The biological effects of microwaves in the hyperfrequency range, 9,4 GHz, and 70-75 GHz were investigated in bacteria and yeast. At power densities below 60 mW/cm2 and SAR values not exceeding 28 mW/g no significant effects on survival of repair competent an deficient strains were observed in Escherichia coli and Saccharomyces cerevisiae. In addition, microwaves of 17 GHz did not induce mutations in E. coli B/r WP2 trp- uvr- above the spontaneous level, and the induction of nuclear reversions, cytoplasmic "petite" mutations and mitotic recombination as well as the efficiency of sporulation was not affected in yeast.

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The authors report a study of the behavior of Permalloy thin films at high microwave signals. The cases where films are polarized either parallel or perpendicular to the film plane are successively investigated at X and V bands. With a parallel polarization, the absorption via a first-order process can be present at X band either as a subsidiary absorption or as a premature decline of the main resonance, depending on the film thickness. At V band, only a subsidiary absorption was expected; it was effectively observed in some films with a large critical field (≃45 Oe). With perpendicular polarization, new experimental observations (such as an important main resonance shifting, a large variation of the linewidth at low level, a saturation of the uniform mode via a second order process, and a foldover effect leading to relaxation oscillations) at X and V bands were made and explained. Finally, with a strong interaction between films and electromagnetic waves having thus been shown, possible applications such as power limiters are indicated.