12.3.6 Bandwidth

We will see shortly that the physical dimensions of an antenna are related to the wavelength of operation—the larger the wavelength, the larger the antenna. That generally means that an antenna is built for a particular wavelength and will need to be adjusted in size when the frequency of operation is changed. For many applications, the antenna should preferably not require readjustment when the frequency is changed (within limits of course) and should operate effectively across a range of frequencies—that is, have a wide bandwidth (or be broadband). We discuss antenna bandwidth in more detail in Section 12.4.5, and as we examine the antenna designs that follow, we will identify which are inherently broadband and what modifications may extend operational bandwidth.