In-situ real-time monitoring of spurious modes in HE11 transmission lines using multi-hole couplers in miter bendsAlexander Zach, Walter Kasparek, Carsten Lechte, Burkhard Plaum, Francesco Monaco, Harald Schütz, Jörg Stober, Hiroshi Idei and Thomas HirthEPJ Web Conf., 203 (2019) 04018DOI: https://doi.org/10.1051/epjconf/201920304018