Three-dimensional Electromagnetic Field Intensity Measurement using an Infrared Two-dimensional Lock-in Amplifier

Abstract

We have developed a three-dimensional electromagnetic field intensity measurement system using an infrared two-dimensional lock-in amplifier. This system uses an amplitude modulated electromagnetic source to heat an absorption screen. Electromagnetic field intensity distributions are converted to temperature images on the screen. The temperature images can be observed by infrared thermography, the variation of which can be detected by the amplifier system. The system can detect very small changes, less than 1/100 K, in temperature image on the absorption film. This inexpensive measurement system should therefore be very useful in detecting electromagnetic field distributions rapidly without using any antenna.