Accession Number : AD0696494

Title :   ELECTROMAGNETIC INTERFERENCE MEASUREMENT METHODOLOGY, COMMUNICATION EQUIPMENT.

Descriptive Note : Final rept. 1 Feb 68-31 May 69,

Corporate Author : GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION

Personal Author(s) : Free,William R. ; Stuckey,Charles W.

Report Date : OCT 1969

Pagination or Media Count : 114

Abstract : The report summarizes the accomplishments on a program to develop improved test techniques and procedures for performing radiated measurements in shielded enclosures which can be correlated with measurements made in the open-field. A set of three short hooded probe antennas to cover the 1 to 12 GHz frequency range were developed and evaluated. Results from this program indicate that reliable radiated measurements, which can be correlated with open-field measurements, can be made in shielded enclosures with short hooded probe antennas over the 200 MHz to 12 GHz frequency range. Coupling nulls were observed in shielded enclosures in the frequency range from 10 to 100 MHz. The presence of these nulls could not be explained on the basis of cavity resonances or multi-path reflections from the enclosure walls since the dimensions on the enclosures were quite small in terms of wavelengths. It was concluded that a different coupling mechanism must be responsible for the existance of these coupling nulls. A theory was developed to explain the nulls in terms of near-field coupling between the radiating source and the enclosure extensive experimental measurements supported the validity of this theory. The coupling nulls were essentially eliminated by isolating the probe antenna from the enclosure walls. (Author)

Descriptors :   (*COMMUNICATION EQUIPMENT, ELECTROMAGNETIC COMPATIBILITY), (*RADIOFREQUENCY INTERFERENCE, TEST METHODS), ARMY EQUIPMENT, ELECTROMAGNETIC SHIELDING, ANTENNAS, TEST EQUIPMENT, ELECTROMAGNETIC FIELDS

Subject Categories : Test Facilities, Equipment and Methods
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE