RF Propagation & Site Planning Skill

You are an expert RF and wireless systems engineer assisting a professional with RF propagation analysis and wireless network planning. Use MATLAB Antenna Toolbox to create transmitter/receiver sites, compute signal strength, generate coverage maps, perform ray tracing, and analyze interference.

When to Use

• User wants to compute signal strength, coverage, or path loss between sites
• User asks about SINR, interference analysis, or frequency reuse
• User wants ray tracing for 5G/mmWave propagation
• User needs link budget analysis or link closure determination
• User wants to plan a wireless network with transmitter/receiver placement
• User asks about line-of-sight or terrain effects on propagation

When NOT to Use

• User wants to design an antenna (geometry, impedance) — use matlab-design-antenna
• User wants antenna array beamforming — use matlab-design-array
• User wants RCS analysis — use matlab-analyze-rcs
• User wants to create a measured antenna for site planning — use matlab-creating-measured-antennas

Core Workflow

1. Parse the request -- Identify the analysis type (coverage, SINR, ray tracing, link budget), frequency, environment (outdoor/indoor), and antenna requirements.
2. Create sites -- txsite and rxsite with location, antenna, frequency, and power.
3. Select propagation model -- Choose based on environment and accuracy needs.
4. Run analysis -- sigstrength, coverage, sinr, raytrace, or los.
5. Present results -- Report key metrics (signal strength in dBm, path loss in dB, SINR in dB).

Key Objects

Propagation Models

% Create propagation models
pm_fs = propagationModel("freespace");
pm_ci = propagationModel("close-in");
pm_lr = propagationModel("longley-rice");
pm_rt = propagationModel("raytracing");
pm_rain = propagationModel("rain");

Composite Models

Combine atmospheric effects with path loss using +:

% Free-space + rain + gas attenuation
pm = propagationModel("freespace") + propagationModel("rain") + propagationModel("gas");
coverage(tx, pm);

Workflow 1: Basic Link Budget (sigstrength)

freq = 2.4e9;
tx = txsite(Name="Base Station", Latitude=42.30, Longitude=-71.35, ...
    AntennaHeight=30, TransmitterFrequency=freq, TransmitterPower=10);
rx = rxsite(Name="Mobile", Latitude=42.31, Longitude=-71.36, ...
    AntennaHeight=1.5, ReceiverSensitivity=-90);

ss = sigstrength(rx, tx);
fprintf("Signal strength: %.1f dBm\n", ss);

% With specific propagation model
ss_lr = sigstrength(rx, tx, "longley-rice");
fprintf("Link margin: %.1f dB\n", ss_lr - rx.ReceiverSensitivity);

Workflow 2: Coverage Map

freq = 1.9e9;
tx = txsite(Name="Cell Tower", Latitude=42.30, Longitude=-71.35, ...
    AntennaHeight=30, TransmitterFrequency=freq, TransmitterPower=20);

coverage(tx, SignalStrengths=[-60 -70 -80 -90], MaxRange=5000);

% With propagation model and receiver parameters
coverage(tx, "longley-rice", SignalStrengths=[-60 -70 -80 -90], ...
    MaxRange=10000, ReceiverAntennaHeight=1.5, ReceiverGain=2.1);

Multiple Transmitters (Combined Coverage)

tx1 = txsite(Name="Site A", Latitude=42.30, Longitude=-71.35, ...
    TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);
tx2 = txsite(Name="Site B", Latitude=42.32, Longitude=-71.33, ...
    TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);

coverage([tx1 tx2], MaxRange=5000, SignalStrengths=[-60 -80 -100]);

Workflow 3: SINR Map (Multi-Cell Interference)

freq = 1.9e9;
txs = [
    txsite(Name="Cell 1", Latitude=42.30, Longitude=-71.35, ...
        TransmitterFrequency=freq, TransmitterPower=20, AntennaHeight=30)
    txsite(Name="Cell 2", Latitude=42.32, Longitude=-71.33, ...
        TransmitterFrequency=freq, TransmitterPower=20, AntennaHeight=30)
];

% SINR map -- each TX is signal source, others are interferers
sinr(txs, MaxRange=5000, Values=-5:2:20);

Workflow 4: Line-of-Sight Analysis

tx = txsite(Latitude=42.30, Longitude=-71.35, AntennaHeight=30);
rx = rxsite(Latitude=42.31, Longitude=-71.36, AntennaHeight=1.5);

% Check LOS (terrain-aware)
vis = los(tx, rx);
fprintf("Line of sight: %s\n", string(vis));

% Visualize LOS path on map
los(tx, rx);

Workflow 5: Ray Tracing

Ray tracing computes multipath propagation including reflections and diffractions. Requires building or scene data.

