Panel Controls

Input Controls

• Wire Length in cm and Wire Radius in cm
  Two type-in boxes set the size of the scattering wire in centimeters.
  The wire is aligned along the z axis. You can type in any numeric value for length and radius. Entries must be positive decimal numbers. You must click Solve for these values to take effect. The condition for validity of the calculated results is only that wavelength of incident wave is large compared to the radius. Results are valid for any length of wire if sufficiently many Basis functions are used. (See Number of functions below.)
• Number of Functions
  This selects the number of piecewise sinsusoidal current basis functions used along the wire. Increasing this will give a more accurate current, but will take more time to compute. Excessively large number of basis functions (e.g. more than 20,000) can lead to numerical instabilities. You must click Solve for this value to take effect.
• Frequency in MHz
  This sets the frequency of the incoming plane wave in MegaHertz. You must click Solve for this value to take effect.
• Incident Angle
  This slide bar sets the incident angle defined so that its cosine is the dot product of the incident propagation direction with the z-axis. Changing this value will display results with various incident angles.
  Note the polarization is always assumed to be in the plane defined by the propagation direction and the wire. The thin wire approximation neglects the scattering of the other polarization.

Output Boxes

• Total Cross Section
  This is an output result. It is the usual total power radiated divided by the incident flux. The result is in cm².
• Radar Cross Section
  Radar Cross Section is also called the monostatic radar cross section in the engineering literature. It is the differential backscatter cross section (i. e. evaluated at theta=pi-theta incident) per solid angle multiplied by 4 pi.
• Solve and Stop
  Clicking Solve is necessary to fill the impedance matrix. The Stop button will be disabled except when calculating. Clicking Stop will cancel the current calculation.
• Blank Panel to the right of Solve
  This panel is used for messages if bad input is given. Try setting the wire length to -1 or nonumeric input to see it work.