While AN-SOF was originally designed for simulating wire structures using the Method of Moments (MoM), its calculation engine has been extended to support simple PCB and microstrip antenna designs that meet the following requirements. For structures that do not comply with these conditions, a Finite Element Method (FEM) solver (not included in AN-SOF) should be used instead.

Key Limitations & Requirements:

1. Single-Layer, Lossless Substrate Only
   • Only one dielectric layer is supported (multilayer substrates are not).
   • The substrate must be lossless (loss tangent is assumed zero).
   • No holes or cutouts are permitted in the substrate.
2. Finite-Size Substrate Constraints
   • The substrate must be rectangular.
   • Traces must be at least 5× the trace width away from the substrate edges.
3. Ground Plane & Vias
   • A perfect electric conductor (PEC) ground plane is mandatory and cannot be removed.
   • Vertical vias can be modeled as short vertical wires connecting traces to the ground plane (e.g., for antenna feeding).
4. No Slot-Based Designs
   • Slot antennas or patches with slots cannot be modeled due to software limitations.

We currently have no plans to integrate an FEM solver into AN-SOF. For advanced PCB or antenna designs—such as multilayer structures, lossy substrates, or slotted geometries—we recommend using alternative simulation tools.