Question: In determining the uncertainty contribution of the reflectivity level of an anechoic chamber for UE/MS OTA antenna performance testing, how are the 264 standard deviation values in both polarizations typically obtained?
Option 1: By conducting a single free space VSWR measurement at the center of the quiet zone and extrapolating to cover the entire area.
Option 2: Through repeating a free space VSWR measurement in a 5-degree grid in elevation and azimuth across the quiet zone.
Option 3: By repeating a free space VSWR measurement in a 15-degree grid in elevation and azimuth, yielding 264 standard deviation values in both polarizations.
Option 4: Via efficiency calibration with a directional antenna, focusing on the quiet zone's central axis.
Explanation: This method comprehensively covers the quiet zone by repeating measurements across a defined grid (15-degree intervals in elevation and azimuth), ensuring a thorough assessment of the electric field's standard deviation in both polarizations, crucial for accurately determining the uncertainty contribution of the anechoic chamber's reflectivity level.