# Documentation

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# loopCircular

Create circular loop antenna

## Description

The loopCircular object is a planar circular loop antenna on the X-Y plane.

The thickness of the loop is related to the diameter of an equivalent cylinder loop by the equation

$t=2d=4r$

, where:

• d is the diameter of equivalent cylindrical loop

• r is the radius of equivalent cylindrical loop

For a given cylinder radius, use the cylinder2strip utility function to calculate the equivalent width. The default circular loop antenna is fed at the positive X-axis. The point of the X-axis is at the midpoint of the inner and outer radii.

## Creation

### Syntax

h = loopCircular
h = loopCircular(Name,Value)

### Description

h = loopCircular creates a one wavelength circular loop antenna in the X-Y plane. By default, the circumference is chosen for the operating frequency 75 MHz.

example

h = loopCircular(Name,Value) creates a one wavelength circular loop 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

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Outer radius of loop, specified as a scalar in meters.

Data Types: double

Thickness of loop, specified as a scalar in meters.

Example: 'Thickness',2

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

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Create and view a circular loop with 0.65 m radius and 0.01 m thickness.

show(c)

Calculate the impedance of a circular loop antenna over a frequency range of 70MHz-90MHz.

impedance(c,linspace(70e6,90e6,31))

## References

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