Details the modulation and demodulation of circuits and relates resonant circuits to practical needs. The author provides a logical progression of material that moves from medium frequencies to microwave frequencies. He introduces rectangular waveguides as high-pass devices and explains conditions under which dielectric breakdown may limit the amount of power that may be transmitted in a completely expanded chapter. The section on antennas is completely updated to demystify the useful characteristic of antennas and relate their performance to the requirements of digital communication systems.