Interactive 3D model — auto-rotates, drag to orbit
915 MHz CPS ring (r25 · w2.4 · gap1.8) authored as a .kicad_pcb from the SAME param dict as the FDTD model — no GUI in the loop · KiCad 9 headless on Modal: DRC 0 violations / 0 unconnected, Gerbers+drill fab-ready, board STEP, raytraced renders · copper: two ring annuli broken over the 315°±10° window, top diagonal + bottom underpass + 2×2 via farms = the 180° inverter · solder-mask windows at the Δ/A/Σ/B ports (pigtails solder straight across the CPS gap) · 78×78 board, M3 mounts matching the rev-B box bosses — fit-checked in cadquery against the box CAD: 6.0 mm wall gap, 0 mm³ interference, pilots clear · fully interactive board below (KiCanvas: pan/zoom, layer toggles, object inspect)
⬗ stack-up: FR4 1.6 mm · 1 oz Cu · 2 layers · 78×78 mm · authored + verified headless (kicad-cli on Modal)