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Introduction
1.1 Introduction
Microwaves, as the word spells, are extremely short waves. Their region
extends from approximately 1/3 meter to millimetre or even to sub-milli-
metre range of wavelengths. The term microwave is loosely coupled with
frequencies of 1 GHz and above but is less than those of optical signals. This
broad denition includes ultra-high frequency (UHF), super-high frequency
(SHF) and extremely high-frequency (EHF) bands.
The existence of electromagnetic waves was predicted by J. C. Maxwell in
1864 and was rst demonstrated by Heinrich Hertz in 1888 by building an
apparatus to produce and detect signals in UHF ...