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

CMD240P4 MMIC Distributed Amplifier eliminates external RF port matching.

ThomasNet News (press release) (blog) CMD240P4 MMIC Distributed Amplifier eliminates external RF port matching. ThomasNet News (press release) (blog) Custom MMIC, a leading developer of performance driven...

Jan 12, 2017

Mitsubishi Electric Develops World's First Ultra-Wideband GaN Doherty Power Amplifier for Next Generation Wireless ...

Mitsubishi Electric Develops World's First Ultra-Wideband GaN Doherty Power Amplifier for Next Generation Wireless ... Yahoo Finance Technical details will be presented at the IEEE Topical Conference on RF /Microwave...

Jan 12, 2017

DC To 22 GHz Wideband GaAs MMIC Distributed Amplifier Exhibits Excellent Dynamic Range At Low Power

Electronics Weekly DC To 22 GHz Wideband GaAs MMIC Distributed Amplifier Exhibits Excellent Dynamic Range At Low Power RF Globalnet (press release) Custom MMIC, a leading developer of performance driven monolithic...

Jan 10, 2017

Carbonics Introduces First ZEBRA Carbon-on-Silicon Solution for RF Components in Rapidly Expanding Next ...

Carbonics Introduces First ZEBRA Carbon-on-Silicon Solution for RF Components in Rapidly Expanding Next ... Business Wire (press release) BUSINESS WIRE)--Carbonics, Inc. today launched its ZEBRA carbon-on-silicon...

Jan 11, 2017

Mitsubishi Electric develops first GaN Doherty power amplifier with 600MHz bandwidth above 3GHz

Mitsubishi Electric develops first GaN Doherty power amplifier with 600MHz bandwidth above 3GHz Semiconductor Today Details will be presented at the IEEE Topical Conference on RF /Microwave Power Amplifiers for...

Jan 12, 2017

Radio Frequency Front End Module Market

Radio Frequency Front End Module Market - Increase In Next-Generation Wireless Networks Drives Growth RF Globalnet (press release) In a superheterodyne radio receiver, the circuit between antenna and mixer is generally...

Dec 28, 2016

Interview with Kos Galatsis, Carbonics

socalTech.com Interview with Kos Galatsis, Carbonics socalTech.com In the startup world, one of the most difficult journeys to market is by companies who are taking basic scientific advances and technologies originally...

Jan 11, 2017

Seven from MIT are named 2017 IEEE Fellows

Seven from MIT are named 2017 IEEE Fellows MIT News ... waveguide amplifiers .” Currently, Juodawlkis' work includes developing photonic integrated circuit technology for application to optical communication, laser...

Jan 5, 2017

Testing the RF circuit for IoT success

Testing the RF circuit for IoT success Electronics Weekly The next step is to connect the amplifier between the generator output and the spectrum analyzer input. The following figures show the frequency-response curve...

Jun 22, 2016

Carbonics introduces first ZEBRA carbon-on-silicon solution

Carbonics introduces first ZEBRA carbon-on-silicon solution Printed Electronics World ... in step with Carbonics' mission to enable design engineers, foundries, integrated device manufacturers and advanced development...

Jan 13, 2017

Units & Modules