pifa

Create regular or AI-based planar inverted-F antenna

Description

The default pifa object is a planar inverted-F antenna resonating around 2.34 GHz. The default PIFA antenna is centered at the origin. The feed point is along the length of the antenna.

You can perform full-wave EM solver based analysis on the regular pifa antenna or you can create a pifa type AIAntenna and explore the design space to tune the antenna for your application using AI-based analysis.

Creation

Syntax

pf = pifa

pf = pifa(Name=Value)

Description

pf = pifa creates a planar inverted-F antenna with default property values. The default dimensions are chosen for an operating frequency of around 2.34 GHz.

pf = pifa(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 pair arguments in any order as Name1=Value1,...,NameN=ValueN. Properties that you do not specify, retain their default values.

• You can also create a pifa antenna resonating at a desired frequency using the design function.

• You can also create a pifa antenna from a microstrip patch type AIAntenna object using the exportAntenna function.

• A pifa type AIAntenna has some common tunable properties with a regular pifa antenna for AI-based analysis. Other properties of the regular pifa antenna are retained as read-only in its AIAntenna equivalent. To find the upper and lower bounds of the tunable properties, use tunableRanges function.

Properties

Length — PIFA antenna length

0.0300 (default) | positive scalar | tunable for pifa type AIAntenna

PIFA antenna length, specified as a scalar in meters. By default, the length is measured along the x-axis. This property is tunable for pifa type AIAntenna object created using the design function.

Example: 75e-3

Data Types: double

Width — PIFA antenna width

0.0200 (default) | positive scalar | tunable for pifa type AIAntenna

PIFA antenna width, specified as a scalar in meters. By default, the width is measured along the y-axis. This property is tunable for pifa type AIAntenna object created using the design function.

Example: 35e-3

Data Types: double

Height — Height of substrate

0.0100 (default) | positive scalar | tunable for pifa type AIAntenna

Height of the substrate, specified as a scalar in meters. This property is tunable for pifa type AIAntenna object created using the design function.

Example: 37e-3

Data Types: double

Substrate — Type of dielectric material

"Air" (default) | dielectric object

Type of dielectric material used as a substrate, specified as an object. For more information see, dielectric. For more information on dielectric substrate meshing, see Meshing.

Note

The substrate dimensions must be equal to the ground plane dimensions.

Example: dielectric("FR4")

GroundPlaneLength — Ground plane length

0.0360 (default) | positive scalar

Ground plane length, specified as a scalar in meters. By default, ground plane length is measured along the x-axis.

Note

Infinite ground plane length is currently unsupported.

Example: 3

Data Types: double

GroundPlaneWidth — Ground plane width

0.0360 (default) | positive scalar

Ground plane width, specified as a scalar in meters. By default, ground plane width is measured along the y-axis.

Note

Infinite ground plane width is currently unsupported.

Example: 2.5

Data Types: double

PatchCenterOffset — Signed distance from center along length and width of ground plane

[0 0] (default) | two-element vector

Signed distance from the center along length and width of the ground plane, specified as a two-element vector in meters. Use this property to adjust the location of the patch relative to the ground plane.

Example: [0.01 0.01]

Data Types: double

ShortPinWidth — Shorting pin width of patch

0.0200 (default) | positive scalar | tunable for pifa type AIAntenna

Shorting pin width of patch, specified as a scalar in meters. By default, the shorting pin width is measured along the y-axis. This property is tunable for pifa type AIAntenna object created using the design function.

Example: 3

Data Types: double

FeedOffset — Signed distance of feed point from origin

[–0.0020 0] (default) | two-element vector

Signed distance from center along length and width of ground plane, specified as a two-element vector. Use this property to adjust the location of the feed point relative to ground plane and patch.

