My project is to design a single turn rectangular loop antenna on GaAs (100µm) substrate. I am trying to simulate a loop on GaAs subtrate only; without any background metalization/ground. But my problem is: I cann´t define the subtrate without ground/metalization. Whenever I want to defíne air-metal-GaAs-Air, it automatically brings another metal layer in between the GaAs and bottom Air layers. Though this unexpected metal layer is not mapped, I am not sure whether it affects my results or not! I am attaching the substrate definition window.
Can anyone tell me the exact way of defining such kind of substrate?
Thanks in advance
Sifat