For the students entering my grad program without any EM background (save for a physics class), I recommend Engineering Electromagnetics by Nathan Ida. It's good for an undergraduate text, mostly touching on static fields with a lot of worked examples.
For more advanced EM, I'd recommend Advanced Engineering Electromagnetics by Constantine Balanis. Fairly well written, with a number of examples. The Jin book recommended by u/arosh25 is good, but half of it covers computational EM. It's a great resource, especially if you're going to eventually do some kind of computation, but if you're coming from the ground level, it's probably not what you are looking for just yet.
I like the Practical Antenna Handbook even better.
Carr’s Practical Antenna Handbook is excellent. Good combo of theory plus (as the name suggests) practical design tips.
Great questions and finding the answers and figuring it all out is the best part of the hobby for me. Literally any copy of the ARRL Antenna Book will help with most of these, but it is not made to be read through but rather to use the index and cover a topic or a particular antenna at a sitting.
I am a book collector and spend a great deal of books in any area of interest I have and have a stack of books on antenna theory and a recent copy of the ARRL Antenna book along with O4UN's Low Band DXing (also excellent resource). However, on a whim, I got a copy of the book below and it was so "just what the doctor ordered" for where I was in my understanding, that I read it from cover to cover. I honestly feel I am a better ham for it.
https://www.amazon.com/Practical-Antenna-Handbook-Joseph-Carr/dp/0071639586
In energy terms, I guess the difference is that this is harvesting energy from a variety of signals, whereas a passive UHF RFID tag is designed to harvest energy only from the very specific frequency of the energising pulse, but the physics must be the similar.
In data terms, there is more going on when reading UHF RFID tags than just a simple 'chirp', but it's definitely not general purpose computing like this.
PS: "The RF in RFID" by Dobkin is an excellent book.
The RF in RFID: Passive UHF RFID in Practice https://www.amazon.co.uk/dp/0750682094/ref=cm_sw_r_cp_apa_i_JvMqCb8RXHFCE
Check out Dobkin's, RF Engineering for Wireless Networks. It gives a nice overview of real radio systems at a level that is appropriate for a sophomore. It doesn't have problems for you to work like a textbook but it is a good survey to start looking at radios in modern wireless devices.
I recently picked up a copy of Modern Small Antennas by Fujimoto and Morishita. Very useful resource for small antennas.
To do an electrically small antenna design you typically need a 3D field simulator. They are not cheap.
It is the defacto 'just above layman' text on the subject. It gets somewhat dense on the math in places, but you can skim through that without losing the most important bits.