Broadband reflectometry for diagnostics and monitoring applications

Reflectometry is a powerful technique that can be effectively employed for a number of practical applications; in particular, the high versatility, the real-time response, and the potential for practical implementation have contributed to the success of microwave reflectometry for monitoring purposes. In this regard, this paper provides a survey of the current state of the art of reflectometry-based methods for diagnostics and monitoring applications. After a brief overview of the theoretical principles at the base of this technique, the different approaches of microwave reflectometry (time domain, frequency domain, and combined approaches) are fully discussed; particular attention is given to the strategies for enhancing measurement accuracy. Finally, the major practical applications of reflectometry and related results are discussed, thus evidencing current achievements, limitations, and potential.