Microwave spectrometer, Continuous In Line measurement of density and dry matter Description The microwave measurement generate an electromagnetic wave of low energy. This signal is coupled via an antenna into the product (Paper, Tobacco, Sand, etc.). Depending on the dielectric properties of the product the signal propagates in the product. After the signal has passed the product a second antenna receives the signal (Transmission). Amplitude and phase shift of the received signal are an expression for the water content or dry matter of the product. The microwave measurement is very stable and it has a quick response to product changes.