In this application note, we analyze two spiral antennas. The first one is with the air substrate, while the other one has the dielectric substrate between spiral arms and metallic reflector.
In WIPL-D Pro, a spiral can be easily created and modified using built in Helix object. Especially if the same mesh over the close surfaces is required (here, antenna reflector and surface where spiral arms are located), built in manipulation named Copy\Layer can be very useful.
The antennas are simulated from 0.3 GHz to 6 GHz in wide frequency band. For this type of simulation, number of frequencies can reduced by using the logarithmic scale and built-in interpolation. The simulation was carried out at regular desktop PC, requiring extremely low number of unknowns, with simulation time measured in seconds.