Microwaves with grid. Transmitter and receiver are polarized.

Microwaves with grid. Transmitter and receiver are polarized. The horn of a 3 cm. microwave transmitter is designed to produce polarized microwaves with the electric field in the vertical direction (see Fig.1). 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, its reception drops to zero. If a vertical wire grid is placed between the transmitter and receiver (see Fig.2), the microwave vertical electric field is dissipated in the wires, and the reception is blocked. If the wire grid is rotated ninety degrees (horizontal wires), reception becomes maximum.