Microwave Engineering Europe - June 2008 - (Page 21)

60 GHZ WIRELESS 21 operate at a high sample rate of about 4 Gsamples/s at a resolution of 5 to 6 bit. Such characteristics are difﬁcult to realize in CMOS, especially with reasonable power consumption. This high sample rate is also challenging for the digital processing unit of the radio. Several good ultra-low-power ADCs were presented at ISSCC2008. A fourth problem with 60 GHz radios is the low signal to noise ratio (SNR). The reason for this is twofold: the high carrier frequency implies a low receive power; and, a high bandwidth (2 GHz for 60 GHz communication) contributes to a high noise level at the receiver side; hence, the system works at low SNR. To circumvent this phenomenon, beamforming techniques both at the receiver and transmitter sides are applied for 60 GHz communications. Intelligent beam forming is achieved by using multiple antenna paths combined with programmable phase shifters. For very demanding applications in terms of data rate, larger antenna arrays are needed. Another consideration is that beam forming is more important for plugged applications (e.g. wireless HDMI) than for nomadic applications (video kiosk) since in Figure 2: One application ﬁeld of 60 GHz wireless communication is the fast up and download of high-deﬁnition movies. the latter case, part of the problem can be solved by bringing the portable device closer to the video kiosk. And ﬁnally, the ﬁfth challenge with 60 GHz communications is that designers have to be aware of the fact that the standard will incorporate three physical (PHY) layers: one single-carrier modulation with frequency domain equalization (SC-FDE) and two OFDM variants. About the authors Els Parton received her engineering degree and PhD in Biological Sciences at the Katholieke Universiteit Leuven (K.U.Leuven), Belgium. She joined IMEC in 2001 as a scientiﬁc editor and is jointly responsible for authoring and editing the research organization’s numerous company technical documents and publications. She can be reached at Els.Parton@imec.be. André Bourdoux is principal scientist in the Wireless Research group of the Nomadic Embedded Systems Division of IMEC, Leuven. He currently coordinates the system level research on millimeter-wave communications, helping antenna specialists, analog designers and DSP specialists to align their research efforts. He is also involved in research activities in the areas of ﬂexible air interfaces for “4G” systems and cognitive radio. Reprinted courtesy of Wireless Net DesignLine Visit us at MTT-S Booth 1617 Leader in Discrete and Integrated RF Solutions Microwave Engineering ● June 2008 ● www.mwee.com http://www.skyworksinc.com http://www.skyworksinc.com http://www.mwee.com

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Microwave Engineering Europe - June 2008 Contents Comment News Cover Feature Designing and Simulating a Wireless LAN Antenna 60GHz: Achieving the Ultimate Wireless Dream New Radar Developments Include HFETs to Challenge DMOS/LDMOS and a 77-GHz CMOS PA for Automotive Applications Testing Raises Concerns Over 802.11-Based High-Speed Bluetooth IP2 & IP3 Design Considerations with Direct Conversion I/Q Demodulator Receiver Products Calendar

Microwave Engineering Europe - June 2008

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