Add IFA/meander/stub antenna templates with SVG and KiCad export.

Progetta now returns a parametric radiator geometry (segments + preview + .kicad_mod) so the layout can be replicated without inventing EM results.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/pinscopex/antenna_geometry.py

@@ -0,0 +1,321 @@
+"""Parametric PCB antenna templates → segments, SVG, KiCad footprint.
+
+Templates (IFA / meander / stub) use a documented λ/4 electrical length with
+εeff≈(εr+1)/2. This is a routing-first drawing aid — not an EM / VSWR result.
+"""
+
+from __future__ import annotations
+
+import math
+from typing import Literal
+
+from pydantic import BaseModel, Field
+
+_C_MPS = 299_792_458.0
+
+AntennaTemplate = Literal["ifa", "meander", "stub"]
+FitStatus = Literal["ok", "scaled", "overflow", "need_f0"]
+
+_NOTE = (
+    "Parametric template from λ/4 (εeff≈(εr+1)/2) — routing aid only, "
+    "not an EM / VSWR result. Tune matching on the board."
+)
+
+
+class AntennaSegment(BaseModel):
+    points: list[tuple[float, float]]  # local mm, origin = feed
+    width_mm: float
+
+
+class AntennaGeometry(BaseModel):
+    template: AntennaTemplate
+    fit: FitStatus
+    segments: list[AntennaSegment] = Field(default_factory=list)
+    total_length_mm: float | None = None
+    length_ideal_mm: float | None = None
+    scale: float = 1.0
+    svg: str | None = None
+    kicad_mod: str | None = None
+    footprint_name: str | None = None
+    note: str = _NOTE
+    detail: str = ""
+
+
+def quarter_wave_mm(f0_mhz: float, er: float) -> float:
+    """Electrical λ/4 in mm using εeff≈(εr+1)/2."""
+    eeff = (er + 1.0) / 2.0
+    f_hz = f0_mhz * 1e6
+    return (_C_MPS / (4.0 * f_hz * math.sqrt(eeff))) * 1e3
+
+
+def build_geometry(
+    template: AntennaTemplate,
+    *,
+    f0_mhz: float | None,
+    w_mm: float,
+    er: float,
+    zone_bbox_mm: tuple[float, float, float, float] | None = None,
+    feed_xy: tuple[float, float] | None = None,
+) -> AntennaGeometry:
+    if f0_mhz is None or f0_mhz <= 0:
+        return AntennaGeometry(
+            template=template,
+            fit="need_f0",
+            detail="Set f0 (MHz) to generate radiator geometry.",
+        )
+    if w_mm <= 0:
+        return AntennaGeometry(
+            template=template,
+            fit="overflow",
+            detail="Feed width w_mm must be > 0.",
+        )
+
+    ideal = quarter_wave_mm(f0_mhz, er)
+    segs_local, length = _template_segments(template, ideal, w_mm)
+    fit: FitStatus = "ok"
+    scale = 1.0
+    detail = f"{template.upper()} template at {f0_mhz:g} MHz."
+
+    avail = _available_span(zone_bbox_mm, feed_xy)
+    if avail is not None:
+        need_w, need_h = _bbox_size(segs_local)
+        free_w, free_h = avail
+        max_span = max(free_w, free_h)
+        need_span = max(need_w, need_h)
+        if need_span > max_span + 1e-6 and max_span > 0:
+            scale = max_span / need_span
+            min_scale = 0.45
+            if scale < min_scale:
+                return AntennaGeometry(
+                    template=template,
+                    fit="overflow",
+                    length_ideal_mm=round(ideal, 2),
+                    total_length_mm=None,
+                    scale=round(scale, 4),
+                    detail=(
+                        f"Zone too small for {template.upper()} "
+                        f"(need ~{need_span:.1f} mm, have {max_span:.1f} mm)."
+                    ),
+                )
+            segs_local = _scale_segments(segs_local, scale)
+            length *= scale
+            fit = "scaled"
