Isolated sensor for an antenna

• US 7,457,594 B2
• Filed: 02/03/2005
• Issued: 11/25/2008
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Wright, Edward, Amos, James, Theobold, David
• Primary Examiner(s): Nguyen; Duc M
• Application Number:
  US11/050,518
• Publication Number:
  US 20060014503A1
• Time in Patent Office: 1,391 Days
• Field of Search: 455/126, 455/127.1, 455/522, 455/115.1, 455/115.3, 398/33, 398/38, 398/197
• US Class Current: 455/115.1
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04B 17/102 Power radiated at antenna

Abstract

A system for measuring output power from an antenna. A sensor receives a sample of wireless signals from the antenna and communicates data about the signal back to the transmitter in a manner such that the antenna pattern is undisturbed. An optical coupler, e.g., fiber optic, is used to send data from the sensor to the transmitter. Power for the sensor can be derived parasitically from the wireless signal or can be provided to the sensor optically.

Claims

1. A method for monitoring an antenna with an isolated sensor, comprising:

receiving RF energy from the antenna;

generating data based on the received RF energy from the antenna; and

optically communicating the data to a transmitter coupled to the antenna;

wherein the power for the isolated sensor is obtained by one of a group consisting of passively from the received RF energy and optically from an optical coupler.

2. A method according to claim 1, further comprising

the generating an optical signal further comprising

rectifying the RF energy, and

modulating a light emitting diode, thereby converting the RF energy to light energy;

and

the communicating an optical signal further comprising

detecting the light energy, and

converting the detected light energy to an electrical signal.

3. A method according to claim 1, further comprising:

transmitting power to the sensor wirelessly from the transmitter.

4. A method according to claim 3, the transmitting power further comprising sending power optically to the sensor.

5. A system, comprising:

an adjustable transmit power source;

an antenna coupled to the adjustable power source;

a sensor adapted for receiving wireless signals from the antenna, the sensor comprising a copper loop for receiving wireless signals from the antenna; and

an optical coupler for providing data from the sensor to the adjustable transmit source;

wherein power for the sensor is obtained passively from the wireless signals from the antenna.

6. A system according to claim 5, further comprising:

a circuit communicatively coupled to the antenna for storing data about the antenna;

a bidirectional communication interface coupling the circuit to the adjustable transmit power source;

wherein the optical coupler is coupled to the circuit and provides the data from the sensor to the circuit; and

wherein the adjustable transmit power source obtains the data from sensor via the bidirectional interface from the circuit.

7. A system according to claim 6, the circuit further comprising:

a microcontroller; and

a memory for storing the data and antenna parameters.

8. A system according to claim 6, wherein the adjustable transmit power source adjusts the transmit power based on the data received via the bidirectional interface from the circuit.

9. A system according to claim 5, the sensor further comprising:

a capacitor connected in parallel with the copper loop for storing energy received from the copper loop;

a diode coupled between the capacitor and copper loop; and

a light emitting diode coupled in parallel with the capacitor;

wherein the light emitting diode provides optical energy to the optical coupler.

10. A system according to claim 5, wherein the optical coupler comprises a fiber optic cable.

11. A system according to claim 5, the adjustable transmit power source further comprising a microprocessor configured to adjust the transmit power of the adjustable transmit power source based on the data received from the sensor.

12. A system, comprising:

an adjustable transmit power source;

an antenna coupled to the adjustable power source;

a sensor adapted for receiving wireless signals from the antenna; and

an optical coupler for providing data from the sensor to the adjustable transmit source;

wherein the sensor receives power optically via the optical coupler.

13. A system according to claim 12, further comprising:

a circuit communicatively coupled to the antenna for storing data about the antenna;

a bidirectional communication interface coupling the circuit to the adjustable transmit power source

wherein the optical coupler is coupled to the circuit and provides the data from the sensor to the circuit; and

wherein the adjustable transmit power source obtains the data from sensor via the bidirectional interface from the circuit.

14. A system according to claim 13, the circuit further comprising:

a microcontroller; and

a memory for storing the data and antenna parameters.

15. A system according to claim 13, wherein the adjustable transmit power source adjusts the transmit power based on the data received via the bidirectional interface from the circuit.

16. A system according to claim 12, the sensor further comprising:

a copper loop for receiving wireless signals from the antenna; and

wherein power for the sensor is obtained passively from the wireless signals from the antenna.

17. A system according to claim 16, the sensor further comprising:

a capacitor connected in parallel with the copper loop for storing energy received from the copper loop;

a diode coupled between the capacitor and copper loop; and

a light emitting diode coupled in parallel with the capacitor;

wherein the light emitting diode provides optical energy to the optical coupler.

18. A system according to claim 12, wherein the optical coupler comprises a fiber optic cable.

19. A system according to claim 12, wherein data is sent from the sensor via the optical coupler using a first frequency, and power is sent from the adjustable transmit power source via the optical coupler using a second frequency.

20. A system according to claim 12, the optical coupler further comprising:

a first optical link for sending data from the sensor; and

a second optical link for sending power from the adjustable transmit power source;

wherein power for the sensor is received via the second optical link.

21. A system according to claim 12, further comprising:

the adjustable transmit power source further comprising a light emitting diode optically coupled to the optical coupler;

the sensor further comprising an optical transistor coupled to the optical coupler;

wherein power from the adjustable transmit power source is transmitted by the light emitting diode to the optical transistor.

22. A system according to claim 12, the adjustable transmit power source further comprising a microprocessor configured to adjust the transmit power of the adjustable transmit power source based on the data received from the sensor.