How to simulate a microwave absorber in IE3D?

hi everybody,

i am trying to implement one planar archimedean spiral antenna ( 0.5 - 3 GHz ) with microwave absorber backing (to absorb some fields and get a better current distibution over the outer periphery of the spiral , so that overall vswr is good over a larger bandwidth), 2.54cm over metal plate back ground.but i don't know how to simulate the absorber in IE3D, i know we can do with finite shape dielectrics in IE3D, now is there any method to define such a dielectric as a very lossy one probably by choosing some parameter values such as loss tangent or something else appropriately for the dielectric block? And what should be a typical value of such a parameter to get a good microwave absorbing material for my purpose??

plz share ur views on this matter. eagerly waiting for ur replies.

with regards
abhi

Hi, Abhi:

I think you can model it as either an infinite layer or a finite size layer of dielectrics with appropriate dielectric materials (Er and Sigma). For infinite dielectrics, you can even give non-1 MUr. However, what should be those values? I think you need to check with material vendor.

Regards.