Antenna theory

What Hacker News says

1. antegamisouJul 2023
   For those with some fundamental undergrad math background, check out the gold standard book on antennas

       Antenna Theory: Analysis and Design, Constantine Balanis
   

   https://www.amazon.com/Antenna-Theory-Analysis-Constantine-B...
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2. kawfeyApr 2020
   As an antenna engineer, I've referred to this site hundreds of times. To be fair, it's almost an eli5 version of how antennas work, but it's been a good reference for basics.

   http://www.antenna-theory.com/basics/whyantennasradiate.php is as deep as it gets.

   For DEEP antenna theory, I can't recommend the Balanis book high enough. https://www.amazon.com/Antenna-Theory-Analysis-Constantine-B...

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3. humbfool2Apr 2020
   Recommended reading - Antenna Theory Analysis and Design, by Constantine Balanis
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4. dbcurtisApr 2019
   >I still haven't been able to find a general equation for a have wavelength dipole antenna explained in simple English.

   Equation for what? Length at resonance? Feed point impedance? Other interesting parameters?

   Antennas are one of those things where it takes a long time to develop intuition, and there are no simple formulas for anything, just useful models that get you close, and simulation programs that work well enough to give an answer within your manufacturing tolerances. (All models are wrong, some are useful.)

   So start with a couple of fundamental ideas: 1) Accelerate an electron, get a photon. 2) An antenna is a transformer that couples the end of your feed line to free space.

   The reason the general family of dipole antennas is efficient is that the Ohmic resistance is usually around an Ohm or less, and the "radiation resistance" can be raised to around 70 to 80 Ohms. So 80/(80+1) is the ratio of energy coupled to space versus total energy input. Pretty good efficiency.

   In a center fed dipole, the driving voltage creates an electrostatic force that attempts to slosh electrons in the conductor one way or the other. At resonance, a small amount of energy input creates lots of sloshing, because the driving voltage just needs to give a boost to the resonant sloshing. Off resonance, effectiveness is much lower. Actual length at resonance depends on the length:diameter ratio of the conductor, the dielectric constant of the surrounding medium, the height above ground, and the dielectric constant and conductivity of the ground. If you know all of those, the dipole can be modeled as a just barely tractable boundary value problem.

   The empirical formulas that you see usually assume a practical conductor diameter and practical height. You might enjoy playing with one of the NEC2-based antenna modeling programs out there. NEC2-family solvers do "method of moments", where each wire is chopped up into segments, and then for an N-segment model, an NxN matrix of mutual inductances models the coupling among wire segments.

   The ARRL Antenna Book takes more time to explain fundamentals than the Handbook. The ARRL also publishes an antenna physics book that I haven't read. I notice that PhD committee chair for the author of the Antenna Theory web site we are yakking about was Balanis, who wrote a pretty good book called "Antenna Theory" -- but the book assumes you are an EE graduate student with at least a semester of multi-dimmensional DiffEQ beyond the elementary DiffEQ course.

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5. madengrDec 2018
   Antennas:

   ARRL Antenna Compendium for the layman.

   Antenna Theory and Design by Stutzman and Theile for a textbook. Books by Constantin Balanis or John Krauss are good too.

   Modern Antenna Design by Milligan for a practicing engineer reference book.

   DSP:

   Understating Digital Signal Processing by Richard Lyons is a excellent as it has theory and practicality.

   Discrete-time Signal Processing by Oppenheim and Schafer for a textbook.

   I don't know what would be a practicing reference book as I'm a hardware guy.

   Comms theory: Digital Communications by Sklar for a textbook.

   SDR: SDR covers such a broad area, you need a little of everything. RF hardware, DSP, FPGA/HDL, comms theory, python/C++ programming

   This looks really good, but I have never read it: https://www.analog.com/en/education/education-library/softwa...

   I keep notes here for when you want to build GR from source (though I have not used GR 3.8 yet): https://rfpoweramp.com/category/sdr/gnu-radio/

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6. escherplexSep 2018
   Might want to try

   Antenna Theory - Analysis and Design - Balanis (2016)

   But noticed a 2005 3rd edition is available in .pdf for download gratis at:

   https://archive.org/details/AntennaTheoryAnalysisAndDesign3r...

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