EdgeFeed

R2026b

Create an edge feed

Since R2026b

Description

Use the EdgeFeed object to specify the FeedDefinitions property in a parent pcbStack object.

The EdgeFeed object excites the structure from the edge of the PCB, typically representing a microstrip or stripline launch.

Creation

Syntax

f1 = EdgeFeed

f1 = EdgeFeed(PropertyName=Value)

Description

f1 = EdgeFeed creates a defaultEdgeFeed object.

f1 = EdgeFeed(PropertyName=Value) sets object properties using one or more name-value arguments. PropertyName is the property name, and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN. Properties that you do not specify retain their default values.

Properties

SignalLocations — Location to apply positive excitation

[-0.01,0] (default) | 1-by-2 vector

Location to apply positive excitation, specified as a 1-by-2 vector in meters.

The first and the second elements correspond to the X- and Y-coordinates in meters, respectively. This location must lie on the edge of a metal layer. Locations of negative excitation are assumed to lie directly above (+z) and/or below (-z) the location of positive excitation.

Example: [-0.02,0]

Data Types: double

SignalLayers — Layer index for positive excitation site

1 (default) | positive integer scalar

Layer index for positive excitation site, specified as a positive integer scalar. SignalLayers is the layer index into the pcbStack layer stack.

Example: 2

Data Types: double

GroundLayers — Layer indices for all negative excitation sites

3 (default) | N-by-1 vector of integers

Layer indices for all negative excitation sites, specified as a N-by-1 vector of integers. GroundLayers(n) is the layer index into the pcbStack layer stack.

Example: 5

Data Types: double

SignalWidths — Width of positive excitation site

0.002 (default) | positive scalar

Width of the positive excitation site, specified as a positive scalar in meters.

Example: 0.003

Data Types: double

Examples

Edge-fed Rectangular Patch Antenna

Define the patch, feed line, and board dimensions. The patch dimensions set the resonant frequency, in this case, near 2.4 GHz on a 1.6 mm FR4 substrate. Define the feed line width for a nominal 50 Ω line impedance. The feed line runs from the patch edge to the board edge. Apply the EdgeFeed here.

Lp = 0.0275;       
Wp = 0.0375;        
Wf = 0.0030;        
Lb = 0.070;          
Wb = 0.070;          
sub = 1.6e-3;
Lf = Lb/2 - Lp/2;

Define an FR4 substrate and set its thickness.

d = dielectric("FR4");
d.Thickness = sub;

Create the patch and the feed line as rectangles using the antenna.Rectangle class, then combine them into a single conductor. Position the feed line so that it joins the patch at one edge and extends to the edge of the board.

patch = antenna.Rectangle(Length=Lp, Width=Wp, Center=[0 0]);
feedX = -(Lp/2 + Lf/2);
feedLine = antenna.Rectangle(Length=Lf, Width=Wf, Center=[feedX 0]);
top = patch + feedLine;

Define the ground plane as a full-board rectangle. Create the pcbStack object as a three-layer stack: the patch and feed line on top, the dielectric in the middle, and the ground plane on the bottom.

gnd = antenna.Rectangle(Length=Lb, Width=Wb);
p = pcbStack;
p.BoardShape = antenna.Rectangle(Length=Lb, Width=Wb);
p.BoardThickness = sub;
p.Layers = {top, d, gnd};

To enable the FeedDefinitions property, set the FeedFormat property to FeedDefinitions.

p.FeedFormat = 'FeedDefinitions';

Create and orient the EdgeFeed object at the board edge where the feed line terminates. Use the SignalLocations property to place the feed at the outer end of the feed line. Set SignalWidths to match the feed line width. Reference the top conductor and the ground plane in the SignalLayers and GroundLayers properties respectively. The feed line must reach the board edge for the edge feed to attach to the conductor.

xEdge = -Lb/2;
f = EdgeFeed(SignalLocations=[xEdge 0], SignalWidths=Wf, ...
    SignalLayers=1, GroundLayers=3);
p.FeedDefinitions = f;

View the structure to confirm the patch, the feed line reaching the board edge, and the ground plane.

figure
show(p)

Compute and plot the reflection coefficient. The patch resonates near 2.47 GHz.

s = sparameters(p, linspace(1.5e9, 3.5e9, 61));
figure
rfplot(s)

Version History

Introduced in R2026b