+            detail = (
+                f"Scaled to {scale:.2f}× to fit antenna zone "
+                f"({max_span:.1f} mm free). Retune matching."
+            )
+
+    name = f"Antenna_{template.upper()}_{int(round(f0_mhz))}"
+    svg = _segments_to_svg(segs_local, w_mm)
+    mod = _segments_to_kicad_mod(name, segs_local, w_mm, template)
+
+    return AntennaGeometry(
+        template=template,
+        fit=fit,
+        segments=segs_local,
+        total_length_mm=round(length, 2),
+        length_ideal_mm=round(ideal, 2),
+        scale=round(scale, 4),
+        svg=svg,
+        kicad_mod=mod,
+        footprint_name=name,
+        detail=detail,
+    )
+
+
+def _template_segments(
+    template: AntennaTemplate,
+    length_mm: float,
+    w_mm: float,
+) -> tuple[list[AntennaSegment], float]:
+    if template == "ifa":
+        return _ifa(length_mm, w_mm)
+    if template == "meander":
+        return _meander(length_mm, w_mm)
+    return _stub(length_mm, w_mm)
+
+
+def _ifa(length_mm: float, w_mm: float) -> tuple[list[AntennaSegment], float]:
+    """Inverted-F: shorting stub + horizontal arm; feed on the arm at origin.
+
+    Local: feed (0,0) on the arm. Shorting at x=-d toward -Y (GND edge).
+    Arm runs to +X. Proportions: stub ≈ 0.12 L, feed offset ≈ 0.15 L.
+    """
+    L = max(length_mm, 4.0 * w_mm)
+    stub_h = max(0.12 * L, 2.0 * w_mm)
+    d = max(0.15 * L, 2.0 * w_mm)
+    open_x = L - d
+    segs = [
+        AntennaSegment(points=[(-d, 0.0), (-d, -stub_h)], width_mm=w_mm),
+        AntennaSegment(points=[(-d, 0.0), (open_x, 0.0)], width_mm=w_mm),
+    ]
+    path = stub_h + L
+    return segs, path
+
+
+def _meander(length_mm: float, w_mm: float) -> tuple[list[AntennaSegment], float]:
+    """Serpentine that consumes ~length_mm inside a compact bbox."""
+    pitch = max(3.0 * w_mm, 1.2)
+    run = max(length_mm / 6.0, 4.0 * w_mm)
+    pts: list[tuple[float, float]] = [(0.0, 0.0)]
+    x = 0.0
+    y = 0.0
+    going_up = True
+    consumed = 0.0
+    target = max(length_mm, 4.0 * w_mm)
+    guard = 0
+    while consumed < target - 1e-6 and guard < 80:
+        guard += 1
+        dy = run if going_up else -run
+        remain = target - consumed
+        if remain < abs(dy):
+            dy = math.copysign(remain, dy)
+        y2 = y + dy
+        pts.append((x, y2))
+        consumed += abs(dy)
+        y = y2
+        if consumed >= target - 1e-6:
+            break
+        remain = target - consumed
+        dx = min(pitch, remain)
+        x2 = x + dx
+        pts.append((x2, y))
+        consumed += dx
+        x = x2
+        going_up = not going_up
+    segs = [AntennaSegment(points=pts, width_mm=w_mm)]
+    return segs, consumed
+
+
+def _stub(length_mm: float, w_mm: float) -> tuple[list[AntennaSegment], float]:
+    """Open L-stub monopole: short vertical then horizontal arm."""
+    L = max(length_mm, 4.0 * w_mm)
+    h = max(0.2 * L, 2.0 * w_mm)
+    arm = max(L - h, 2.0 * w_mm)
+    segs = [
+        AntennaSegment(points=[(0.0, 0.0), (0.0, -h)], width_mm=w_mm),
+        AntennaSegment(points=[(0.0, -h), (arm, -h)], width_mm=w_mm),
+    ]
+    return segs, h + arm
+
+
+def _available_span(
+    zone_bbox: tuple[float, float, float, float] | None,
+    feed_xy: tuple[float, float] | None,
+) -> tuple[float, float] | None:
+    """Free width/height from feed into the zone (mm)."""
+    if zone_bbox is None or feed_xy is None:
+        return None
+    xmin, ymin, xmax, ymax = zone_bbox
+    fx, fy = feed_xy
+    fx = min(max(fx, xmin), xmax)
+    fy = min(max(fy, ymin), ymax)
