Can someone recommend a book?
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| Aug 12th 2018, 15:20 | |
ag7ovTotal Topics: 0 Total Posts: 0 |
Hi All, I'm looking for a book that explains some of the mechanisms of antennas and electromagnetic waves with more detail than the books I have, but without getting too far into Maxwell's equations and vector calculus. I have background knowledge in engineering (software), signals and systems (audio), and electronics. The books I've been able to find are (understandably) heavy on how-to, light on theory. But I'd like to grasp the theory in more detail. Subjects I'm looking to understand better are things like how antennas radiate, how radiation resistance is affected by antenna geometry, balanced versus unbalanced antenna systems and transmission lines, dialectric effects including those of earth, and so forth. I bought the ARRL's "Antenna Physics: An Introduction" thinking it would provide what I'm looking for. Sadly, despite the fact that there are a lot of equations in it, the book seems to explain little. To give an example: in the section on how antennas radiate, it starts presenting some background equations, and then at some point it jumps to the conclusion that accelerating charges (changing currents) in an antenna conductor cause radiation. It never attempts to explain why, or any specifics. Writing this kind of book would be a challenge, but this author doesn't quite seem to meet that challenge. I have that book, the ARRL Antenna Book, Basic Antennas, Propagation and Radio Science, the ARRL Guide to Antenna Tuners, and a few others. I realize that a deep understanding of electromagnetics requires studying electrodynamics, and that can't really be done without the vector calculus. On the other hand, most actual calculations of antenna behavior will be done via modeling these days. What I want is to start with some basic grasp of the physics before delving deeper. Can anyone recommend a good book for this--one that does what "Antenna Physics" promised to do but didn't quite deliver? Many thanks, Dan AG7OV |
| Aug 13th 2018, 09:16 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
Yes, there is a gap. Modeling is done by number crunching. The numbers you get can be very good, but number crunching doesn't provide any real insight or guidance. I don't know of a way of achieving the understanding you are looking for with simplified math. An early edition of Antennas by Kraus has the basics, but is likely to be too math intensive for most hams. Zak Lau W1VT ARRL Senior Lab Engineer |
| Aug 13th 2018, 13:16 | |
ag7ovTotal Topics: 0 Total Posts: 0 |
Hi Zak, Thanks for the response. I'm not averse to math. It's just that math can become a black hole. I can set out to gain an understanding of something and find that six months later I'm still studying math. Much as I actually enjoy that, it's a surefire way to never get anything done. It may be fair to say that it's hard to find practical math presented well for nonmathematicians. I've been a professional engineer for over 20 years and I still find this to be true. Each branch of math seems defined in terms of a half dozen other branches. It's difficult to find a straightforward definition of something that doesn't skim over important details and yet doesn't pull in a lot of unnecessary math concepts. For some reason authors don't seem to see the value of such things. Either we get shoddy, ambiguous half-math without any precision in definitions or clarity, or we get, "You need postgraduate coursework in the theory of abstract algebras to follow this explanation." The problem may well be that the authors are usually far more advanced in their understanding of the specific maths of their field than their readers, and they simply find it convenient to use all the concepts in their books. Ironically, I'm a person who loves math and would happily study it for eight hours a day. But there are few of us in this world who have the luxury of time to do that, even when we work in engineering fields. There are esoteric maths of my field (things like advanced graph theory) that I use every day. But there aren't enough hours in the day for a mortal like me to be both a senior-level software engineer and an RF expert. It still ought to be possible to learn RF concepts, though, or so it seems to me. Sorry to rant. I guess I'll start with some undergraduate-level explanations of Maxwell's equations and see if that can get me to a place where I can follow a text like Krause. Thanks again for the response. Dan AG7OV |
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