Biomedical Engineering Reference
In-Depth Information
CHAPTER ONE
Fundamentals of
Electromagnetics
1.1
RF AND MICROWAVE FREQUENCY RANGES
The rapid technological advances in electronics, electro-optics, and computer
science have profoundly affected our everyday lives. They have also set the
stage for an unprecedented drive toward the improvement of existing medical
devices and the development of new ones. In particular, the advances in radio-
frequency (RF)/microwave technology and computation techniques, among
others, have paved the way for exciting new therapeutic and diagnostic
methods. Frequencies, from RF as low as 400 kHz through microwave fre-
quencies as high as 10 GHz, are presently being investigated for therapeutic
applications in areas such as cardiology, urology, surgery, ophthalmology,
cancer therapy, and others and for diagnostic applications in cancer detection,
organ imaging, and more.
At the same time, safety concerns regarding the biological effects of
electromagnetic (EM) radiation have been raised, in particular at a low level
of exposure. A variety of waves and signals have to be considered, from pure
or almost pure sine waves to digital signals, such as in digital radio, digital
television, and digital mobile phone systems. The field has become rather
sophisticated, and establishing safety recommendations or rules and making
adequate measurements require quite an expertise.
In this topic, we limit ourselves to the effects and applications of RF and
microwave fields. This covers a frequency range from about 100 kHz to 10 GHz
and above. This choice is appropriate, although effects at RF and microwaves,
