Millimeter-wave Systems and Technologies for Multi-gigabit Wireless Transmission Applications

Increasing the carrier frequency is one of the most promising solutions to deliver gigabit data rates in wireless communication systems. Applications like kiosk downloading or wireless high definition video transmission will certainly demand up to 10 Gbps in a few years. As these are highly consumer oriented applications, a low-cost implementation of the system is mandatory, which can be achieved by using planar structures with standard fabrication processes. This research focuses on exploring the relevant technologies for this next generation of millimeter-wave systems capable of multi-gigabit data rates.

In millimeter-waves, interconnections play a key role: they are needed in antenna characterization and connection and system integration. Therefore, current and new interconnection structures for millimeter-waves are investigated. In particular, an efficient D band waveguide to microstrip transition for antenna measurement or interconnection is developed. An electromagnetic theory explaining its coupling mechanism is also presented. For multi-gigabit applications, very broad bandwidth antennas are needed. A planar antipodal dipole antenna for 122 GHz which features such broad bandwidth is discussed. Moreover, it was designed to be relatively insensitive to fabrication innacuracies. A transmission line model for the antenna is also presented. Several other antenna structures with different radiation patterns for a variety of applications are also addressed.

It is clear from the power budget of a millimeter-wave system that moderate high gain antennas will be needed. Therefore, array structures for current "hot" applications are sketched. Focusing on a particular application, the high definition video transmission, the Quality of Service problem is addressed. This problem comes with the fact that the direct signal path might be temporarily blocked in a regular home environment. To overcome the problem, beamforming with a Rotman lens is proposed. Several antenna demonstrators for this application at 60 GHz were built. In order to correctly measure the antenna structures, a millimeter-wave antenna measurement setup was developed. It is highly flexible and delivers accurate and repeatable results. The system is useful for the measurement of antenna structures at D or V band.

Finally, a whole end-to-end millimeter-wave system is discussed by the construction of a full demonstrator for 60 GHz with Quality of Service. The front end consists of transmitter and receiver and is built using off the shelf components. It is fully configurable and adaptable for the utilization of different antennas and beamforming devices, which can be very useful for channel measurement operations.