Scattering of ambient radiation into receivers by secondary mirror supports can potentially degrade performance of radiotelescopes. A geometry for the support struts with slanted planar faces to keep scattering sidelobes close to the antenna pointing direction is analyzed. Scattering of the plane wave is within ~15o of boresight, while the spherical wave scattering is within ~1o of boresight. ...

We initiate a study of homeomorphisms f with constant principal strains (cps) between smoothly bounded planar domains D, D′. An initial result shows that in order for there to be such a mapping of a given Jordan domainD ontoD′, a certain condition of an isoperimetric nature must be satisfied by the latter. Thereafter, we establish the fundamental fact that principal strain lines (characteristic...

The classical Schwarz-Christoffel formula gives conformal mappings of the upper half-plane onto domains whose boundaries consist of a finite number of line segments. In this paper, we explore extensions to boundary curves which in one sense or another are made up of infinitely many line segments, with specific attention to the “infinite staircase” and to the Koch snowflake, for both of which we...