pcbStack

Single feed or multi-feed PCB antenna

Description

The pcbStack object is a single feed or multi-feed printed circuit board (PCB) antenna. Use the pcbStack object:

• 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 from antenna and array catalog elements.

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 Convert Circular Microstrip Patch into PCB Antenna

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 one or more name-value arguments. Name is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as Name1=Value1,...,NameN=ValueN. Properties that you do not specify, retain their default values.

For example, pcbStack(FeedDiameter=2e-04) creates a PCB antenna with a feed diameter of 0.2 mm.

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 convert antenna array objects from the antenna array catalog to a PCB antenna. For a list of supported catalog elements, see Supported Catalog Elements.

Properties

Name — Name of PCB antenna

"MyPCB" (default) | string

Name of PCB antenna, specified as a string.

Example: "PCBPatch"

Data Types: string

Revision — Revision details of PCB antenna design

"1.0" (default) | string

Revision details of PCB antenna design, specified as a string.

Example: "2.0"

Data Types: string

BoardShape — Shape of PC board

antenna.Rectangle object (default) | shape object

Shape of the PC board, specified as one of the following shape object:

• antenna.Rectangle object.

• antenna.Circle object.

• antenna.Ellipse object.

• antenna.Polygon object.

• antenna.Triangle object.

Example: 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: 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 — Cartesian coordinates of feed points for PCB antenna

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

Cartesian coordinates of feed points for the PCB antenna, specified as either N -by-3 array for a balanced feed or N-by-4 array for an unbalanced feed. You can place the feed/feeds 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: [-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 the feed connector, specified as a positive scalar in meters.

Example: 2.000e-04

Data Types: double

ViaLocations — Cartesian coordinates of electrical shorts

M-by-4 array

Cartesian coordinates of electrical shorts, specified as a M-by-4 array. The array translates to the following:

• M-by-4 – [x, y, SigLayer, GndLayer]

Example: [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: 1.0e-3

Data Types: double

FeedVoltage — Excitation voltage applied at each feed point

1 (default) | positive scalar in volts | positive 1-by-N array in volts

Excitation voltage applied at each feed point, specified as a positive scalar in volts for a single feed point or a positive 1-by-N array for N feed points. The default excitation voltage is 1V.

Example: 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: "octagon"

Data Types: string

FeedPhase — Excitation phase at each feed point

0 (default) | real scalar in degrees | real 1-by-N vector in degrees

Excitation phase at each feed point, specified as a real scalar in degrees for a single feed point or a real 1-by-N vector in degrees for N feed points. The default excitation phase is 0 degrees.

Example: 2

Data Types: double

Conductor — Type of metal material

metal("PEC") (default) | metal object

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

Example: metal("Copper")

Load — Lumped elements

[1x1 lumpedElement] (default) | lumpedElement object

Lumped elements added to the antenna feed, specified as a lumpedElement object. You can add a load anywhere on the surface of the antenna. By default, the load is at the feed.

Example: Load=lumpedElement(Impedance=75)

Example: antenna.Load = lumpedElement(Impedance=75)

Tilt — Tilt angle of antenna

0 (default) | scalar | vector

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

Example: 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.

Data Types: double

TiltAxis — Tilt axis of antenna

[1 0 0] (default) | three-element vector | 2-by-3 matrix | "X" | "Y" | "Z"

Tilt axis of the antenna, specified as one of these values:

• 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, specified as a 2-by-3 matrix corresponding to two three-element vectors of Cartesian coordinates. In this case, the antenna rotates around the line joining the two points.

• "x", "y", or "z" to describe a rotation about the x-, y-, or z-axis, respectively.

For more information, see Rotate Antennas and Arrays.

Example: [0 1 0]

Example: [0 0 0;0 1 0]

Example: "Z"

Data Types: double | string

Object Functions

array	Create array of PCB stack objects
axialRatio	Calculate and plot axial ratio of antenna or array
bandwidth	Calculate and plot absolute bandwidth of antenna or array
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
correlation	Correlation coefficient between two antennas in array
current	Current distribution on antenna or array surface
efficiency	Calculate and plot radiation efficiency of antenna or array
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrent	Calculate current at feed for antenna or array
gerberWrite	Generate Gerber files
impedance	Calculate and plot input impedance of antenna or scan impedance of array
info	Display information about antenna, array, or platform
layout	Display array or PCB stack layout
memoryEstimate	Estimate memory required to solve antenna or array mesh
mesh	Mesh properties of metal, dielectric antenna, or array structure
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwrite	Write antenna or array analysis data to MSI planet file
pattern	Plot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuth	Azimuth plane radiation pattern of antenna or array
patternElevation	Elevation plane radiation pattern of antenna or array
peakRadiation	Calculate and mark maximum radiation points of antenna or array on radiation pattern
phaseShift	Calculate phase shift values for arrays or multi-feed PCB stack
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequency	Calculate and plot resonant frequency of antenna
returnLoss	Calculate and plot return loss of antenna or scan return loss of array
show	Display antenna, array structures, shapes, or platform
sparameters	Calculate S-parameters for antenna or array
stlwrite	Write mesh information to STL file
vswr	Calculate and plot voltage standing wave ratio (VSWR) of antenna or array element

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 = 0.015;
gapy = 0.01;
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 = 0.02*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);

Create PCB Antenna From Antenna Library Element

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);

Convert Circular Microstrip Patch into PCB Antenna

Create a circular microstrip patch.

p = patchMicrostripCircular;
d = dielectric;
d.EpsilonR = 4.4;
p.Radius = 0.0256;
p.Height = 1.6e-3;
p.Substrate = d;
p.GroundPlaneLength = 3*0.0256;
p.GroundPlaneWidth = 3*0.0256;
p.FeedOffset = [0.0116 0];

Create a PCB of this 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)

Define the RF SMA connector and use it with the Mayhew writer service to generate Gerber files of the design.

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.

Create PCB Antenna Using Antenna Array Library Element

Create a coplanar inverted-F antenna.

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

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

la = linearArray;
la.Element = fco;
la.NumElements = 4;
show(la)

Use this antenna array to create the PCB antenna.

p = pcbStack(la);
show(p)

Create PCB Antenna Using 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

Supported Catalog Elements

The following antennas and arrays from the catalog can be converted into a PCB antenna by the pcbStack object:

Antennas

Note

Orient these antennas in the xy-plane if required, before conversion to pcbStack.

• Dipole Antennas: dipole, bowtieTriangular, bowtieRounded, and dipoleBlade.

• Fractal Antennas: fractalCarpet, fractalGasket, fractalIsland, fractalKoch, fractalSnowflake

• Loop Antennas: loopCircular, loopRectangular

• Monopole Antennas: invertedFcoplanar, invertedLcoplanar

• Patch Antennas: patchMicrostrip, patchMicrostripCircular, patchMicrostripElliptical, patchMicrostripEnotch, patchMicrostripHnotch, patchMicrostripInsetfed, patchMicrostripTriangular

• Reflector Antennas: reflector and reflectorCircular with a finite ground plane.

• Slot Antennas: slot, vivaldi, vivaldiAntipodal, vivaldiOffsetCavity

• Spiral Antennas: spiralArchimedean, spiralEquiangular, spiralRectangular

• Other Antennas: lpda, customAntennaGeometry, customArrayGeometry

Arrays

Note

The arrays must be homogeneous, with uniform elements.

• linearArray

• circularArray

• rectangularArray

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