Antenna Basics.
You can find the index of the source material here, on the Navy server.
The Basics page has a wonderful graphic explanation of "Effective Area" showing a sphere illuminated by an imaginary isotropic antenna. This is the right way to explain antenna gain as a function of effective area, and I have run into engineers that don't get it. I guess it is too simple. But, if it were not simple, I couldn't understand it!
This is off topic, but an understanding of effective area can make understandable why, using parabolic antennas of fixed physical dimensions and distance, and ignoring attenuation by the atmosphere, the power transfer between the two antennas will increase as wavelength decreases. Just imagine this. As the wavelength decreases, the reflector seems bigger to the wave. So the focus of the "spotlight" gets sharper, the spot brighter. As the effective area is constant regardless of wavelength, the receiving parabolic gets more power as the wave length shortens since power density on the receiving dish is greater. But.... I digress.... onward.
Polarization.
Radiation Patterns.
Frequency-Phase.
The following is from D.Jefferies.
For more info follow the link.
The term "isotropic radiator". A certain transmit antenna has boresight gain which is a factor 2.6 over isotropic. Express this gain as dBi.