For third-year BTech students interested in antennas, "Antenna Theory" by Balanis is highly recommended as a foundational textbook. The ARRL also publishes valuable resources, including a comprehensive antenna book that covers various types of antennas such as verticals, dipoles, and Yagis, along with topics on propagation. While the ARRL book is detailed and priced around $50, many amateur radio operators suggest learning through practical experience by building antennas. Online resources are plentiful, with numerous amateur radio enthusiasts sharing their knowledge and experiences on personal websites. For further information, the ARRL website (arrl.org) is a useful resource.