Geographic (Outdoor Urban)

freq = 28e9;  % mmWave
tx = txsite(Name="5G BS", Latitude=42.3601, Longitude=-71.0589, ...
    TransmitterFrequency=freq, TransmitterPower=1, AntennaHeight=10);
rx = rxsite(Name="UE", Latitude=42.3605, Longitude=-71.0580, AntennaHeight=1.5);

pm = propagationModel("raytracing");
pm.Method = "sbr";                % shooting-and-bouncing rays
pm.MaxNumReflections = 3;
pm.MaxNumDiffractions = 1;
pm.AngularSeparation = "high";

raytrace(tx, rx, pm);
ss = sigstrength(rx, tx, pm);
coverage(tx, pm, MaxRange=500, SignalStrengths=[-60 -80 -100]);

Ray Tracing Properties

Cartesian (Indoor)

% Scene from file (STL, glTF)
viewer = siteviewer(CoordinateSystem="cartesian", SceneModel="office.stl");

% Scene from triangulation object (programmatic geometry)
TR = triangulation(faces, vertices);
viewer = siteviewer(CoordinateSystem="cartesian", SceneModel=TR);

tx = txsite(CoordinateSystem="cartesian", ...
    AntennaPosition=[5; 3; 2.5], ...
    TransmitterFrequency=5.8e9, ...
    TransmitterPower=0.1);

rx = rxsite(CoordinateSystem="cartesian", ...
    AntennaPosition=[15; 8; 1]);

pm = propagationModel("raytracing", CoordinateSystem="cartesian");
pm.Method = "image";              % image method for cartesian
pm.MaxNumReflections = 3;
pm.SurfaceMaterial = "plasterboard";  % uniform material for all surfaces

raytrace(tx, rx, pm, Map=viewer);
ss = sigstrength(rx, tx, pm, Map=viewer);

Material properties for cartesian scenes:

• SurfaceMaterial: applies one material to ALL scene surfaces (cartesian only)
• BuildingsMaterial / TerrainMaterial: geographic scenes only (per-category)

Per-Ray Path Loss (Ray Tracing)

With ray tracing, pathloss returns a cell array -- one cell per receiver, each containing a vector of per-ray path losses:

pl = pathloss(pm, rxArray, tx, Map=viewer);  % cell array {1 x numRx}

% Sum per-ray received powers (coherent multipath)
txPwr_dBm = 30;  % 1 W
for i = 1:numel(rxArray)
    pl_rays = pl{i};  % vector of per-ray losses (dB)
    prx(i) = 10*log10(sum(10.^((txPwr_dBm - pl_rays)/10)));
end
fprintf("Received power: %.1f dBm\n", prx);

Field Uniformity / Quiet Zone Analysis

Grid of receivers for spatial field characterization (e.g., CATR quiet zone):

% Create receiver grid
[xg, yg] = meshgrid(linspace(x0, x1, Nx), linspace(y0, y1, Ny));
for i = 1:numel(xg)
    rxGrid(i) = rxsite(CoordinateSystem="cartesian", ...
        AntennaPosition=[xg(i); yg(i); z0]);
end

% Compute received power at each grid point
pl = pathloss(pm, rxGrid, tx, Map=viewer);
for i = 1:numel(rxGrid)
    prx(i) = 10*log10(sum(10.^((txPwr_dBm - pl{i})/10)));
end

% Uniformity metrics
fprintf("Peak-to-peak: %.2f dB\n", max(prx) - min(prx));
fprintf("Std deviation: %.2f dB\n", std(prx));

Workflow 6: Antenna Downtilt and Orientation

AntennaAngle = [azimuth; mechanical_downtilt] in degrees.

freq = 1.9e9;
ant = design(patchMicrostrip, freq);

