Petteri Alinikula

Design of Class E power amplifier with nonlinear parasitic output capacitance

The Class E amplifier exploits the output shunt capacitor for charge-storing during the operation cycle. The amplifier works even with a nonlinear output capacitor, but the required component values are different from the values resulting with the linear capacitor. In this paper the equations and component values are solved for the first time for a Class E amplifier having a nonlinear output capacitor with hyperabrupt junction voltage-capacitance characteristics. A hyperabrupt junction capacitor is present especially at the drain-to-bulk junction of practical MOS devices. The results of the analysis are presented in plots providing initial component values for MOS Class E power amplifier design. The procedure is validated with a design example of a single-stage 900 MHz MOS power amplifier operating from a 2-V supply voltage.

Optimum component values for a lossy Class E power amplifier

The Class E power amplifier offers a means to increase the battery efficiency in wireless terminals. The losses can be taken into account by solving the drain waveforms for a switch having a non-zero on resistance. In this paper a new analysis formulation is presented in which the input values (P/sub OUT/, V/sub DD/ and R/sub ON/) are combined into one parameter k. Then, the efficiency and optimum component values for a lossy Class E amplifier can be solved with relatively simple calculations. The analysis reveals that there is a maximum value for switch losses that can be accepted in order to operate in the Class E mode. The results of the analysis are presented in plots providing initial component values for practical Class E power amplifier design. The validation simulation results show excellent match with the calculated values.

Microwave Active Filters for Wireless Applications: Systems Approach

The trends in wireless telecommunication terminals speak in favor of adjustable miniature microwave filters. The most potential integrated high-frequency active filter topologies, the active inductors and the loss compensated passive resonators, can be designed to reach the low microwave region. The dynamic range requirements for the cellular phones have proven to be still too demanding for the reported circuits. However, the less demanding filtering specifications of some applications, e.g., the wireless LANs, might be fulfilled with microwave active filters.

Wireless for the Convergence Era

The handportable convergence devices, multimedia computers, are extremely complex embedded systems that need to have all functional blocks custom-made for mobility. The combination of miniaturization and functionality is unprecedented compared to other consumer products. This paper discusses the challenges that digital convergence is introducing to research in wireless systems and radio implementation. In the area of wireless systems, there are several competing standards in particular for wireless broadband. The modem, on the other hand, is evolving into a multiradio. For radio implementation, the invariant requirements for competitiveness call for continuous innovativeness. The main showstopper in terms of performance and functionality of a convergence device is the strictly limited power consumption.

Plenary session: Innovating openly in wireless

In this presentation, experiences in open innovation in wireless research are discussed from Nokia Research Centers perspective. The research agenda has been geared toward challenging new radio systems, disruptive device implementation aspects, and innovative usage of electromagnetic waves. Nokia Research Center has taken a systematic approach in promoting open innovation and in building a global open innovation network with strong university partners. The wireless industry is in transition from telecom toward convergence of mobility and the Internet. The next billion new Internet users will get to know the Internet through mobile devices. Simultaneously, the offering of consumer Internet services is exploding, driven by advertisement-based business models and Web 2.0 services.

RF Challenges for Tomorrow’s Wireless Terminals

Wireless telecommunications will enter a new era in the coming years. New systems and new customer needs are already introducing vast challenges, in particular for the implementation of the terminals. The RF section is a major contributor to the size and cost of the terminal. Consequently, the winning terminal implementations will be those with the best RF section.