pcbStack

Single-feed or multifeed PCB antenna

Description

The pcbStack object is a single-feed or multi-feed printed circuit board (PCB) antenna. The pcbStack object can be used

• To create single-layer, multilayer metal, or metal-dielectric substrate antennas

• To create an arbitrary number of feeds and vias in an antenna

• To create a PCB antenna with Antenna Toolbox™ antenna catalog elements

• To convert antenna array elements to PCB stack

Note

To generate a Gerber file, a substrate layer is required. Use the Substrate property to create this layer in the PCB antenna. For more information, see Stack Conversion

Creation

Syntax

pcbant = pcbStack

pcbant = pcbStack(Name,Value)

pcbant = pcbStack(ant)

Description

pcbant = pcbStack creates an air-filled single-feed PCB with two metal layers.

pcbant = pcbStack(Name,Value) sets Properties using name-value pairs. For example, pcbStack('FeedDiameter', 2.000e-04) creates a PCB antenna with a feed diameter of 2.000e-04 meters. You can specify multiple name-value pairs. Enclose each property name in quotes creates a PCB antenna, with additional properties specified by one or more name-value pair arguments. Properties not specified retain their default values.

pcbant = pcbStack(ant) converts any 2-D or 2.5-D antenna from the antenna catalog into a PCB antenna for further modeling and analysis. You can also use antenna array objects from the antenna array catalog elements them convert it into PCB antennas.

Properties

Name — Name of PCB antenna

'MyPCB' (default) | character vector

Name of PCB antenna, specified a character vector.

Example: 'Name','PCBPatch'

Data Types: char | string

Revision — Revision details of PCB antenna design

'1.0' (default) | character vector

Revision details of PCB antenna design, specified as a character vector.

Example: 'Revision','2.0'

Data Types: char | string

BoardShape — Shape of PC board

antenna.Rectangle (default) | object

Shape of PC board, specified as an object. The shape can be a rectangle or a polygon.

Example: 'BoardShape',antenna.Polygon

BoardThickness — Thickness of PC board

0.0100 (default) | positive scalar

Thickness of the PC board, specified as a positive scalar. The value of this property is the sum of the thicknesses of all the dielectric layers that lie below the top metal layer. The object treats dielectric layers that are above the top metal layer as coating. Set this property before you set the Layers property. For more information on BoardThickness, see Board Thickness versus Dielectric Thickness in PCB.

Example: 'BoardThickness',0.02000

Data Types: double

Layers — Metal and dielectric layers

{[1×1 antenna.Rectangle] [1×1 antenna.Rectangle]} (default) | cell array of metal layer shapes and dielectric

Metal and dielectric layers, specified a cell array of metal layer shapes and dielectric. You can specify one metal shape or one dielectric per layer starting with the top layer and proceeding down.

Data Types: cell

FeedLocations — Feed locations for antenna in Cartesian coordinates

[-0.0187 0 1 2] (default) | N -by-3 or N-by-4 array

Feed locations for PCB antenna in Cartesian coordinates, specified as N -by-3 or N-by-4 array. You can place feed inside the board or at the edge of the board. The arrays translate to the following:

• N -by-3 – [x, y, Layer]

• N-by-4 – [x, y, SigLayer, GndLayer]

  Antenna Toolbox uses Delta-Gap source feed model to excite the antenna structure. For more information, see Feed Model

Example: 'FeedLocations',[-0.0187 0 1 2]

Data Types: double

FeedDiameter — Center pin diameter of feed connector

1.0000e-03 (default) | positive scalar in meters

Center pin diameter of feed connector, specified as a positive scalar in meters.

Example: 'FeedDiameter',2.000e-04

Data Types: double

ViaLocations — Electrical short locations for antenna in Cartesian coordinates

real vector of size M-by-4 array

Electrical short locations for antenna in Cartesian coordinates, specified as a real vector of size M-by-4 array. The arrays translate to the following:

• M-by-4 – [x, y, SigLayer, GndLayer]

Example: 'ViaLocations',[0 -0.025 1 2]

Data Types: double

ViaDiameter — Electrical shorting pin diameter between metal layers

positive scalar | positive vector

Electrical shorting pin diameter between metal layers, specified as a positive scalar in meters for a single pin or a positive vector in meters for multiple pins. Number of values specified in this property must match the number of pins.

Example: 'ViaDiameter',1.0e-3

Data Types: double

FeedVoltage — Magnitude voltage applied at the feeds

1 (default) | positive scalar in volts

Magnitude voltage applied at the feeds, specified as a positive scalar in volts.

Example: 'FeedVoltage',2

Data Types: double

FeedViaModel — Model for approximating feed and via

'strip' (default) | 'square' | 'hexagon' | 'octagon'

Model for approximating feed and via, specified as one of the following:

• 'strip' – A rectangular strip approximation to the feed or via cylinder. This approximation is the simplest and results in a small mesh.

