Filling level measuring device operating with microwaves

Level measuring instrument which operates with microwaves, having

• a housing section,
• which is designed as a wave guide short-circuited at one side and one end by a rear wall,
• which is virtually completely filled with an insert made of a dielectric,
• an exciter element,
• which projects into the housing section and
• which is connected to a microwave source,
• an antenna, adjoining the housing section, for transmitting and/or receiving microwaves, and
• a gap arranged in the insert between the exciter element and the antenna,
• which gap forms a filter which is essentially non-transparent to higher modes of the waveguide, wherein
• the insert comprises
• a first element in which is provided the gap arranged in the insert between the exciter and the antenna, the gap running parallel to a longitudinal axis of the housing section, and
• a second element that defines between the gap of the first element and the antenna a second gap running perpendicular to the longitudinal axis of the housing section, the second element of the insert comprising a spacer that defines a width for the second gap when the second element abuts the first clement.