IEEE Std 1302:1998 pdf free download

IEEE Std 1302:1998 pdf free download.IEEE Guide for the Electromagnetic Characterization of Conductive Gaskets in the Frequency Range of DC to 18 GHz.
The aperture transmission measurement techniques provide results in decibels, which are very attractive to equipment and system designers who tend to visualize gasket performance in such temis. however, the field attenuation that is exhibited by a gasketed seam is strongly dependent upon the nature of the electromagnetic field on the illuminated side of the seani, and on the particular field coniponent thai is being measured on the “receive” side of the seam. The effects of the aperture that is used for measurements can overshadow the attenuation that is provided by the gasket alone. Hecause of the many factors that can affect measurement results, data taken under different test conditions can be markedly different. Furthermore, test results are hard to relate to the gasket’s intrinsic transfer impedance.
The standardized aperture transmission techniques measure the signal through the gasketed aperture at specific orientations and look angles. As noted above, however, the signal coupled through the gasket is strongly influenced by the measurement antenna locations relative to the aperture and by the surrounding enclosures. To fully characterize the coupling through the gasket, the illuminating antenna is often moved about, so as to expose the seam to various incident field conditions, and detailed field measurements over the hemispherical volume on the output side of the gasketed joint are made, Since each possible antenna pairing involves a measurement of the coupling with and without a gasket present, the level of effort required to perform the evaluation is high.
The effects of enclosure and fixture resonances must be recognized. Fixture resonances currently limit the transfer impedance technique to below about 2000 MHz. The chambers used with radiated techniques are resonant cavities. Once their longest dimension (typically the distance between diagonally opposite corners) reaches one-half wavelength, resonant modes exist from that frequency upward. Some of these resonances can be very sharp. Consequently, very small changes in antenna position inside the chamber can produce very large changes in the measured signal level. In addition, the size of the aperture influences the attenuation of the field that is coupled through it. If the aperture is significantly less than one wavelength, the attenuation through it is very high, and is inversely proportional to frequency. This attenuation limits the lowest frequencies that can be effectively measured.