Measurements and analysis of the effects associated with the panel gaps in a millimetrewave CATR

The antenna laboratory of Queen Mary and Westfield College is now operating a new compact Antenna Test Range (CATR) facility. The associated reflector is made of 18 panels each with surface accuracy of about 10-18 mu m RMS, which makes the range operational for frequencies in excess of 200 GHz. Practical experience gained during measurements of antenna patterns at 183 GHz revealed that the gap formed between the panels have a significant impact on the recorded pattern especially when the antenna under test possesses significant directivity. These effects are expected to persist even in the absence of any misalignment errors.