Antenna capacitance for energy storage

• US 20080055092A1
• Filed: 08/25/2006
• Published: 03/06/2008
• Est. Priority Date: 08/25/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Burr, Jeremy
• Granted Patent: US 7,479,886 B2
• Time in Patent Office: Days
• US Class Current: 340/572.7
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• 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 1/248 provided with an AC/DC converting device, e.g. rectennas

Abstract

Various embodiments of the invention may include an antenna for a wireless device, the antenna operable to store electrical energy received from a power source. The stored electrical energy may then be used to power the circuitry of the device. Storing electrical power in this manner may allow the device to temporarily continue operating when the incoming harvested energy becomes too weak to instantaneously provide all the power needed to continue operating the device. In some embodiments the wireless device is a radio frequency identification (RFID) tag.

Claims

1. An apparatus, comprising

a device for wireless communications, comprising:

an antenna;

an electronic circuit coupled to the antenna;

a power harvesting circuit coupled to the antenna, the power harvesting circuit to obtain electrical energy from a power source;

wherein the antenna is operable as a capacitor to store at least a portion of the electrical energy harvested by the power harvesting circuit, and to provide at least a portion of the stored electrical energy as operating power to the electronic circuit.

2. The apparatus of claim 1, wherein the antenna comprises a dipole antenna.

3. The apparatus of claim 1, wherein an element of the antenna comprises two layers of conductive material separated by a dielectric material.

4. The apparatus of claim 3, wherein the antenna comprises capacitive coupling between the element and an antenna input of the electronic circuit.

5. The apparatus of claim 1, wherein the electronic circuit is part of a radio frequency identification (RFID) tag.

6. The apparatus of claim 5, further comprising an object connected to the RFID tag, the object to be identified by an identification number contained in the RFID tag circuit.

7. An apparatus, comprising

an antenna assembly for connection to a device for wireless communications, the antenna assembly comprising:

a first antenna element having a dielectric material between a first electrical conductor and a second electrical conductor to form a first electrical capacitor to store electrical energy to operate the device;

a first set of electrical contacts to couple a radio frequency (RF) signal from the first antenna element to a set of antenna connections of the device; and

a second set of electrical contacts to couple the first electrical capacitor to a set of power connections of the device.

8. The apparatus of claim 7, further comprising a second antenna element having a dielectric material between a third electrical conductor and a fourth electrical conductor to form a second electrical capacitor to store the electrical energy to operate the device.

9. The apparatus of claim 7, wherein the antenna assembly further comprises a balun transformer to match an impedance of the antenna assembly to an impedance of the device.

10. The apparatus of claim 7, wherein the antenna assembly further comprises a capacitor circuit to block direct current from draining from the first electrical capacitor to the first set of electrical contacts.

11. The apparatus of claim 7, wherein the first antenna element comprises multiple layers of the first conductor interspersed between multiple layers of the second conductor, with the dielectric material between the multiple layers of the first conductor and the multiple layers of the second conductor.

12. The apparatus of claim 7, wherein the device is to include a radio frequency identification (RFID) tag circuit.

13. The apparatus of claim 13, further comprising the RFID tag circuit.

14. A method, comprising:

receiving electrical energy from a power generating source;

storing at least a portion of the received electrical energy in an antenna element configured as a capacitor; and

providing at least a portion of the stored electrical energy as electrical power to operate circuitry that controls wireless communications through the antenna.

15. The method of claim 14, wherein all operating power for the circuitry is obtained from said receiving, said storing, and said providing.

16. The method of claim 14, wherein said receiving comprises receiving the electrical energy from a power generating source that does not include a battery.

17. The method of claim 16, wherein:

said receiving comprises receiving the electrical energy as radio frequency signals through the antenna; and

said providing comprises providing the stored electrical energy to a radio frequency identification (RFID) tag circuit.