An isotropic antenna element radiates equal power in all nonbaffled
directions. To construct an isotropic antenna, use
When you use this object, you must specify these aspects of the antenna:
Operating frequency range of the antenna
Whether the response of the antenna is baffled at azimuth angles outside the interval [–90,90]
You can find your isotropic antenna element's voltage
response at specific frequencies and angles using the antenna element's
This example shows how to construct a backbaffled isotropic antenna element with a uniform frequency response over azimuth angles from [–180,180] degrees and elevation angles from [–90,90] degrees. The antenna operates between 300 megahertz (MHz) and 1 gigahertz (GHz). Plot the antenna response at 1 GHz.
ha = phased.IsotropicAntennaElement(... 'FrequencyRange',[3e8 1e9],'BackBaffled',false) plotResponse(ha,1e9,'RespCut','3D','Format','Polar',... 'Unit','pow');
BackBaffled property to
the response to azimuth angles in the interval [–90,90].
ha.BackBaffled=true; figure; plotResponse(ha,1e9,'RespCut','3D','Format','Polar',... 'Unit','pow');
This example shows how to design a backbaffled isotropic antenna element and obtain the response of that element.
Construct an isotropic antenna element to operate in the IEEE® X band between 8 and 12 GHz. Backbaffle the response of the antenna. Obtain your antenna element's response at 4 GHz intervals between 6 and 14 GHz and at azimuth angles between –100 and 100 in 50-degree increments.
ha = phased.IsotropicAntennaElement(... 'FrequencyRange',[8e9 12e9],'BackBaffled',true) respfreqs = 6e9:4e9:14e9; respazangles = -100:50:100; anresp = step(ha,respfreqs,respazangles)
The antenna response in
anresp is a matrix
whose row dimension equals the number of azimuth angles in
whose column dimension equals the number of frequencies in
The response voltage in the first two and last two columns of
zero because those columns contain the antenna response at 6 and 14
GHz respectively. These frequencies are not included in the antenna's
operating frequency range.
Similarly, the first and last rows of
all zeros because the
BackBaffled property is
true. The first and last row contain the
antenna's response at azimuth angles outside of [–90,90].
To obtain the antenna response at nonzero elevation angles,
input the angles to
step as a 2-by-M matrix where
each column is an angle in the form
release(ha) respelangles = -90:45:90; respangles = [respazangles; respelangles]; anresp = step(ha,respfreqs,respangles)
the antenna voltage response at the aziumth-elevation pairs (–100,–90)
and (100,90). Because the elevation angles are equal to +/–
90 degrees, these responses are equal to one even though the
is set to
true. Thus, the resulting elevation
cut degenerates into a point.