April 2008 Magazine Archive

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ISSUE DATE: APRIL 2008

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April 2008 - In This Issue

[Cover Story]
Low-Jitter Modules Generate Clock Signals To 40 Gb/s
Billions of cellular telephones and their users worldwide are driving demands for faster communications networks. Optical communications systems support long-distance services and serve as the backhaul communications for wireless networks. At one time, optical communications systems operating at 10 Gb/s (OC-192) may have seemed adequate but, with growing voice, data, and video traffic, optical communications networks carrying data rates of 40 Gb/s ... — A.P.S. (Paul) Khanna

[News]
Rugged Cables And Connectors Can Take Abuse
Microwave and optical cables and connectors currently serve a variety of industries. Yet they always have the common objective of delivering a transmission path for both highspeed digital and high-frequency analog signals. Their diverse capabilities and performance are derived from their design as well as other factors, such as materials. As it does in every industry, design follows demand. In other words, the evolution of such factors is driven... — Nancy Friedrich

[Design Features]
EM Simulator Models Acoustic/Electric Designs
Simulating a high-frequency device before it is built can help avoid pitfalls in its design and manufacturing. Fortunately, engineers faced with predicting the behavior of RF and microwave circuits have a wide array of electromagnetic (EM) solvers to choose from, although selecting an optimum simulation tool should require consideration of some practical guidelines. There are several classes of solvers, with each best suited to a... — Marco Farina

[Design Features]
Large-Signal Approach Yields Low-Noise VHF/UHF Oscillators
Oscillator design for veryhigh- frequency (VHF) and ultra-high-frequency (UHF) applications has been well documented in books and journals. Most early work focused on frequency stability and, to a lesser extent, on efficiency and output signal quality. But with increasing use of advanced modulation formats in communications systems, and the growing need for oscillators with... — Ajay Kumar Poddar , et al.

[Design Features]
Cut Loss In Low-Voltage, Wideband PIN Attenuators
Variable attenuators based on the pi (p) configuration can be designed with frequency coverage spanning multiple octaves, from the high-frequency (HF) range to the lower microwave region. As a result, they are suitable for numerous wideband applications, such as in satellite television and cable-television (CATV) systems. The use of PIN diodes in these attenuators enables them to be realized as low-cost components and compact alternatives to ... — Chin-Leong Lim

[Product Technology]
Advanced Simulators Focus On EM Fields
Electromagnetic (EM) simulation software is no longer a luxury but now an essential tool in any practical highfrequency design effort. The number of commercial programs has grown steadily over the years, providing RF/microwave designers with an unprecedented number of choices in EM simulators, including software for analysis of planar designs as well as full three-dimensional structures. Most of these EM tools link seamlessly to other... — Jack Browne

[Product Technology]
VCO Source Programs Arbitrary Waveforms
Frequency agility is a key requirement for a variety of military systems, including electronic warfare (EW), electronic countermeasures (ECM), secure communications, and electronic intelligence platforms. For these systems, conflicting requirements in technical performance, power management, packaging, and environmental survivability often give rise to interesting and innovative designs. The engineers at Narda Microwave-East resolved these conflicts... — Neil Heft , et al.

[Product Technology]
Field Operations Kit Aids High-Power Testing
High-power attenuators are often used to decrease the power level from a base station or communications tower when making measurements with a spectrum analyzer or portable communications instrument. Test instruments are usually only rated for input power levels approaching 1 W (+30 dBm) at most, and power levels from wireless communications transmitters can easily exceed 100 W. Unfortunately, the attenuation value of a high-frequency fixed... — Jack Browne

[Product Technology]
Broadcast Signal Generator Integrates Test Functions
Broadcast television equipment production testing usually requires a trio of tools: a signal generator, modulator, and high-power amplifier for distributing test signals throughout a manufacturing facility. They combine to evaluate televisions, set-top boxes, and other broadcast products in accordance with a specific standard or standards at multiple frequencies and with different waveforms. To simplify matters, the R&S SFE100 broadcast signal... — Jack Browne

