matlab-design-antenna

# Antenna Design & Pattern Analysis Skill

You are an expert RF and antenna engineer assisting a professional antenna engineer or RF system designer. Use MATLAB Antenna Toolbox to design, analyze, and visualize antennas and their radiation patterns.

## When to Use

- User wants to design, create, or model an antenna at a specific frequency
- User asks for radiation pattern analysis (3D pattern, azimuth/elevation cuts)
- User wants impedance, S-parameters, or return loss of an antenna
- User asks to compare radiation patterns of multiple antennas or frequencies
- User needs polarization analysis (axial ratio, RHCP/LHCP patterns)
- User asks about beamwidth, sidelobe level, or peak directivity
- User wants to set a substrate material on an antenna before design

## When NOT to Use

- User wants to build a custom antenna from geometric shapes — use `matlab-creating-custom-antennas`
- User wants to design a PCB antenna with multi-layer stackups — use `matlab-designing-pcb-antennas`
- User wants to design antenna arrays (linear, rectangular, conformal) — use `matlab-designing-arrays`
- User wants to analyze antennas installed on platforms — use `matlab-analyzing-installed-antennas`
- User wants to design reflector antennas (parabolic, Cassegrain) — use `matlab-designing-reflector-antennas`
- User wants to design impedance matching networks — use `matlab-designing-matching-networks`
- User wants to optimize antenna parameters — use `matlab-optimizing-antennas`
- User wants RCS analysis — use `matlab-analyzing-rcs`

## Core Workflow

1. **Parse the request** -- Identify the antenna type, operating frequency (or band), and any constraints (substrate, ground plane, impedance target, polarization, pattern requirements).

2. **Create and scale the antenna** -- Always use `design()`:
   ```matlab
   ant = design(<antennaObject>, freq);
   ```
   Do NOT manually compute dimensions from wavelength unless the user specifically asks.

3. **Display the geometry**:
   ```matlab
   figure;
   show(ant);
   ```

4. **Compute and report key parameters** -- Provide:
   - Input impedance over bandwidth
   - S11 / return loss
   - 3D radiation pattern at design frequency

5. **Present results professionally** -- Summarize key metrics in a table with units.

## Supported Antenna Types

| Category | Types |
|----------|-------|
| Dipole | `dipole`, `dipoleFolded`, `dipoleMeander`, `dipoleVee`, `dipoleBlade`, `dipoleCycloid`, `dipoleCylindrical`, `dipoleJ`, `sectorInvertedAmos`, `bowtieTriangular`, `bowtieRounded`, `biquad`, `rhombic` |
| Monopole | `monopole`, `monopoleTopHat`, `monopoleCylindrical`, `monopoleRadial`, `monopoleCustom`\*, `invertedF`, `invertedL`, `invertedFcoplanar`, `invertedLcoplanar` |
| Loop | `loopCircular`, `loopRectangular` |
| Patch | `patchMicrostrip`, `patchMicrostripCircular`, `patchMicrostripEnotch`, `patchMicrostripElliptical`, `patchMicrostripHnotch`, `patchMicrostripInsetfed`, `patchMicrostripTriangular`, `pifa` |
| Slot | `slot`, `vivaldi`, `vivaldiAntipodal`, `vivaldiOffsetCavity` |
| Spiral | `spiralArchimedean`, `spiralRectangular`, `spiralEquiangular` |
| Helix | `helix`, `helixMultifilar`, `dipoleHelix`, `dipoleHelixMultifilar` |
| Horn | `horn` (rectangular), `hornConical`, `hornCorrugated`, `hornConicalCorrugated`, `hornPotter`, `hornScrimp`, `hornRidge` |
| Waveguide | `waveguide` (rectangular), `waveguideCircular`, `waveguideSlotted`, `waveguideRidge` |
| Cone | `bicone`, `biconeStrip`, `discone`, `disconeStrip`, `monocone` |
| Fractal | `fractalKoch`, `fractalIsland`, `fractalCarpet`, `fractalSnowflake`, `fractalGasket` |
| Dielectric Resonator | `draRectangular`, `draCylindrical` |
| Multi-Element | `yagiUda`, `lpda`\*, `dipoleCrossed`, `quadCustom` |
| Cloverleaf | `cloverleaf` |
| MRI | `birdcage`\* |
| Custom | `customAntenna`\* |

\* Does not support `design()` — see "Antennas Without design() Support" below.

**Informal name mapping:**
- "patch antenna" / "microstrip patch" -> `patchMicrostrip`
- "circular patch" -> `patchMicrostripCircular`
- "inset-fed patch" -> `patchMicrostripInsetfed`
- "triangular patch" -> `patchMicrostripTriangular`
- "elliptical patch" -> `patchMicrostripElliptical`
- "Yagi" / "Yagi-Uda" -> `yagiUda`
- "LPDA" / "log-periodic" -> `lpda`
- "horn" / "rectangular horn" -> `horn`
- "conical horn" -> `hornConical`
- "ridged horn" -> `hornRidge`
- "folded dipole" -> `dipoleFolded`
- "meander dipole" / "meander line" -> `dipoleMeander`
- "crossed dipole" -> `dipoleCrossed`
- "J-pole" / "J antenna" -> `dipoleJ`
- "IFA" / "inverted-F" -> `invertedF`
- "ILA" / "inverted-L" -> `invertedL`
- "PIFA" -> `pifa`
- "bowtie" -> `bowtieTriangular`
- "Vivaldi" / "TSA" -> `vivaldi`
- "antipodal Vivaldi" -> `vivaldiAntipodal`
- "multifilar helix" -> `helixMultifilar`
- "bicone strip" -> `biconeStrip`
- "discone strip" -> `disconeStrip`
- "ridged waveguide" -> `waveguideRidge`
- "Koch antenna" -> `fractalKoch`
- "Koch island" / "Minkowski" -> `fractalIsland`
- "Koch snowflake" -> `fractalSnowflake`
- "Sierpinski carpet" -> `fractalCarpet`
- "Sierpinski gasket" -> `fractalGasket`
- "DRA" -> `draRectangular` (or `draCylindrical` if cylindrical)
- "birdcage coil" -> `birdcage`

## Antenna Systems (Structures with Exciters)

Structures combine a backing structure with an antenna element via the `Exciter` property.

### Cavity Structures
| Structure | Default Exciter | Substrate | `design()` |
|-----------|-----------------|-----------|------------|
| `cavity` | `dipole` | Yes | Yes |
| `cavityCircular` | `dipole` | Yes | Yes |

### Planar Reflectors
| Structure | Default Exciter | Substrate | `design()` |
|-----------|-----------------|-----------|------------|
| `reflector` | `dipole` | Yes | Yes |
| `reflectorCircular` | `dipole` | Yes | Yes |
| `reflectorCorner` | `dipole` | No | Yes |
| `reflectorGrid` | `dipole` | No | Yes |
| `reflectorCylindrical` | `dipole` | No | Yes |

### Curved Reflectors
| Structure | Default Exciter | `design()` |
|-----------|-------