FiniteGapFeed

Create a finite gap feed object

Since R2024b

Description

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

Creation

Syntax

f1=FiniteGapFeed

f1=FiniteGapFeed(PropertyName=Value)

Description

f1=FiniteGapFeed creates a default FiniteGapFeed object.

f1=FiniteGapFeed(PropertyName=Value) set Properties using one or more name value arguments.

Properties

SignalLocations — Positive excitation locations of the feed

[0.001,0] (default) | Nx 2 matrix

Specifies the locations that require positive excitation as a matrix of size Nx2 in meters.

The first and second columns correspond to the x and Y coordinates, receptively, in meters. Each location must lie on the edge of a metal layer.

Example: f1=FiniteGapFeed;f1.SignalLocations=[0.002,0]

Data Types: double

GroundLocations — Negative excitation locations of the feed

[-0.01,0] (default) | Nx2 matrix

Specifies the locations that require negative excitation as a matrix of size Nx2 in meters.

The first and second columns correspond to the x and Y coordinates, receptively, in meters. Each location must lie on the edge of a metal layer.

Example: f1=FiniteGapFeed;f1.GroundLocations=[-0.02,0]

Data Types: double

SignalLayers — Metal layer of the positive and negative excitation sites

1 (default) | scalar

Specifies the metal layer on which the positive and negative excitation sites lie as a scalar

Example: f1-FiniteGapFeed;f1.SignalLayers=2

Data Types: double

SignalWidths — Width of each excitation site

0.002 (default) | Nx1 matrix

Specifies the width of each excitation site as a Nx1 matrix in meters. The metal edges on which SignalLocations(n,:) and GroundLocations(n,:) lie must be longer than or equal to SignalWidths(n).

Example: f1=FiniteGapFeed;f1.SignalWidths=0.003

Data Types: double

Examples

Finite Gap Feed Setup for an Internal Port

This example shows how to use a FiniteGapFeed object to define an internal port on a pcbComponent object.

Start with the Wilkinson splitter catalog element and convert it to a pcbComponent. Save its resistor length.

w = wilkinsonSplitter;
rL = w.ResistorLength;
p = pcbComponent(w);

The catalog element has a lumped load bridging the two output terminals. Save its location, replace it by the placeholder lumpedElement, and delete the leftover metal strip.

internalPortLocation = p.Load.Location;
p.Load = lumpedElement;
rectangleCut = traceRectangular('Center', internalPortLocation(1:2), 'Length', 0.5e-3, 'Width', rL);
p.Layers{1} = p.Layers{1} - rectangleCut;

Switch the pcbComponent object's FeedFormat property to 'FeedDefinitions' to expose the FeedDefinitions property. Instantiate a FiniteGapFeed at the saved lumped load site and add it to the list of feeds.

p.FeedFormat = 'FeedDefinitions';
f = FiniteGapFeed('SignalLocations', internalPortLocation(1:2) + [0 rL/2], 'GroundLocations', internalPortLocation(1:2) + [0 -rL/2], 'SignalLayers', 1, 'SignalWidths', 0.5e-3);
p.FeedDefinitions(end+1) = f;
figure; show(p);

Calculate 4-port S-parameters for the splitter. Terminate the internal port into a 100-ohm resistance and plot the result.

s = sparameters(p, linspace(1e9, 5e9, 51));
s100 = snp2smp(s, 1:3, 100);
figure; rfplot(s100)

Version History

Introduced in R2024b