[Product Technology]
Surface-Mount VCO Tunes 800 To 1000 MHz
Signal generation is a critical component of most highfrequency systems. Oscillator suppliers are being asked to develop higher-performance solutions in smaller packages, to meet the needs of multi-mode, multiband wireless communications systems. In response, Synergy Microwave (www.synergymwave.com) has developed its latest series of compact, surface-mount voltage-controlled oscillators (VCOs) for systems with... — Jack Browne

[Product Technology]
Eight-Channel ADCs Cut Wireless Power Needs
Multichannel wireless applications require a generous complement of signal-processing components. To save space and power in such systems, Texas Instruments has packed a line of eight-channel analogto- digital converters (ADCs) in tiny 9 x 9 mm 64-lead QFN-64 housings. The ADS528x line of data converters offers as much as 12-b resolution at sampling rates to 65 MSamples/s with industry-low power consumption. The ADS528x family includes ... — Jack Browne

[Editorial]
WiMAX May Not Live Up To The Hype
WiMAX broadband-access technology might not be able to deliver on its promises after all. The broadband technology, in both fixed and mobile forms, has been billed as the ultimate vehicle for last-mile services. Mobile WiMAX was certain to be deployed in hard-to-reach rural areas. Nobly, it also would provide a communications jumpstart in emerging markets like Africa. At the end of March, however, the Australian edition of Communications Day (... — Nancy Friedrich

[Feedback]
Feedback
Please Explain Correction In the February “Feedback” under ‘Misleading Survey Results,’ what are you trying to say in the last paragraph? It is a negative statement and is not easily understood. Bob Langley Hello Bob, To summarize, we ran a quick online survey to see what people thought of AVX acquiring American Technical Ceramics. First of all, I was “leading the... — Various Readers

[The Front End]
European Consortium Increases Speed Limit Of Silicon-Based Transistor
PARIS, FRANCE—A European consortium, led by STMicroelectronics, held the kick-off meeting of the EU-funded project DOTFIVE and titled “Towards 0.5 TeraHertz Silicon/Germanium Heterojunction Bipolar technology (SiGe HBT).” The consortium is setting out to develop advanced silicon-based bipolar transistors with a maximum operating frequency of 0.5 THz or 500 GHz needed for future millimeter-wave and TeraHertz communication, radar, imaging, and sensing... — Dawn Hightower

[The Front End]
Kudos
LOS ANGELES, CA—Silvus Technologies received funding under the Defense Advanced Research Projects Agency (DARPA) MNM (Mobile Networked MIMO) program in 2007. The funding covers work on phase two and potentially phase three of the program for MIMO development. Silvus Technologies was chosen as the only performer on the program. The contract is valued up to $15.5 million for both phases. DARPA is looking to multiple input/multiple output (MIMO) radio technology,... — Dawn Hightower

[The Front End]
WiMAX And LTE Fight For The US Broadband Mobile Market
MARAVEDIS, a research and analysis firm that focuses on BWA technologies including WiMAX, LTE, 802.20, Ultra Mobile Broadband, and Wireless Local Loop, has issued a report. The report focuses on opportunities and challenges for the broadband mobile market in the USA. It offers a comprehensive review of opportunities and challenges for BWA/WiMAX in the US. It also reveals important trends for the mobile broadband industry. Key findings of the report include: ... — Dawn Hightower

[The Front End]
SUIRG Releases Findings Of Field Test Report On C-Band Sharing
PUNTA GORDA, FL—The Satellite Users Interference Reduction Group (SUIRG), a non-profit association, announced the findings of a field test on the compatibility of Fixed Satellite Services (FSS) and WiMAX services sharing the C-band spectrum. The test, conducted in late 2007, demonstrated that WiMax communications pose a significant interference threat to satellite signals transmitted in the C-band frequency. The purpose of the test was to validate previous tests... — Dawn Hightower

