Rotatable Inductive Probe in Waveguides

It is shown by calculation of the field distribution in waveguides with TE waves in the presence of both the forward and the reflected waves that the voltage induced in a pure inductive probe depends on its angular position in the same manner that a probe in a slotted line depends on its axial position. Thus, a rotatable probe consisting of a wire loop and a compensating arrangement extending through an aperture into the waveguide can be used as a standing wave detector. An instrument for S-band waveguides utilizing this principle, its advantages and disadvantages and its error are further subjects of this paper.