A test system and method characterize a balanced device under test with a vector network analyzer measurement system using a differential or balanced stimulus signal and further calibrate the VNA using conventional calibration standards. A holding device which retains the reflector on the mounting ring is designed in such a way that the reflector is retained on the mounting ring merely by lying thereon. The system may furthermore align the one or more apertures with at least one of the first array of magnets and the second array of magnets to align the injected charged particles from the charged particle source with one or more magnetic regions for an effective charged particle diffusion into the ion beam. The power distributor for the battery side connection and the power distributor for the alternator side connection are placed facing each other oppositely, and have respective heat sinks facing outwardly. It is characterized in that the use of film hinges permits simpler and lower-cost assembly than has heretofore been possible with comparable reflector arrangements. Since no vertical load is exerted on the low-k film, the low-k film can be prevented from being broken, and device quality is not lowered.