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How to Measure the Field Intensity of a Microwave Horn

Microwaves are used for cooking and communication. They're also used for other applications, such as radar and remote sensing. Microwaves are typically generated by a magnetron, which is then hooked up to some sort of antenna, depending upon the application. Without some sort of antenna or waveguide, the microwaves -- electromagnetic waves between about 30 cm and 0.3 cm long -- would rapidly spread out from the generator. One choice of antenna is a horn antenna, and measuring the field strength from a horn antenna is simple, with the right equipment.

Things You'll Need

Microwave generator with horn antenna
RF field strength meter
Anechoic chamber

Instructions

- 1
  Place the microwave horn in a protected area. For very precise measurements, you want to use an anechoic chamber, with radar-absorbing material on the walls.
- 2
  Place the probe in front of the horn. If you're working with low intensities, you can record the measurement by hand, but for higher intensities, you'll want to use a computer to remotely gather the data.
- 3
  Move the probe to a different spot in front of the horn. Because the radiation pattern spreads out in a relatively broad angle, you'll want to measure the field intensity at several locations.
- 4
  Combine the measurements to create a map of the field intensity distribution over the range of output angles of the horn antenna.

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