The problem of diffraction around a smooth, finitely conducting earth is reexamined with the objective of obtaining an exact solution for the case of an exponential profile of refractivity. The methods employed are largely conventional. However, care is taken to avoid approximations of doubt· ful accuracy, and the solution is illustrated by numerical computations. It is shown that the method of using an effective earth radius and assuming a homogeneous medium is generally sound.
Phase and amplitude of simulated troposcatter signals have been computed as functions of time, using thin layers of randomly spaced point scatterers moving horizontally and uniformly, normal to the path. The layer heights and cross‐wind speeds were chosen to agree with the atmospheric conditions known to exist in two radio experiments. Comparisons of the simulated and actual radio signals show good agreements in amplitude fading rate and average Doppler shift versus antenna pointing angle in one case when the scattering angular dependence used in the simulation matched the classical −11/3 power‐law isotropic refractivity spectrum. In the other case, where slower fading was observed, an anisotropic model of the refractivity spectrum produced excellent agreement between the simulated and radio data. Knowledge of the cross‐wind speed allowed the degree of anisotropy for the model to be evaluated.
An exact so lu t io n is fo nnd for t h e field of a dipolc ovcr p la ne, finitely co ndu ctin g ear t h th r'o ug h a n atm osp here ill which t he refractivity va r ies exponentia lly w it h h eig ht. The m ethod of J l anke l t ransform s is used, so t hat t he fin a l l'esult t" kes t he fo rm of a n in tegral wi t h infin ite limi ts. Th is integra l is evalu ated numer ically for a typi cal pro fi le a nd for seve ra lwave le ngths, a nd t he results a re com p il rcd wit h t hose for a homogcnco us at mos ph ere . At s ho rt wavelcngths an d largc dista nces, t he stratifi ed at mosp here abovc a planc cart h can act as a ver.v efficient \\·avC'guid C' .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.