A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular WaveguidesD. Wagner, W. Bongers, W. Kasparek, F. Leuterer, F. Monaco, M. Münich, H. Schütz, J. Stober, M. Thumm and H. v.d. BrandEPJ Web of Conferences, 87 (2015) 04012DOI: https://doi.org/10.1051/epjconf/20158704012