Biological Effects and Health Hazards of RF and MW Energy: Fundamentals and Overall Phenomenology

Extensive investigations into microwave bioeffects during the last quarter century have shown that for frequencies between 200 and 24,500 MHz, exposure to a power density of 100 mW/cm2 for several minutes or hours can result in pathophysiologic manifestations of a thermal nature in laboratory animals. Such effects may or may not be characterized by a measurable temperature rise, which is a function of thermoregulatory processes and active adaptation of the animal. The end result is either reversible or irreversible change, depending on the irradiation conditions and the physiologic state of the animal. At lower power densities, clear evidence of pathologic changes or physiologic alteration is nonexistent or equivocal. A great deal of discussion, nevertheless, has taken place on the relative importance of thermal or nonthermal effects of radiofrequency (RF) and microwave (MW) radiation.