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Create biquad or double-biquad antenna


The biquad antenna is center fed and symmetric about its origin. The default length is chosen for an operating frequency of 2.8 GHz.

The width of the strip is related to the diameter an equivalent cylinder:


, where:

  • d is the diameter of equivalent cylindrical dipole.

  • r is the radius of equivalent cylindrical dipole.

For a given cylinder radius, use the cylinder2strip utility function to calculate the equivalent width. The default strip dipole is center-fed. The feed point coincides with the origin. The origin is located on the yz- plane.



bq = biquad creates a biquad antenna.


bq = biquad(Name,Value) creates a biquad antenna with additional properties specified by one or more name-value pair 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 not specified retain their default values.


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Number of loops for the biquad, specified as a scalar integer. Setting this property to 4 supports a double biquad antenna.

Example: 'NumLoops',4

Data Types: double

Length of two arms, specified as a scalar in meters. The default length is chosen for an operating frequency of 2.8 GHz.

Example: 'ArmLength',0.0206

Data Types: double

Biquad arm width, specified as a scalar in meters.

Example: 'Width',0.006

Data Types: double

Angle formed by biquad arms to the xy- plane, specified a scalar in meters.

Example: 'ArmElevation', 50

Data Types: double

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

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

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

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

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

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

axialRatioCalculate and/or plot axial ratio of antenna or array
bandwidthCalculate and/or plot absolute bandwidth of antenna
beamwidthBeamwidth of antenna
chargeCharge distribution on antenna or array surface
currentCurrent distribution on antenna or array surface
designDesign prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
efficiencyRadiation efficiency of antenna
EHfieldsElectric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
impedanceInput impedance of antenna or scan impedance of array
infoDisplay information about antenna, array, or platform
memoryEstimateEstimate memory required to solve antenna or array mesh
meshMesh properties of metal, dielectric antenna, or array structure
meshconfigChange meshing mode of antenna, array, custom antenna, custom array, or custom geometry
optimizeOptimize antenna or array using SADEA optimizer
patternPlot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuthAzimuth plane radiation pattern of antenna or array
patternElevationElevation plane radiation pattern of antenna or array
rcsCalculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequencyCalculate and/or plot resonant frequency of antenna
returnLossReturn loss of antenna or scan return loss of array
showDisplay antenna, array structures, shapes, or platform
sparametersCalculate S-parameters for antennas and antenna arrays
vswrVoltage standing wave ratio (VSWR) of antenna or array element


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Create a biquad antenna with arm angles at 50 degrees and view it.

bq = biquad('ArmElevation',50);

Calculate the impedance of a biquad antenna over a frequency span 2.5GHz-3GHz.

bq = biquad('ArmElevation',50);

Create and view a double biquad antenna using default property values.

ant = biquad('NumLoops',4)
ant = 
  biquad with properties:

        NumLoops: 4
       ArmLength: 0.0305
    ArmElevation: 45
           Width: 1.0000e-03
       Conductor: [1x1 metal]
            Tilt: 0
        TiltAxis: [1 0 0]
            Load: [1x1 lumpedElement]


Version History

Introduced in R2015b