Compact omni-directional RF system

• US 7,683,789 B2
• Filed: 03/04/2005
• Issued: 03/23/2010
• 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
• Primary Examiner(s): Previl; Daniel
• Application Number:
  US11/073,239
• Publication Number:
  US 20060208958A1
• Time in Patent Office: 1,845 Days
• Field of Search: 340/572.7, 340/10.1, 340/572.1, 340/540, 340/568.1, 340/10, 340/572.5, 340/572.8, 340/825, 340/825.49, 340/10.4, 340/10.5, 340/825.59, 235/462.46, 235/462.01, 342/463, 342/465, 342/350, 342/450, 343/700.R, 343/867, 455/41.1, 455/39
• US Class Current: 340/572.7
• 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 circuit for summing signals from multiple lobes of an antenna includes circuitry for converting RF signals from lobes of an antenna to baseband signals, and circuitry for summing the baseband signals from the lobes of an antenna.

Claims

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

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

circuitry for summing the baseband signals from the lobes of the antenna prior to conversion of the baseband signals to digital signals 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 an adder to an input of the adder.

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 signals are input to a negative pole of an amplifier circuit.

4. A circuit as recited in claim 1, wherein the feedback loop includes at least one of a capacitor and a resistor.

5. A circuit as recited in claim 1, wherein the feedback loop includes a capacitor, a resistor, and a pair of back to back diodes.

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

7. A circuit as recited in claim 1, wherein the circuit is implemented in a radio frequency identification tag.

8. A circuit, comprising:

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

circuitry for summing the baseband signals from the lobes of the antenna,

wherein the circuitry for summing the baseband signals from each lobe further comprises an adder,

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,

wherein the feedback loop includes at least one of a capacitor and a resistor.

9. A circuit, comprising:

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

circuitry for summing the baseband signals from the lobes of the antenna,

wherein the circuitry for summing the baseband signals from each lobe further comprises an adder,

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.

10. A circuit as recited in claim 9, further comprising a multistage multiplier for enhancing the RF signals from the lobes of the antenna, wherein the circuitry for summing the baseband signals from the lobes of the antenna sums the baseband signals prior to conversion of the baseband signals to digital signals.

11. A circuit as recited in claim 10, 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.

12. A circuit as recited in claim 11, wherein the circuit is implemented in a radio frequency identification tag.

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

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

circuitry for summing the analog baseband signals from each lobe of the 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 tag.

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

circuitry for converting RF signals from lobes of an antenna to analog baseband signals, wherein the circuitry for converting RF signals from lobes of an antenna to analog 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 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 an adder to an input of the adder.