and coplanar with the active portion; and an extension portion being selectively coupleable to the active portion for altering a wavelength of the inverted F antenna.

Claims

1. A Radio Frequency Identification (RFID) device, comprising:

an inverted F antenna having an active portion, a ground plane spaced from the active portion, and a feed coupled to and coplanar with the active portion;

an RFID controller coupled to the feed;

a battery coupled to the RFID controller and in direct electrical communication with the ground plane, wherein

the RFID device is configured to respond to an interrogator using backscatter communication;

wherein the active portion and the ground plane lie on parallel planes;

wherein

the battery is positioned on a plane located between the active portion and the ground plane;

wherein

the inverted F antenna is designed to match an impedance of the controller;

wherein

an extent of the ground plane in a direction parallel to its plane is greater than an extent of the active portion in a direction parallel thereto.

2. The RFID device as recited in claim 1, wherein the RFID device is a semi-active device.

3. The RFID device as recited in claim 1, wherein the RFID device is an active device.

4. The RFID device as recited in claim 1, wherein all portions of the active portion lie along a common plane.

5. The RFID device as recited in claim 1, wherein the feed is coplanar to the active portion for a full extent thereof.

6. The RFID device as recited in claim 1, wherein the feed is of continuous construction with the active portion.

7. The RFID device as recited in claim 1, further comprising an extension portion being selectively coupleable to the active portion for altering a wavelength of the inverted F antenna.

8. A Radio Frequency Identification (RFID) device, comprising:

a substrate;

an inverted F antenna having an active portion coupled to the substrate, a ground plane spaced from the active portion, and a feed coupled to and coplanar with the active portion, wherein the active portion and ground plane lie in parallel planes;

a battery in direct electrical communication with the ground plane, and

a controller coupled to the battery and the feed;

wherein

the substrate includes a ground portion for coupling to a terminal of the battery, wherein the ground portion is in electrical communication with the ground plane and is positioned on a plane located between the active portion and the ground plane, and the ground portion electrically connects the battery to the ground plane, wherein

the RFID device is configured to respond to an interrogator using backscatter communication;

the inverted F antenna is designed to match an impedance of the controller, and

an extent of the ground plane in a direction parallel to its plane is greater than an extent of the active portion in a direction parallel thereto.

9. The RFID device as recited in claim 8, wherein the feed is coplanar to the active portion for a full extent thereof.

10. The RFID device as recited in claim 8, wherein the feed is of continuous construction with the active portion.

11. The RFID device as recited in claim 8, further comprising an extension portion being selectively coupleable to the active portion for altering a wavelength of the inverted F antenna.