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Cosine Antenna Element

Support for Cosine Antenna Elements

The phased.CosineAntennaElement object models an antenna element whose response follows a cosine function raised to a specified power in both the azimuth and elevation directions.

The cosine response, or cosine pattern, is given by:

P(az,el)=cosm(az)cosn(el)

In this expression:

  • az is the azimuth angle.

  • el is the elevation angle.

  • The exponents m and n are real numbers greater than or equal to 1.

The response is defined for azimuth and elevation angles between –90 and 90 degrees, inclusive. There is no response at the back of a cosine antenna. The cosine response pattern achieves a maximum value of 1 at 0 degrees azimuth and elevation. Raising the response pattern to powers greater than one concentrates the response in azimuth or elevation.

When you use the cosine antenna element, you specify the exponents of the cosine pattern using the CosinePower property and the operating frequency range of the antenna using the FrequencyRange property.

Concentrating Cosine Antenna Response

This example shows the effect of concentrating the cosine antenna response by increasing the exponent of the cosine factor. The example computes and plots the cosine response for exponents equal to 1 and 2 for a single angle between -90 and 90 degrees. The angle can represent azimuth or elevation.

theta = -90:.01:90;
costh1 = cosd(theta);
costh2 = costh1.^2;
plot(theta,costh1)
hold on
plot(theta,costh2,'r')
hold off
legend('Exponent = 1','Exponent = 2','location','northeast');
xlabel('Angle (degrees')
ylabel('Response')

Plot 3-D Response of Cosine Antenna Element

This example shows how to construct an antenna with a cosine-squared response in both azimuth and elevation. The operating frequency range of the antenna is 1 to 10 GHz. Plot the 3-D antenna response at 5 GHz.

sCos = phased.CosineAntennaElement(...
    'FrequencyRange',[1 10]*1e9,'CosinePower',[2 2]);
pattern(sCos,5e9,[-180:180],[-90:90],'CoordinateSystem',...
    'Polar','Type','powerdb')

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