WIWIC

is an acronym for

Radio design principles for low-cost terminals and base stations of wideband wireless communications.

WIWIC is a research programme at The NTNU and sponsored by NFR . The research goals are:

Principal objective: To enhance microwave antennas and microwave solid state electronics suited for wideband radio access networks.

Sub-goals: Radiation from small antennas for low-cost terminals. Undesired RF exposure from terminals and consequences for radiation. To investigate the possibility for multiple antennas and (polarization) diversity for low-cost terminals. Study of critical microwave hardware, in particular oscillators and transmitter amplifiers. Power efficient designs, designs principles suited for modern semiconductor technologies.

Continue the cooperation between the radio group and Norwegian industry.

Award 3 dr.ing. degrees during the project and graduate 6 siv.ing per year.

Staff

The NTNU academic staff will typically share their time about equally between research and teaching. The academic staff members associated with WIWIC for their research activities are:

Professor Dr. Techn. Petter M Bakken - his research interests include satellite communications, wave propagation for satellite communications, satellite on-board processing principles and equipment for communication satellites, ocsillators and synthesizers

Associate Professor Kjell Aamo - his research effort is within the field of high-frequency circuits and systems, with emphasis on MMIC/HMIC circuit design and measurement techniques. Non-linear effects in large-signal amplifiers have recently been of special interest.

Associate Professor Jon Anders Aas - his principal interests include antenna analysis and design, including numerical solutions of electromagnetic radiation and scattering problems.

Siv. Ing. Morten Olavsbråten is currently completing his Dr.Ing. thesis, the defence is planned for April 2003.

Siv. ing. Mikael Hammer is currently completing his Dr. Ing. Thesis, planned for defence in spring 2003. The topic of his research work is integrated high frequency synthesizers based on multi-loop topologies. He is currently working at Bluechip Communication AS, Oslo, a RF CMOS design house. He continues his research activities in cooperation with WIWIC.

There are three Dr. Ing. students with fellowships from the WIWIC project. The duration of their fellowships is 4 years, their salaries for three of these years are paid by the WIWIC project while the last year is paid by NTNU.

Siv. Ing. Terje Mathiesen joined the project 1st of February 2001, and the planned completion is February 2005. The topic of his research work is design and linearization of high efficiency, microwave power amplifiers for use in wireless wideband communication. He is also busy with teaching assistance duties and as an assistant supervisor for project/diploma student.

Siv. Ing. Irene A. Jensen joined the project September 1st , 2001, with planned completion August 2005. The topic of her thesis will be antenna design adapted to production by plastic injection moulding and metallising. The topic is motivated by the need for low cost terminals, including antennas, for mass produced systems like LMDS (Local Multipoint Distribution System) and WLAN (Wireless Local Area Network). Reflector type antennas and smooth walled feed horns are of particular interest. Irene is also an assistant supervisor for project/diploma students.

Siv. Ing. Karl J. Sand began his Dr. Ing. training on the 6th of May 2002, with the completion of his degree planned for May 2006. The topic of his thesis work will be Semiconductor System Components for Wireless Wideband Communication. He is currently busy studying for additional exams and with teaching assistance duties. No direct thesis related work is expected until the second semester of 2003.

Dr. Ing. students associated with WIWIC. These students have no financial support from WIWIC, but the same topics and with supervision from the same teachers:

Djordje Kokotovic, MSEE, began his Dr. Ing. studies in January 2000, with the completion planned for mid-2004. The topic of his research is design and analysis of robust microwave and RF oscillators. The programme is funded by NERA AS, Oslo, and NTNU. Currently on a research sabbatical at TTPCom, United Kingdom, working on RFIC VCO design."

Activities

Antenna development at the WIWIC project:

Recent work on antennas may be summarized in five subtopics:

Slot array antennas
There has been an investigation of slot arrays in waveguide design. The reason for choosing an implementation in waveguide technology is that such feed networks have lower losses than corresponding feed networks in microstrip design. This is particularly important at high frequencies, e.g. in the 40 GHz band and above, where a number of new activities are coming. The activity has so far resulted in a project work and a M.Sc. thesis in which a 2 x 4 array module has been designed and successfully built. A low frequency of about 10 GHz was chosen for easy manufacturing and measurements.
Jan Terje Nymoen: Antenna module for LMDS, completed Nov., 2001
Jan Terje Nymoen: Antenna module for LMDS (Local Multipoint Distribution Service), completed June 2002
Two more actions are planned in the near future: A journal paper by J. A. Aas and J. T. Nymoen entitled "Design of center-inclined waveguide slot couplers for uniformly excited slot arrays" will be submitted in early 2003. An abstract for a similar paper will be submitted for the Antenn 03 (Nordic Antenna Symposium) to be held in May 2003.

