Patent ID: 6499346
Filing Date: 2002-12-31
Classification: G01F,H01Q

Abstract:
A level measuring instrument, comprisingan exciter element that excites microwaves; an antenna that transmits microwaves received from the exciter element; a waveguide between the exciter element and the antenna that guides microwaves between the exciter element and the antenna, the waveguide defining a longitudinal axis between the exciter element and the antenna; and a dielectric insert positioned in the waveguide between the exciter element and the antenna, the dielectric insert comprising dielectric material and a longitudinal gap in the dielectric material of the dielectric insert that lies along the longitudinal axis, the longitudinal gap sized to pass to the antenna a fundamental mode portion of the microwaves received from the exciter element, and filter from the antenna a higher mode portion of the microwaves received from the exciter element.