Introduction - Broadband Reflectometry for Enhanced Diagnostics and Monitoring Applications - page 1

Chapter 1
Introduction

'Common sense is the collection of prejudices acquired by
age eighteen'.
Albert Einstein

Abstract. This chapter introduces to broadband microwave reflectometry (BMR),
which is the expression used in this topic to indicate an electromagnetic technique
used for monitoring and diagnostics purposes. The adjective broadband emphasizes
the fact that the analysis can be carried out over a wide frequency range. A brief
survey of the typical applications of BMR is also provided.

1.1 The Concept Behind This Topic

Under the term monitoring , the Cambridge dictionary states the following definition

to watch and check a situation carefully for a period of time in order to discover
something about it.

Similarly, the word diagnosis indicates

a judgment about what a particular illness or problem is, made after examining it.

Such broad, and yet unambiguous definitions seem to emphasize the urgency asso-
ciated with the terms themselves [1]. As a matter of fact, now more than ever, 'keep-
ing the situation under control', for cognitive or predictive purposes, is a transversal
need in a number of interdisciplinary sectors, especially in industrial, environmen-
tal, civil, and agricultural areas. As a direct consequence, strict regulations have
been enforced and guidelines have been issued that dictate specific standards (either
qualitative or quantitative) that should be complied with, in order to ensure the suit-
ability of the 'product' or of the 'process'. In this scenario, monitoring and diagnosis
procedures are used for the optimization of process and for triggering possible cor-
rective actions, or for checking the compliance of the product with pre-established
quality standards.
In general, a monitoring program gathers data for several purposes, such as

• to draw comparisons against standard or target status ;

• to make comparisons between different conditions or to conduct analyses;