The Influence of the Probe Connection on mm-Wave Antenna Measurements

Commonly used connection methods for measuring antennas in the mm-wave range, like connectors or probes, influence the intrinsic behavior of the antenna under test (AUT). It is shown that nearby structures supporting the antenna and probe or connector cause strong interference on the measured antenna pattern. A new connection setup is proposed eliminating the interfering signal. This is confirmed by a detailed simulation model and verified with experimental results. Furthermore, the probe radiates significantly due to the discontinuity from the transitions of the probe tip to the microstrip line. This radiation influences the signal-to-noise ratio, i.e., the dynamic range. Measures are proposed to reduce this interference, resulting in an improved signal-to-noise ratio by approximately 15 dB.