Engee documentation

EngeePhased.ULA

Uniform Linear Antenna Array (ULA).

Library

EngeePhased

Description

System object EngeePhased.ULA simulates a uniform linear antenna array (ULA) and calculates its response.

To calculate the response for each element of the antenna array for the specified directions, follow these steps:

  1. Create the EngeePhased.ULA object and set its properties.

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

Syntax

Creation

The constructor of a system object can be called in the following ways:

  • object = EngeePhased.ULA Creates a uniform linear antenna array (ULA) formed from identical isotropic elements of a phased array sensor with default property values. The origin of the local coordinate system is the phase center of the antenna array. The positive axis x is the direction normal to the antenna array, and the antenna array elements are located along the y axis.

    Example:

    array = EngeePhased.ULA
  • object = EngeePhased.ULA(Name=Value) creates a uniform linear antenna array (ULA) with each specified Name property set to the specified Value. You can specify additional arguments as a name-value pair in any order (Name1=Value1,…​,NameN=ValueN).

    Example:

    array = EngeePhased.ULA(ElementSpacing=1.5,ArrayAxis="z")
  • object = EngeePhased.URA(N,D,Name=Value) creates a uniform linear antenna array (ULA) with the numElements property set to N, for the ElementSpacing property, the value is D, and other specified Name properties set to the specified Value. N and D they are arguments for values only. When specifying a value-only argument, all preceding value-only arguments must be specified. The arguments of the Name-Value pair can be specified in any order.

    Example:

    array = EngeePhased.ULA(N,D,NumElements=5)

Using

  • resp = object(freq,ang) returns the responses of the elements of the linear antenna array, the resp argument, at the operating frequencies specified in the freq argument and in the directions specified in ang.

Features

Element — element of the phased array antenna

+ EngeePhased.AbstractAntennaElement

Details

An element of the antenna array.

Example: EngeePhased.CosineAntennaElement

numElements — the number of antenna array elements

+ 2 (by default) | a positive integer

Details

The number of elements of the linear antenna array, set as a positive integer.

Data types: Float64

ElementSpacing — the distance between the elements of the antenna array

+ 0.5 (default) | positive scalar

Details

The distance between two adjacent elements of a linear antenna array, defined as a positive scalar.

The units of measurement are m.

Data types: Float64

ArrayAxis is the axis of the linear antenna array

+ y (default) | x | z

Details

The axis of the linear antenna array, defined as x, y or z.

The elements of the linear antenna array are located along the selected axis of the coordinate system. The axis of the antenna array determines the direction along which the normal vectors of the elements are directed.

Value of the ArrayAxis property The normal direction of the Element

x

azimuth = 90°, altitude = 0° (y axis)

y (by default)

azimuth = 0°, altitude = 0° (x axis)

z

azimuth = 0°, altitude = 0° (x axis)

Taper — cones of elements

+ 1 (default) | the complex scalar | a complex vector of 1 by N rows | a complex vector of N-by-1 columns

Details

The narrowing of the elements of a linear antenna array, defined as a complex scalar, a complex vector of rows 1 by N, or a complex vector of columns N by 1. N is the number of elements of the antenna array. Cones, also known as weighting coefficients, are applied to each antenna element of a linear antenna array and change the amplitude and phase of the received data.

  • If Taper is a scalar, the same cone value is applied to all elements.

  • If Taper is a vector, then each cone value is applied to the corresponding antenna element.

Data types: Float64

Entrance

freq — the operating frequency of the antenna element

+ a positive real vector of 1 on L lines

Details

The operating frequency of the antenna element, set as a positive real vector of 1 per L lines.

The units of measurement are Hz.

Data types: Float64

ang — azimuth and elevation angles of the response directions

+ a real vector of lines 1 by M | the real matrix is 2 by M

Details

Azimuthal and elevation angles of the response directions, given as a real vector of rows 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 azimuthal angle should be in the range from -180° to 180° inclusive. The elevation angle should be in the range from -90° to 90° inclusive.

If ang is a vector of 1 by M, each element sets the azimuth angle of the direction. In this case, the corresponding elevation angle is assumed to be zero.

If ang is a 2-by-M matrix, each column of the matrix defines a direction in the form [azimuth; altitude].

The azimuthal 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. The elevation angle is the angle between the direction vector and the xy plane. This angle is positive when measured in the direction of the z axis.

Data types: Float64

Output

resp — antenna array radiation pattern

+ the complex N-by-L matrix

Details

The voltage response of the antenna element, returned as a complex matrix N by L. In this matrix, N is the number of angles specified in ang, and L is the number of frequencies specified in freq.

Data types: Float64

Methods

Common to all system objects

step!

Running the system object operation algorithm

release!

Permission to change the value of a system object property

reset!

Resetting the internal states of a system object

  1. Brookner, E., ed. "Radar Technology". Lexington, MA: LexBook, 1996.

  2. Van Trees, H. "Optimum Array Processing". New York: Wiley-Interscience, 2002.