A patch antenna is a popular type of microstrip antenna that is also known as a flat panel antenna. It derives its name from the fact that it is formed by suspending a single metal patch over another larger metallic plate with a dielectric sheet in between the two pieces. Some patch antennas use dielectric spacers between the two plates instead of a continuous sheet in order to achieve better bandwidth. There are several different types of microstrip or printed antennas, but the most common type is the patch antenna. The increased production and use of portable electronic equipment has increased the need for a reliable and compact antenna. Patch-type microstrip antennas have met this need, and are now built-in to cellular phones, palm electronic devices, and GPS receivers, as well as laptop computers and wireless local area network (LAN) equipment.
A patch antenna assembly is commonly enclosed in a protective white or black plastic case, called a radome, in order to shield the antenna from inclement weather and make it easier to mount. Patch antennas are thin, lightweight, and relatively simple to construct, modify or customize. These antennas are commonly fabricated into rectangular, square, elliptical, or circular shapes. In view of the fact that they will easily blend into almost any background, patch antennas are often hung on interior ceilings and walls.
Since patch antennas are durable and can be designed to conform to nearly any shape, they are frequently mounted to the outside of not only aircraft, but spacecraft as well. This type of directional antenna is also suitable for small single-floor office buildings, stores, and many other indoor locations where a central access point is not available. A patch antenna can also used as an external antenna to increase the signal reception and transmission of wireless devices such as cellular telephones and Global Positioning Systems (GPS).
Although antennas can be found in a wide variety of shapes, sizes, and types, they all operate in the same basic manner. An antenna is used either to receive electromagnetic waves and convert them into electrical currents, or to convert electrical currents into electromagnetic waves, and transmit them. Typically constructed of some type of metal, antenna configurations can range from the simple wire-like whips found on many automobiles, to the large dish-like reflectors used to receive satellite signals from outer space. Antennas are vital components of television, radio, and radar systems, as well as all types of wireless communication devices.