LESSON 3
NONIONIZING RADIATION
Section I. MICROWAVE RADIATION
3-1. GENERAL
a. Microwave/radio frequency radiation, a form of nonionizing radiation, has
been with us for many years now. We are all exposed to this type of radiation every day
without giving it much thought. However, there is increasing concern about the
exposure to radiation in the microwave region.
b. When discussing the electromagnetic spectrum and the radiations thereof, we
c. Frequency (υ) defines the number of waves that pass a given point in one
second. The old term for this was cycles per second. It was replaced by the Hertz (Hz).
1 Hz = 1 cycle/second
d. Wavelength (λ) is a measure of distance and is expressed in meters,
centimeters, etc. An old term that is used infrequently is the angstrom unit.
1 = 10-10 meter
e. In the case of microwaves, frequency is the descriptive term commonly used.
Microwave frequencies range from 100 Megahertz (MHz) to 300,000 MHz.
3-2. MICROWAVE RANGE
a. The microwave band (frequency range) includes frequencies normally used
by radar and communication facilities.
b. Other subregions in the microwave band include the following:
(1) AM broadcast (535 to 1,605 MHz)
(2) Medical diathermy (271.2 to 406.8 MHz)
(3) Microwave ovens (915 and 2,450 MHz)
MD0180
3-2