# Documentation

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# invertedL

Create inverted-L antenna over rectangular ground plane

## Description

The invertedL object is an inverted-L antenna mounted over a rectangular ground plane.

The width of the metal strip is related to the diameter of an equivalent cylinder by the equation

$w=2d=4r$

where:

• d = diameter of equivalent cylinder

• a = radius of equivalent cylinder

For a given cylinder radius, use the cylinder2strip utility function to calculate the equivalent width. The default inverted-L antenna is center-fed. The feed point coincides with the origin. The origin is located on the X-Y plane.

## Creation

### Syntax

h = invertedL
h = invertedL(Name,Value)

### Description

h = invertedL creates an inverted-L antenna mounted over a rectangular ground plane. By default, the dimensions are chosen for an operating frequency of 1.7 GHz.

example

h = invertedL(Name,Value) creates an inverted-L 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.

## Properties

expand all

Height of inverted element along z-axis, specified a scalar in meters.

Example: 'Height',3

Data Types: double

Strip width, specified as a scalar in meters.

### Note

Strip width should be less than 'Height'/4 and greater than 'Height'/1001. [2]

Example: 'Width',0.05

Data Types: double

Stub length along x-axis, specified as a scalar in meters.

Example: 'Length',0.01

Ground plane length along x-axis, specified a scalar in meters. Setting 'GroundPlaneLength' to Inf, uses the infinite ground plane technique for antenna analysis.

Example: 'GroundPlaneLength',4

Data Types: double

Ground plane width along y-axis, specified as a scalar in meters. Setting 'GroundPlaneWidth' to Inf, uses the infinite ground plane technique for antenna analysis.

Example: 'GroundPlaneWidth',2.5

Data Types: double

Signed distance from center along length and width of ground plane, specified as a two-element vector.

Example: 'FeedOffset',[2 1]

Data Types: double

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

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

Tilt angle of antenna, specified as a scalar or vector with each element unit in degrees.

Example: 'Tilt',90

Example: 'Tilt',[90 90 0]

Data Types: double

Tilt axis of the antenna, specified as:

• A three-element vector of Cartesian coordinates in meters. In this case, each vector starts at the origin and lies along the specified points on the X, Y, and Z axes.

• Two points in space as three-element vectors of Cartesian coordinates. In this case, the antenna rotates along the line joining the two points.

• A string input for simple rotations around the principal planes, X, Y, or Z.

Example: 'TiltAxis',[0 1 0]

Example: 'TiltAxis',[0 0 0;0 1 0]

Example: 'TiltAxis','Z'

Data Types: double

## Object Functions

 show Display antenna or array structure; Display shape as filled patch info Display information about antenna or array axialRatio Axial ratio of antenna beamwidth Beamwidth of antenna charge Charge distribution on metal or dielectric antenna or array surface current Current distribution on metal or dielectric antenna or array surface design Design prototype antenna for resonance at specified frequency EHfields Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays impedance Input impedance of antenna; scan impedance of array mesh Mesh properties of metal or dielectric antenna or array structure meshconfig Change mesh mode of antenna structure pattern Radiation pattern of antenna or array; Embedded pattern of antenna element in array patternAzimuth Azimuth pattern of antenna or array patternElevation Elevation pattern of antenna or array returnLoss Return loss of antenna; scan return loss of array sparameters S-parameter object vswr Voltage standing wave ratio of antenna

## Examples

expand all

Create and view an inverted-L antenna that has 30mm length over a ground plane of dimensions 200mmx200mm.

il = invertedL('Length',30e-3, 'GroundPlaneLength',200e-3,...
'GroundPlaneWidth',200e-3);
show(il)

Plot the radiation pattern of an inverted-L at a frequency of 1.7GHz.

iL = invertedL('Length',30e-3, 'GroundPlaneLength',200e-3,...
'GroundPlaneWidth',200e-3);
pattern(iL,1.7e9)

## References

[1] Balanis, C.A. Antenna Theory. Analysis and Design, 3rd Ed. New York: Wiley, 2005.

[2] Volakis, John. Antenna Engineering Handbook, 4th Ed. New York: Mcgraw-Hill, 2007.