Compact omni-directional RF system

• US 20060208958A1
• Filed: 03/04/2005
• Published: 09/21/2006
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Stewart, Roger Green, Shyu, Jyn-Bang
• Granted Patent: US 7,683,789 B2
• Time in Patent Office: Days
• US Class Current: 343/852
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00

Abstract

A radio frequency (RF) system having omindirectional functionality includes a supporting substrate, a circuit coupled to the substrate, and an antenna coupled to the circuit, the antenna having multiple lobes, wherein responses from the lobes are demodulated and combined at baseband. The circuit is positioned over a physical area of a portion of the antenna, the antenna acting as a virtual ground plane for the circuit.

Claims

1. A radio frequency (RF) circuit for summing signals from multiple lobes of an antenna, comprising:

circuitry for converting RF signals from lobes of an antenna to baseband signals;

circuitry for summing the baseband signals from the lobes of an antenna.

2. A circuit as recited in claim 1, wherein the circuitry for summing the baseband signals from each lobe further comprises an adder.

3. A circuit as recited in claim 2, wherein the circuitry for summing the baseband signals from each lobe further comprises a feedback loop for feeding back a signal from an output of the adder to an input of the adder.

4. A circuit as recited in claim 3, wherein the feedback loop includes a capacitor.

5. A circuit as recited in claim 3, wherein the feedback loop includes a resistor.

6. A circuit as recited in claim 3, wherein the feedback loop includes a capacitor, a resistor, and a pair of back to back diodes.

7. A circuit as recited in claim 2, wherein the signals are input to a negative pole of an amplifier circuit.

8. A circuit as recited in claim 1, wherein the circuitry for converting RF signals from lobes of an antenna to baseband signals further comprises circuitry for creating a differential output from the RF signals from the lobes of the antenna, the circuitry combining positive signals from the lobes in one path, the circuit combining negative signals from the lobes in another path.

9. A circuit as recited in claim 8, further comprising a multistage multiplier for enhancing the RF signals from the lobes of the antenna.

10. A circuit as recited in claim 9, wherein the multistage multiplier includes several voltage multipliers, one voltage multiplier being associated with each lobe of the antenna, wherein a voltage multiplier is coupled to the positive and negative inputs from the associated lobe of the antenna.

11. A circuit as recited in claim 1, further comprising band pass filtering circuitry.

12. A circuit as recited in claim 1, wherein the circuit is implemented in a radio frequency identification (RFID) tag.

13. A radio frequency (RF) circuit for summing signals from multiple lobes of an antenna, comprising:

circuitry for converting RF signals from lobes of an antenna to baseband signals;

circuitry for creating a differential output from the RF signals from the lobes of the antenna, the circuitry combining positive signals from the lobes in one path, the circuit combining negative signals from the lobes in another path

circuitry for summing the baseband signals from each lobe of an antenna;

wherein the circuitry for summing the baseband signals from each lobe further comprises an adder, the baseband signals being input into the adder.

14. A circuit as recited in claim 13, further comprising a multistage multiplier for enhancing the RF signals from the lobes of the antenna, the multistage multiplier including several voltage multipliers, one voltage multiplier being associated with each lobe of the antenna, wherein a voltage multiplier is coupled to the positive and negative inputs from the associated lobe of the antenna.

15. A circuit as recited in claim 13, further comprising band pass filtering circuitry.

16. A circuit as recited in claim 13, wherein the circuit is implemented in a radio frequency identification (RFID) tag.

17. A radio frequency (RF) circuit for summing signals from multiple lobes of an antenna, comprising:

circuitry for converting RF signals from lobes of an antenna to baseband signals, wherein the circuitry for converting RF signals from lobes of an antenna to baseband signals further comprises circuitry for creating a differential output from the RF signals from the lobes of the antenna, the circuitry combining positive signals from the lobes in one path, the circuit combining negative signals from the lobes in another path.