SPIDER operation, started in 2018, pointed out performance-limiting issues caused by the technology employed RF generators, based on tetrode free-running oscillators. One of these limits, namely onset frequency instabilities, prevented operation at full rated power 200 kW. In addition, tetrodes require high voltage to operate, which translates risk flashovers and necessity perform conditioning ...

Target audience: This work is relevant to those interested in parallel transmit amplifiers. Purpose: Previous work has demonstrated the use of high efficiency switch mode power amplifier (SMPA) topologies for miniature on-coil amplifiers aimed at use in parallel transmit coil arrays. Though such amplifiers demonstrate very high efficiency and power density in isolation, there has not yet been a...

In a digital class D power amplifier, the distortion is introduced into the input signal being amplified in power stage, due to the effect of power supply noise. A method used to eliminate the distortion is presented in the paper. This method is adding correction factors to all integrators of Delta-Sigma modulator, and introducing power supply noise to the input of the class D power amplifier a...

In Class-D Power Amplifiers (CDPAs), the power supply noise can intermodulate with the input signal, manifesting into power-supply induced intermodulation distortion (PS-IMD) and due to the memory effects of the system, there exist asymmetries in the PS-IMDs. In this paper, a new behavioral modeling based on the Elman Wavelet Neural Network (EWNN) is proposed to study the nonlinear distortion o...

This paper presents a concept for a Continuous-Time Bandpass-Delta-Sigma Modulator (CT BPDSM) for class-S amplifiers. Class-S amplifiers are very efficient for signals with high dynamic range and are considered to be one possible replacement for conventional linear amplifiers in RF transmitters. A multi-feedback architecture with return-tozero (RZ) and half-return-to-zero (HRZ) pulses is chosen...

This paper shows how intermodulation distortion, IMD, sweet spots can be used as a practically meaningful technology to design highly linear microwave power amplifiers. It starts by reviewing the physical origins of these points of large signal to nonlinear distortion ratio, distinguishing the ones uniquely determined by the active device’s quiescent point – small-signal IMD sweet spots – from ...

An essential modification to a conventional four-stage pseudo-class AB amplifier results in a true class AB amplifier. As opposed to the conventional pseudoclass AB scheme, which uses a current mirror in the third stage, our work uses an adaptive biasing circuit in the third stage in order to drastically reduce quiescent current. The pseudo-class AB and new class AB amplifiers are designed in a...

This paper presents an analysis of a reconstruction filter in a switched mode power amplifier system. Doubly and singly terminated filters for current-mode class-S power amplifiers were analysed previously through analytical, numerical, and experimental approaches, and it was shown that only singly terminated filters can fulfil the requirements of current-mode switching amplifiers, owing to the...

Class-E power amplifiers have high efficiency, which makes them attractive in modern wireless mobile communication systems. There are several techniques and approaches developed solely to design the output load networks of such amplifiers to shape the RF power device’s output voltage and current for minimum power loss. However, little attention is brought to the design of the input matching net...

This work addresses the enormous efficiency and linearity potential of optimized AlGaN/GaN high-electron mobility transistors (HEMT) in conventional Doherty linear base-station amplifiers at 2.7 GHz. Supported by physical device simulation, the work further elaborates on the use of AlGaN/GaN HEMTs in high-speed current-switch-mode classD (CMCD)/class-S MMICs for data rates of up to 8 Gbit/s equ...