This instrument measures the attenuation of a microwave emission produced by an obstacle between a transmitter and a receiver antenna. The instrument has a transmitter and a tuned receiver. The frequency can be programmed from 800 to 1600 MHz at 10 KHz steps.

The transmitter sends two signals, a strong one to the antenna, and a reference sample, directly to the receiver, but with a power of 30 dB below that sent to the antenna.

The receiver has two inputs, one from the receiver antenna, and other for the reference sample. Then the instrument calculates the following equation:

Log10 ( Power Received Through Antenna / Power of the Reference Sample )

and converts it into a 16 bit digital word. Also it is available an output voltage signal proportional to the instantaneous phase angle between antenna and reference signal.

This instrument can be used to measure in real time the moisture content of materials passing through a transport belt, and the transmission spectrum of materials, where relative amplitude in dB and relative phase angle are parameters that can be correlated to the conditions of the material.

Since we filled a patent application before the Chilean Industrial Property Department of the Economy Ministry, this instrument staid under non-disclosure agreement with that office for almost two years, until November 10, when our patent was finally granted to us and published in the Official Newspaper of the Government.