Zonal reflectors
A zonal reflector may replace the conventional but bulky paraboloidal reflector when a flat reflector design is desired. The electromagnetic properties of zonal reflectors (pattern and frequency bandwidth) are, however, degraded by diffraction effects. An ongoing M.Sc. thesis work is studying these effects, both theoretically and experimentally. A 2-D reflector model has been chosen for simplicity.
Bjørn Anton Lybeck: Theoretical and practical investigation of 2-D zonal reflector antenna, to be completed in Jan. 2003

Smart reflectarrays
A reflectarray consisting of 2 4 dual polarized path elements, space-fed by a single patch element has been designed. The array elements receive in one polarization and transmit in the other. Each element is equipped with two ports connected by a microstrip line that determines the phase of the radiated signal. The demonstrator has been designed to give an antenna beam steered 20 degrees off broadside. This work has resulted in a student project.
Christian Sveli: 5.8 GHz reflectarray of dual polarized patch elements, completed Nov. 2002
This work is part of a cooperation where the ultimate goal is to include phase shifters and amplifiers in the in the microstrip lines, so the antenna beam may be steered electronically

Antennas for the Norwegian cubesat
Deployable VHF and UHF wire antennas (monopoles made from measuring tape) are being studied for applications on the Norwegian Student Satellite nCube. The antennas should be packed into one 10 x 10 cm2 face before launch, and deploy successfully after. Impedances and radiation patterns, taking the presence of the satellite into account, are studied with a commercial software. The work is reported in a student project.
Jan Otterstad: Antenna system for NCUBE, Nov. 2002

Cost effective antennas made from metallized plastics
A Dr.Ing. student Irene Jensen is pursuing this topic, see special summary.

Microwave circuit techniques within WIWIC.

Design of GaAs MMIC components for smart reflectarrays

Two MMIC chips - to be included in the beam control circuitry of a smart reflectarray - have been designed. These are a 3-bit phase shifter and a 2-stage amplifier. One of each will be included in the microstrip line connecting the two ports of orthogonal polarization exitation for each individual element in the array (ref. Antenna development). The phase shifter is able to set the relative phase of each antenna element with a resolution of 45 degrees, and the amplifier is included in the same microstrip line in order to increase signal-to-noise in receive mode, or to increase the radiated power - relative to the power available from the source patch - in transmit mode. Both circuits are designed for TriQuint Semiconductors TQTRx GaAs MESFET process. The chips will be received at NTNU in the end of March 2003 for test and evaluation.

The two works are reported in student projects:

Miriam Myhre Tunold: "Low Noise Amplifier for 5.8GHz in MMIC - based on TriQuint TQTRx process" - NTNU Dec 2002

Morten Engjom: "Design of an MMIC 3-bit Phase Shifter in GaAs MESFET Technology to be used in a Smart Antenne Demonstrator at 5.8GHz" - NTNU Dec 2002 A M.Sc. thesis to be submitted in June 2003 concentrates on the design of a voltage controlled amplifier which will replace the 2-stage amplifier in order to allow more beamforming flexibility.

DC/RF Efficiency in Power Amplifiers

This is a "hot" topic and has many aspects in wireless applications. A central goal in a number of modern systems is to maintain efficiency over a wide signal dynamic range, which is also the main focus in the present work. One technique - based on the Doherty method - has been investigated. The results so far have initiated a M.Sc. thesis work, with the main goal to design an MMIC Doherty amplifier ready for processing at TriQuint Semiconductor. The thesis will be finished in June 2003. Another thesis to be submitted in June 2003 is entitled "Improved Power Efficiency in Transmit Amplifiers by Dynamic Biasing" The work so far is reported in a student project:
Bjørn Waage Skogtrø: "Improved DC/RF Efficiency by the Doherty technique" - NTNU Dec 2002

A M.Sc. thesis - closely related to the previous work (but not originally within WIWIC) - was submitted in Dec 2002:
Ketil Johansen: "Dynamical Load Match in Mobil Transmitters" - NTNU Dec 2002

Parameter Extraction Methods for Transistor Modelling

This topic has been a main activity in the Radio group for some years and is now included as a part of our WIWIC program. An extensive piece of work has been executed on modelling both InGaP/GaAs and Si/Ge HBT transistors. The parameter extractions for the VBIC modell have been based on measurements made by the foundry GMMT-Caswell Technology and by own measurements within WIWIC. Thermal properties have been of great concern in the work. The results will be published in a Dr.ing.thesis, which will be defended by Morten Olavsbråten in April 2003.
Further work on this topic will start as soon as new instrumentation - an 8-slot Parametric Measurement Mainframe (Agilent E5270A) with Source/Monitor units together with the software IC-CAP - are in operation in March 2003.

Four M.Sc. thesis connected to WIWIC will be submitted in June 2003.

Laboratory equipment and software

The most important laboratory equipment and software aids for the WIWIC activity are:

A Microwave Laboratory equipped with - Agilent 8510C Automatic Network Analyzers covering the frequency range up to 50 GHz - Cascade Probe Station and Component Test Fixtures up to 60 GHz - Noise measurement facilities (including phase noise) up to 26 GHz

An Antenna Laboratory - Anechoic chamber (10x6x4m) for 1-20 GHz frequency range - Test instrumentation up to 20 GHz - Equipment for radar cross-section measurements and scattering studies

Three "mobile"automatic network analyzers covering the 0.3 MHz - 20 GHz frequency range

Five spectrum analyzers covering up to 50 GHz

Five synthesized sources covering up to 50 GHz

The whole range of Agilent EEsof software for circuit and system simulation, analysis and design. (ADS - Advanced Design System)

Electromagnetic simulations tools (HFSS and Momentum)

Parameter Extraction and Device Modelling Software (IC-CAP)

Relations:

Irene is a representative from Norway in COST 284 Innovative Antennas for Emerging Terrestrial & Space-based Applications.

EU, FP 6, WIWIC is represented in three Expressions of Interests, and intend to apply for participation in Networks of Excellence (NoE)

Nera and other Norwegian industries.

Member of a contract group or Norwegian companies and institutes active in space activities. The contract group is initiated and hosted by The Norwegian Space Centre.