+    free_w = max(fx - xmin, xmax - fx)
+    free_h = max(fy - ymin, ymax - fy)
+    return free_w, free_h
+
+
+def _bbox_size(segs: list[AntennaSegment]) -> tuple[float, float]:
+    xs: list[float] = []
+    ys: list[float] = []
+    for s in segs:
+        for x, y in s.points:
+            xs.append(x)
+            ys.append(y)
+    if not xs:
+        return 0.0, 0.0
+    return max(xs) - min(xs), max(ys) - min(ys)
+
+
+def _scale_segments(
+    segs: list[AntennaSegment], scale: float,
+) -> list[AntennaSegment]:
+    out: list[AntennaSegment] = []
+    for s in segs:
+        out.append(
+            AntennaSegment(
+                points=[(x * scale, y * scale) for x, y in s.points],
+                width_mm=s.width_mm,
+            )
+        )
+    return out
+
+
+def _segments_to_svg(segs: list[AntennaSegment], default_w: float) -> str:
+    xs: list[float] = []
+    ys: list[float] = []
+    for s in segs:
+        for x, y in s.points:
+            xs.append(x)
+            ys.append(y)
+    if not xs:
+        return '<svg xmlns="http://www.w3.org/2000/svg" width="120" height="80"/>'
+    pad = max(default_w * 2, 1.0)
+    xmin, xmax = min(xs) - pad, max(xs) + pad
+    ymin, ymax = min(ys) - pad, max(ys) + pad
+    bw = max(xmax - xmin, 1e-3)
+    bh = max(ymax - ymin, 1e-3)
+    paths: list[str] = []
+    for s in segs:
+        if len(s.points) < 2:
+            continue
+        d_parts = []
+        for i, (x, y) in enumerate(s.points):
+            cmd = "M" if i == 0 else "L"
+            d_parts.append(f"{cmd}{x:.3f},{-y:.3f}")
+        sw = s.width_mm
+        paths.append(
+            f'<path d="{" ".join(d_parts)}" fill="none" stroke="#1a1a1a" '
+            f'stroke-width="{sw:.3f}" stroke-linecap="round" '
+            f'stroke-linejoin="round"/>'
+        )
+    paths.append(
+        f'<circle cx="0" cy="0" r="{max(default_w, 0.3):.3f}" fill="#c45c26"/>'
+    )
+    vb = f"{xmin:.3f} {-ymax:.3f} {bw:.3f} {bh:.3f}"
+    body = "\n  ".join(paths)
+    return (
+        f'<svg xmlns="http://www.w3.org/2000/svg" viewBox="{vb}" '
+        f'width="280" height="160" style="background:#f7f5f2">'
+        f"\n  {body}\n</svg>"
+    )
+
+
+def _segments_to_kicad_mod(
+    name: str,
+    segs: list[AntennaSegment],
+    w_mm: float,
+    template: AntennaTemplate,
+) -> str:
+    lines = [
+        f'(footprint "{name}"',
+        "  (version 20240108)",
+        '  (generator "pinscope")',
+        '  (layer "F.Cu")',
+        f'  (descr "Pinscope {template.upper()} PCB antenna template '
+        f'— not EM-validated")',
+        "  (attr smd)",
+        f'  (pad "1" smd circle (at 0 0) (size {w_mm * 2:.4f} {w_mm * 2:.4f}) '
+        f'(layers "F.Cu") (uuid 00000000-0000-4000-8000-000000000001))',
+    ]
+    if template == "ifa" and segs:
+        tip = segs[0].points[-1]
+        lines.append(
+            f'  (pad "2" smd circle (at {tip[0]:.4f} {tip[1]:.4f}) '
+            f"(size {w_mm * 2:.4f} {w_mm * 2:.4f}) "
+            f'(layers "F.Cu") (uuid 00000000-0000-4000-8000-000000000002))'
+        )
+    uid = 10
+    for s in segs:
+        pts = s.points
+        for i in range(len(pts) - 1):
+            x1, y1 = pts[i]
+            x2, y2 = pts[i + 1]
+            lines.append(
+                f"  (fp_line (start {x1:.4f} {y1:.4f}) (end {x2:.4f} {y2:.4f}) "
+                f"(stroke (width {s.width_mm:.4f}) (type default)) "
+                f'(layer "F.Cu") (uuid 00000000-0000-4000-8000-{uid:012d}))'
+            )
+            uid += 1
+    lines.append(")")
+    return "\n".join(lines) + "\n"

