Getting Your Head Around Field And Wave Electromagnetics 2nd Edition
I ran into this book back when I was trying to actually understand what happens inside a waveguide, not just plug numbers into formulas for an exam. The Cheng Field And Wave Electromagnetics 2nd Edition is still one of the most commonly assigned textbooks for upper-level electromagnetics courses. It covers the fundamentals pretty thoroughly, from vector analysis through transmission lines and waveguides. The math is rigorous. That is kind of the point. The book was originally published by Addison-Wesley, and the second edition came out in 1989. You can find it on Amazon, AbeBooks, and various academic resellers. Physical copies run anywhere from thirty to a hundred dollars depending on condition. Digital versions pop up everywhere, though I am not going to link to anything pirate-y. If you are a student, check your library first. A lot of universities have electronic access through their engineering library portals, and that is the cleanest route if your school has it set up. Most EM textbooks either go super applied or super abstract. Cheng sits somewhere in the middle, which is why professors keep assigning it. The first chapter on vector analysis is necessary because you cannot do this stuff without being comfortable with gradients, divergence, curl, and the integral theorems. Some books assume you already know this. Cheng does not. He derives things from Maxwell's equations in the integral form and then transitions to differential form, which is how most working engineers actually think about fields.
The transmission line chapter is where a lot of people get tripped up. The Smith chart section is dense but useful. I found myself going back to it constantly during microwave design work. The waveguide treatment is solid, though it assumes you are okay with separation of variables. If that technique feels rusty, spend a weekend on it before diving into the TE and TM mode derivations. You will thank yourself later.
The Problem I Hit With This Book
There is a specific edge case that drove me nuts for about three weeks. Chapter on hollow waveguides, specifically the derivation of the cutoff frequency for the TE10 mode in a rectangular waveguide. Cheng presents the solution using separation of variables, applies the boundary conditions, and arrives at the result. The problem is that the textbook glosses over why the longitudinal component Hz must satisfy the Helmholtz equation separately from the transverse components. My professor never clarified it in lecture either. I ended up with gaps in my understanding that showed up later when I was modeling a waveguide junction in simulation and got baffling reflections at the discontinuity. The workaround was going to the original paper by Collin, Field Theory of Guided Waves, and cross-referencing the boundary condition derivations there. Collin shows explicitly how the longitudinal and transverse components decouple under the assumption of propagation in only one direction. Once I saw that derivation laid out, everything in Cheng's chapter clicked. I wish the book had included that intermediate step. It does not. That is my main criticism of it, honestly.
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Practical Warnings About Using This Book
Do not attempt to read this cover to cover in one semester unless you already have a strong complex variables background. The chapter on radiation and antennas assumes you are comfortable with retarded potentials and vector potential integrals. If you are not, go back and practice those integrals first. I watched students lose two weeks just because they skipped the prerequisite math review. Another thing: the problem sets at the end of each chapter are where the real learning happens. The worked examples are fine but they tend to be straightforward applications. The end-of-chapter problems, especially the odd-numbered ones, are where you actually test whether you understand the material. There is a solutions manual available separately. If you are self-studying, getting that is worth it. Otherwise you will waste a lot of time stuck on problem 4-17 trying to figure out where your sign error crept in. The book does not cover finite element methods or modern computational electromagnetics at all. It is strictly analytical. If you need to simulate antennas or scattering problems, you will need something like HFSS, CST, or at minimum a MATLAB FDTD implementation. Cheng will give you the physics foundation, but it will not teach you how to run a simulation. That comes from other sources entirely.
Is It Still Relevant After All These Years
Yes and no. The core physics has not changed. Maxwell's equations are the same. The wave equation is the same. What has changed is how we teach and apply this material. The book does not touch on metamaterials, photonic crystals, or computational techniques. For a first course in electromagnetic field theory, it is still genuinely good. For someone entering the industry today, you will need to supplement it with modern references if you plan to do simulation work or work with materials that do not fit the classical framework. My recommendation if you are taking the course is to read Cheng alongside a more applied text like Pozar's Microwave Engineering. Cheng gives you the rigor. Pozar gives you the context for where these concepts actually show up in hardware. Together they cover a wider range than either one alone.
How to Actually Use This Book
Read the chapter overview first. Cheng puts a summary at the start of each chapter that lists the key results. Skim it. Then read the derivations actively, meaning with a pen in hand, working through each algebraic step. Do not skip the intermediate math. That is where most people lose track. After the derivations, do at least five of the end-of-chapter problems before moving on. If you cannot solve three of those without looking at the solution manual, go back and re-read the relevant section. The material builds on itself too fast to power through passively. Focus especially hard on Chapter 6 on transmission lines and Chapter 8 on waveguides. Those are the chapters that show up repeatedly in graduate qualifying exams and in actual RF engineering work. The antenna chapter is lighter and less emphasized in most courses, but if you are heading into RF hardware, do not skip it entirely. The polarization discussion there is actually quite useful. I have been using this material for nearly twenty years across academic and industrial roles. The Cheng text has stayed on my shelf through every job change. It is not the flashiest book on the shelf. It is not the most accessible. But when I need to verify a derivation or remind myself how boundary conditions propagate across an interface between two lossy media, it is the first place I reach for. That says something about its durability as a reference, even if it was not written for reference use in the first place.