• 'square' – A 4-sided polyhedron approximation to the feed or via cylinder.

• 'hexagon' – A 6-sided polyhedron approximation to the feed or via cylinder.

• 'octagon' – A 8-sided polyhedron approximation to the feed or via cylinder.

Example: 'FeedViaModel','octagon'

Data Types: char | string

FeedPhase — Excitation phase at each feed

0 (default) | real vector in degrees

Excitation phase at each feed, specified as a real vector in degrees.

Example: 'FeedPhase',2

Data Types: double

Conductor — Type of metal material

'PEC' (default) | metal object

Type of the metal used as a conductor, specified as a metal material object. You can choose any metal from the MetalCatalog or specify a metal of your choice. For more information, see metal. For more information on metal conductor meshing, see Meshing.

Example: m = metal('Copper'); 'Conductor',m

Example: m = metal('Copper'); ant.Conductor = m

Load — Lumped elements

[1x1 LumpedElement] (default) | lumped element object handle

Lumped elements added to the antenna feed, specified as a lumped element object handle. For more information, see lumpedElement.

Example: 'Load',lumpedelement. lumpedelement is the object handle for the load created using lumpedElement.

Example: pcbant.Load = lumpedElement('Impedance',75)

Tilt — Tilt angle of antenna

0 (default) | scalar | vector

Tilt angle of the antenna, specified as a scalar or vector with each element unit in degrees. For more information, see Rotate Antennas and Arrays.

Example: Tilt=90

Example: Tilt=[90 90],TiltAxis=[0 1 0;0 1 1] tilts the antenna at 90 degrees about the two axes defined by the vectors.

Note

The wireStack antenna object only accepts the dot method to change its properties.

Data Types: double

TiltAxis — Tilt axis of antenna

[1 0 0] (default) | three-element vector of Cartesian coordinates | two three-element vectors of Cartesian coordinates | 'X' | 'Y' | 'Z'

Tilt axis of the antenna, specified as:

• Three-element vector of Cartesian coordinates in meters. In this case, each coordinate in the vector starts at the origin and lies along the specified points on the X-, Y-, and Z-axes.

• Two points in space, each specified as three-element vectors of Cartesian coordinates. In this case, the antenna rotates around the line joining the two points in space.

• A string input describing simple rotations around one of the principal axes, 'X', 'Y', or 'Z'.

For more information, see Rotate Antennas and Arrays.

Example: TiltAxis=[0 1 0]

Example: TiltAxis=[0 0 0;0 1 0]

Example: TiltAxis = 'Z'

Data Types: double

Object Functions

show	Display antenna, array structures or shapes
array	Create array of PCB stack objects
axialRatio	Axial ratio of antenna
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
current	Current distribution on antenna or array surface
efficiency	Radiation efficiency of antenna
EHfields	Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
impedance	Input impedance of antenna; scan impedance of array
info	Display information about antenna or array
layout	Display array or PCB stack layout
mesh	Mesh properties of metal, dielectric antenna, or array structure
meshconfig	Change mesh mode of antenna structure
pattern	Radiation pattern and phase of antenna or array; Embedded pattern of antenna element in array
patternAzimuth	Azimuth pattern of antenna or array
patternElevation	Elevation pattern of antenna or array
returnLoss	Return loss of antenna; scan return loss of array
sparameters	Calculate S-parameter for antenna and antenna array objects
vswr	Voltage standing wave ratio of antenna
plot	Plot boundary of shape

Examples

End Loaded Planar Dipole

Setup parameters.

vp  = physconst('lightspeed');
f   = 850e6;
lambda = vp./f;

Build a planar dipole with capacitive loading at the ends.

L = 0.15;
W = 1.5*L;
stripL = L;
gapx = .015;
gapy = .01;
r1 = antenna.Rectangle('Center',[0,0],'Length',L,'Width',W,'Center',[lambda*0.35,0]);
r2 = antenna.Rectangle('Center',[0,0],'Length',L,'Width',W,'Center',[-lambda*0.35,0]);
r3 = antenna.Rectangle('Length',0.5*lambda,'Width',0.02*lambda,'NumPoints',2);
s = r1 + r2 + r3;
figure
show(s)

Assign the radiator shape to pcbStack and make the changes to the board shape and feed diameter properties.

boardShape = antenna.Rectangle('Length',0.6,'Width',0.3);
p = pcbStack;
p.BoardShape = boardShape;
p.Layers = {s};
p.FeedDiameter = .02*lambda/2;
p.FeedLocations = [0 0 1];
figure
show(p)

Analyze the impedance of the antenna. Effect of the end-loading should result in the series resonance to be pushed lower in the band.

figure
impedance(p,linspace(200e6,1e9,51))

