title: Novel mono-static arrangement of the ASDEX Upgrade high field side             reflectometers compatible with electron cyclotron resonance heating stray             radiation.
abstract: The ASDEX Upgrade frequency modulated continuous wave broadband reflectometer             system uses a mono-static antenna configuration with in-vessel hog-horns and 3 dB             directional couplers. The operation of the new electron cyclotron resonance heating             (ECRH) launcher and the start of collective Thomson scattering experiments caused             several events where the fragile dummy loads inside the high field side directional             couplers were damaged, due to excessive power resulting from the ECRH stray fields. In             this paper, we present a non-conventional application of the existing three-port             directional coupler that hardens the system to the ECRH stray fields and at the same             time generates the necessary reference signal. Electromagnetic simulations and             laboratory tests were performed to validate the proposed solution and are compared with             the in-vessel calibration tests.
authors.affiliation: Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal. silva@ipfn.ist.utl.pt
authors.forename: A
authors.initials: A
authors.lastname: Silva
authors.forename: P
authors.initials: P
authors.lastname: Varela
authors.forename: L
authors.initials: L
authors.lastname: Meneses
authors.forename: M
authors.initials: M
authors.lastname: Manso