High-power high-voltage dc power supply has been developed based on series resonant converter technology for a MW class RF amplifier. For low-voltage ripple, an IGBT inverter consisting of 1400 V-600 A devices is drives with a maximum switching frequency of 31.2 kHz. A performance test was carried out using an RF amplifier. We examined this power supply under two different conditions. One was w...

Introduction: Coupling between coil elements of a transmit array is one of the key challenges faced by designers of MRI transmitter arrays. To address this challenge, methods and systems have been developed to change the output impedance of the RF power amplifiers driving the array coils in order to suppress inter-element coupling effects. Chu [1], for example, proposed an output-matching netwo...

Gallium Nitride (GaN) amplifiers have demonstrated very high power density as well as wide band width in previous research. This paper examines their use in supplying flat gain, power, and linearity across a large band width. It demonstrates two types of power amplifiers: a Ft Doubler (FT2) amplifier and a Cascode amplifier, both of which require a simple PCB tune. Both amplifiers show 0.2 to 4...

The new generation mobile communication systems are very sensitive to the nonlinearities in their transmitting paths. The power amplifier is a key component which generates the nonlinear distortions. Power amplifier linearization techniques are very important to reduce the distortion of the transmitted signal and the adjacent band interference of users. As its facility of implementation, adapti...

An active-feedback frequency-compensation (AFFC) technique for low-power operational amplifiers is presented in this paper. With an active-feedback mechanism, a high-speed block separates the low-frequency high-gain path and high-frequency signal path such that high gain and wide bandwidth can be achieved simultaneously in the AFFC amplifier. The gain stage in the active-feedback network also r...