Abstract
The work of this thesis was part of the joint EPSRC project entitled "75-300GHz Multi-Chip Module (MCM) Technology", involving the Universities of Surrey, Kent and Glasgow. This joint research was to investigate novel mm-wave MCM technology using dielectric-filled rectangular waveguide as a transmission medium, and to investigate the feasibility of replacing signal propagation through conventional chip interconnects such as bond wires with an electromagnetic input/output signal coupling technique. A simple transmitter and a receiver are first demonstrated at 77 and 140GHz. This thesis covers the design and development of mixers and modulators using multilayer technology. The mixer is a very versatile microwave component and as wireless systems become more advanced, its use is not limited to just frequency up- or down-conversion in superheterodyne systems, but mixers are also used for complex digital modulation and demodulation in direct conversion transceivers. The design and development of inexpensive, low power consumption, physically small yet highly integrated multifunctional wireless system is one of the major challenges for researchers today. The use of large planar passive structures, restricted circuit configuration and high manufacturing cost are the major motivations for looking into new system architectures or circuit topologies or to adopt for high-density integration through novel interconnecting techniques, where these problems can be more easily addressed. One such avenue is multilayer technology. The first part of the research studies the feasibility of employing HIBRIDAS photoimageable thick-film materials for microwave applications. This has led to the characterisation of thin-film microstrip (TFMS) lines to 110GHz, with miniature hybrids demonstrated for the first time in MCM-C technology. A microstrip broadband coupler and an RF Marchand balun using overlaid configuration have achieved low-loss performance in the microwave range. This work is followed with the development of more sophisticated circuits that house high performance MMICs together with high-Q printed passive structures and readily available SMT components onto a common substrate. This includes a compact double-balanced resistive FET mixer as well as a resistive IQ vector modulator introduced for high linearity operations. 3D MMIC technology is the focus of the second part of this research on realising compact microwave subsystems. Again, a resistive FET mixer employing the balun that possesses direct matching and all-ports isolation capability through the use of multilayer configuration is developed. To assess the chip size reduction factor achievable with a multilayer approach, IQ direct carrier modulators of the reflection-type attenuator (RTA) topology and the diode-ring configuration are also investigated using a combination of miniaturisation techniques. These frequency conversion and modulation circuits use the Marconi-Caswell (now Bookham Technology) H40P foundry process enhanced to incorporate multiple metal and BCB dielectric layers.