Dual-mode stripline resonator array for fast error compensated moisture mapping of paper web

A mechanically simple and therefore inexpensive sensor array for fast mapping of the water content of wet paper has been developed. The sensors are UHF stripline resonators, which have two degenerate resonance modes, even and odd. The difference of these two frequencies can be used to achieve a high accuracy, because the resonance frequency of the odd mode is not affected by moisture changes in the wet paper, and can therefore be used for error compensation. Because of the electronic scanning, the measurement is very fast and it makes almost real-time water content profiling possible.<>