Title: Communications satellite
Content:   A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. As of 1 January 2021, there are 2,224 communications satellites in Earth orbit. Most communications satellites are in geostationary orbit 22,300 mi above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites use a wide range of radio and microwave frequencies. To avoid signal interference, international organizations have regulations for which frequency ranges or "bands" certain organizations are allowed to use. This allocation of bands minimizes the risk of signal interference.
Title: Radio
Content: Communication satellite – an artificial satellite used as a telecommunications relay to transmit data between widely separated points on Earth. These are used because the microwaves used for telecommunications travel by line of sight and so cannot propagate around the curve of the Earth., there were 2,224 communications satellites in Earth orbit.  Most are in geostationary orbit 22200 mi above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it.  In a satellite ground station a microwave transmitter and large satellite dish antenna transmit a microwave uplink beam to 
Title: Solar vehicle
Content:   Solar energy is often used to supply power for satellites and spacecraft operating in the inner solar system since it can supply energy for a long time without excess fuel mass. A Communications satellite contains multiple radio transmitters which operate continually during its life. It would be uneconomic to operate such a vehicle (which may be on-orbit for years) from primary batteries or fuel cells, and refuelling in orbit is not practical. Solar power is not generally used to adjust the satellite's position, however, and the useful life of a communications satellite will be limited by the on-board station-keeping fuel supply.
Title: Benefits of space exploration
Content:  Communications satellites are used for a variety of purposes including television, telephone, radio, internet and military applications. According to statistics, there were 2,666 active artificial satellites orbiting the Earth in 2020. Of these, 1,327 belonged to the US and 363 to China. Many of these satellites are in geostationary orbit 22236 mi above the equator, so that the satellite appears stationary at the same point in the sky. Communications satellites can also be in Medium Earth orbit (known as MEO satellites) with an Orbital altitude ranging from 2000 to 36000 km above Earth and low Earth orbit (known as LEO satellites) at 160 to 2,000 km above Earth. MEO and LEO orbits are closer to the surface of the Earth and therefore a larger number of satellites are required in such a constellation to provide continuous communications. Satellites are vital for providing communications to remote areas and ships.
Title: Radio
Content:  homes and vehicles on Earth, in satellite radio and TV systems. It uses a higher transmitter power than other communication satellites, to allow the signal to be received by consumers with a small unobtrusive antenna.  For example, satellite television uses downlink frequencies from 12.2 to 12.7 GHz in the ku band transmitted at 100 to 250 watts, which can be received by relatively small 43-80 cm satellite dishes mounted on the outside of buildings. This is radio communication between a spacecraft and an Earth-based ground station, or another spacecraft. Communication with spacecraft involves the longest transmission distances of any radio links, up to billions of kilometers for interplanetary spacecraft. In order to receive the weak signals from distant 
Title: Commercial use of space
Content:  Satellites can be used to broadcast Wi-Fi energy power from space to any place in the planet Earth.
Title: Radio receiver
Content:  limited by the visual horizon to 30–40 miles. Microwave links are used for private business data, wide area computer networks (WANs), and by telephone companies to transmit distance phone calls and television signals between cities. ; Satellite communications - Communication satellites are used for data transmission between widely separated points on Earth. Other satellites are used for search and rescue, remote sensing, weather reporting and scientific research. Radio communication with satellites and spacecraft can involve very long path lengths, from 35,786 km (22,236 mi) for geosynchronous satellites to billions of kilometers for interplanetary spacecraft. This and the limited power available to 
Title: Communications satellite
Content:  160 to 2,000 km above Earth. Communications satellites usually have one of three primary types of orbit, while other orbital classifications are used to further specify orbital details. MEO and LEO are non-geostationary orbit (NGSO). As satellites in MEO and LEO orbit the Earth faster, they do not remain visible in the sky to a fixed point on Earth continually like a geostationary satellite, but appear to a ground observer to cross the sky and "set" when they go behind the Earth beyond the visible horizon. Therefore, to provide continuous communications capability with these lower orbits requires a larger number of satellites, so that one of these satellites will always be visible in the sky for transmission of communication signals. However, due to their relatively small distance to the Earth their signals are stronger.
Title: Satellite
Content:  The power subsystem may consist of solar panels to convert solar energy into electrical power, regulation and distribution functions, and batteries that store power and supply the satellite when it passes into the Earth's shadow. Nuclear power sources (Radioisotope thermoelectric generator) have also been used in several successful satellite programs including the Nimbus program (1964–1978).
Title: Space segment
Content:  Geostationary earth orbit (GEO) supports businesses in satellite television and radio broadcasting, as well as data and mobile communications. The medium earth orbit (MEO) and low earth orbit (LEO) configurations can also be used for various applications. A communications satellite is composed of a communications payload (repeater and antenna) and supporting spacecraft bus (including solar arrays and batteries, attitude and orbit control systems, structure and thermal control system), and is placed in orbit by a launch vehicle. A successful satellite operator needs the right orbital slot or constellation, and satellites that deliver effective power and bandwidth to desirable regions and markets (i.e., those with growing demand for satellite services). Satellite radio now serves nearly 5 million subscribers, and satellite mobile telephone and data operators offer connectivity throughout the globe. Broadband mobile terminals now provide improved access to the Internet for a range of applications, including videoconferencing.

Question: what type of energy do satellites generally use to communicate with earth?
Answer: radio and microwave frequencies.
electromagnetic waves.