RF Amplifier Circuits

  

A linear amplifier is an electronic circuit whose output is proportional to its input, but capable of delivering more power into a load. The term usually refers to a type of radio-frequency (RF) power amplifier, some of which have output power measured in kilowatts, and are used in amateur radio. Other types of linear amplifier are used in audio and laboratory equipment. An RF linear amplifier can be based on either solid state or vacuum tube technology.

Most commercially manufactured one to two kilowatt linear amplifiers used in amateur radio still use vacuum tubes (valves) and can provide between 10 to 20 times RF power amplification. For example, a transmitter driving the input with 100 watts will be amplified to 2000 watts (2 kW) output to the antenna. Solid state linear amplifiers are more commonly in the 500 watt range and can be driven by as little as 25 watts. However, AM radio broadcast transmitters of up to 50 kW are now solid state.
 
Large vacuum valves are still used for international long, medium, and shortwave broadcast transmitters between 500 kW up to 2 MW. The basic applications of the RF power amplifier include driving to another high power source, driving a transmitting antenna, microwave heating, and exciting resonant cavity structures. Among these applications, driving transmitter antennas is most well known. The transmitter–receivers are used not only for voice and data communication but also for weather sensing (in the form of a RADAR).
 
Microwave or RF heating is an industrial application which is also benefiting our homes in the form of microwave ovens. Class-A operation is characterized by a constant DC collector (or drain) voltage and current. This class of operation is required for linear amplifiers with severe linearity requirements including: Drivers in SSB transmitters where a 2-tone 3rd-order intermodulation of at least -40 dB is required. Drivers in TV transmitters where the contribution to the gain compression must be very low, i.e. not more than a few tenths of a dB.
 
 

 

 

News

Wolfspeed Sponsors Free Access to RF Tutorials

Wolfspeed Sponsors Free Access to RF Tutorials Compound Semiconductor Wolfspeed, a maker of GaN-on-SiC HEMTs and monolithic microwave integrated circuits (MMICs) is sponsoring one year of free access to a multimedia...

Nov 16, 2016

RF coupling

RF coupling Hackaday Shortly after applying power to the amp , [B Arnold] started hearing things – faint, far-off voices, scratchy but discernible. ... We've heard of RF coupling of AM radio stations before, but...

Dec 5, 2016

Wolfspeed Sponsors Free Access To RF Tutorial Series

Wolfspeed Sponsors Free Access To RF Tutorial Series RF Globalnet (press release) In the more than 12 hours of circuit design video tutorials that accompany the textbook, Dr. Fornetti illustrates how to design, test,...

Nov 18, 2016

MaxLinear MxL277 Full-Spectrum Capture™ DOCSIS® 3.1 Cable Receiver & Amplifier Chipset Powers Hitron's ...

MaxLinear MxL277 Full-Spectrum Capture™ DOCSIS® 3.1 Cable Receiver & Amplifier Chipset Powers Hitron's ... Business Wire (press release) CARLSBAD, Calif.--(BUSINESS WIRE)--MaxLinear, Inc. (NYSE: MXL), a leading...

Dec 1, 2016

Rating Sentiment of The Day: MaxLinear, Inc. (NYSE:MXL) has analysts on the Bullish side this week.

MoneyMakingArticles Rating Sentiment of The Day: MaxLinear, Inc. (NYSE:MXL) has analysts on the Bullish side this week. MoneyMakingArticles The Firm offers semiconductor products, such as RF Receivers, RF Receiver...

Dec 5, 2016

Noteworthy Earnings: Analysis and MX Gold Corp (MXL) Earnings Review

MoneyMakingArticles Noteworthy Earnings: Analysis and MX Gold Corp (MXL) Earnings Review MoneyMakingArticles Wall Street await MX Gold Corp (CVE:MXL) to release earnings on December, 5. The stock decreased 3.57% or...

Dec 4, 2016

InventionShare™ Client Circuit Seed™ Releases IoT-IoE Industry Breakthrough with Ultra Low Noise Transimpedance ...

InventionShare™ Client Circuit Seed™ Releases IoT-IoE Industry Breakthrough with Ultra Low Noise Transimpedance ... Satellite PR News (press release) Mr. Waite said, “With Circuit Seed we have a team of highly-skilled,...

Nov 29, 2016

Testing the RF circuit for IoT success

Testing the RF circuit for IoT success Electronics Weekly Input (receivers) and output stages (transmitters) typically utilize an amplifier module to help increase the signal amplitude. With respect to this it makes...

Jun 22, 2016

Radio Frequency Front End Module Market

Radio Frequency Front End Module Market - Global Industry Analysis, Size, Share, Growth, Trends And Forecast 2016 ... RF Globalnet (press release) In a superheterodyne radio receiver, the circuit between antenna and mixer...

Nov 15, 2016

Understanding and designing differential filters for communications systems

EDN Europe (registration) (blog) Understanding and designing differential filters for communications systems EDN Europe (registration) (blog) They can provide higher linearity, immunity to common mode interference...

Nov 22, 2016