《The Archimedean two-wire spiral antenna - 天线 微带 螺旋 通讯》.pdf

312 TRAMSACTIONSIRE Oh: AXTEXNAS AND PR.0Pz4GATION ods, especially in the V H F region. Moreover, the great Demonstration of Formulas (8) and ( 9 ) variations of the constants with frequency, contrary to We have from ordinary transmission line theory the commonlyaccepted “fact” that they should be practi- cally constant, justify the somewhat extensive discus- ” L O sion of the results obtained. In this discussion it is seen z1 = Z) = ~ tanh yl that,althoughtheconstantsvarygreatlywith fre- quency, the general behavior of soil as a reflecting layer zo for radiopropagation compares qualitatively well with zz = Z,,(21) = ~ tanh 2yl the other methods cited. Though local variations of the soil may be of less im- Z 2 - tanh VI 1 (1 + tanh2yl), _ _ - = _ portanceinradiopropagation,wheretheaverage soil Z1 tanh 271 2 condition over a large area should be taken, the present method may prove useful as a means for investigating which results in generalphysicalproperties of soil and geological sur- face phenomena through their