Methodical problems of solid-propellant burning-rate measurements using microwaves

A brief review of microwave techniques for measuring solid-propellant burning rate is given, and the principles of the techniques are described. A burning-rate meter operating in the 2-mm microwave band, which was designed by the authors, is described, and tentative results obtained using this device are reported. Limitations of the method, sources of errors, and problems related to the choice of the microwave band and measurement systems are discussed. Problems that should be solved to increase the accuracy and reliability of burning-rate measurements using microwave techniques are considered.