Power Efficient RF/mm-wave Oscillators and Power Amplifiers for Wireless Applications

Design of a power-electronic-assisted OLTC for grid voltage regulation

High penetration of distributed generation (DG) has led to frequent voltage fluctuations in the distribution network. This paper describes the design of a partially rated, power-electronic-assisted onload tap-changing (OLTC) autotransformer. Positive and negative compensation of the grid voltage can be achieved on feeders that have high...

Energy Efficient and Compact RF High-Power Amplifiers

The main objectives of this thesis are to improve the energy efficiency and physical form-factor of high-power amplifiers in base station applications. As such, the focus of this dissertation is placed on the outphasing amplifier concept, which can offer high-efficiency, good linearity and excellent opportunities for system integration. With...

All-Digital I/Q RF-DAC

Due to the severe cost pressure of consumer electronics, a migration to an advanced nanoscale CMOS processes, which is primarily developed for fast and low-power digital circuits operating at low supply voltages, is necessary, but it forces wireless RF transceivers to exploit more and more digital circuitry. These basic CMOS properties tend to...

A Wideband 2x13-bit All-Digital I/Q RF-DAC

This paper presents a wideband 2 13-bit in-phase/quadrature-phase (I/Q) RF digital-to-analog converter-based all-digital modulator realized in 65-nm CMOS. The isolation between I and Q paths is guaranteed employing 25% duty-cycle differential quadrature clocks. With a 1.3-V supply and an on-chip power combiner, the digital I/Q transmitter...

An Investigation of 800kHz Flyback

A 800kHz flyback with input voltage 350V and output 20V, 150W is designed in this thesis. The goal of the investigation is to reveal the problems during the designing process when flyback converter goes to high frequency. Because of the fact that boundary conduction mode (BCM) operation exhibits the lowest possible switching losses, the...

Experimental and theoretical analysis of vacuum circuit breaker prestrike effect on a transformer

The work presented in this paper deals with the investigation of circuit breaker prestrike effect that occurs during energizing a distribution transformer. An experimental test setup that consists of a supply transformer, a vacuum circuit breaker (VCB), a cable and a test transformer is built, and the prestrikes in the VCB are recorded. The test...