10.1 Introduction

This chapter describes the technology choices and circuit topologies associated with monolithic integrated antennas. MMICs are well known for their applications in transmit/receive modules, although in recent years, there has been a great deal of research undertaken to extend the level of integration to include the antenna subsystem. This area is a difficult one for traditional MMIC designers who are largely unfamiliar with antenna techniques, and vice versa. Fortunately, there is synergy between classical MMIC and antenna technologies, although relatively few engineers have a thorough appreciation of both disciplines. It is hoped that this chapter will go some of the way towards bringing the two technologies together.

Recent trends in mobile wireless communications systems indicate the need for unrestricted mobility associated with improved bandwidth availability. This has led to developments in mobile broadband systems technology [1]. For example, business communications in a wireless office, where the potentially high data rates available through broadband wireless could lead to systems that could improve video conferencing quality [2]. Present indicators show that integration of millimetre-wave technology, using MMIC techniques, can be made economically viable [3 5], although assembly and integration of the MMIC components with the antenna appear to be largely unresolved issues at present. Frequencies into the terahertz range are also under consideration for use in remote sensing, radio astronomy, radar and covert communications [6]. Much has been written about how MMIC integration of front-ends, minus the antenna, can be achieved and multifunctional and hybrid realisations have been...