Reflector Antenna Basics

1. General information

I made a summary about gain, efficiencies, beam factor, HPBW, beam efficiency, Tspillover, Tsky of parabolic reflector antennas.

Download of Reflector Antenna Basics

Here is a summary about feed pattern, dish illumination and resulting antenna beam pattern (from ideal to real).

Download of Feed pattern Basics

2. Useful formulas about prime focus and offset antennas

Legon's equation: for flat surface offset dish and position of maximum dish depth is known


Another more general equation: for flat/bended surface and known depth in dish center
version 1.1 (with addendum), October 2021, registration needed:
"a33-calculation-of-the-focal-length-of-an-offset-satellite-dish-antenna v1.1"
version 1.0, July 2020, no registration needed:
"a33-calculation-of-the-focal-length-of-an-offset-satellite-dish-antenna v1.0"

More offset antanna equations:

offset geometry

I made a calc tool for prime-focus and offset parabolic reflector antennas. This tool can also handle bended surface/rim offset antenna. It calculates efficiencies, gain and G/T.

offset geometry

3. References

1 Paul Wade W1GHZ, "The W1GHZ Online Microwave Antenna Book"
2 John D. Kraus, 1988, "Antennas for all applications" Second edition
3 John D. Kraus, 1986, "Radio Astronomy" Third edition
4 Jacob W.M. Baars, 2007, "The paraboloidal reflector antenna in radio astronomy and communication"
5 Samuel Silver, 1949, "Microwave antenna theory and design" First edition
6 Thomas A. Milligan, 2005, "Modern antenna design" Second edition
7 Constantine A. Balanis, 2005, "Antenna theory" Third edition
8 Thomas L. Wilson, Kristen Rohlfs, Susanne Hüttemeister, 2009, "Tools of radio astronomy" Fifth edition
9 Joachim Köppen, DF3GJ,
10 Dimitry Fedorov, UA3ARV, DUBUS 3/2016, "Solar flux and temperature at millimeter wavelengths"
11 W. Stutzman, M. Terada, "IEEE Antennas and Propagation Magazine, Vol.35, No.6, December 1993"
12 A. Cornejo, S. Landeros-Ayala, R.M. Rodriguez-Osorio, J.M. Matias, 2018, "A method for designing an offset-parabolic-reflector antenna for a ultra-high throughput satellite"