Microwave Engineering June 1999 Cover story This month's cover shows the steps Ericsson has taken towards components for the Bluetooth wireless data standard. World's without wires The next step in the wireless world is set to appear in real products later this year as interest in Bluetooth grows - see this issue's In focus . Bluetooth, the 2.5GHz wireless data standard proposed by Ericsson and now shared with anyone who signs up to the special interest group, promises 1Mbit/s data transfer across distances of a few metres, without the line of sight issues that affect IRDA infrared ports. In fact, the use of those infrared ports is really pretty limited precisely because of the need for line-of-sight to be maintained. In a recent straw poll of fellow technical journalist, all with their laptops and mobile phones ready for action, not one of them admitted to having used the infrared ports that were invariably fitted to their machines. Bluetooth must do better if it is to justify the greater cost of fitting the circuits into portable devices. That certainly looks like a strong possibility, given the ease of use which makes the connection simpler than a wire link from laptop computer to cell phone and even the possibility of a wireless docking station for a laptop, wireless other than the need for power! The demand projections look very interesting with the possibility of winning a design slot in every computer, mobile phone and a whole host of other portable electronic devices. The companies involved, many of them household names like Intel, IBM, Nokia and Ericsson, certainly seem confident. Timing will be important too, and it further confirms our industry's reliance on consumer products when you consider a time scale for implementation that leads up to mass production just in time for Christmas! Time for simulation We take a further look this month at the need for time domain simulation to be based on transistor models that work well for radio frequency devices. Joe Barnard's paper, Prediction of waveform in fast microwave and optoelectronic circuits , uses models derived from S-parameter data and applies them in a time domain simulation of non-linear waveforms. Those waveforms can be externally defined to make sure that they are appropriate to modern communications systems, including high data rate optical systems, with bit rates between 40 and 160GHz. The examples that have been run through the simulator certainly go well beyond simple MMIC amplifiers and include a GaAs IC with more than 20 six-port travelling-wave feed structures, 70 Schottky barrier diodes and 70 FETs. It's an interesting piece of work and we look forward to seeing more papers on this important aspect of RF and microwave circuit design. Paul Jackson

Contents In focus 3G road map spelled out at Workshops; Ericsson takes steps to Bluetooth hardware Focus on Antenna technology Adaptive arrays reap COST benefits; Components line up for BS antennas; Antennas find position for radio monitoring; Scanner measures ship-borne radars in-situ; Horns extend frequency range for test. Prediction of waveform in fast microwave and optoelectronic circuits The use of popular transistor models from the frequency domain when a simulation is required in the time domain presents a challenge. Joseph Barnard and Michael Taylor of Barnard Microsystems describe the development of a time domain simulator that can make use of S-parameter data. Designing in-line divider/combiner networks In this paper, Samir Tozin of Anaren Microwave Inc, presents an approach to designing in-line networks, focusing on the design of a three way system. Dehydration of waveguides: economical solutions for radio link systems Wolfgang Kohnen and Thomas Horn of Radio Frequency Systems, investigates in this paper, the relationship between temperature, pressure and related humidity inside open and closed waveguide systems. Sommaire d' articles Zusammenfassung der Artikel New Products and Data Calendar Classified Catalogue Update & Appointments