# Aperture Antennas

The electric far field components radiated by a circular aperture antenna are given by
where r is the distance from the antenna to the point of observation, a is the radius of the circular aperture, E _{o} is the constant field over the aperture and k = 2Pi / wavelength.
Two applets can be used to explore the properties such as radiation pattern of circular apertures.
1 - Click on the button to start the applet. 2 - Use the top slider to increase the radius (relative to wavelength) of the circular aperture. What happens to the radiation pattern? 3- Keep the radius constant and change angle Phi. Any major changes in the radiation pattern?
1 - Click on the button to start the applet. 2 - Change the radius of the aperture antenna. What happens to the field distribution and the half power beam width? More on antennas antennas and parabolic reflectors. |