Design and optimization of a Goubau line for calibration of BPMs for particle accelerators

A Goubau line calibration system was built to evaluate the quality of beam position monitors (BPMs) for the High Energy Photon Source (HEPS). A tapered launcher and receiver were used to achieve good impedance matching. The taper was designed as Klopfenstein-type, featuring a smooth impedance transition. A metal wire covered with a dielectric layer (Goubau line) was used to guide surface wave transmission in air. The generated electromagnetic field was used to simulate the beam and calibrate the BPMs. According to the test results, the system exhibits negligible electromagnetic field interference and can be used for BPM calibration.