Experimental analysis of the effects of antenna tilting on antenna types and test results in consideration of measurement uncertainty

Abstract

The antenna tilting has not been specifically mentioned in the EMC product standards which include radiated emission test. However, CISPR 16-4-2 standard, which is the reference for the measurement uncertainty calculations of the radiated emission test in these standards, shows that directivity difference parameter changes according to using antenna tilt feature. The reproducibility of the tests gets worse since test results vary depending on whether antenna has tilting feature or not between laboratories which perform these tests. The main purpose of this study is to examine the effect of the antenna tilting on test results. Besides, the test results are aimed to be interpreted taking into account the parameters related to the antenna tilt in the measurement uncertainty table which is mentioned in CISPR 16-4-2. A comparison noise emitter (CNE III) and a television (TV) were used as equipment under test (EUT) so as to increase the test validity. Furthermore, same products were tested with and without tilting function with different antenna types. Measurements were performed in a semi anechoic chamber (SAC) in the frequency range 30 MHz-1 GHz with reference to EN 55032 standard. The measurements were performed by changing the antenna height between 1–4 m in accordance with this standard. The differences between the measurement results with tilting and without tilting were evaluated by considering the parameter related to antenna tilt in the measurement uncertainty standard.