CoaxialFeed

Create a coaxial feed object

Since R2024b

Description

Use the CoaxialFeed object to create and specify the FeedDefinitions property in a parent pcbComponent object.

Creation

Syntax

f1=CoaxialFeed(name=value)

Description

f1=CoaxialFeed(name=value) sets object properties using one or more name value arguments.

Properties

PadShape — Shape object that defines the feed's pad shape

shape object

Specifies the cross-sectional shape of the feed's via pad as a scalar shape, with dimensions in meters.

Example: c=antenna.Circle(Radius=0.002);PadShape=c

Data Types: double

AntipadShape — Shape object that defines the feed's antipad shape

shape object

Specifies the cross-sectional shape of the feed's via antipad as a scalar shape, with dimensions in meters.

Note

The size of the AntipadShape must be greater than the size of its associated PadShape.

Example: c=antenna.Circle(Radius=0.004);

Data Types: double

SignalLayers — Board layer to be positively excited

1 (default) | scalar

Specifies the board layer to be positively excited as a scalar. This layer is usually the same layer as the top of the via.

Example: f1=CoaxialFeed;f1.SignalLayers=2

Data Types: double

GroundLayers — Board layer to be negatively excited

3 (default) | scalar

Specifies the board layer to be excited as a scalar. This layer is usually the same layer as the bottom of the via.

Example: f1=CoaxialFeed;f1.GroundLayers=4

Data Types: double

Examples

Create Coaxial Feed for a Microstrip Patch Antenna

This example shows how to configure a CoaxialFeed object to model a probe feed with an antipad gap for a pcbComponent.

Create a microstrip patch antenna using a pcbComponent object.

r1 = traceRectangular('Length', 0.075, 'Width', 0.0357);
r2 = traceRectangular('Length', 0.150, 'Width', 0.0750);
d = dielectric('Air');
p = pcbComponent;
p.BoardShape = r2;
p.BoardThickness = d.Thickness;
p.Layers = {r1, d, r2};

Set the FeedLocations property to "FeedDefinitions" to expose the FeedDefinitions property.

p.FeedFormat = 'FeedDefinitions';

Create two circles: one to define a via shape at the feed site, and the other to define the via's antipad shape at the feed site.

cPad = antenna.Circle('Center', [-0.0187 0], 'Radius', 0.5e-3, 'NumPoints', 16);
cAntipad = antenna.Circle('Center', [-0.0187 0], 'Radius', 1.5e-3, 'NumPoints', 16);

Punch out the antipad shape on the ground plane, and add back in the pad shape.

p.Layers{3} = p.Layers{3} - cAntipad + cPad;

Instantiate the CoaxialFeed object using cPad and cAntipad as the shapes for the PadShape and AntipadShape properties.

f = CoaxialFeed('PadShape', cPad, 'AntipadShape', cAntipad, 'SignalLayers', 1, 'GroundLayers', 3);
p.FeedDefinitions = f;

Show the structure, then calculate and plot its S-parameters over a frequency band.

figure; show(p);

a=1;

Version History

Introduced in R2024b