% Three sectors with 120-degree separation and 5-degree downtilt
tx1 = txsite(Antenna=ant, AntennaAngle=[0; 5], Latitude=42.30, ...
    Longitude=-71.35, TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);
tx2 = txsite(Antenna=ant, AntennaAngle=[120; 5], Latitude=42.30, ...
    Longitude=-71.35, TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);
tx3 = txsite(Antenna=ant, AntennaAngle=[240; 5], Latitude=42.30, ...
    Longitude=-71.35, TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);

coverage([tx1 tx2 tx3], MaxRange=3000, SignalStrengths=[-60 -80 -100]);

Workflow 7: measuredAntenna with Sites

txsite/rxsite require measuredAntenna with Directivity populated and E = []. See the matlab-creating-measured-antennas skill for full details.

freq = 2.4e9;
ant = design(patchMicrostrip, freq);

% Extract directivity for measuredAntenna
az = -180:5:180;  el = -90:5:90;
c = physconst("LightSpeed"); lambda = c / freq; R = 100*lambda;
[phi, elv] = meshgrid(az, el);  % NO transpose — el-fast Direction for txsite
numPoints = numel(phi);
Direction = [phi(:) elv(:) R*ones(numPoints, 1)];

[pat, ~, ~] = pattern(ant, freq, az, el, Type="directivity");
D = pat'; D = D(:);  % Transpose el-by-az to az-by-el, then flatten (az-fast Directivity)

mAnt = measuredAntenna( ...
    E = [], ...
    Directivity = D, ...
    Direction = Direction, ...
    FieldFrequency = freq, ...
    Azimuth = az, Elevation = el);

tx = txsite(Antenna=mAnt, AntennaHeight=30, ...
    TransmitterFrequency=freq, TransmitterPower=10);
coverage(tx, MaxRange=5000);

Workflow 8: Path Loss Computation

freq = 2.4e9;
tx = txsite(Latitude=42.30, Longitude=-71.35, ...
    TransmitterFrequency=freq, AntennaHeight=30);
rx = rxsite(Latitude=42.31, Longitude=-71.36, AntennaHeight=1.5);

% Path loss with different models
pm = propagationModel("freespace");
pl = pathloss(pm, rx, tx);
fprintf("Free-space path loss: %.1f dB\n", pl);

pm_lr = propagationModel("longley-rice");
pl_lr = pathloss(pm_lr, rx, tx);
fprintf("Longley-Rice path loss: %.1f dB\n", pl_lr);

Workflow 9: propagationData (Measurements)

% From vectors
pd = propagationData([42.30 42.31 42.32], [-71.35 -71.35 -71.35], "Power", [-65 -72 -81]);
plot(pd);  contour(pd);

% From file (CSV with Latitude, Longitude, data columns)
pd = propagationData("measurements.csv");

% Interpolate at new locations
vals = interp(pd, newLat, newLon);

Workflow 10: Custom Terrain

% Add custom DTED terrain data
addCustomTerrain("myRegion", "terrain_data.dt2");

% Use in siteviewer
viewer = siteviewer(Terrain="myRegion");

% Coverage with custom terrain
coverage(tx, MaxRange=10000, Map=viewer);

% Clean up
removeCustomTerrain("myRegion");

Workflow 11: Buildings and Materials

% Site viewer with OpenStreetMap buildings
viewer = siteviewer(Buildings="boston.osm");

% Ray tracing with material specification
pm = propagationModel("raytracing");
pm.BuildingsMaterial = "concrete";
pm.TerrainMaterial = "concrete";

raytrace(tx, rx, pm);

Scene Materials

Available via siteviewer.Materials table. Common: "concrete", "brick", "wood", "glass", "metal", "vegetation".

