Plenary session: Innovating openly in wireless

In this presentation, experiences in open innovation in wireless research are discussed from Nokia Research Center's 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.     

Active inductors for GaAs and bipolar technologies

Integrated high performance gallium arsenide and silicon active inductor configurations for microwave frequencies are examined in this article. The existing topologies are considered and a new aspect of comparing the performance of different topologies based on a more complete analysis is utilised. Drawbacks of GaAs technology in this particular case are recognised, while benefits attained by using bipolar technology are presented. A theoretical basis for designing bipolar inductors is examined. On the basis of these studies a new method for raising the Q-factor of an active inductor is found and applied to two novel GaAs Q-enhanced active inductors. New applications for active high-Q resonators are found and their realisation aspects are considered. Integrated test circuits have been designed, and the simulated and experimental results are presented.     

Millimetre Wave Signal Generation Using Monolithic HEMT Technologies

We have designed, processed and tested monolithic 40GHzfrequency doublers and amplifiers using enhancement and depletionHEMT processes. The passive parts included microstrip, coplanarwaveguide and lumped component circuits. The on-chip measuredoutput power of frequency doublers at 40GHz was +2dBm and the conversion loss was 2–;5 dB. The EHEMT doublersoperated at low input power level from a single DC supply andthe CPW passive parts enabled economical design. The integratedsystem of depletion PHEMT doubler and amplifier chips enclosedin hermetic packages delivered +10 dBm output powerat 38GHz frequency band. This is the first time that the applicationof enhancement mode HEMTs in frequency doublers is reported andcompared to the performance with depletion mode HEMTs. We haveproven that EHEMT and DHEMT frequency multiplier circuits areefficient solutions for local oscillator use in modern millimetrewave systems.     

Local Oscillator Generation Circuit for Direct Conversion Transmitter

In this paper a fully monolithic on-chip local oscillator signal generation circuit is presented for eliminating the negative effect of coupling between bond-wires, package pins and output and input lines of the power amplifier output to the local oscillator input for direct conversion transmitters. The proposed circuit generates the local oscillator signal at frequencies 1710–1785 GHz which is harmonically uncorrelated from two input signals at 464 MHz and 1792–2088 MHz. The required building blocks are a frequency divider, a mixer and an active band-pass filter. Fully monolithic high frequency band-pass filters have not been available until recently, and the designed circuit is in fact one of the first applications reported for MMIC active filters in cellular phones. The circuit is designed with a 0.5 m GaAs MESFET technology and the performance is verified with on-chip measurements.