Inquiry method of the source which generates electromagnetic wave

• US 6,697,744 B2
• Filed: 08/17/2001
• Issued: 02/24/2004
• Est. Priority Date: 03/16/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Suga, Takashi, Uesaka, Kouichi
• Primary Examiner(s): Chapman, John E.
• Assistant Examiner(s): KERVEROS, JAMES C
• Application Number:
  US09/932,420
• Publication Number:
  US 20020158640A1
• Time in Patent Office: 921 Days
• Field of Search: 324/638, 324/529, 324/530, 324/765, 324/750, 324/627, 324/628, 324/637, 324/639, 324/642, 343/703, 702/57
• US Class Current: 702/57
• 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

Abstract

The electromagnetic-wave-generating-source search method includes the steps of calculating a first electric field strength at a measuring point based on a current distribution belonging to an object to be measured; calculating a second electric field strength at said measuring point by employing the current distribution at a preselected position on said measuring object, the preselected position corresponding to a portion of the current distribution of said measuring object; and calculating a relative ratio of said first electric field strength with respect to said second electric field strength, thereby determining the source generating a remote electric field.

Claims

1. An electromagnetic wave generating source searching method, comprising the steps of:

(a) calculating a current distribution with use of a magnetic field strength and a phase measured from an object to be measured;

(b) calculating a first electric field strength at a measuring point based upon said current distribution;

(c) calculating a second electric field strength at said measuring point by employing a current distribution at a predetermined position on said measuring object, which corresponds to a part of the current distribution of said measuring object; and

(d) calculating a relative ratio of said fist electric field strength with respect to said second electric field strength.

2. An electromagnetic wave generating source searching method as claimed in claim 1 wherein:

in said step (d), a difference between said first electric field strength and said second electric field strength is calculated, and a ratio of said difference with respect to said first electric field strength is calculated.

3. An electromagnetic wave generating source searching method as claimed in claim 1 wherein:

the step (a) of calculating said current distribution with use of said magnetic strength and said phase includes a step of executing an inner product between a measured magnetic field synthesized complex vector and a calculated magnetic field synthesized complex vector.

4. An electromagnetic wave generating source searching method as claimed in claims 1 wherein:

while said measuring object is subdivided alto a mesh shaped object, said current distribution is constituted by such a fact as to whether or not a current is present at a cross point of said mesh shaped object, and also a current distribution present at a predetermined position over said measuring object is used as current information related to said cross point.

5. An electromagnetic wave generating source searching method as claimed in claim 1 wherein:

while the magnetic distribution is measured by a frequency spectrum said current distribution is calculated based upon this measurement result of the magnetic distribution.

6. A electromagnetic wave generating source searching method as claimed in claim 5 wherein:

a frequency characteristic of said current distribution is calculated by way of a simutation.

7. An electromagnetic wave generating source searching method as claimed in claim 1, further comprising a step of editing the current distribution to calculate a third electric field strength from the edited current distribution.