Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. Multifunctional RF front ends need to transmit signals with varying peak-to-average ratios requiring high linearity which often implies low efficiency. This thesis studies high-efficien...

Introduction The need for highly efficient, linear microwave power amplifiers has grown rapidly, especially as mobile and satellite communication systems have been developed and expanded [1]. These systems employ multilevel digital modulation techniques to achieve higher-data-rate and multimedia services. This results in a band-limited multi-carrier signal, which is spectrally efficient but exh...

approved: Andreas Weisshaar In cellular telephones, RF power amplifiers consume a significant part of the total phone current. Reducing the average PA current will extend battery life. In GSM systems the handset is commanded by the base station to transmit at power levels lower than full power much of the time. A Doherty amplifier can be used to improve efficiency at these lower power levels, p...

Out-of-band noise (OBN) is troublesome in analog circuits that process the output of a noise-shaping audio DAC. It causes slewing in amplifiers and aliasing in sampling circuits like ADCs and class-D amplifiers. Non-linearity in these circuits also causes cross-modulation of the OBN into the audio band. These mechanisms lead to a higher noise level and more distortion in the audio band. OBN als...

The distortion produced by a typical solid-state Class-B power amplifier is shown to consist of eight mechanisms, all of which may coexist and whose distortion products overlap to give a complex result. Methods for isolating each mechanism for study, and minimising its contribution, are given. If the avoidable distortions are designed out, Class-B amplifiers of unusually low distortion (Below 0...

Series stacking of multiple devices in power amplifiers is a promising technique that has been explored recently at millimetre-wave frequencies to overcome some of the fundamental limitations of metal–oxide–semiconductor (CMOS) technology. Stacking multiple devices improve the output power and efficiency by increasing the achievable output voltage swing. Switching power amplifiers (PAs), such a...

In this paper, the research advances in silicon based millimeter wave and THz ICs in the State Key Laboratory of Millimeter Waves is reviewed, which consists of millimeter wave amplifiers, mixers, oscillators at Q, V and W and D band based on CMOS technology, and several research approaches of THz passive ICs including cavity and filter structures using SIW-like (Substrate Integrated Waveguide-...

This letter presents a new design method of a low-power transmitter for inductive link. The proposed method introduces the concept of class-F RF amplifiers into an inductive data link. The power dissipation of the class-F transmitter is analyzed for carrier and symbol transition. It is revealed that the proposed transmitter consumes extremely low power of less than 0.2 nJ/bit with BPSK modulati...

The stability margin of an audio power amplifier is reduced by a pole in the loopgain transfer function caused by shunt capacitance in the loudspeaker load. The problem is most severe in amplifiers with output stages that have a high output impedance before feedback. Because MOSFET devices can have an output impedance that is much higher than BJT devices, amplifiers with WFlT output stages are ...

Active filters play important role in communication systems. They can be obtained and constructed by different methods. Recently, there is a tendency of designing current-mode circuits using unity-gain active elements such as, CFOAs, CCIIs, etc. instead of classical infinite gain operational amplifiers in active filter design. This paper presents transresistance multifunction filter realization...