step

System object: phased.CrossedDipoleAntennaElement
Package: phased

Output response of antenna element

Syntax

RESP = step(H,FREQ,ANG)

Description

RESP = step(H,FREQ,ANG) returns the antenna's voltage response, RESP, at the operating frequencies specified in FREQ and in the directions specified in ANG. For the crossed-dipole antenna element object, RESP is a MATLAB® struct containing two fields, RESP.H and RESP.V, representing the horizontal and vertical polarization components of the antenna's response. Each field is an M-by-L matrix containing the antenna response at the M angles specified in ANG and at the L frequencies specified in FREQ.

    Note:   H specifies the System object™ on which to run this step method.

    The object performs an initialization the first time the step method is executed. This initialization locks nontunable properties and input specifications, such as dimensions, complexity, and data type of the input data. If you change a nontunable property or an input specification, the System object issues an error. To change nontunable properties or inputs, you must first call the release method to unlock the object.

Input Arguments

H

Antenna element object.

FREQ

Operating frequencies of antenna in hertz. FREQ is a row vector of length L.

ANG

Directions in degrees. ANG can be either a 2-by-M matrix or a row vector of length M.

If ANG is a 2-by-M matrix, each column of the matrix specifies the direction in the form [azimuth; elevation]. The azimuth angle must be between –180 and 180 degrees, inclusive. The elevation angle must be between –90 and 90 degrees, inclusive.

If ANG is a row vector of length M, each element specifies a direction's azimuth angle. In this case, the corresponding elevation angle is assumed to be 0.

Output Arguments

RESP

Voltage response of antenna element returned as a MATLAB struct with fields RESP.H and RESP.V. Both RESP.H and RESP.V contain responses for the horizontal and vertical polarization components of the antenna radiation pattern. Both RESP.H and RESP.V are M-by-L matrices. In these matrices, M represents the number of angles specified in ANG, and L represents the number of frequencies specified in FREQ.

Examples

Find the response of a crossed-dipole antenna at boresight, 0° azimuth and 0° elevation, and off-boresight at 30° azimuth and 0° elevation. The antenna operates at frequencies between 100 and 900 MHz. Find the response of the antenna at these angles at 250 MHz.

hcd = phased.CrossedDipoleAntennaElement(...
     'FrequencyRange',[100 900]*1e6);
ang = [0 30;0 0];
fc = 250e6;
resp = step(hcd,fc,ang);
resp.H = 
   0.0000 - 1.2247i
   0.0000 - 1.0607i
resp.V = 
   -1.2247
   -1.2247

Algorithms

The total response of a crossed-dipole antenna element is a combination of its frequency response and spatial response. phased.CrossedDipoleAntennaElement calculates both responses using nearest neighbor interpolation, and then multiplies the responses to form the total response.

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