backend/pinscopex/antenna_rf.py

@@ -2,9 +2,10 @@
 
 Verify: matching topology from IC ANT/RF pin toward ANT footprint / ANT_FEED.
 Design: KiCad marker (ANT* footprint or ANT_FEED/RF_ANT net) → microstrip w
-for target Z0 from stackup; optional λ/4 length if f0_mhz is given.
+for target Z0 from stackup; optional λ/4 length if f0_mhz is given;
+parametric IFA / meander / stub geometry (segments + SVG + .kicad_mod).
 
-No EM/VSWR. No CPWG clearance. Length suggestion is a documented estimate only.
+No EM/VSWR. No CPWG clearance. Geometry is a documented routing template only.
 """
 
 from __future__ import annotations
@@ -15,6 +16,11 @@ from typing import Any, Literal
 
 from pydantic import BaseModel
 
+from backend.pinscopex.antenna_geometry import (
+    AntennaGeometry,
+    AntennaTemplate,
+    build_geometry,
+)
 from backend.pinscopex.impedance import GeometryError, solve_width
 from backend.pinscopex.models import (
     ComponentType,
@@ -87,6 +93,7 @@ class AntennaDesignRecipe(BaseModel):
     feed_point: dict[str, Any] | None = None
     feed_line: AntennaFeedLine | None = None
     radiator: AntennaRadiator | None = None
+    geometry: AntennaGeometry | None = None
     zone: AntennaZoneInfo | None = None
     keepout_checklist: list[str] = []
     detail: str = ""
@@ -111,6 +118,7 @@ def build_antenna_report(
     h_mm: float | None = None,
     er: float | None = None,
     t_mm: float | None = None,
+    template: AntennaTemplate = "ifa",
 ) -> AntennaReport:
     verify = _verify(graph, layout, impedance_nets, target_z_ohm)
     design = build_design_recipe(
@@ -118,6 +126,7 @@ def build_antenna_report(
         f0_mhz=f0_mhz,
         target_z_ohm=target_z_ohm,
         h_mm=h_mm,
+        template=template,
         er=er,
         t_mm=t_mm,
     )
@@ -133,6 +142,7 @@ def build_design_recipe(
     h_mm: float | None = None,
     er: float | None = None,
     t_mm: float | None = None,
+    template: AntennaTemplate = "ifa",
 ) -> AntennaDesignRecipe:
     marker = _find_marker(graph, layout)
     zone = _find_antenna_zone(layout)
@@ -141,6 +151,8 @@ def build_design_recipe(
         "Short GND return from the matching network to the RF reference.",
         "Avoid long stubs and right angles on the 50 Ω feed.",
         "Place matching parts close to the RF pin / feed point.",
+        "IFA pad 2 (shorting tip) must connect to RF ground / pour edge.",
+        "Place the footprint with feed (pad 1) on the ANT* / ANT_FEED join.",
     ]
 
     stack = _resolve_stackup(layout, h_mm=h_mm, er=er, t_mm=t_mm)
@@ -197,14 +209,36 @@ def build_design_recipe(
             f0_mhz=f0_mhz,
         )
 
