Trends in antenna design over 100 years

Antennas are an essential part of every radio system and they have been in use for more than 100 years. The continual growth of radio has steadily increased the types of antennas in use. Hertz used reflector antennas and loops in his classic experiments in the 1880s. Other pioneers, such as Lodge, developed early examples of microwave horns and lenses. The simple monopole wire antenna was crucial to the success of Marconi's first experiments. The indispensable nature of the antenna was recognised even in the early days. This paper surveys the general trends in antenna design over the 100 years of radio. It concentrates on describing early antennas, antennas for mobile communications, antennas for microwave communications and a short review of the methods of antenna design and validation.