Calculating Volumetric Site Voltage Standing Wave Ratio in Hybrid Chambers
Volumetric site voltage standing wave ratio in hybrid chambers isolates 3D quiet zone reflections by converting normalized spatial field ripples into linear ratios.
Spatial Sampling Grid
Meaning
Coordinate systems used to position measurement probes in an electromagnetic field determine the resolution of the recorded radiation pattern. The geometry of the spatial sampling grid dictates the number and location of the points where the test software records the field strength. This configuration must balance the need for detail with the time required for the test.
Density Selection
High-frequency signals require a tighter spacing of measurement points to prevent aliasing. In an antenna test, the spatial sampling grid must have a density that meets the Nyquist criteria for the shortest wavelength tested. If the points are too far apart, the recorded data will miss the narrow nulls in the radiation pattern.
This resolution is calculated during the test plan creation phase.
Algorithm Execution
Automated motion controllers move the antenna positioner according to the defined coordinate plan. This execution of the spatial sampling grid must be synchronized with the sweep of the receiver to ensure each data point is captured correctly. The recorded values are processed to calculate the total radiated power of the module.
This analysis is critical for verifying compliance with emission limits. High-speed measurement setups use continuous sweeps to scan these points without stopping the positioner.
Scan Duration
Scanning a dense grid of points increases the total time the device is in the test chamber. Optimization of the spatial sampling grid reduces the test run time from hours to minutes. This efficiency is achieved by using spherical near-field scanning techniques that require fewer points to reconstruct the far-field pattern.