biquad

Create biquad or double-biquad antenna

Description

The default biquad object creates a biquad antenna resonating around 2.74 GHz. The antenna is center fed and symmetric about its origin.

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

$$w=2d=4r$$

, 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.

Creation

Syntax

b = biquad

b = biquad(PropertyName=Value)

Description

b = biquad creates a biquad antenna with default property values. The default dimensions are chosen for an operating frequency of around 2.74 GHz.

b = biquad(PropertyName=Value) sets properties using one or more name-value arguments. PropertyName is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN. Properties that you do not specify, retain their default values.

For example, b = biquad(NumLoops=4) creates a double biquad antenna with default values for other properties.

Properties

NumLoops — Number of loops

2 (default) | 4

Number of loops for the biquad, specified as one of the following options:

• 2 — to create a biquad antenna.

• 4 — to create a double biquad antenna.

Example: 4

Data Types: double

ArmLength — Length of two arms

0.0305 (default) | positive scalar

Length of two arms, specified as a positive scalar in meters.

Example: 0.0206

Data Types: double

ArmElevation — Angle formed by biquad arms to xy-plane

45 (default) | positive scalar

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

Example: 50

Data Types: double

Width — Biquad arm width

1e-03 (default) | positive scalar

Biquad arm width, specified as a positive scalar in meters.

Example: 0.006

Data Types: double

Conductor — Type of metal

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: 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	Create antenna, array, or AI-based antenna resonating at specified frequency
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	Generate and view mesh for antennas, arrays, and custom shapes
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 and array catalog elements using SADEA or TR-SADEA algorithm
pattern	Plot radiation pattern of antenna, array, or embedded element of 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 Biquad Antenna

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

bq = biquad(ArmElevation=50);
show(bq)

Impedance of Biquad Antenna

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

bq = biquad(ArmElevation=50);
impedance(bq,linspace(2.5e9,3e9,51));

Double Biquad Antenna

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: [1×1 metal]
            Tilt: 0
        TiltAxis: [1 0 0]
            Load: [1×1 lumpedElement]

show(ant)

Version History

Introduced in R2015b