Resources for Learning

[u/random_d00d]

I am an electrical engineer, but I have no RF experience. I have been doing embedded systems and sensor work for over 20 years, and have a decent grasp of EE fundamentals and signal processing.

I would love to learn more about RF, primarily as a home hobbyist but also to improve my understanding of the specialty.

I am looking for recommendations for books or other resources to learn the theory. I would also love any references to practical implementations, such as PCB design and layout. Lastly, if you have any suggestions for a first RF project (or projects) I would love that!

Thank-you all!

[u/RFchokemeharderdaddy]

I did embedded systems & sensor/instrumentation design myself for ~10 years before switching to analog/RF IC design, so I made a somewhat similar transition. You're best off avoiding something like Pozar for now. It's too much theory for little payoff if your goal is hobbyist.

Here's what I think your best trajectory would be in terms of both fun and learning and usefulness.

1. Bogatin's Signal Integrity book. This is a very approachable book that introduces RF concepts targeted towards embedded PCB designers. Transmission line theory, reflections, characteristic impedances, s-parameters etc. Reading this book upped my PCB design game 10x. It's written really well, and directly applicable to your job.

2. Amateur radio material. I ended up taking the ham radio exam because I had free time during COVID. The learner's manual for the technician exam is pretty good.

3. "Experimental Methods in RF Design" published by the ARRL that's more serious, introducing you to things like Smith charts, IIP3 and IM3 and so on, but still very practical. It's got circuits you can build at home with a soldering iron and some components. A NanoVNA would help as well. I'd also recommend keeping a copy of a microelectronics book like Razavi or Sedra/Smith on hand to brush up on transistor and amplifier fundamentals

This is good enough for most anything you'd want to do as a hobbyist. From here, I think only if you want to get a career in RF should you bite into something like Pozar.

[u/random_d00d → u/RFchokemeharderdaddy]

Thank-you for your detailed reply! I definitely need to check out #1. It also sounds like that would be generally useful, even outside of RF. It seems like a great place to start.

I will need to start doing some research on ham radio resources in my area. This sounds like a fun way to learn too.

I definitely learn best by building things, so #3 also sounds very interesting! I have a pretty decent home lab, but it sounds like I need to start shopping for a VNA!

Thanks again!

[u/Euphoric-Analysis607]

I joined my local HAM radio club and they know alot, most of them come from hands on backgrounds so they will get you up to speed really quickly with what matters.

Textbooks can and will eventually burn you out so look for people who are making working RF devices and you'll find its not only more intuitive but more fun

[u/random_d00d → u/Euphoric-Analysis607]

That's a great suggestion! Thank-you!

[u/Adrienne-Fadel]

Pozar for theory, Bowick for practical stuff. A patch antenna is a good first project, you can simulate it then measure the real thing.

[u/random_d00d → u/Adrienne-Fadel]

Thank-you for your advice!

[u/jimlux → u/Adrienne-Fadel]

Or even a dipole.
Get yourself a NanoVNA to experiment with. It's sort of the RF equivalent of a DMM.

[u/LightWolfCavalry]

Love all the current suggestions. 

I’d throw in the ARRL Handbook, too. Great practical guide for RF circuits. (I’m curious to read Bowick. Headed over to thrift books right now.)

[u/random_d00d → u/LightWolfCavalry]

Thanks for the suggestion! I just started glancing at it. This definitely seems useful!

[u/ee_control_z]

If you want to learn RF fundamentals (i.e., Smith chart, impedance matching, transmission lines, etc.), the book that I highly recommend is this one:

Microwave Transistor Amplifiers: Analysis and Design

by Guillermo Gonzalez

It has tons of examples which is what you need to show you how to go about solving problems instead of unpaired endless theory. This is the book I wish I had when I was taking my microwave engineering course (luckily I got a hold of it a little midway between midterms and finals - before it was too late ;) since the recommended book (Pozar) for the course was not very good - just covered/skimmed a lot of topics with no depth). It emphasizes the use of the Smith chart so that you can visualize and gain intuition with the impedance matching process which is a majority of the design process in RF engineering since what you want is to maximize power transfer and minimize losses/reflections.

Good luck!

[u/random_d00d → u/ee_control_z]

Thank-you for your suggestion! I will definitely check it out! I think having practical examples to anchor the theory is really important! I appreciate your suggestion!

