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A MINIATURE BROADBAND ISOTROPIC MAGNETIC FIELD PROBE

IP.com Disclosure Number: IPCOM000005524D
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2001-Oct-11
Document File: 2 page(s) / 105K

Publishing Venue

Motorola

Related People

Tadeusz M. Babij: AUTHOR

Abstract

Recently, there has been a rapid and widespread increase in the application of electromagnetic (EM) energy to a variety of human activities: communication, industrial processing, and medical practice to mention a few. Extremely strong EM fields can damage living tissue, trigger explosive devices, and ignite volatile fuels. Along with the rapid increase of the use of EM energy there has been a surge in the need for accurate EM-field sensing equipment for safety and monitoring purposes.

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MOTOROLA Technical Developments Volume4 April 1984

A MINIATURE BROADBAND ISOTROPIC MAGNETIC FIELD PROBE

by Tadeusz M. Babij

STATEMENT OF PROBLEM

    Recently, there has been a rapid and widespread increase in the application of electromagnetic (EM) energy to a variety of human activities: communication, industrial processing, and medical practice to mention a few. Extremely strong EM fields can damage living tissue, trigger explosive devices, and ignite volatile fuels. Along with the rapid increase of the use of EM energy there has been a surge in the need for accurate EM-field sensing equipment for safety and monitoring purposes.

The space surrounding electromagnetic radiation and/or reradiation sources is usually subdivided into three regions:

a. induction-near field.
b. radiation-near field (Fresnel).
c. far field (Fraunhofer) regions.

In the near-field, the relationship between the electric and magnetic field components cannot be expressed in simple terms. Near-field regions are characterized by complicated field structures, including reactive (stored) and real (propagating) energies, standing and traveling waves, and complicated constant phase surfaces.

   At distances remote(far-field region) from a radiating/reradiating source, the EM fieldsare fairly easy to measure, and the methods for doing so are well known. In near-field regions it has been a common practice to measure separately the electric field components and magnetic field components. In the literature one can find the desired characteristics of the sensors for near-field measurements, The sensors for the electric vector component and/or the magnetic vector component should have:

- Isotropic detection pattern. - Small dimensions of the sensor in comparison to wavelength. - Hiph resistance feed line (transparent to the RF field) to convey the detected sianal to readout electronics.

While the above conditions have been met for E-field probes, H-field probes operating at frequencies above 300 MHz have been difficult to manufacture and are not commercially available.

SOLUTION

    The objective of the device is to provide a miniature...