CoaxialFeed

Create a coaxial feed object

Since R2024b

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    Description

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

    Creation

    Syntax

    f1=CoaxialFeed(PropertyName=Value)

    Description

    f1=CoaxialFeed(PropertyName=Value) sets object Properties using one or more name value arguments. Properties not set retain their default value.

    example

    Properties

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    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

    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

    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

    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

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    Open Live Script

    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);

    Figure contains an axes object. The axes object with title pcbComponent element, xlabel x (mm), ylabel y (mm) contains 7 objects of type patch, surface. These objects represent PEC, feed.

    Warning: An error occurred while drawing the scene: GraphicsView error in command: interactionsmanagermessage:  TypeError: Cannot read properties of null (reading '_gview')
    at new b (https://127.0.0.1:31515/toolbox/matlab/uitools/figurelibjs/release/bundle.mwBundle.gbtfigure-lib.js?mre=https

    s = sparameters(p, linspace(1e9, 5e9, 51));
figure; rfplot(s);

    Figure contains an axes object. The axes object with xlabel Frequency (GHz), ylabel Magnitude (dB) contains an object of type line. This object represents dB(S_{11}).

    Version History

    Introduced in R2024b