PCB Stack of Dielectric Antenna

Create a pcb stack antenna with 2 mm dielectric thickness at the radiator and air below it. Display the structure.

p = pcbStack;
d1 = dielectric('FR4');
d1.Thickness = 2e-3;
d2 = dielectric('Air');
d2.Thickness = 8e-3;
p.Layers = {p.Layers{1},d1,d2,p.Layers{2}};
p.FeedLocations(3:4) = [1 4];
show(p)

Directivity Pattern of PCB Stack Antenna

Create a PCB stack antenna from reflector backed bowtie.

b = design(bowtieRounded,1e9);
b.Tilt = 90

b = 
  bowtieRounded with properties:

        Length: 0.0959
    FlareAngle: 90
     Conductor: [1x1 metal]
          Tilt: 90
      TiltAxis: [1 0 0]
          Load: [1x1 lumpedElement]

b.TiltAxis = [0 1 0];
r = reflector('Exciter',b);
p = pcbStack(r);

Plot the directivity pattern of the antenna at 1 GHz.

pattern(p,1e9);

PCB Antenna From Antenna Library Elements

Create a coplanar inverted F antenna.

fco = invertedFcoplanar('Height',14e-3,'GroundPlaneLength', 100e-3,  ...
                  'GroundPlaneWidth', 100e-3);

Use this antenna to create a pcbStack object.

p = pcbStack(fco);

Stack Conversion

Create a circular microstrip patch.

p = patchMicrostripCircular;
d = dielectric;
d.EpsilonR = 4.4;
p.Radius = .0256;
p.Height = 1.6e-3;
p.Substrate = d;
p.GroundPlaneLength = 3*.0256;
p.GroundPlaneWidth = 3*.0256;
p.FeedOffset = [.0116 0];

Create a PCB circular microstrip patch using pcbStack.

pb = pcbStack(p);
pb.FeedDiameter = 1.27e-3;
pb.ViaLocations = [0 pb.FeedLocations(1)/1.1 1 3];
pb.ViaDiameter = pb.FeedDiameter;
figure
show(pb)

C = SMA_Jack_Cinch;
O = PCBServices.MayhewWriter;
O.DefaultViaDiam = pb.ViaDiameter;
O.Filename = 'Microstrip circular patch-9a';
Am = PCBWriter(pb,O,C);
gerberWrite(Am)

Images using Mayhew Labs 3-D Viewer.

PCB Antenna from Antenna Array Library Elements

Create a coplanar inverted-F antenna.

fco = invertedFcoplanar('Height',14e-3,'GroundPlaneLength', 100e-3,  ...
                  'GroundPlaneWidth', 100e-3);

Create a linear array with inverted-F antenna as its elements.

la = linearArray;
la.Element = fco;
la.NumElements = 4;

Use this antenna array to create the PCB antenna.

p = pcbStack(la);

PCB Stack from Linear Dipole Array and Dipole Antenna Element

Create a dipole antenna object and linearArray antenna array object. In the linearArray antenna object, leave the Element property set to its default value of dipole. Set the ElementSpacing property to 4."

d1 = dipole;
d2 = linearArray('ElementSpacing', 4);

To set the Z-coordinate of pcbStack antenna object to zero, rotate the dipole and linear dipole array around 90 degrees using the Tilt property. Then set the TiltAxis property to [ 0 -1 0 ] for dipole and linear dipole array antennas.

d1.Tilt = 90;
d2.Element.Tilt = 90;
d1.TiltAxis = [0 -1 0];
d2.Element.TiltAxis = [0 -1 0];

Create and view PCB stack antenna created using the dipole antenna object.

p1 = pcbStack(d1);
show(p1)

Create and view PCB stack antenna using the linearArray antenna array object.

p2 = pcbStack(d2);
show(p2)

Circular Microstrip Patch Antenna on Polygon Shaped Board

Create a circular microstrip patch antenna.

ant = design(patchMicrostripCircular,3e9);
ant.Substrate = dielectric( 'FR4' );
show(ant)

c = antenna.Circle;
show(c)

c.NumPoints = 6;
c.Radius = 3*ant.Radius;
figure
show(c)

Create the PCB stack using the vertices derived from the circle shape.

v = getShapeVertices(c);
cp = antenna.Polygon( 'Vertices' ,v);
pb = pcbStack(ant);
pb.Layers{3} = cp;
pb.BoardShape = cp;
show(pb)
axis equal

References

[1] Balanis, C. A. Antenna Theory. Analysis and Design. 3rd Ed. Hoboken, NJ: John Wiley & Sons, 2005.

[2] Stutzman, W. L. and Gary A. Thiele. Antenna Theory and Design. 3rd Ed. River Street, NJ: John Wiley & Sons, 2013.

Version History

Introduced in R2017a