Electromagnetic Field Detection Systems and Methods

• US 20110092181A1
• Filed: 10/18/2010
• Published: 04/21/2011
• Est. Priority Date: 10/16/2009
• Status: Active Grant

• Current Assignee: Techhold, LLC
• Original Assignee: Emprimus, LLC
• Inventors: Noe, Terrence R., Faxvog, Frederick R., Fuchs, Greg, Jackson, David Blake
• Granted Patent: US 8,860,402 B2
• Time in Patent Office: Days
• US Class Current: 455/341
• CPC Class Codes: G01R 15/185 with compensation or feedback windings or interacting coils, e.g. 0-flux sensors using galvano-magnetic field sensors G01R15/20; conversion of DC into AC using transductors G01R19/20
• CPC Class Codes: G01R 19/20 using transductors , i.e. a magnetic core transducer the saturation of which is cyclically reversed by an AC source on the secondary side
• CPC Class Codes: G01R 29/0814 Field measurements related to measuring influence on or from apparatus, components or humans EMC, EMI and similar testing in general G01R31/001, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24

Abstract

Detectors and other apparatus for determining the presence of electromagnetic events are disclosed. One such system includes an electromagnetically shielded enclosure and a detector configured to detect an electromagnetic field event occurring in the proximity of the enclosure. The detector includes an antenna and a circuit electrically connected to the antenna. The circuit includes electronics communicatively connected to the antenna via a direct current isolation circuit, and an equalizer compensating for the differentiating frequency response of the antenna. The circuit also includes a logarithmic amplifier electrically connected to the equalizer and configured to generate a range of signals based on signals received at the antenna, and a peak detector receiving signals from the logarithmic amplifier and configured to capture a peak value of the signals. An electromagnetic field event is detected at least in part based on the peak signal value.

Claims

1. An electromagnetic event detection system comprising:

an electromagnetically shielded enclosure; and

a detector configured to detect an electromagnetic field event, the detector comprising;

an antenna;

a circuit electrically connected to the antenna, the circuit including;

an equalizer communicatively connected to the antenna via a direct current isolation circuit, the equalizer compensating for differentiating frequency response of the antenna;

a logarithmic amplifier electrically connected to the equalizer and configured to generate a range of signals based on signals received at the antenna; and

a peak detector receiving signals from the logarithmic amplifier and configured to capture a peak value of the signals;

wherein an electromagnetic field event is detected at least in part based on the peak value.

2. The electromagnetic event detection system of claim 1, wherein the detector is located within the electromagnetically shielded enclosure.

3. The electromagnetic event detection system of claim 2, whereby detection of an electromagnetic event indicates that the electromagnetically shielded enclosure has been compromised.

4. The electromagnetic event detection system of claim 1, further comprising a microprocessor communicatively connected to the peak detector and configured to determine the existence of an electromagnetic field event.

5. The electromagnetic event detection system of claim 1, further comprising a computing system configured to monitor the detector, the computing system configured to determine whether an electromagnetic field event occurs based on a comparison of the peak value to a predetermined value.

6. The electromagnetic event detection system of claim 5, wherein, upon determination of an electromagnetic event, the computing system generates a notification.

7. The electromagnetic event detection system of claim 6, wherein the notification is a notification selected from the group consisting of:

a door ajar notification;

a compromised shielding notification; and

an electronic equipment malfunction.

8. The electromagnetic event detection system of claim 1, wherein the detector resides external to the electromagnetically shielded enclosure.

9. The electromagnetic event detection system of claim 8, wherein the electromagnetically shielded enclosure includes an opening sized to receive an electrical cable connecting the circuit to a computing system within the electromagnetically shielded enclosure, the opening including a radio frequency gasket sized and positioned to prevent electromagnetic signals from penetrating the electromagnetically shielded enclosure through the opening.

10. An electromagnetic event detection apparatus comprising:

a circuit configured to detect an electromagnetic event, the circuit comprising;

an equalizer communicatively connected to an antenna via a direct current isolation circuit, the equalizer compensating for differentiating frequency response of the antenna;

a logarithmic amplifier electrically connected to the equalizer and configured to generate a range of signals based on signals received at the antenna;

a peak detector receiving signals from the logarithmic amplifier and configured to capture a peak value of the signals; and

a microprocessor configured to detect an electromagnetic field events at least in part based on the peak value; and

a housing at least partially enclosing the circuit.

11. The electromagnetic event detection apparatus of claim 10, wherein the housing provides electromagnetic shielding around the circuit.

12. The electromagnetic event detection apparatus of claim 10, further comprising an antenna extending from the housing.

13. The electromagnetic event detection apparatus of claim 10, further comprising a communication interface communicatively connected to the microprocessor and positioned within the housing, the communication interface configured to translate electrical signals to optical signals for transmission on an optical fiber extending from the housing.

14. The electromagnetic event detection apparatus of claim 13, further comprising a waveguide beyond cutoff positioned at least partially within the housing and along the optical fiber.

15. The electromagnetic event detection apparatus of claim 10, further comprising a filtered signal wire extending from the housing and configured for communication with a remote computing system.

16. The electromagnetic event detection apparatus of claim 15, wherein the signal wire is an analog signal cable additionally configured to provide power to the circuit.

17. The electromagnetic event detection apparatus of claim 15, wherein the signal wire is a digital signal cable additionally configured to provide power to the circuit.

18. The electromagnetic event detection apparatus of claim 15, wherein the signal wire is selected from a group of signal wire types comprising:

an RS-232 cable; and

an RJ-45 twisted pair cable.

19. An electromagnetic detector system comprising:

a plurality of detectors positioned at a plurality of locations at a facility, each of the plurality of detectors including;

an antenna;

a circuit electrically connected to the antenna, the circuit including;

an equalizer communicatively connected to the antenna via a direct current isolation circuit, the equalizer compensating for differentiating frequency response of the antenna;

a logarithmic amplifier electrically connected to the equalizer and configured to generate a range of signals based on signals received at the antenna; and

a peak detector receiving signals from the logarithmic amplifier and configured to capture a peak value of the signals;

a detection system communicatively connected to each of the plurality of detectors, the detection system including one or more computing systems configured to receive information from the plurality of detectors regarding observed electromagnetic fields and further configured to detect the presence of an electromagnetic event at one or more of the detectors.

20. The electromagnetic detector system of claim 19, wherein the detection system is configured to store the information from the plurality of detectors and the observed electromagnetic events.

21. The electromagnetic detector system of claim 19, wherein the detection system is configured to communicate an alarm message to a remote monitoring system.

22. The electromagnetic detector system of claim 19, wherein the circuit further includes a microprocessor configured to capture the peak value and periodically communicate one or more peak values to the detection system.

23. The electromagnetic detector system of claim 19, wherein each of the plurality of detectors includes an electromagnetically shielded housing enclosing the circuit.