Microwave Engineering Europe - March 2008 - (Page 21)

BENEFITS OF BeO 21 Figure 2: BeO can be formed into a wide variety of shapes to accommodate many applications. so BeO/metal ﬁlms provide an effective solution for RF power packages. In fact, over the temperature range at which RF power transistors operate, BeO also offers about 30 percent better thermal dissipation properties than AlN, and at temperatures lower than ambient (or even cryogenic conditions), BeO is superior to all other ceramics. Heat dissipation The longevity of semiconductor devices is directly related to its ability (and that of its package and surroundings) to rapidly remove heat. For example, studies have shown that most failures in base station transmitters are caused by issues of thermal management. At the device level, the heat-dissipating abilities of the transistor package play a key role in how fast the device will degrade. For this reason, BeO has long been used in RF power devices because its exceptional insulating properties rapidly move heat away from the device. Other parameters relevant to RF and microwave design include dielectric constant and dissipation factor, and BeO provides advantages in these areas as well. In the transmission lines and passive structures that are fundamental elements of RF and microwave circuits, lower dielectric constants are generally preferred because losses are lower and conductors can be wide. The result is a circuit that can be more easily produced. In microstrip circuits, the cut-off frequency of a substrate of a given thickness increases as dielectric constant decreases. The low dielectric constant of a BeO substrate makes it usable at frequencies about 20 percent higher than alumina substrates. Thick-ﬁlm, lithographicallyetched, gold-metalized substrates manufactured on BeO exhibit these important characteristics and can operate at frequencies higher than 44 GHz. Comprehensive Electromagnetic Solutions FEKO EMC Antenna Placement Antenna Design • MLFMM Microstrip Antennas • FEM/MoM • UTD • PO • GO Dielectric Bodies RF & Microwave 3D EM SIMULATION SOFTWARE for real life problems, with FREE 45 days evaluation Microwave Engineering ● March 2008 ● www.mwee.com 020_021_022_MWEE.indd 21 21/02/08 11:12:37 w w w. f e k o . i n f o http://www.feko.info http://www.feko.info http://feko.info http://www.mwee.com

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Microwave Engineering Europe - March 2008 News Contents Comment Wireless Infrastructure: A Direct Conversion I/Q Demodulatordrives Favorable Basestation Cost-performance Metrics Wireless Infrastructure: Mobile World Set to Reshape the Internet RF Amplifiers: Latest Advances in RF Amplifiers Include a CMOS PA Operating at 77 GHz and Significant Advances in PAs for WiMAX and Broadband Applications Many Applications Still Require Unique Performance Benefits of BeO ACE Automated Circuit Extraction Returns to Real Design by Exploring Design Alternatives and Changes in Seconds Exceeding the Standard for Wireless Sensor Networks Products Calendar

Microwave Engineering Europe - March 2008

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