System object: phased.ULA
Output responses of array elements
RESP = step(H,FREQ,ANG)
Starting in R2016b, instead of using the
step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example,
y = step(obj,x) and
y = obj(x) perform equivalent operations.
The object performs an initialization the first time the object 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
release method to unlock the object.
Operating frequencies of array in hertz.
Directions in degrees.
Voltage responses of the phased array. The output depends on whether the array supports polarization or not.
Response of Antenna ULA
Create a 4-element ULA of isotropic antenna elements and find the response of each element at boresight. Plot the array response at 1 GHz for azimuth angles between -180 and 180 degrees.
ha = phased.ULA('NumElements',4); fc = 1e9; ang = [0;0]; resp = step(ha,fc,ang); c = physconst('LightSpeed'); pattern(ha,fc,[-180:180],0,... 'PropagationSpeed',c,... 'CoordinateSystem','rectangular')
Step Response of Microphone ULA Array
Find the response of a ULA array of 10 omnidirectional microphones spaced 1.5 meters apart. Set the frequency response of the microphone to the range 20 Hz to 20 kHz and choose the signal frequency to be 100 Hz. Using the
step method, determine the response of each element at boresight: 0 degrees azimuth and 0 degrees elevation.
sMic = phased.OmnidirectionalMicrophoneElement(... 'FrequencyRange',[20 20e3]); Nelem = 10; sULA = phased.ULA('NumElements',Nelem,... 'ElementSpacing',1.5,... 'Element',sMic); fc = 100; ang = [0;0]; resp = step(sULA,fc,ang)
resp = 10×1 1 1 1 1 1 1 1 1 1 1
Plot the array directivity. Assume the speed of sound in air to be 340 m/s.
c = 340; pattern(sULA,fc,[-180:180],0,'PropagationSpeed',c,'CoordinateSystem','polar')