A wireless semiconductor, such as a diode, transistor, or integrated circuit, is an electronic component that makes wireless communications possible. Diodes may work as one-way valves or as emitters of specific wavelengths of light, such as those used in optical wireless communications. Transistors are current-controlled devices that may generate, process, or reshape signals. Integrated circuits are compact functional circuits in small packages usually less than 1 square inch in size with three up to a few dozen connector pins.
Wireless communications may be digital, analog, sonic, ultrasonic, radio, or optical. Sound navigation and ranging (SONAR) is used in submarines to measure distance to targets using wireless semiconductor technology by alternately transmitting, waiting, and measuring any received bounced sound waves. Radio frequencies (RFs) are emissions that are 50,000 cycles per second (cps) or more. RF emissions include electromagnetic (EM) components that are used in all forms for personal, commercial, and military communications.
In general, wireless technology has more advantages than wired technology. Wireless personal communications is very popular because of widespread support infrastructure and convenience due to unrestrained mobility. Low-power wireless semiconductor products are the choice for portable devices powered with batteries. Although there are many wired communications standards that support modern wireless communications, most communications subscribers rely on wireless communications.
Wireless RF communications makes up the majority of wireless communications. The basic concept is an RF transmitter and an RF receiver, and both need an antenna or a device that sends or receives EM waves. Some of the antennas used may be inside the units so they are hidden from view. The broadcast RF transmitters send signal via antenna systems in high towers. Television broadcast transmitter sites, for example, have an antenna array on a high tower to maintain line-of-sight (LOS) to as many receiver antennas as possible.
Besides broadcasting, RF transmitters may also be used for all types of communications. Two-way radios allow people to keep in touch via push-to-talk RF transmissions. These radios are able to work even with no infrastructure. Cellular phones use wireless communications with total dependence on cell sites and their supporting sites.
There are health standards that ensure the safety of people that may be exposed to wireless emissions from wireless semiconductor circuits and other active devices. Mobile phone systems are designed so that RF power emissions will not pose any danger to personal health. Personnel who work with RF emissions are aware of safety practices, such as keeping away from transmitter antennas.