Microwave Engineering Europe - June 2008 - (Page 22)

22 RADAR TECHNOLOGY New radar developments include HFETs to challenge DMOS/LDMOS and a 77-GHz CMOS PA for automotive applications Edited by Jean-Pierre Joosting Innovative FET RF PA topology beneﬁts radar, avionics applications The HVVFET (high-voltage vertical ﬁeld effect transistor) from relative newcomer HVVi Semiconductors is a family of silicon power transistors targeted at L-band avionics and pulsed-radar applications such as IFF, TCAS, TACAN, Mode-S and ground-based radar systems. The company claims that their innovative FET design is the next generation after designs based on DMOS and LDMOS lateral structures, with a vertical structure which allows heat to be extracted from the hottest spot of the device and ﬂow directly to the heatsink In turn, this allows the single-supply, 24 to 48-V power ampliﬁers (PA) to offer twice the power density of competitive devices along with a 30 percent efﬁciency improvement, operating ruggedness with 20:1 VSWR load mismatch (twice that of comparable devices), and 3 dB more gain than available devices. The greater efﬁciency also yields a much smaller footprint, or the ability to use a single device in place of multiple ampliﬁer stages. The VSWR tolerance reduces or eliminates the need, and thus the cost and board space, for isolators and circulators common in these applications, while the 48-V operation supports reduced current and thus higher-efﬁciency, higher-reliability operation. The initial offering from HVVI includes three devices: • In an industry-standard ﬂanged package, the HVV1011-300, for pulsed applications covers the L-band from 1030 to 1090 MHz. It provides over 300 W of pulsed output power with 15 dB gain and 48 percent typical efﬁciency, at pulse widths of 50 µs and pulse period of 1 ms. • The surface-mount HVV1214-25 for pulsed radar over the 1.2 to 1.4 GHz L-band delivers 25 W output with typical gain of 17.5 dB with 200 µs pulse width and 10 percent duty cycle. • The ﬂanged HVV1214-100 offers 100 W output and 19.5 dB typical gain, under the same conditions as the HVV1214-25. HVVI Semiconductors www.mwee.com/207501724 77-GHz CMOS power ampliﬁer targets automotive radar applications Fujitsu Laboratories (Tokyo, Japan) claims to have developed a millimeter-waveband power ampliﬁer (PA) using a standard 90-nm CMOS process technology. The laboratory applied CMOS modeling technology and design techniques to minimize high-frequency signal loss and get the extreme operational frequencies out of the process technologies. Fujitsu claims the circuit is the ﬁrst CMOS-based PA that operates at 77 GHz. The technology realizes CMOS radio frequency front-end circuitry that includes a power ampliﬁer, thereby enabling integration with baseband circuitry on a single chip, for use in millimeter-wave automotive radar systems. The application of standard CMOS technology in millimeter-wave circuitry has been problematic due to signal loss. In order to boost the gain in an ampliﬁer, a number of factors that are not evident on a circuit diagram, such as parasitic capacitance, need to be accurately reﬂected. In addition, signal loss in a matching circuit needs to be suppressed to enable maximum ampliﬁcation performance. Fujitsu Laboratories developed two technologies that make it possible to apply standard CMOS technology to millimeter-wave ampliﬁers. First they established a transistor model that shows the operating characteristics at millimeter-waveband and developed parameter-extraction method technology. Second, to keep the circuitry compact, Fujitsu Laboratories developed a “short stub” matching circuit and integrated it with the power-supply circuitry in a way that would further reduce signal losses. This reduced the amount of chip space required by the matching circuit to one-tenth previous levels, and also reduced signal loss to 0.4-dB. The resulting CMOS PA operates at 77 GHz with 8.5-dB gain and 6.3 dBm saturated output power. Furthermore, a separate PA operating at 60 GHz was developed and achieved 8.3 dB of gain and 10.6 dBm saturated output power. This technology makes it possible to implement 77 GHz automotive radars using inexpensive standard CMOS technologies. These developments could also be used to extend the transmission range of wireless communications systems in the 60GHz band. Furthermore, by combining baseband circuitry with RF front-end circuitry on one chip, millimeter-waveband transceiver chips — which had been expensive to produce in the past — can now be made considerably smaller. As a result, widespread application of millimeter-waveband technologies in both automotive radar systems and wireless communications systems is anticipated in the future. Fujitsu Laboratories www.mwee.com/206104893 Four-way power divider spans 18 to 40 GHz with low insertion loss Narda, an L-3 Communications company, has introduced a four-way power divider for millimeter-wave applications that is optimized for low insertion loss, high isolation, as well as amplitude and phase stability. The power divider is well suited for applications ranging from electronic warfare and electronic countermeasures to radar, communications systems, and test equipment. The Model 4318-4 operates over a frequency range of 18 to 40 GHz, with insertion loss of 1.7 dB or less, isolation of at least 16 dB, amplitude balance of 1.0 dB or better, phase balance or 10 degrees or better, and input/output VSWR of 1.9:1 or less. The four-way power divider can handle 500 mW average power into a 3:1 VSWR and 3 W into a 1.2:1 VSWR. Narda www.mwee.com/208401081 Microwave Engineering Europe ● June 2008 ● www.mwee.com http://www.mwee.com/206104893 http://www.mwee.com/208401081 http://www.mwee.com/207501724 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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