Circular polarization of microwaves by elliptical metal tube.

Circular polarization of microwaves by elliptical metal tube. The horn of a 3 cm. microwave transmitter is designed to produce polarized microwaves with the electric field in the vertical direction. The 3 cm. microwave receiver is designed to sense these polarized microwaves, and to emit an audible tone from its speaker. If the receiver is rotated 90 degrees to the 'crossed' position, its reception drops to zero. See figures 1, 2 and 3. If a metal tube (bent to an elliptical cross-section 4x6 cm) is placed in the transmitter beam at a 45 deg angle, then the transmitter E field is broken into two equal components. The tube dimensions are such that one component travels faster than the other inside the tube. Upon exiting the tube, one component is 90 deg out of phase with the other component, which is the criteria for circular polarization. No matter how the receiver is rotated, microwaves are detected.