In this paper, the operation of a parallel resonant converter with a capacitive output filter that exploits the parasitic components of its transformer is described briefly. Measurements from a high power DC pulsed generator with Si IGBTs are obtained. Finally, the experimentally calculated losses of the Si IGBTs are compared with SiC MOSFETs' losses using simulations of the system. © 2021 EPE Association.

Current radio frequency power amplifiers in 3G base stations have very high power consumption leading to a hefty cost and negative environmental impact. In this paper, we propose a potential architecture design for future wireless base station. Issues associated with components of the architecture are investigated. The all-digital transmitter architecture uses a combination of envelope elimination and restoration (EER) and pulse width modulation (PWM)/pulse position modulation (PPM) modulation. The performance of this architecture is predicted from the measured output power and efficiency curves of a GaN amplifier. 57% efficiency is obtained for an OFDM signal limited to 8 dB peak to average power ratio. The PWM/PPM drive signal is generated using the improved Cartesian sigma delta techniques. It is shown that an RF oversampling by a factor of four meets the WLAN spectral mask, and WCDMA specification is met by an RF oversampling of sixteen.

Current radio frequency power amplifiers (PAs) in 3G base stations have very high power consumption leading to a hefty cost and negative environmental impact. In this paper, we propose a potential architecture design for future wireless base station. Issues associated with components of the architecture are investigated. A comparison of PA with pulse width modulation drive and PA with envelope elimination and restoration (EER) drive is offered. EER-driven PA promises high efficiency over a wide dynamic range but has bandwidth expansion problems. A novel approach which reduces bandwidth expansion on the envelope by 54% is proposed. A modulator is used to convert amplitude and phase information into the edges of a pulse train. The modulator also eradicates some analog components present in traditional base station design.

In this paper three transmitter architectures are compared, that each use the low-frequency envelope and high-frequency phase component of an RF signal. A power amplifier (PA) with Pulse Width Modulation by Variable Gate Bias (PWMVGB) is compared to an Envelope Elimination and Restoration (EER) and Envelope Tracking (ET) configuration. The test circuit is implemented using a discrete GaN HEMT power amplifier and discrete surface-mount passive components assembled on a PCB. Measurements show that the EER architecture maintains a drain efficiency of 56 to 69% for a wide output power range, while the PA with variable gate bias shows a significant drop in efficiency for lower output powers (from 59 to 6%). Other comparison issues are modulation of the supply voltage and transmitter complexity.

A power amplifier (PA) with variable gate bias is compared to an Envelope Elimination and Restoration (EER) configuration. Each use the lowfrequency envelope and high-frequency phase component of the signal. The test circuit is implemented using a discrete GaN HEMT power device. Measurements show that the EER architecture maintains a relatively high drain efficiency for a wide output power range, while the PA with variable gate bias shows a significant drop in efficiency for lower output powers.

Two class-D RF power amplifiers consisting of CMOS inverter chains have been designed and measured. The first amplifier operates at 1GHz and has a maximum output power of 12dBm, whereas the second operates at 1.5GHz and outputs a maximum of 6dBm. The amplifiers have been characterized for use in two different polar transmitter architectures, Pulse Width Modulation by Variable Gate Bias (PWMVGB) and Envelope Elimination and Restoration (EER). Using a standard 130nm digital CMOS process and off-chip passive components, maximum drain efficiencies of 32% and 39%, respectively, are achieved. The two amplifiers are compared with respect to output power and drain efficiency, including a qualitative analysis of losses. Moreover, their use in the two polar transmitter architectures is discussed.

This paper describes the design, simulation and measurement of a GaN power amplifier suitable for envelope and phase signal combination. The low-frequency envelope signal is used to vary the gate (bias) voltage of the device, resulting in a pulse width modulated drain voltage, while modulation of supply voltage or current is avoided. The test circuit is implemented using a discrete GaN HEMT power amplifier and discrete surface-mount passive components assembled on a PCB. Measurements showed a maximum drain efficiency of 59% at 360 MHz, at an output power of 29 dBm. The output power as a function of the gate bias voltage varied between 3 and 29 dBm, with the drain efficiency varying between 6 and 59%.