Some Technical Aspects of Microwave Radiation Hazards

Man's ability to generate microwave power has been increasing at the rate of about 15 db per decade. Experiments performed by subjecting animals to high power indicate that hazards to personnel could exist if appropriate safety measures are not adopted and observed. This paper reviews the history of the recognition of this potential hazard and the safety measures adopted by the Bell System and others to protect personnel. Some typical and pertinent research work is discussed, and it is shown how these results have influenced the establishment of criteria for safe and potentially hazardous environments for human beings. The currently adopted safety limits of the Bell System and others are reviewed in some detail, and a recommended method of calculating power densities is derived, pointing out the limitations of the approximations used. Some of the commercially available power density meters are mentioned, and their method of operation is described. Their use in surveying a site is discussed, and the shielding effect of wire mesh fences is presented in a nomograph.