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

These 3 Chip Companies Do a Ton of Apple Business: Are They in Trouble?

24/7 Wall St. These 3 Chip Companies Do a Ton of Apple Business: Are They in Trouble? 24/7 Wall St. It offers audio products, including codecs, analog-to-digital converters, digital-to-analog converters, active noise...

Apr 28, 2016

Reinventing Bill Doherty and His High-Efficiency Amplifier

Reinventing Bill Doherty and His High-Efficiency Amplifier Radio World Regardless, Doherty's new linear amplifier concept aroused a lot of interest in the broadcast engineering community, as he claimed that it...

Apr 25, 2016

Quantum filter integrates 20000 Josephson junctions

physicsworld.com Quantum filter integrates 20000 Josephson junctions physicsworld.com ... gaps, as well as uncertainties in estimating the electrical properties of the superconducting thin film. "Accurate...

Apr 26, 2016

GaN microwave transistor rated for 30W & 28V

EDN Europe (registration) (blog) GaN microwave transistor rated for 30W & 28V EDN Europe (registration) (blog) As such, the CGH80030D is ideal for use in a diverse range of applications, including: UHF-, L-, S-,...

Apr 29, 2016

II-VI's (IIVI) CEO Francis Kramer on Q3 2016 Results

II-VI's (IIVI) CEO Francis Kramer on Q3 2016 Results - Earnings Call Transcript Seeking Alpha Their broad product portfolio and the growing end markets that they address are RF wireless, optical and data...

Apr 26, 2016

Supporting the 5G Network

Supporting the 5G Network ECNmag.com The challenges in the integrated circuits and system design include the nonlinear distortion of power amplifiers , phase noise, IQ imbalance, highly directional antenna design, etc....

Apr 27, 2016

Valley National Advisers Inc buys $509419 stake in Analog Devices (ADI)

Valley National Advisers Inc buys $509419 stake in Analog Devices (ADI) Market Digest Analog Devices Inc. is engaged in the design manufacture and marketing of high-performance analog mixed-signal and digital signal...

Apr 29, 2016

MaxLinear, Inc (NYSE:MXL) Updated Price Targets

MaxLinear, Inc (NYSE:MXL) Updated Price Targets FTSE News ... metro and long-haul transport network applications. The Company offers semiconductor products, such as RF Receivers, RF Receiver systems-on-chip (SoCs),...

Apr 28, 2016

Comtech Awarded $12 Mln Contract by Major Telecom Equipment Manufacturer; Shares Up 5% (NASDAQ:CMTL)

Comtech Awarded $12 Mln Contract by Major Telecom Equipment Manufacturer; Shares Up 5% (NASDAQ:CMTL) Sonoran Weekly Review The company operates in three segments: Telecommunications Transmission, RF Microwave Amplifiers...

Apr 27, 2016

Analytical Report: M/A-Com Technology Solutions Holdings, Inc (MTSI)

Analytical Report: M/A-Com Technology Solutions Holdings, Inc (MTSI) CWRU Observer M/A-COM Technology Solutions Holdings, Inc., together with its subsidiaries, designs, develops, manufactures, and markets analog RF ,...

Apr 26, 2016