The effects of VSWR on connector shielding effectiveness measurements in a mode-stirred chamber

It is generally accepted among users of mode-stirred chambers that voltage-standing-wave-ratio (VSWR) differences between a test sample and a reference measurement antenna can affect the measured shielding effectiveness (SE) of the test sample. A connector was tested in two fixtures having different VSWR characteristics. Two different methods were used with each fixture, one which corrects for VSWR differences and one which does not. The results obtained using each method and fixture are compared in order to determine how VSWR differences affect connector shielding measurements in the 1-10-GHz range. For connector testing at 1-10 GHz, VSWR adjustments affect the SE values by only 1-2 dB maximum when the VSWR of the connector/test fixture is less than 5:1. This is within the measurement system error. A VSWR of 8.7:1 was found to affect the SE value by 4 dB. This suggests that the maximum VSWR of the connector/test fixture to be allowed in the revised MIL-STD-1344 method 3008 may be 5:1 or more, but less than 9:1.<
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