+    feed_xy = None
+    if marker.get("x") is not None and marker.get("y") is not None:
+        feed_xy = (float(marker["x"]), float(marker["y"]))
+    zone_bbox = zone.bbox_mm if zone else None
+    geometry = build_geometry(
+        template,
+        f0_mhz=f0_mhz,
+        w_mm=float(feed.w_mm or 0),
+        er=er_v,
+        zone_bbox_mm=zone_bbox,
+        feed_xy=feed_xy,
+    )
+
+    detail = "Recipe ready — feed at w_mm; geometry is a parametric template (not EM)."
+    if geometry.fit == "need_f0":
+        detail = "Feed w ready — set f0 to generate IFA / meander / stub geometry."
+    elif geometry.fit == "scaled":
+        detail = geometry.detail
+    elif geometry.fit == "overflow":
+        detail = geometry.detail
+
     return AntennaDesignRecipe(
         status="ready",
         feed_point=marker,
         feed_line=feed,
         radiator=radiator,
+        geometry=geometry,
         zone=zone,
         keepout_checklist=checklist,
-        detail="Recipe ready — draw the feed at w_mm; radiator length is an estimate only.",
+        detail=detail,
     )
 
 

backend/routers/impedance.py

@@ -133,6 +133,7 @@ class AntennaDesignRequest(BaseModel):
     h: float | None = None
     er: float | None = None
     t: float | None = None
+    template: Literal["ifa", "meander", "stub"] = "ifa"
 
 
 def _load_graph_layout(storage, prefix: str) -> tuple[DesignGraph | None, LayoutGraph | None, dict | None]:
@@ -190,6 +191,7 @@ async def post_project_antenna_design(
         h_mm=body.h,
         er=body.er,
         t_mm=body.t,
+        template=body.template,
     )
     # Recompute design with explicit params (same as report.design but ensure POST body wins)
     report.design = build_design_recipe(
@@ -200,5 +202,6 @@ async def post_project_antenna_design(
         h_mm=body.h,
         er=body.er,
         t_mm=body.t,
+        template=body.template,
     )
     return report.model_dump(mode="json")

docs/piano-implementazione.md

@@ -159,7 +159,7 @@ Passi:
 | 4 Filtri | `check_filters` (solo con poli/numeri in specs) | Niente \(f_c\) inventata | **OK** |
 | 5 Capacità PI | Decoupling sulla net; derating V; DC-bias/ESR se c’è il numero; mm sul PCB (`PS-PLC-001`) | — | **OK** |
 | 6 Elettrico | Pin mux; I2C/reset pull-up; LED; sequencing/IR/power margin se c’è il parametro | Senza numero in specs → skip | **OK** |
-| 7 RF | Tab **RF / Impedance**: verify matching + design recipe (w 50 Ω, λ/4 se f0); Z0 feed se PCB | CPWG / auto-draw radiatore dopo | **Improved** |
+| 7 RF | Tab **RF / Impedance**: verify matching + template geometry (IFA/meander/stub → SVG + `.kicad_mod`); Z0 feed se PCB | CPWG / auto-place into `.kicad_pcb` dopo | **Improved** |
 | 8 HV / isolation | — | Serve `layout_rules` + V/mm dal datasheet, non IEC inventato | — |
 | 9 Termico | `check_thermal` se θJA/I sono in specs; via courtyard vs `min_via_count` | Niente \(T_j\) senza parametro | **OK** |
 | 10 SI / DNP | DNP enable; `PS-SI-001` solo con `length_match` mm | Niente 3W/crosstalk inventati | **OK** |
@@ -428,7 +428,7 @@ Passi:
 
