installedAntenna

Installed antenna setup

Since R2019a

Description

The installedAntenna object creates an installed antenna setup that enables you to mount antennas on a platform for analysis.

Installed antenna analysis involves an electrically large structure called a platform. Around this platform, different antenna elements are placed. You can analyze the effects of the platform on the antenna performance. Installed antenna analysis is commonly used in aerospace, defense, and auto applications. The platform in this case are plane, ship, or an automobile.

Another common application of installed antenna analysis is to determine the interference of different antennas placed on a large platform.

Note

installedAntenna only models pure metal structures.

Creation

Syntax

ant = installedAntenna

ant = installedAntenna(Name=Value)

Description

ant = installedAntenna creates an installed antenna setup. The default setup has a rectangular reflector in the xy-plane as the platform with a dipole as the antenna. The dimensions of the dipole antenna are chosen for an operating frequency of 1GHz.

ant = installedAntenna(Name=Value) creates an installed antenna setup, with additional Properties specified by 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.

Output Arguments

ant — Installed antenna setup

installedAntenna object

Installed antenna setup, returned as an installedAntenna object.

Properties

Platform — Platform object file

platform object

Platform object file, specified as a platform object.

Example: platform(FileName='plate.stl')

Data Types: char

Element — Single or multiple antenna elements

antenna object | cell array of antenna objects

Single or multiple antennas, specified as an antenna object or a cell array of antenna objects. For multiple antenna elements, you must specify ElementPosition for all the elements.

Example: dipole

Example: ant = installedAntenna(Element={discone,monocone}, ElementPosition=[0.1 0.1 0.5; -0.1 -0.1 0.5]) This code creates discone and monocone antenna objects for installed antenna analysis.

Data Types: char

ElementPosition — Position of feed or origin of each antenna element

[0 0 0.0750] (default) | vector of [x,y,z] coordinates

Position of the feed or the origin of each antenna element, specified as a vector of [x,y,z] coordinates in meters. For multiple antenna elements, the number of positions in ElementPosition must be equal to the number of elements specified in the Element property.

Example: [0 0 0.0050]

Data Types: double

Reference — Reference for positioning antenna elements

"feed" (default) | "origin"

Reference for positioning the antenna elements, specified as either "feed" or "origin".

Example: "origin"

Data Types: string

FeedVoltage — Excitation amplitude for antenna elements

1 (default) | vector

Excitation amplitude for the antenna elements, specified as a scalar vector in volts. For multiple antenna elements, the number of elements in FeedVoltage must be equal to the number of elements specified in the Element property.

Example: 2

Example: [2 5]

Data Types: double

FeedPhase — Phase shift of each antenna element

0 (default) | vector

Phase shift of each antenna element, specified as a scalar or vector in degrees. For multiple antenna elements, the number of elements in FeedPhase must be equal to the number of elements specified in the Element property.

Example: 50

Example: [50 60]

Data Types: double

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

SolverType — Solver for antenna analysis

"MoM-PO" (default) | "MoM" | "FMM"

Solver for antenna analysis, specified as either "MoM-PO" (Method of Moments-Physical Optics) or "MoM" (Method of Moments) or "FMM" (Fast Multipole Method).

Example: "MoM"

Data Types: string

Object Functions

show	Display antenna, array structures, shapes, or platform
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 or embedded electric and magnetic fields of antenna element in arrays
impedance	Input impedance of antenna or scan impedance of array
mesh	Mesh properties of metal, dielectric antenna, or array structure
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
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
rcs	Calculate and plot radar cross section (RCS) of platform, antenna, or array
returnLoss	Return loss of antenna or scan return loss of array
solver	Access FMM solver for electromagnetic analysis
sparameters	Calculate S-parameters for antennas and antenna arrays
vswr	Voltage standing wave ratio (VSWR) of antenna or array element

Examples

Installed Antenna Setup and Analysis

Create a default installed antenna.

ant = installedAntenna

ant = 
  installedAntenna with properties:

           Platform: [1x1 platform]
            Element: [1x1 dipole]
    ElementPosition: [0 0 0.0750]
          Reference: 'feed'
        FeedVoltage: 1
          FeedPhase: 0
               Tilt: 0
           TiltAxis: [1 0 0]
         SolverType: 'MoM-PO'

show(ant);

Calculate the impedance of the antenna.

figure;
impedance(ant, linspace(950e6, 1050e6, 51));

Visualize the pattern of the antenna.

figure;
pattern(ant, 1e9);

Radiation Pattern of Antenna Installed on Glider

Create a platform from the STL file containing geometry infomation of a glider.

plat = platform(FileName="glider.stl", Units="m");
figure
show(plat);

Design a dipole antenna operating at 1GHz. Install this dipole antenna element below the nose of the glider.

d = design(dipole,1e9);
d.Tilt = 90;
d.TiltAxis=[1 0 0];
ant = installedAntenna(Platform=plat, Element=d, ElementPosition=[-1.2 0 -0.25]);
figure
show(ant);

Visualize the radiation pattern of the installed dipole.

figure
pattern(ant,1e9)

Algorithms

Solver Recommendations for Installed Antenna Analysis

Hybrid MoM PO Solver

The default solver for installed antenna analysis is the hybrid MoM-PO ( Method of moments and physical optics) solver. This is a hybrid solver, with less stringent requirements on the mesh. This approach does not have full-wave accuracy since the electrically large portion of the geometry is handled using the physical optics approach. For more information on this solver see, Hybrid MoM-PO Method for Metal Antennas with Large Scatterers.

FMM Solver

For full wave accuracy in installed antenna analysis you can use the FMM (fast multiple method) solver. This solver does not fill and store a matrix of interactions and enables the solution of large structures which is not possible when using the MoM solver. For open geometries, this solver builds a preconditioner matrix internally. The preconditioner matrix is sparse but might be less sparse for larger structures. Preconditioner matrices are not built for closed geometries. When using the FMM, you have an option to use the solver object to set up the number of iterations and the relative error. In some circumstances it might be useful to study the nature of the problem and its convergence characteristics by reducing the number of iterations or the relative error initially or both. The FMM solver does need approximately 10 elements per wavelength in the mesh. The number of elements does impact the convergence of the solution. For more information on FMM solvers, see Fast Multipole Method for Large Structures.

MoM Solver

For wavelength and sub-wavelength scale structures, with or without dielectric you can use an MoM (method of moments)solver. For more information on MoM solver, see Method of Moments Solver for Metal Structures and Method of Moments Solver for Metal and Dielectric Structures.

Version History

Introduced in R2019a