matlab-assemble-pcb-layout

# Assembling Custom PCB Components

## When to Use

- Building custom PCB structures that aren't covered by catalog objects (microstripLine, coupledMicrostripLine, etc.)
- Constructing multi-layer stackups with custom metal shapes on each layer
- Combining shape primitives with Boolean operations (union, subtract, intersect)
- Creating defected ground structures (DGS) by etching patterns into ground planes
- Placing feed ports, vias, or using advanced FeedDefinitions (coaxial, edge, delta-gap)
- Assembling stripline or shielded enclosure structures

## When NOT to Use

- Designing standard transmission lines — use `matlab-design-pcb-txline`
- Importing layouts from Gerber, ODB++, or Allegro — use `matlab-read-pcb-layout`
- Defining dielectric or metal materials — use `matlab-manage-pcb-material`
- Running EM analysis after assembly — use `matlab-analyze-em`
- Cascading or connecting multiple pcbComponents — use `matlab-integrate-pcb-circuit`

## Typical Workflow

1. **Before:** `matlab-manage-pcb-material` — set up substrate and conductor
2. **This skill:** Build the custom PCB structure using pcbComponent, shapes, and feeds
3. **After:** `matlab-analyze-em` — validate S-parameters → `matlab-optimize-pcb-design` — tune dimensions → `matlab-write-pcb-layout` — export Gerber

## Quick Reference

| Task | Code |
|------|------|
| Create pcbComponent | `pcb = pcbComponent` |
| Assign layers | `pcb.Layers = {signal, substrate, ground}` |
| Set board shape | `pcb.BoardShape = ground` |
| Set thickness | `pcb.BoardThickness = 1.6e-3` |
| Place feeds | `pcb.FeedLocations = [x1 y1 1 3; x2 y2 1 3]` |
| Feed diameter | `pcb.FeedDiameter = W/2` |
| Set conductor | `pcb.Conductor = metal("Copper")` |
| Add vias | `pcb.ViaLocations = [x y topLayer botLayer]` |
| Visualize | `show(pcb)` |
| Layout view | `layout(pcb)` |
| Boolean union | `shape = s1 + s2` |
| Boolean subtract | `shape = s1 - s2` |
| Boolean intersect | `shape = s1 & s2` |

## pcbComponent Anatomy

`pcbComponent` is the universal container for custom RF PCB structures.

### Minimal 2-Layer Microstrip

```matlab
pcb = pcbComponent;
substrate = dielectric("FR4");
substrate.Thickness = 1.6e-3;

signal = traceRectangular(Length=20e-3, Width=3e-3);
ground = traceRectangular(Length=30e-3, Width=20e-3);

pcb.Layers = {signal, substrate, ground};
pcb.BoardShape = ground;
pcb.BoardThickness = substrate.Thickness;
pcb.Conductor = metal("Copper");
pcb.FeedDiameter = 1.5e-3;
pcb.FeedLocations = [-10e-3 0 1 3; 10e-3 0 1 3];
show(pcb);
```

### 5-Layer Stripline Structure

```matlab
pcb = pcbComponent;
sub = dielectric(Name="FR4", EpsilonR=4.4, LossTangent=0.02, Thickness=0.8e-3);

topGnd = traceRectangular(Length=40e-3, Width=20e-3);
signal = traceRectangular(Length=30e-3, Width=2e-3);
botGnd = traceRectangular(Length=40e-3, Width=20e-3);

pcb.BoardThickness = 2 * sub.Thickness;          % Set BEFORE Layers
pcb.Layers = {topGnd, sub, signal, sub, botGnd};
pcb.BoardShape = topGnd;
pcb.Conductor = metal("Copper");
pcb.FeedLocations = [-15e-3 0 3 1; 15e-3 0 3 5];
pcb.FeedDiameter = 1e-3;
show(pcb);
```

### Key Properties

| Property | Format | Description |
|----------|--------|-------------|
| `Layers` | Cell array | Alternating: metal shape, dielectric, metal shape, ... |
| `BoardShape` | Shape object | Outer boundary of the PCB |
| `BoardThickness` | Scalar (m) | Must equal sum of dielectric thicknesses |
| `FeedLocations` | N×4 matrix | `[x, y, signalLayer, groundLayer]` per port |
| `FeedDiameter` | Scalar (m) | Diameter of feed via/probe |
| `ViaLocations` | M×4 matrix | `[x, y, topLayer, bottomLayer]` per via |
| `ViaDiameter` | Scalar (m) | Via barrel diameter |
| `FeedViaModel` | String | `'strip'`, `'square'`, `'octagon'`, `'hexagon'` |
| `Conductor` | metal object | Conductor for all metal layers |
| `SolverType` | String | `'MoM'` or `'FEM'` |

## Shape Primitives

### Rectangular Traces

```matlab
rect = traceRectangular(Length=20e-3, Width=5e-3, Center=[0 0]);
```

### Line Traces (multi-segment with bends)

```matlab
tl = traceLine;
tl.Length = [10 5*sqrt(2) 10]*1e-3;
tl.Angle = [0 45 0];
tl.Width = 3e-3;
tl.Corner = 1;          % 1 = Miter, 2 = Smooth (default: Sharp)
show(tl);
```

### Point-Defined Traces

```matlab
tp = tracePoint;
tp.TracePoints = [0 0; 10e-3 0; 15e-3 5e-3; 25e-3 5e-3];
tp.Width = 2e-3;
tp.Corner = 2;          % 2 = Smooth
```

### Spiral Traces

```matlab
sp = traceSpiral;
sp.NumTurns = 3;
sp.InnerDiameter = 4e-3;
sp.Spacing = 0.5e-3;
sp.TraceWidth = 0.5e-3;
show(sp);
```

### Tapered Traces

```matlab
tt = traceTapered;
tt.Length = 10e-3;
tt.InputWidth = 1e-3;
tt.OutputWidth = 3e-3;
```

### Bends

Bend `Width` is a 2-element vector `[w1 w2]` for the two arms:

```matlab
bc = bendCurved;
bc.Width = [2e-3 2e-3];
bc.CurveRadius = 5e-3;

bm = bendMitered;
bm.Width = [2e-3 2e-3];

br = bendRightAngle;
br.Width = [2e-3 2e-3];
```

### U-Bends

U-bend `Width` is a 3-element vector `[arm1 bottom arm2]`:

```matlab
uc = ubendCurved;
uc.Width = [2e-3 2e-3 2e-3];
uc.CurveRadius = 3e-3;

um = ubendMitered;
um.Width = [2e-3 2e-3 2e-3];
```

### Other Shapes

```matlab
d = delta;
d.OuterRadius = 5e-3;                           % Triangle/delta

db = dumbbell;
db.SideLength = 6e-3;                           % Head size (square Type, default)
db.ArmLength = 10e-3;
db.ArmWidth = 0.5e-3;                           % Dumbbell (for DGS)
% Note: Type='Square' uses SideLength; Type='Circle' uses Diameter

rt = racetrack;
rt.Length = 15e-3;
rt.Width = 5e-3;                                % Racetrack

rd = radial;
rd.OuterRadius = 5e-3;
rd.Angle = 60;                                  % Radial sector

ar = ringAnnular;
ar.InnerRadius = 1e-3;
ar.Width = 4e-3;                                % Annular ring (InnerRadius must be > 0)

sr = splitRing;
sr.RingDiameter = 10e-3;
sr.TraceWidth = 0.5e-3;
sr.SplitGap = 0.5e-3;                           % Split ring resonator
```

## Boolean Operations

Combine shapes using operators to build comple