 1. Topologia π/T tra pin ANT e connettore/antenna (stesso matcher filtri). **OK** — sezione Verify in RF/Impedance.
 2. Target 50 Ω come **intento**, non misura: WARNING se manca rete. **OK** (status warning su `missing`).
-3. Utility Progetta: marker KiCad `ANT*` / `ANT_FEED` + stackup → `w` microstrip; `f0` → λ/4 stimata; zona `antenna` → bbox. **OK** (auto-draw rame = dopo).
+3. Utility Progetta: marker KiCad `ANT*` / `ANT_FEED` + stackup → `w` microstrip; `f0` → template IFA / meander / stub (segmenti mm + SVG + `.kicad_mod`); zona `antenna` → fit/scale. **OK** (auto-place rame nel PCB = dopo).
 4. CPW clearance: **Wave G** (layout).
 
 ---

frontend/content/changelog.md

@@ -2,6 +2,14 @@
 
 What's new in Pinscope.
 
+## 2.28.12 — 2026-09-13 — Antenna templates: IFA / meander / stub + .kicad_mod
+
+Progetta antenna now returns a full parametric drawing: polyline segments (mm), SVG preview, and a downloadable KiCad footprint. Choose IFA, meander, or stub; geometry scales to the `antenna` zone when present. Still a routing template — no EM/VSWR invented.
+
+- [New] `antenna_geometry.py` (IFA / meander / stub → segments + SVG + `.kicad_mod`).
+- [Changed] `POST /antenna/design` accepts `template`; recipe includes `geometry`.
+- [Changed] RF / Impedance Progetta UI: template select, SVG preview, download footprint.
+
 ## 2.28.11 — 2026-09-13 — RF / Impedance: verify antenna + design recipe
 
 Project tab renamed **RF / Impedance**. Verify matching from IC ANT/RF pins toward an `ANT*` / `ANT_FEED` marker; Progetta returns microstrip `w` for 50 Ω (stackup or UI h/εr), optional λ/4 length from `f0`, and antenna-zone bbox. Auto-draw copper comes later — no EM/VSWR invented.

frontend/src/components/project/impedance-panel.tsx

@@ -55,6 +55,7 @@ export function ImpedancePanel({
   const [extraNets, setExtraNets] = useState("");
   const [antenna, setAntenna] = useState<AntennaReport | null>(null);
   const [f0, setF0] = useState("2440");
+  const [template, setTemplate] = useState<"ifa" | "meander" | "stub">("ifa");
   const [antBusy, setAntBusy] = useState(false);
   const [antError, setAntError] = useState<string | null>(null);
 
@@ -163,6 +164,7 @@ export function ImpedancePanel({
         h: num(h),
         er: num(er),
         t: num(t),
+        template,
       });
       setAntenna(report);
     } catch (e) {
@@ -177,6 +179,19 @@ export function ImpedancePanel({
     void navigator.clipboard.writeText(JSON.stringify(antenna.design, null, 2));
   }
 
+  function downloadKicadMod() {
+    const mod = antenna?.design?.geometry?.kicad_mod;
+    const name = antenna?.design?.geometry?.footprint_name ?? "Antenna";
+    if (!mod) return;
+    const blob = new Blob([mod], { type: "text/plain" });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download = `${name}.kicad_mod`;
+    a.click();
+    URL.revokeObjectURL(url);
+  }
+
   const needsGap = kind === "cpw" || kind === "diff";
   const design = antenna?.design;
 
