Microwave moisture sensor system for wood drying

This goal of this project is to develop a prototype microwave based moisture sensor system to be used in a hardwood dry kiln. Moisture sensors will be battery powered and will communicate with the host kiln control system via spread spectrum wireless communications. We have developed 2 separate designs of launchers working at 4.5 GHz to 6 GHz that give a linear response to moisture content (MC) over a range of 90% MC to 6% MC. These launchers allow us to make a swept frequency transmission measurement through a small area of a board. We have developed electronic circuit boards that provide the microwave excitation and read and store the microwave signal returned through the wood. We are currently testing the "second generation" prototype electronics to go into the kiln mated with these launchers to produce a prototype MC measurement system design to be tested in kilns.