Purpose:Demonstrate a zone plate using microwaves.
Description:A Microwave beam is incident onto a zone plate with two zones. A number of maxima an minima can be observed if the receiver antenna is moved along the optic axis. Positioning the receiver at a minimum, as in the photograph at the left, either the ring or the central disc can be re-installed into the zone plate, resulting in an increase in the microwave intensity at the receiver, as seen in the photographs at the center and right. This system worked nicely for a source to zone plate distance of about 63 cm and a zone plate to receiver distance of about 23 cm.