antenna-theory.com

[RobM]

I have an application for an antenna for which a slot design seems suitable: vertical rectangular waveguide with multiple vertical slots milled in the waveguide's wide dimension, spaced vertically and staggered alternately either side of the centre line.

There are published designs for antennas like this but I would like to model these designs to verify their performance and to make minor adjustments to the radiated pattern. I need about 2 degrees of downtilt and would prefer only 270 degree azimuth coverage.

I am familiar with modelling wire antennas and yagis.

Questions:

1. Can a program suitable for modelling wire antennas be used reliably and successfully to model a slot antenna? If so, how? An example would be appreciated.

2. Is there a (free or reasonably priced) design and/or modelling program available specifically for slot antennas?

Many thanks.

[Schubert]

Slotted Waveguides radiate from electric fields adding in phase, instead of current adding in phase as is the case for wire antennas. Hence, the simplifications (of maxwell's equations) used for wire models won't work well (or at all) for aperture type antennas.

You want a Method of Moment (MoM) or Finite Element Model (FEM) tool. Or FDTD (Finite difference time domain). You might try googling these keywords with "Free" or Trial version and see what you get. I imagine there are free FDTD tools out there, but they might have a steeper than desirable curve to get out the info you are looking for.