@@ -243,13 +258,29 @@ export function ImpedancePanel({
           <p className="text-sm text-muted-foreground">
             Mark the feed join in KiCad (<code className="text-xs">ANT*</code>{" "}
             footprint or net <code className="text-xs">ANT_FEED</code>). Optional
-            zone net <code className="text-xs">antenna</code>. Auto-draw in the
-            zone comes later — this returns w / Z0 / length to draw by hand.
+            zone net <code className="text-xs">antenna</code>. Choose a template
+            (IFA / meander / stub) to get polylines, SVG preview, and a{" "}
+            <code className="text-xs">.kicad_mod</code> — parametric routing aid,
+            not an EM result.
           </p>
           {!hasPcb && (
             <PcbUploadButton projectId={projectId} onUploaded={onPcbUploaded} />
           )}
-          <div className="grid grid-cols-2 gap-3 sm:grid-cols-4">
+          <div className="grid grid-cols-2 gap-3 sm:grid-cols-5">
+            <label className="space-y-1">
+              <Label>Template</Label>
+              <select
+                className="h-8 w-full rounded-lg border border-input bg-transparent px-2 text-sm"
+                value={template}
+                onChange={(e) =>
+                  setTemplate(e.target.value as "ifa" | "meander" | "stub")
+                }
+              >
+                <option value="ifa">IFA</option>
+                <option value="meander">Meander</option>
+                <option value="stub">Stub</option>
+              </select>
+            </label>
             <label className="space-y-1">
               <Label>f0 (MHz)</Label>
               <Input value={f0} onChange={(e) => setF0(e.target.value)} placeholder="2440" />
@@ -278,12 +309,22 @@ export function ImpedancePanel({
             >
               Copy JSON
             </Button>
+            <Button
+              variant="outline"
+              onClick={downloadKicadMod}
+              disabled={!design?.geometry?.kicad_mod}
+            >
+              Download .kicad_mod
+            </Button>
           </div>
           {antError && <p className="text-sm text-destructive">{antError}</p>}
           {design && (
             <div className="rounded-lg border p-3 text-sm space-y-2">
               <div className="flex flex-wrap gap-2 items-center">
                 <Badge variant="secondary">{design.status}</Badge>
+                {design.geometry && (
+                  <Badge variant="outline">{design.geometry.fit}</Badge>
+                )}
                 <span className="text-muted-foreground text-xs">{design.detail}</span>
               </div>
               {design.feed_line && (
@@ -299,6 +340,28 @@ export function ImpedancePanel({
                   {fmt(design.radiator.f0_mhz, 0)} MHz — {design.radiator.note}
                 </p>
               )}
+              {design.geometry?.svg && (
+                <div
+                  className="overflow-auto rounded-md border bg-muted/30 p-2"
+                  dangerouslySetInnerHTML={{ __html: design.geometry.svg }}
+                />
+              )}
+              {design.geometry && design.geometry.fit !== "need_f0" && (
+                <p className="text-xs text-muted-foreground tabular-nums">
+                  {design.geometry.template.toUpperCase()}
+                  {design.geometry.total_length_mm != null
+                    ? ` · path ${fmt(design.geometry.total_length_mm)} mm`
+                    : ""}
+                  {design.geometry.length_ideal_mm != null
+                    ? ` · ideal λ/4 ${fmt(design.geometry.length_ideal_mm)} mm`
+                    : ""}
+                  {design.geometry.segments.length
+                    ? ` · ${design.geometry.segments.length} segment(s)`
+                    : ""}
+                  {" — "}
+                  {design.geometry.note}
+                </p>
+              )}
               {design.zone && (
                 <p className="text-xs text-muted-foreground">
                   Zone {design.zone.net} on {design.zone.layer}

frontend/src/lib/api.ts

@@ -747,6 +747,7 @@ export async function designAntenna(
     h?: number | null;
     er?: number | null;
     t?: number | null;
+    template?: "ifa" | "meander" | "stub";
   },
 ): Promise<AntennaReport> {
   const res = await authFetch(

frontend/src/lib/types.ts

@@ -465,6 +465,20 @@ export interface AntennaVerifyRow {
   marker_ref?: string | null;
 }
 
