ArbitraryFiniteGapFeed

Create an arbitrary finite gap feed object

Since R2024b

Description

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

Creation

Syntax

f1=ArbitraryFiniteGapFeed

f1=ArbitraryFiniteGapFeed(PropertyName=Value)

Description

f1=ArbitraryFiniteGapFeed creates a default ArbitraryFiniteGapFeed object.

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

Properties

SignalLocations — Signal locations of the feed

[-0.01,0] (default) | N-by-2 | array

Specifies the locations that require positive excitation, as an array of size N-by-2 in meters.

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

Example: f1=ArbitraryFiniteGapFeed;f1.SignalLocations=[-0.2 0]

Data Types: double

GroundLocations — Ground locations of the feed

[-0.01,0] (default) | N-by-2 | array

Specifies the locations that require negative excitation as an array of size N-by-2 in meters.

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

Example: f1=ArbitraryFiniteGapFeed;f1.GroundLocations=[-0.2 0]

Data Types: double

SignalWidths — Width of each positive excitation site

0.005 (default) | N-by-1 array

Specifies the widths of the signal locations, in meters, as an N-by-1 array.

The metal edge on which the SignalLocations(n,:) lie must be longer than, or equal to, the SignalWidths(n).

Example: f1=ArbitraryFiniteGapFeed;f1.SignalWidths=.007

Data Types: double

GroundWidths — Width of each negative excitation site

0.005 (default) | N-by-1 array

Specifies the widths the negative excitation sites, in meters, as an N-by-1 array.

The metal edge on which the GroundLocations(n,:) lie must be longer than, or equal to the GroundWidths(n).

Example: f1=ArbitraryFiniteGapFeed;f1.GroundWidths=0.007

Data Types: double

SignalLayers — Board layers for all positive excitation sites

1 (default) | N-by-1 array

Specifies the board layers for all positive excitation sites as an N-by-1 array.

Example: f1=ArbitraryFiniteGapFeed;f1.SignalLayers=2

Data Types: double

GroundLayers — Board layers for all negative excitation sites

3 (default) | N-by1 array

Specifies the board layers for all negative excitation sites as an N-by-1 array.

Example: f1=ArbitraryFiniteGapFeed;f1.GroundLayers=4

Data Types: double

Examples

Arbitrary Finite Gap Feed Setup for a Coplanar Port

This example shows how to configure an ArbitraryFiniteGapFeed to excite a coplanar waveguide with no conductor backing implemented as a pcbComponent object.

Set up three rectangles in a coplanar waveguide configuration.

w = 3e-3;           % width of the strip (m)
s = 0.2e-3;         % spacing from strip to ground planes (m)
t = 1e-3;           % substrate thickness
boardWidth = 4*w;   % Total width of the board (m)
boardLength = 10*w; % Length of the trace and all GPs (m)

d = dielectric('Teflon');
d.Thickness = t;

rect1 = traceRectangular('Length', boardLength, 'Width', boardWidth);
rectCut1 = traceRectangular('Length', boardLength, 'Width', s, 'Center', [0, (s/2+w/2)]);
rectCut2 = copy(rectCut1); rectCut2.Center = -rectCut1.Center;

p = pcbComponent;
p.BoardShape = rect1;
p.BoardThickness = t;
p.Layers = {rect1 - rectCut1 - rectCut2, d};

Switch the pcbComponent's FeedFormat property to 'FeedDefinitions' to expose its FeedDefinitions property, and configure one ArbitraryFiniteGapFeed at each end of the coplanar waveguide. Each property of a given ArbitraryFiniteGapFeed requires two rows in this case. All properties' first rows together will define the first +/- excitation pair - that is, the excitation of the strip against the right ground plane. All properties' second rows together will define the second +/- excitation pair: the strip against the left ground plane.

p.FeedFormat = 'FeedDefinitions';
f1 = ArbitraryFiniteGapFeed('SignalLocations', [-boardLength/2 0; -boardLength/2 0], 'GroundLocations', [-boardLength/2, (w+s); -boardLength/2, -(w+s)], 'SignalWidths', [w;w], 'GroundWidths', [w; w], 'SignalLayers', [1; 1], 'GroundLayers', [1, 1]);
f2 = copy(f1); f2.SignalLocations = -f1.SignalLocations; f2.GroundLocations = -f1.GroundLocations;
p.FeedDefinitions = [f1; f2];
figure; show(p)

Compute and plot S-parameters for the waveguide.

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

Version History

Introduced in R2024b