The widespread use of isolators and circulators, and their advantages, are well known. However, during the rapid expansion of wireless systems, the development of automotive radars and the move up the electromagnetic spectrum towards terahertz systems, comparatively little attention has been given to the integration of isolators and circulators. The lecture will describe new solutions and miniature components and discuss novel approaches, choices of materials and technologies. Recent theoretical developments, experimental results and design trade-offs will be discussed including cost, size and bandwidth. For example: advances in low-temperature co-fired ceramic (LTCC) technology may enable the realization of 900 MHz lumped-element circulators with a volume of a few cubic millimeters. Also, advances in self-biasing ferrites may eliminate the need for external magnets thus providing size and cost benefits for planar integrated circulators up to and beyond 77GHz. At millimetric and sub-millimetric wavelengths it may be possible to replace ferrite parts with semiconductor parts, which in principle would offer a route to full on-chip integration of circulators. The lecture will focus on wireless and automotive applications, but will discuss a broader range of novel developments should these be appropriate to the audience interest. The lecture will be constantly up-dated to keep abreast of the continuing advancements being made in this field.

Lionel Davis is Professor Emeritus at UMIST. He obtained the BSc(Eng) degree from the University of Nottingham, and the PhD and DSc(Eng) degrees from University College London. He joined Mullard (now Philips) Research Laboratories (1959-1964)and then Rice University, Houston, Texas (1964-1972). Returning to the UK, he joined Paisley College, Scotland (1972-1987) where he was Professor and Head of the Department of Electrical and Electronic Engineering. He was also Dean of Engineering for five years. He was appointed Professor of Communication Engineering in the Department of Electrical Engineering and Electronics at UMIST in 1987, and was Head of Department from January 1993 - December 1995. His research interests are broadly in the area of electromagnetics, microwave and millimetre-wave components and materials. His teaching interests (undergraduate and postgraduate) are in the areas of transmission lines, electromagnetic waves, microwave engineering and microwave materials, and he has also taught circuit theory and electromechanical energy conversion at undergraduate levels. He has been a visiting professor at University College London, the University of California San Diego and, more recently, the University of Houston, Texas.

Professor Davis has recently been elected as a Distinguished Microwave Lecturer by the (USA) IEEE Microwave Theory and Techniques Society for the period 2003-2005.