60 GHz Mixer and Multifunctional MMICs in GaAs pHEMT and mHEMT technologies

Licentiate thesis, 2006

In recent years, the 60 GHz band has gained increased academic and commercial interest mainly due to the relative large amount of license free and little used frequency spectrum located in vicinity of 60 GHz. The exact locations of these free frequency bands varies locally but the 59–62 GHz band overlap around the world and is therefore a true world wide license free band. Furthermore, most frequency allocation instances have allocated more than these 3 GHz of bandwidth, for example 59–64 GHz is allocated in the USA by FCC, 59–63 GHz and 65–66 GHz by ETSI in Europe, and 59–66 GHz in Japan by ARIB. These large bandwidths should be compared to the much more crowded licensee free ISM bands at 2.4 and 5 GHz which possess less than 400 MHz of overall bandwidth. The 60 GHz band has therefore been proposed as the frequency band to be used for very high speed (several Gbps) wireless data transmission. The objective of this work has been to design and characterize different 60 GHz mixers and multifunctional monolithic microwave integrated circuits (MMICs) in GaAs pHEMT and mHEMT technologies. The thesis starts with a description of parts of the outcome of the BRAWO project carried out during 2003 to 2005 within Chalmers Center for High-Speed Technology (CHACH) in cooperation with Ericsson AB. The system work and the design and measurements of the multifunctional 60 GHz transmitter and receiver MMICs done in this project are described. The second part in this thesis describes the design and measurement of different kinds of 60 GHz MMIC mixers. The emphasis has been on an image reject mixers (IRMs) and two kinds of mixer topologies for enhanced LO to RF isolation, namely the balanced resistive mixer (BRM) and the dual-quadrature mixer (DQM). Two of the IRMs were directly used in the two different 60 GHz multifunctional receiver MMICs. All of these mixer designs were based on resistive mixers as the mixing element which is the most common mixer element of today in millimeter wave HEMT based MMIC mixers. Furthermore, to explore the properties of an active mixer in the 60 GHz band, a 60 GHz double balanced Gilbert mixer (DBGM) with integrated RF, LO, and IF baluns was also designed and verified by measurements.