System and method for determining attenuation of electromagnetic waves impacting an electromagnetic shield

• US 20070241761A1
• Filed: 03/08/2007
• Published: 10/18/2007
• Est. Priority Date: 03/08/2006
• Status: Active Grant

• Current Assignee: Tritech Applied Sciences, Inc.
• Original Assignee: Tritech Applied Sciences, Inc.
• Inventors: Condon, Gilbert, Stone, George
• Granted Patent: US 7,675,294 B2
• Time in Patent Office: Days
• US Class Current: 324/627
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G01R 29/0871 Complete apparatus or systems; circuits, e.g. receivers or amplifiers G01R29/0878, G01R29/0892 take precedence; dosimeters, warning devices G01R29/0857

Abstract

A method for determining attenuation of electromagnetic waves impacting an electromagnetic shield. A reference amplitude is provided. A signal exhibiting a first frequency is converted to a converted signal exhibiting a second frequency higher than the first frequency. Electromagnetic waves corresponding to the converted signal are transmitted from a first antenna toward a second antenna with the electromagnetic shield positioned between them. Attenuated remnants of the electromagnetic waves received by the second antenna are converted to a corresponding signal exhibiting a third frequency that is lower than the second frequency. The amplitude of the corresponding signal is compared to the reference amplitude.

Claims

1. A system for determining a level of amplitude attenuation of electromagnetic waves impacting an electromagnetic shield, the system comprising:

a signal generator for producing a first signal exhibiting a first frequency;

a first converter for changing the first signal to a second signal exhibiting a second frequency higher than the first frequency;

a first antenna for converting the second signal to electromagnetic waves substantially exhibiting the second frequency and for transmitting the electromagnetic waves toward the electromagnetic shield;

a second antenna for receiving remnants of the electromagnetic waves attenuated by the electromagnetic shield and for converting the remnants to a third signal substantially exhibiting the second frequency;

a second converter for converting the third signal to a fourth signal exhibiting a third frequency lower than the second frequency; and

a measuring receiver coupled to the second converter for determining amplitude of the fourth signal.

2. The system of claim 1, wherein the second antenna receives the attenuated remnants of the electromagnetic waves after the electromagnetic waves pass through the electromagnetic shield.

3. The system of claim 1, wherein the first antenna is positioned on a side of the electromagnetic shield and the second antenna is positioned on a second side of the electromagnetic shield.

4. The system of claim 1, wherein the first frequency is within a VHF range of frequencies.

5. The system of claim 1, wherein the second frequency is within a microwave range of frequencies.

6. The system of claim 1, wherein the third frequency is within a VHF range of frequencies.

7. The system of claim 1, wherein the first antenna is an omnidirectional antenna.

8. The system of claim 1, wherein the first antenna is a directional antenna.

9. The system of claim 1, wherein the first converter is operable to convert the first signal to a second frequency selected from a range of frequencies higher than the first frequency.

10. The system of claim 9, wherein the range of frequencies is from 10 GHz to 10.3 GHz.

11. A system for determining an attenuation level of electromagnetic waves impacting an electromagnetic shield, the system comprising:

a first converter receiving a first signal exhibiting a first frequency and converting the first signal to a second signal exhibiting a second frequency higher than the first frequency;

a first antenna positioned on a side of the electromagnetic shield receiving the second signal for transmitting corresponding electromagnetic waves substantially exhibiting the second frequency through the electromagnetic shield toward a second antenna positioned on another side of the electromagnetic shield, the second antenna receiving attenuated remnants of the electromagnetic waves attenuated by the electromagnetic shield and producing a corresponding third signal substantially exhibiting the second frequency;

a second converter for converting the third signal to a fourth signal exhibiting a third frequency lower than the second frequency for transmission to a measuring receiver.

12. The system of claim 11, further comprising an attenuator coupled between the first converter and the first antenna for decreasing amplitude of the signal transmitted to the first antenna and to the measuring receiver for testing accuracy of the attenuation determination.

13. An apparatus for receiving electromagnetic waves exhibiting a received frequency, the apparatus comprising an antenna coupled to a down-converter, wherein the antenna converts the electromagnetic waves to a signal substantially exhibiting the received frequency and wherein the down-converter converts the signal to a converted signal exhibiting a converted frequency lower than the received frequency, and a connector for transferring the converted signal to a measuring receiver.

14. The apparatus of claim 13, further comprising an amplifier coupled to the antenna for amplifying the signal.

15. The apparatus of claim 13, wherein the received frequency is selected from a microwave range and the converted frequency is selected from a VHF range of frequencies.

16. A method for determining an attenuation level of electromagnetic waves impacting an electromagnetic shield, the method comprising:

converting a produced signal exhibiting a first frequency to a converted signal exhibiting a second frequency higher than the first frequency;

transmitting electromagnetic waves corresponding to the converted signal from a first antenna toward a second antenna without the electromagnetic shield positioned between the first antenna and the second antenna;

converting the electromagnetic waves received by the second antenna to a corresponding signal exhibiting a third frequency lower than the second frequency;

determining a first amplitude of the corresponding signal, thereby providing a reference amplitude;

transmitting the electromagnetic waves corresponding to the converted signal from the first antenna toward the second antenna with the electromagnetic shield positioned between the first antenna and the second antenna;

converting attenuated remnants of the electromagnetic waves received by the second antenna to a second corresponding signal exhibiting a fourth frequency lower than the second frequency;

determining a second amplitude of the second corresponding signal; and

comparing the second amplitude to the reference amplitude.

17. The method of claim 16, wherein the second frequency is a microwave.

18. The method of claim 16, wherein at least one of the third frequency and the fourth frequency is selected from a VHF range of frequencies.

19. The method of claim 16, wherein the fourth frequency is substantially the same frequency as the second frequency.

20. A method for determining an attenuation level of electromagnetic waves impacting an electromagnetic shield, the method comprising:

providing a reference amplitude;

converting a signal exhibiting a first frequency to a converted signal exhibiting a second frequency higher than the first frequency;

transmitting electromagnetic waves corresponding to the converted signal from a first antenna toward a second antenna with the electromagnetic shield positioned between the first antenna and second antenna;

converting attenuated remnants of the electromagnetic waves received by the second antenna to a corresponding signal exhibiting a third frequency lower than the second frequency;

determining a second amplitude of the corresponding signal;

comparing the second amplitude to the reference amplitude.