+export interface AntennaGeometry {
+  template: "ifa" | "meander" | "stub";
+  fit: "ok" | "scaled" | "overflow" | "need_f0";
+  segments: { points: number[][]; width_mm: number }[];
+  total_length_mm?: number | null;
+  length_ideal_mm?: number | null;
+  scale?: number;
+  svg?: string | null;
+  kicad_mod?: string | null;
+  footprint_name?: string | null;
+  note?: string;
+  detail?: string;
+}
+
 export interface AntennaDesignRecipe {
   status: "ready" | "need_pcb" | "need_stackup" | "need_marker";
   feed_point?: Record<string, unknown> | null;
@@ -481,6 +495,7 @@ export interface AntennaDesignRecipe {
     f0_mhz?: number | null;
     note?: string;
   } | null;
+  geometry?: AntennaGeometry | null;
   zone?: {
     net: string;
     layer: string;

tests/test_antenna_rf.py

@@ -177,3 +177,79 @@ def test_design_recipe_ready_with_ant_and_stackup():
     assert recipe.radiator.length_mm_suggest is not None
     assert recipe.zone is not None
     assert recipe.zone.bbox_mm is not None
+    assert recipe.geometry is not None
+    assert recipe.geometry.template == "ifa"
+    assert recipe.geometry.fit in ("ok", "scaled")
+    assert len(recipe.geometry.segments) >= 2
+    assert recipe.geometry.svg and "<svg" in recipe.geometry.svg
+    assert recipe.geometry.kicad_mod and '(footprint "' in recipe.geometry.kicad_mod
+    assert "fp_line" in recipe.geometry.kicad_mod
+
+
+def test_geometry_templates_produce_export():
+    from backend.pinscopex.antenna_geometry import build_geometry
+
+    for tmpl in ("ifa", "meander", "stub"):
+        geo = build_geometry(tmpl, f0_mhz=2440.0, w_mm=0.4, er=4.5)
+        assert geo.fit == "ok"
+        assert geo.total_length_mm is not None and geo.total_length_mm > 10
+        assert geo.length_ideal_mm is not None
+        assert geo.total_length_mm >= geo.length_ideal_mm * 0.9
+        assert geo.svg and "path" in geo.svg
+        assert geo.kicad_mod and '(pad "1"' in geo.kicad_mod
+        assert len(geo.segments) >= 1
+
+
+def test_geometry_overflow_tiny_zone():
+    from backend.pinscopex.antenna_geometry import build_geometry
+
+    geo = build_geometry(
+        "ifa",
+        f0_mhz=2440.0,
+        w_mm=0.4,
+        er=4.5,
+        zone_bbox_mm=(0.0, 0.0, 2.0, 1.0),
+        feed_xy=(0.0, 0.0),
+    )
+    assert geo.fit == "overflow"
+    assert not geo.segments
+
+
+def test_design_recipe_meander_template():
+    g = DesignGraph(
+        components={
+            "ANT1": Component(
+                reference="ANT1", value="feed", footprint="",
+                component_type=ComponentType.CONNECTOR,
+                pins={"1": "ANT_FEED"},
+            ),
+        },
+        nets={
+            "ANT_FEED": Net(
+                name="ANT_FEED", net_type=NetType.SIGNAL,
+                pins=[PinConnection(component_ref="ANT1", pin_number="1")],
+            ),
+        },
+    )
+    layout = LayoutGraph(
+        footprints={
+            "ANT1": LayoutFootprint(
+                reference="ANT1", x=0.0, y=0.0, layer="F.Cu",
+                pads=[LayoutPad(number="1", x=0.0, y=0.0, net="ANT_FEED")],
+            ),
+        },
+        nets={"ANT_FEED": 1},
+        stackup=LayoutStackup(
+            copper_layers=["F.Cu", "B.Cu"],
+            dielectrics=[LayoutDielectric(name="FR4", er=4.5, height_mm=0.2)],
+            copper_thickness_mm=0.035,
+        ),
+    )
+    recipe = build_design_recipe(
+        g, layout, f0_mhz=2440.0, template="meander",
+    )
+    assert recipe.status == "ready"
+    assert recipe.geometry is not None
+    assert recipe.geometry.template == "meander"
+    assert recipe.geometry.fit == "ok"
+    assert recipe.geometry.kicad_mod is not None