Example: [0.01 0.01]

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: 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

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
current	Current distribution on antenna or array surface
design	Design prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
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
impedance	Calculate and plot input impedance of antenna or scan impedance of array
info	Display information about antenna, array, or platform
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
optimize	Optimize antenna or array using SADEA optimizer
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
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

Create and View Planar Inverted-F Antenna(PIFA) Antenna

Create and view a PIFA antenna with 30 mm length, 20 mm width over a 35 mm x 35 mm ground plane, and feedpoint at (-2 mm,0,0).

pf = pifa

pf = 
  pifa with properties:

               Length: 0.0300
                Width: 0.0200
               Height: 0.0100
            Substrate: [1x1 dielectric]
    GroundPlaneLength: 0.0360
     GroundPlaneWidth: 0.0360
    PatchCenterOffset: [0 0]
        ShortPinWidth: 0.0200
           FeedOffset: [-0.0020 0]
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(pf)

Radiation Pattern of PIFA Antenna

Plot the radiation pattern of a PIFA antenna at a frequency of 2.3 GHz.

pf = pifa(Length=30e-3,Width=20e-3,GroundPlaneLength=35e-3,...
          GroundPlaneWidth=35e-3)

pf = 
  pifa with properties:

               Length: 0.0300
                Width: 0.0200
               Height: 0.0100
            Substrate: [1x1 dielectric]
    GroundPlaneLength: 0.0350
     GroundPlaneWidth: 0.0350
    PatchCenterOffset: [0 0]
        ShortPinWidth: 0.0200
           FeedOffset: [-0.0020 0]
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

pattern(pf,2.3e9);

Impedance of PIFA Antenna

Create a PIFA antenna using a dielectric substrate 'RO4725JXR'.

d = dielectric("RO4725JXR");
pf = pifa(Length=30e-3, Width=20e-3, Height=0.0060, GroundPlaneLength=35e-3, ...
         GroundPlaneWidth=35e-3, Substrate=d)

pf = 
  pifa with properties:

               Length: 0.0300
                Width: 0.0200
               Height: 0.0060
            Substrate: [1x1 dielectric]
    GroundPlaneLength: 0.0350
     GroundPlaneWidth: 0.0350
    PatchCenterOffset: [0 0]
        ShortPinWidth: 0.0200
           FeedOffset: [-0.0020 0]
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(pf)

Calculate the impedance of the antenna over the specified frequency range. GHz.

impedance(pf,linspace(2.2e9,2.5e9,31));

Create AI Model Based PIFA Antenna

This example shows how to create an AI model based PIFA antenna at 2.4 GHz and calculate its resonant frequency.

pAI = design(pifa,2.4e9,ForAI=true)

pAI = 
  AIAntenna with properties:

   Antenna Info
               AntennaType: 'pifa'
    InitialDesignFrequency: 2.4000e+09

   Tunable Parameters
                    Length: 0.0292
                     Width: 0.0194
                    Height: 0.0097
             ShortPinWidth: 0.0194

Use 'showReadOnlyProperties(pAI)' to show read-only properties

Vary its length and width and calculate its resonant frequency.

pAI.Length = 0.03;
pAI.Width = 0.0175;
resonantFrequency(pAI)

ans = 
2.4132e+09

Convert the AIAntenna to a regular PIFA antenna.

pmC = exportAntenna(pAI)

pmC = 
  pifa with properties:

               Length: 0.0300
                Width: 0.0175
               Height: 0.0097
            Substrate: [1x1 dielectric]
    GroundPlaneLength: 0.0350
     GroundPlaneWidth: 0.0350
    PatchCenterOffset: [0 0]
        ShortPinWidth: 0.0194
           FeedOffset: [-0.0019 0]
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

References

[1] Balanis, Constantine A. Antenna Theory: Analysis and Design. Fourth edition. Hoboken, New Jersey: Wiley, 2016.

Version History

Introduced in R2015a

R2023b: AI model based antenna analysis

Design, tune, and analyze this antenna using an AI model. Using AI-based antenna models over conventional full-wave solvers significantly reduces the simulation time required to fine-tune the antenna to meet your design goals. Set the ForAI argument in the design function to true to create a pifa type AIAntenna. To use this feature, you need license to the Statistics and Machine Learning Toolbox™ in addition to the Antenna Toolbox™.