A position detecting device finds the position of a specimen arranged in a conductive structure on the basis of microwaves and includes an electrical circuit for the production and/or reception of the microwaves and a microwave antenna arrangement for emitting and/or receiving the microwaves. Said position detecting device includes a dielectric antenna body with a first pole face and a second pole face for the transmission of microwaves. The antenna body forms a component of the microwave antenna arrangement. The electrical circuit is at least in part arranged on the antenna body.