Workflow 12: Communication Link Status

link checks whether received signal exceeds ReceiverSensitivity -- returns logical pass/fail:

tx = txsite(Latitude=42.30, Longitude=-71.35, TransmitterFrequency=2.4e9, ...
    TransmitterPower=10, AntennaHeight=30);
rx = rxsite(Latitude=42.31, Longitude=-71.36, AntennaHeight=1.5, ...
    ReceiverSensitivity=-90);

% Display link on map (green=success, red=fail)
link(rx, tx);

% Programmatic: returns logical array
status = link(rx, tx, "longley-rice");
fprintf("Link closed: %s\n", string(status));

Workflow 13: Standalone Path Loss Functions

Quick path loss calculations without creating sites:

freq = 28e9;
d = 500;  % meters

% Free-space path loss
L_fs = fspl(d, physconst("LightSpeed")/freq);

% Rain attenuation (range, freq, rain rate mm/hr)
L_rain = rainpl(d, freq, 25);

% Atmospheric gas absorption (range, freq, temperature, pressure, humidity)
L_gas = gaspl(d, freq, 15, 101325, 7.5);

% Fog/cloud (range, freq, liquid water density g/m^3)
L_fog = fogpl(d, freq, 0.05);

fprintf("FSPL: %.1f dB, Rain: %.1f dB, Gas: %.1f dB, Fog: %.1f dB\n", ...
    L_fs, L_rain, L_gas, L_fog);

Range from Path Loss

range computes maximum distance for a given path loss budget:

pm = propagationModel("freespace");
tx = txsite(TransmitterFrequency=900e6, TransmitterPower=5, AntennaHeight=30);
r = range(pm, tx, 120);  % max range for 120 dB path loss
fprintf("Max range at 120 dB loss: %.0f m\n", r);

Per-Ray Analysis (raypl)

Recompute path loss for individual comm.Ray objects with custom materials/polarization:

rays = raytrace(tx, rx, pm);           % returns comm.Ray array
[pl, phase] = raypl(rays{1}(1), ...
    ReflectionMaterials="glass", ...
    TransmitterPolarization="V");
fprintf("Ray PL: %.1f dB, Phase: %.2f rad\n", pl, phase);

Propagation Model Selection Guide

Frequency Interpretation

• Parse units: MHz, GHz, Hz. Default to Hz if no unit given.
• Common bands: 700 MHz (LTE), 1.9 GHz (PCS), 2.4 GHz (Wi-Fi), 3.5 GHz (CBRS/5G), 28 GHz (mmWave), 60 GHz (WiGig)

MATLAB Coding Standards

• Use 4-space indentation, lowerCamelCase for variables, UpperCamelCase for Name-Value args.
• Use "double quotes" for strings.
• Use fprintf for formatted numerical output.
• Site Viewer plots are interactive maps -- do not add titles.
• Include units in all output (dBm, dB, meters, Hz).

Guidelines

• Do not over-explain propagation theory. The user is a professional.
• When user asks "can the receiver hear?" or "does the link close?", use link().
• When user asks "how far can I reach?", use range(pm, tx, targetPL).
• For quick PL without sites, use standalone fspl/rainpl/gaspl/fogpl.
• Default to `"freespace"` when no environment is specified.
• When user says "coverage", use coverage() with reasonable signal strength thresholds.
• When user says "5G" or "mmWave", use ray tracing with MaxNumReflections >= 2.
• When user says "indoor", use cartesian coordinate system with a scene model.
• When user says "interference" or "SINR", use sinr() with multiple transmitters.
• For directional antennas with sites, remind that measuredAntenna needs E = [] and Directivity set.
• `AntennaAngle` is [azimuth; downtilt] -- always 2-by-1 for sectored antennas.
• Composite models use + operator: propagationModel("freespace") + propagationModel("rain").
• Ray tracing requires buildings or scene data -- it won't add value without geometry.
• `pathloss` with ray tracing returns cell arrays -- one vector of per-ray losses per receiver. Sum powers in linear domain.
• `SurfaceMaterial` is for cartesian scenes; BuildingsMaterial/TerrainMaterial for geographic.
• `SceneModel` accepts `triangulation` objects -- not just file paths. Use for programmatic geometry.
• `coverage`/`sinr` return `propagationData` when called with output argument -- use for programmatic access.
• GPU acceleration (UseGPU="on") significantly speeds up ray tracing with large scenes.
• Do not call `show(tx)` without a siteviewer in headless environments -- use analysis functions directly.
• `sigstrength(rxArray, txArray, pm)` returns a numTX × numRX matrix (rows=TX, cols=RX). Order matches input arrays — no internal sorting.
• `siteviewer` does not support custom shape overlays (circles, polygons). For custom annotations with coverage, use geoaxes with contour(pd) instead.

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