The volcanic ash affecting air travel to the UK could not dampen the mood of the ARMMS RF and Microwave Society’s April conference, which took place at Milton Hill House, Steventon, UK. Despite visitors from Switzerland, Ireland and the US being affected, attendance was up on the previous conference and technology came to the rescue when Austin Harney of Analog Devices gave his presentation titled, Fractional-N PLL based Frequency Sweep Generator for Automotive FMCW Radar, via an audio link from Limerick, Ireland.
His disembodied voice synched perfectly with his PowerPoint presentation which introduced some of the approaches to collision avoidance taken by automotive suppliers. He then focused specifically on FMCW Radar, and a compact and highly linear implementation of a FMCW sweep generator using Analog Devices’ ADF4158 PLL.
Other presenters appeared in person during the two-day conference to elaborate on a wide range of topics with particular focus on high millimetre waves. Opening the proceedings the ARMMS chairman, Roger Hopper of Roke Manor described the opportunities in the field and emphasised the necessity to share knowledge.
One particular hot topic was covered by Liam Devlin of Plextek Ltd whose paper titled, The Design of E-band MMIC Amplifiers, which addressed the fact that the worldwide availability of a large amount of spectrum at 71 to 76 GHz and 81 to 86 GHz (E-band) for high data-rate wireless links has led to substantial interest. The design of electronic equipment at such high frequencies is challenging. Devlin’s presentation addressed the design and implementation of E-band MMIC amplifiers. He considered process selection, design challenges and practical approaches and presented the measured and modelled performance of a single-stage E-band gain block.
At the other end of the scale was the presentation by John Lillington of Libra Design Associates Ltd – A 100kHz to 6GHz Fast Scanning Receiver for under £1,000 – his original design brief was to achieve a receiver capable of scanning a band from 100 kHz to 6 GHz in less than 1 second. With an instantaneous bandwidth of up to 20 MHz and a final IF to feed a digital receiver with around 100 Msps sample rate. A minimum signal sensitivity of -107 dBm and a dynamic range of at least 80 dB, presented many design challenges to overcome, especially within a budget of £1k production cost. His approach caught the audience’s imagination and prompted them to select his paper as the Best in Conference.
Academia was also well represented with Paul Tasker of the University of Cardiff presenting, I-V Waveform Measurement and Engineering Systems – addressing the High Power Amplifier Design Challenge, which gave an overview of the potential of RF waveform measurement and engineering to support the developments of transistors, circuits and systems that rely on strong non-linear affects. He stated that to date these concepts have mainly been focused towards aiding the development of RF power amplifiers (RFPAs).
Research carried out at the University of Glasgow is investigating Enhancement mode GaN-based MOS-HEMTs. Edward Wasige explained how they are developing a totally new method for fabricating enhancement mode GaN-based HEMTs using the conventional AlGaN/GaN material system.
Nural Osman of the University of Surrey addressed the issue that with more communication systems moving into the millimetre-wave frequency range there is a need for accurate data on circuit materials being used at these very high frequencies. In her paper titled, The Behaviour and Characterisation of Circuit Materials at High Millimetre-Wave Frequencies she discussed modern techniques for characterizing materials at high mm-wave frequencies, supported by practical measured data on typical materials.
Other papers included:
● A Brief Introduction to Glass Microwave Integrated Circuits (GMIC) aimed as an Enabling Technology for Millimetre-Wave Sensor Applications presented by David Sims of Cobham MAL
● Millimetre Wave Gunn Diode Technology and Applications by Nigel Priestley of e2v
● Ultra Wideband Time Domain Radar Systems by David Daniels of Cobham Technical Services
● Polymer Bonded LCP Device Housing enables Selective Thermal Management for RF Device Packages by Andy Longford of PandA Europe
● RF Architectural Tools for the Modern System Designer by Malcolm Edwards of Applied Wave Research UK Ltd
● A High Linearity FMCW Sweep Generator by Craig Winter of Cobham Technical Services
● Quartzlock Model A7MX Frequency/Phase Difference Comparator Measurement of Microwave Sources by Clive Green of Quartzlock
● The use of Higher Order Resonance Modes to shape the Radiation Pattern of Patch Antennas for use in Low Cost ISM Applications by Nigel Gaylard of Trimerix
● Time Domain Theory on a Network Analyser by Clive Barnett of Agilent
Alongside the conference a table-top exhibition provided a practical perspective to complement the academic. It featured equipment from a wide range of radio frequency and microwave companies including Agilent, Amplifier Research, Anritsu, APC Novacom, AWR, BSC Filters, Cobham, Cobham Microwave, Libra Design, MCS Microwave, Microwave Marketing, NGK, Optiprint, Quartzlock, Rohde & Schwarz, SJ Technologies and The Technology Academy.
As well as a vehicle for finding out about the latest technology and techniques the ARMMS Conference is also a social event, with a dinner on the first night offering delegates, presenters and exhibitors the opportunity to network, meet old friends and make new ones. Wide ranging discussions continued until late in the evening and were not strictly limited to technical topics. Finally, during the business meeting John Crute of The Technology Academy was elected as Chairman to follow Roger Hopper.