How does a Yagi antenna work?

A Yagi antenna is a type of directional antenna that consists of a long element called a boom and several shorter elements arranged perpendicular to the boom. These elements are typically an active feed line (the dipole), one or more directors in front of the feed element, and a reflector behind the feed element. The Yagi antenna works on the principle of wave amplification, in which the dipole absorbs and radiates the signal. The directors help amplify the radiation of the signal in a particular direction while the reflector reflects the signal in the opposite direction, thus increasing the forward gain. This arrangement creates a directional pattern that allows the Yagi antenna to efficiently receive and transmit signals in a specific direction, making it particularly suitable for long-distance communications via amateur radio.