kicad-emsimlisted

# EM simulation (gerber2ems + openEMS) Engine: `$(kx root)/kicad_lib/emsim.py`. STATUS: chain VALIDATED — meander_loose example simulated end-to-end (rc 0; |S11|≈1 + 455 ps delay on the open meander = physically correct). Image `gerber2ems` (6.6 GB); rebuild if missing: `docker build -t gerber2ems $(kx root)/.tools/gerber2ems/`. NEVER mount over /home/docker — it shadows the image toolchain; emsim.run mounts at /home/docker/sim. ## Flow 1. `emsim.prepare(pcb, workdir)` — gerbers+drill+pos via fab.py (names already match), `stackup.json` translated from the board's `(setup (stackup ...))`, `simulation.json` template. 2. **Fill ports** in simulation.json (width/length in µm, impedance, layer index, excite flag) and `traces` (start/stop port indices) — ports sit at position-file footprint locations (use simulation-port footprints on the board for clean port placement). 3. `emsim.run(workdir, export_field=True)` — dockerized `gerber2ems -a --export-field`: geometry → FDTD → postprocess. 4. Read the outputs: `ems/*.csv` S-params/impedance; **field PNGs are the agent feedback** — Read them, check field concentration against expectations (return paths, gaps, stubs). VTR dumps open in ParaView for the user. ## Notes - Frequency range/grid in SIM_TEMPLATE: 0.2–6 GHz, sane FR-4 defaults; finer grids explode runtime (FDTD is O(cells × steps)). - Worked examples: `.tools/gerber2ems/examples/*` (differential pair, filters, stubs) — copy a simulation.jso