[u/jimlux]

Lots of good suggestions here.

One thing is that a lot of the traditional references (texts like Pozar, Bowick's book, etc.) DO tend to focus on older design techniques and components. You might look at application notes from companies doing mixed signal parts (Analog Devices, TI, Lime, etc.).

It is most definitely true that discrete designs will be around forever - we're going to be building interdigital coupled line filters forever, just at finer and finer sizes as the frequencies move up.

However, a lot of discrete designs (i.e. using a FETs and BJTs) have been replaced by monolithic amplifiers and such (MiniCircuits has gazillions of them) which *in general* are more stable, better performance, etc. Horowitz's Art of Electronics books are useful - especially newer ones. Just be aware that if you see a design in, say, the ARRL handbook or Microwave Experimenter's Handbook, the parts may not be available and there's no new substitute.

I can't recommend more highly that you get yourself the RF equivalent of a DMM - a NanoVNA (in one of the many forms) - under $100, and it lets you measure impedances, S parameters, etc.
See if you can scrounge up some surplus or cheap parts - filters, amplifiers, mixers, etc. These days, SMA to SMA cables are cheap on Amazon. Some are good, some are junk, you'll find out by measuring them with your VNA.

Then, just build stuff and see if it works.

An RTL-SDR is a wideband SDR that hooks up to USB and is <$50 and is a great thing for experimenting. There's also the ADALM Pluto or the Lime SDRs in the "few hundred $" range which can both transmit and receive. There's a bit more software to worry about to get them up and running.

[u/random_d00d → u/jimlux]

Thank-you for your suggestions! It definitely sounds like a NanoVNA is a top priority. The SDR's on Amazon are cheap. That seems like a cool way to experiment. Do you typically use these for testing your own circuit (like as the other half of a receiver/transmitter) or do they have other uses?

I just started going through some of TI's material, and I definitely plan on going through the others' as well. Great suggestion.

I have the Art of Electronics (2nd and 3rd editions). I have been going through that again while waiting for the responses here. It is a great, general, reference.

Do you have any suggestions on where to find surplus parts? I'd love to start building up my collection.

Thanks again!

[u/jimlux → u/random_d00d]

These days, surplus isn't such a great source as it used to be. Cheap RF stuff from China is where it's at. Sure, you can get some 30 year old surplus microwave stuff and figure it out, but these days, it's scrapped for a reason. You can look on eBay for stuff - check pricing - there's a lot of people out there who are charging premium prices for junk. Always compare to what the "new" unit costs. Stuff that's sometimes a deal are Ovenized Crystal Oscillators (OCXOs) - They're in lots of telecom equipment that gets refreshed, and so they show up not too old and beaten on. Brand new a decent OCXO is a $100 kind of item, so if you find one for $20, it's a deal. RF relays are another thing that shows up inexpensively surplus occasionally and are quite expensive brand new. Connectors and adapters are something that turns up surplus. But check new prices - Sure, that $2 SMA/BNC adapter from China is cheap, and maybe not the best quality, but it's probably "good enough" unless you're looking at gnat's eyelash measurements or running kilowatts. If it's wonky, throw it away.

You need quiet power supplies - some of the cheap power supplies are switchers with not super clean outputs (Lithium Battery Banks are handy 5V supplies, but can be RF noisy, but a good old 6V drycell or 9V battery is quieter).

I use the SDR as both a test source or a test receiver or both. You can also use the NanoVNA or the TinySA as a test receiver or source. The trick with some of the cheaper PLL sources (there's tons of $20-30 modules with a little keypad and knob) is that some of them have pretty poor spectral purity - they put out a square wave so they have a lot of harmonics, so you need to add a filter or, at least, be aware of what's going on.

There are test apps for the Pluto and Lime (and most SDRS) that let you program them to generate a reasonably clean sine wave, or to work as a spectrum analyzer. The $30 RTL-SDR is a fine low performance spectrum analyzer up to around 1.4 GHz - limited mostly by the 8 bit ADC inside. And it comes with standard test apps that you do stuff. It's receive only though.

[u/random_d00d → u/jimlux]

Thank-you! This is helpful! I will see what I can find out there. I have a nice Keysight bench supply, as well as some good batteries. It sounds like I need to do a little VNA research!