Re: NEC-LIST: microstrip patch simulation

On Wed, 11 Jun 1997, Chuck Counselman wrote:

> Andre Fourie <fourie_at_odie.ee.wits.ac.za> wrote:
> >We have simulated circular patches with feed networks to provide circular
> >polarization using NEC-2 with FREE SPACE as dielectric. We used wire grids
> >above a perfect ground plane and even if actual devices will incorporate some
> >dielectric I believe some very useful information can be obtained....
>
> With NEC-2 I simulated a (rectangular) patch by means of a suitably dense,
> horizontal, wire mesh above a ground plane; then, to simulate a
> dielectrically loaded patch, I connected short vertical wires between the
> mesh and the ground plane, with capacitive loads (negative-imaginary
> impedance) inserted in these wires. The simulation results seemed
> realistic, but I never totally convinced myself that these little simulated
> capacitors validly represented reality.
>
> Can anyone comment on the validity of this method?
>
> BTW, since a dielectrically loaded patch is small in comparison with a
> wavelength, I figured that very few simulated capacitors were sufficient.
> So I didn't have to extend NEC's limit on the number of loads allowed.
>
> -C.

  My question would be how does the model take into consideration
  the effects of the surface and leaky waves, characteristic of any
  microstrip antenna ?
 
  In fact, I believe that such are approximations. For electrically
  thick substrates one may not be able to get past the exact Green's
  functions for microstrip antennas.

  - cheers,
 =================================================================
  Deb Chatterjee

  Radar Systems and Remote Sensing Laboratory
  Department of Electrical Engineering and Computer Science
  Room 322, Nichols Hall
  2291 Irving Hill Road
  Lawrence, KS 66045-2969

  tel: (913)864-7742
  fax: (913)864-7789
  e-mail: dchatterjee_at_kuhub.cc.ukans.edu
Received on Fri Jun 13 1997 - 11:42:57 EDT