Engee documentation

EngeePhased.URA

Uniform rectangular antenna array (URA).

Library

EngeePhased

Description

The EngeePhased.URA system object models a rectangular antenna array (URA) formed from identical isotropic phased array elements. The elements of the rectangular antenna array are arranged in the yz plane as a rectangular array.

To calculate the response of the array for the given directions, perform the following steps:

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

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

Syntax

Create

You can call the system object constructor in the following ways:

  • object = EngeePhased.URA creates a uniform rectangular antenna array (URA) formed from identical isotropic phased array elements with by default property values. The elements of the rectangular antenna array are arranged in the yz plane as a rectangular array. The direction of view of the antenna array (boresight) is along the positive x axis. Example:

    array = EngeePhased.URA

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

    array = EngeePhased.URA(Taper=[2 0.2 1])

  • object = EngeePhased.URA(SZ,D,Name=Value) creates a uniform rectangular antenna array (URA) with the Size property set to SZ and the ElementSpacing property set to D, and the other specified properties Name (name) set to the specified Value (value). Example:

    array = EngeePhased.URA(SZ,D,Lattice="Triangular")

SZ and D are value-only arguments. 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.

Usage

  • RESP = object(FREQ,ANG) returns the responses of the rectangular antenna array elements, argument RESP, at the operating frequencies specified in the FREQ argument and the directions specified in the ANG arguments.

When the object is first executed, it is initialised. This initialisation fixes the non-configurable properties and input characteristics such as size, complexity and input data type. If you change an unconfigurable property or input specification, the EngeePhased.URA system object generates an error. To change an unconfigurable property or input specification, you must first call the release! method to unlock the object.

Properties

Element - phased antenna array element
`IsotropicAntennaElement with property values by default ` | `antenna, acoustic element or transducer element from Phased Array System Toolbox ` | `antenna array from Antenna Toolbox `

Details

A phased array element specified as an antenna element, acoustic element or transducer from the Phased Array System Toolbox or an antenna from the Antenna Toolbox.

*Example: EngeePhased.CosineAntennaElement.

Size - dimensionality of the rectangular antenna array
[2 2] (by default) | positive scalar | vector of positive values 1 by 2

Details

The dimensionality of a rectangular antenna array, given as a vector of 1-by-2 integers or a single integer.

  • If Size is a 1-by-2 vector, the vector is [NumberOfRows, NumberOfColumns].

  • If Size is a scalar, then the rectangular antenna array has the same number of elements in each row and each column. For URA, the elements of the antenna array are indexed from top to bottom of a column and then to the next columns from left to right. In this figure, a Size rectangular antenna array with a value of [3,2] has three rows and two columns.

so ura

Example: [3,2].

Data types: Float64

ElementSpacing - element spacing
[0.5 0.5] (by default) | positive scalar | vector of positive values 1 by 2

Details

The distance between elements, given as a positive scalar or a vector of positive 1-by-2 values.

  • If ElementSpacing is a 1-by-2 vector, it has the form [SpacingBetweenRows,SpacingBetweenColumns].

  • If ElementSpacing is a scalar, the spacing between rows and columns is equal.

The units of measurement are m.

Example: [0.3, 0.5].

Data types: Float64

Lattice - lattice type
Rectangular (by default) | Triangular

Details

The grid type of the element, set as Rectangular or Triangular.

  • If the Lattice parameters are set to Rectangular, all URA elements are aligned in both row and column directions.

  • If the Lattice parameters are set to Triangular, elements in even-numbered rows are offset towards the positive direction of the row axis. The offset is half the distance between the elements in the row.

Data types: Float32

ArrayNormal - antenna array normal direction
x (by default) | y | z

Details

The normal direction of a rectangular antenna array specified as one of x, y or z.

The URA elements lie in a plane orthogonal to the selected normal direction of the rectangular antenna array. The sighting directions of the elements are along the normal direction of the antenna array.

x The elements of a rectangular antenna array lie in the yz-plane. All normal vectors of the elements are directed along the x axis. This value is used by default.

y

The elements of the rectangular antenna array lie in the zx plane. The normal vectors of all elements are directed along the y axis.

z

The elements of the rectangular antenna array lie in the xy plane. The normal vectors of all elements are directed along the z axis.

Taper - cones of the elements
1 (by default) | complex scalar | complex vector of rows 1 on MN | complex matrix M on N

Details

Cones of elements given as a complex scalar, a complex vector 1 on MN or a complex matrix M on N.

The cones are applied to each antenna element of an antenna array. The cones are often referred to as element weights. M is the number of elements along the z axis and N is the number of elements along the y axis. M and N correspond to the [NumberofRows,NumberOfColumns] values in the SIze property.

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

  • If Taper is a vector or matrix, the cone values are applied to the corresponding elements. Cone values are used to change the amplitude and phase of the received data.

Example: [0.4 1 0.4].

Data types: Float64

Entry

FREQ - antenna element operating frequency
positive real vector 1 on L lines

Details

The operating frequency of the antenna element given as a positive real vector 1 on L lines.

The units of measurement are Hz.

Data types: Float64

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

Details

Azimuthal and altitude angles of the answer directions given as a real vector of strings 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.

Data types: Float64

Output

RESP - antenna array pattern
`complex matrix N on M

Details

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

Data types: Float64

Methods

Common for all system objects

step!

Starts the system object’s operating algorithm
release!

Permission to change the value of a system object property
reset!

Reset the internal states of the system object

References

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

  2. Brookner, E., ed. "Practical Phased Array Antenna Systems." Boston: Artech House, 1991.

  3. Mailloux, R. J. "Phased Array Theory and Technology," Proceedings of the IEEE, Vol., 70, Number 3s, pp. 246-291.

  4. Mott, H. "Antennas for Radar and Communications," A Polarimetric Approach. New York: John Wiley & Sons, 1992.

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