System object: phased.ReplicatedSubarray
Plot replicated subarray directivity or pattern versus azimuth
PAT = patternAzimuth(___)
The integration used when computing array directivity has a minimum sampling grid of 0.1 degrees. If an array pattern has a beamwidth smaller than this, the directivity value will be inaccurate.
in addition, plots the 2-D array directivity pattern versus azimuth (in dBi) for the array
sArray at the elevation angle specified by
EL is a vector, multiple overlaid plots are created.
the array pattern.
PAT = patternAzimuth(___)
PAT is a matrix whose entries
represent the pattern at corresponding sampling points specified by
'Azimuth' parameter and the
sArray — Replicated subarray
Replicated subarray, specified as a
phased.ReplicatedSubarray System object.
Specify optional pairs of arguments as
the argument name and
Value is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name in quotes.
ElementWeights — Weights applied to elements within subarray
1 (default) | complex-valued NSE-by-N
Subarray element weights, specified as complex-valued NSE-by-N matrix. Weights are applied to the individual elements within a subarray. All subarrays have the same dimensions and sizes. NSE is the number of elements in each subarray and N is the number of subarrays. Each column of the matrix specifies the weights for the corresponding subarray.
To enable this name-value pair, set the
SubarraySteering property of the array to
Complex Number Support: Yes
Parent — Handle to axis
Handle to the axes along which the array geometry is displayed specified as a scalar.
Azimuth Pattern of Array with Subarrays
Create a 2-element ULA of isotropic antenna elements, and arrange three copies to form a 6-element ULA. Plot the directivity azimuth pattern within a restricted range of azimuth angles from -30 to 30 degrees in 0.1 degree increments. Plot directivity for 0 degrees and 45 degrees elevation.
Create the array
fmin = 1e9; fmax = 6e9; c = physconst('LightSpeed'); lam = c/fmax; sIso = phased.IsotropicAntennaElement(... 'FrequencyRange',[fmin,fmax],... 'BackBaffled',false); sULA = phased.ULA('Element',sIso,... 'NumElements',2,'ElementSpacing',0.5); sRS = phased.ReplicatedSubarray('Subarray',sULA,... 'Layout','Rectangular','GridSize',[1 3],... 'GridSpacing','Auto');
Plot azimuth directivity pattern
fc = 1e9; wts = [0.862,1.23,0.862]'; patternAzimuth(sRS,fc,[0,45],'PropagationSpeed',physconst('LightSpeed'),... 'Azimuth',[-30:0.1:30],... 'Type','directivity',... 'Weights',wts);
Directivity describes the directionality of the radiation pattern of a sensor element or array of sensor elements.
Higher directivity is desired when you want to transmit more radiation in a specific direction. Directivity is the ratio of the transmitted radiant intensity in a specified direction to the radiant intensity transmitted by an isotropic radiator with the same total transmitted power
where Urad(θ,φ) is the radiant intensity of a transmitter in the direction (θ,φ) and Ptotal is the total power transmitted by an isotropic radiator. For a receiving element or array, directivity measures the sensitivity toward radiation arriving from a specific direction. The principle of reciprocity shows that the directivity of an element or array used for reception equals the directivity of the same element or array used for transmission. When converted to decibels, the directivity is denoted as dBi. For information on directivity, read the notes on Element Directivity and Array Directivity.