Engee documentation

EngeePhased.SincAntennaElement

Antenna element with directional pattern of sinc.

*Library: EngeePhased

Description

The EngeePhased.SincAntennaElement object models an antenna with a response as a sinc function. A sinc antenna is a uniformly irradiated rectangular antenna.

Sinc antenna patterns are often used as an approximation for sector antennas or antenna arrays.

The side lobes are -13.6 dB relative to the main beam gain. An axis of 0° in azimuth and 0° in elevation is considered the main response axis of the antenna. When placed in a linear or rectangular array, the principal response axis coincides with the normal of the array.

To calculate the response of an antenna element for a given direction, follow the steps below:

  1. Create an EngeePhased.SincAntennaElement object and set its properties.

  2. Call the object with arguments as if it were a function.

Constructor

  • antenna = EngeePhased.SincAntennaElement creates a system object, a sync antenna, antenna. The object models an antenna element whose response is a sync antenna, which is a uniformly illuminated rectangular antenna. The side lobes are -13.6 dB relative to the main beam gain.

  • antenna = EngeePhased.SincAntennaElement(Name,Value) creates a sync antenna object, antenna, with each specified Name (name) property set to the specified Value (value). You can specify additional arguments as a name-value pair in any order (Name1,Value1,…​,NameN,ValueN). For example, FrequencyRange=[1e6 1e9] indicates that the antenna operates in the frequency range from 1 MHz to 1 GHz.

  • RESP = antenna(FREQ,ANG) returns the amplitude response of the antenna voltage RESP at the operating frequencies specified in FREQ and the directions specified in ANG.

Properties

FrequencyRange - range of operating frequencies
[0 1e20] (by default) | ` non-negative real vector of strings 1 by 2`

The operating frequency range of the antenna, specified as a non-negative real vector of 1 by 2 rows in the form [LowerBound HigherBound]. The antenna element has no response outside the specified frequency range.

The units of measurement are Hz.

Data types: Float64.

Beamwidth - antenna beamwidth
[10 10] (by default) | scalar | real vector 1 by 2

Antenna pattern beamwidth specified as a scalar or vector with a real value of 1 by 2.

If the specified value is a 1-by-2 vector, it is [AzimuthBeamwidth ElevationBeamwidth].

If the specified value is a scalar, the azimuth and elevation beamwidths are equal.

The units of measurement are degrees.

*Example: 15

Data types: Float64.

Arguments

Input

FREQ - operating frequency of the antenna element
non-negative scalar | non-negative real vector 1 on L lines

Operating frequency of the antenna element specified as a non-negative scalar or non-negative real vector 1 on L lines.

The units of measurement are Hz.

FREQ must lie within the range of values specified by the FrequencyRange property of the element. Otherwise, the element does not respond and the response is returned as -Inf.

*Example: [1e8 2e6].

Data types: Float64.

ANG - azimuthal and altitude angles of the response directions
real vector of rows 1 on M | real matrix 2 on M

Azimuthal and altitude angles of the answer directions given as a real vector of lines 1 by M or a real matrix 2 by M, where M is the number of angular directions.

The units of measurement are degrees.

The azimuth angle must lie in the range from -180° to 180° inclusive. Elevation angle shall lie in the range from -90° to 90° inclusive.

If ANG is a vector 1 on M, each element specifies an azimuthal angle of direction. In this case, the corresponding elevation angle is assumed to be zero.

If ANG is a matrix 2 on M, each column of the matrix specifies a direction in the form [azimuth;elevation].

The azimuth angle is the angle between the x-axis and the projection of the direction vector onto the xy plane. This angle is positive when measured from the x-axis towards the y-axis. Elevation angle is the angle between the direction vector and the xy plane. This angle is positive when measured in the z-axis direction.

*Example: [110 125; 15 10]

Data types: Float64.

Output

RESP - antenna amplitude characteristic
complex matrix M on L

The voltage response of the antenna element, returned as a complex matrix M on L. In this matrix, M is the number of angles specified in ANG and L is the number of frequencies specified in FREQ.

Data types: Float64.

Methods

Common for all system objects

step!

Start the algorithm of the system object

release!

Allow changing the value of the system object property

reset!

Reset internal states of the system object

Optional

Sync antenna response

The EngeePhased.SincAntennaElement object returns the field response (also called the radiation pattern) of the antenna element sinc.

If is the azimuth angle in degrees and is the elevation angle in degrees, the field response is:

where

  • The azimuthal coefficient depends on and the azimuthal beam width at half power level :

Specify as the first element of the Beamwidth property.

  • The elevation factor depends on the elevation angle at half power level :

Specify as the second element of the Beamwidth property.

  • The normalisation factor provides half power corresponding to half power beamwidth. This factor is the solution: