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What are the different types of class A power amplifiers available? 

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With its separated baseband - which by theory is free of distortion - this concept enables the design of ultra-linear class-D power amplifiers.
Continuous class-F power amplifiers with resistive second-harmonic impedance is for the first time analyzed and employed in a multi-sub-band mode to enhance the bandwidth of a conventional continuous class-F PA.
This paper describes a highly efficient class-E power amplifier.
Highvoltage, high-power class-D amplifiers [2]-[5] are ideal drivers for such loads, because of their high power efficiency.
The amplifier is a complementary class-E tuned power amplifier because of both P-type and N-type transistors are employed to achieve a highly symmetrical topology, thereby reducing the significant distortion in the output signal of the conventional single-ended class-E power amplifier.
These high-efficiency, high-power amplifiers are well suited for telecommunication satellite transponders.
The proposed method can be used in the design of many other types of amplifiers.
To the authors' knowledge, this is the highest power added efficiency for class-E amplifiers at Ka-band reported up to date.
The validity and feasibility of the new modified class E power amplifier are proved by a simulation and an experiment circuits.
Furthermore, the design equations highlight several important practical constraints, which help develop effective designs for improving the performance of practical Class E amplifiers.
Class-E power amplifiers [1]–[6] achieve significantly higher efficiency than for conventional Class-B or -C. Class E operates the transistor as an on/off switch and shapes the voltage and current waveforms to prevent simultaneous high voltage and high current in the transistor; that minimizes the power dissipation, especially during the switching transitions.
It is a promising candidate to design broadband and high-efficiency power amplifiers.
Compared with the classical class-E power amplifier, the presented class-E power amplifier with shunt filter has a higher achievable maximum frequency and requires less quality factor of the filter.
Furthermore, the method can also be applied for power amplifiers that do not fulfill the class E switching conditions.
Open accessProceedings ArticleDOI
Mustafa Acar, Anne-Johan Annema, Bram Nauta 
10 Dec 2006
33 Citations
The presented design equations for Class-EVS power amplifiers give more degrees of freedom in the design and optimization of switching RF power amplifiers.
This paper proposes a novel and easily-implemented method for Class-J power amplifiers.
It is valuable to the design of Class E amplifiers by offering designers insight into circuit behavior.
This method is applicable to analyse Class E power amplifiers with any circuit configuration and parameters at any switching-on duty cycle, and does also take into account the switching transistor ON resistance.
According to the authors' knowledge, this study represents the first systematic approach to design class-E power amplifiers at UHF using devices with larger COUT by taking into account the use of arbitrary finite-feed class-E topologies.

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