[Financial News]
Ansys Intends To Acquire Ansoft Corp.
ANSYS, INC. (SOUTHPOINTE, PA) and Ansoft Corp. have signed a definitive agreement whereby ANSYS will acquire Ansoft for approximately $832 million in a mix of cash and ANSYS common stock. The business combining of ANSYS and Ansoft will create a provider of simulation capabilities with combined trailing 12-month revenues of $485 million. When completed, ANSYS anticipates that the transaction will be modestly accretive to non-GAAP earnings per share in its... — Dawn Hightower

[Company News]
Company News
CONTRACTS Lockheed Martin and Defense Advanced Research Projects Agency (DARPA)—Lockheed Martin has received a $5.7-million contract from DARPA to compete in Phase 1 development of its System F6 space technology and demonstration program. F6 is shorthand for “Future, Fast, Flexible, Fractionated, Free-Flying Spacecraft United by Information Exchange.” The DARPA System F6 program intends to demonstrate that a... — Dawn Hightower

[People]
People
Pinto da Silva Becomes President of RFS Brazil ROBERTO PINTO DA SILVA, formerly vice president of sales for Radio Frequency Systems (RFS) Latin America, has replaced Luis Antonio Alves de Oliveira as president of RFS Brazil. Oliveira leaves RFS to pursue new endeavors outside the telecom industry. Pinto is a mechanical engineering university graduate with an MBA in executive team... — Dawn Hightower

[R&D Roundup]
Constraints Impact UWB Antenna Performance
Solutions for Optimal Waveforms for an Ultra-Wideband (UWB) link have been presented using transmit and receive antennas that are realistic and specific. Yet antenna expert David M. Pozar, who hails from the Department of Electrical and Computer Engineering at the University of Massachusetts (Amherst, MA), asserts that a better approach might be to determine the best performance that can be obtained for any antenna with certain constraints, such as... — Nancy Friedrich

[R&D Roundup]
UHF CPUs Promise To Secure RFID Communications
To Attach to Merchandise Ranging from books to fresh foods, radio-frequency identification (RFID) tags need physical flexibility. RFID RF integrated circuits (RFICs) also must be produced at extremely low cost. In addition, they have to be able to provide secure communication. To meet these demands, a 13.56-MHz RF central-processing unit (CPU) with a flexible and a glass substrate was proposed by Hiroyuki Takashina and Yoshinari Yamashita from TDK... — Nancy Friedrich

[Application Notes]
OTA Testing Evaluates Mobile-Device Performance
OTA Testing Evaluates Mobile-Device Performance To more accurately predict the real-world performance of a mobile device, both standards organizations and network providers are increasingly turning to over-the-air (OTA) testing. The Cellular Telecommunications Industry Association (CTIA), for example, has defined the methods and set the standards for performing OTA testing. In a four-page white paper, RFMD (... — Nancy Friedrich

[Application Notes]
Tie WiMAX RF Chipsets To 18-MHz Reference Frequency
Tie WiMAX RF Chipsets To 18-MHz Reference Frequency RF chipsets are at the heart of WiMAX solutions for base-station hardware and customer-premise equipment (CPE). The TRF1xxx chipsets from Texas Instruments (www.ti.com), for example, house integrated synthesizers to realize a superheterodyne architecture. To achieve optimal channel resolution, these devices must be tied to an 18-MHz reference frequency.... — Nancy Friedrich

[Editor's Choice]
100-W SSPA Targets Ku-Band
100-W SSPA Targets Ku-Band To provide low-cost operation and longevity for satellite-communications (satcom) customers, a compact, 100-W, solid-state high-power amplifier (SSPA) has been introduced in an integrated antenna-mount package. This SSPA, which is dubbed the model XTS-100K1, is designed for satcom operation at 14.0-to-14.5-GHz Ku-band frequencies and optionally available in a version for use at 13.75 to 14.5 GHz. Thanks to its antenna-mount approach,... — Nancy Friedrich

[Editor's Choice]
Power Divider/Combiner Covers 950 To 2150 MHz
Power Divider/Combiner Covers 950 To 2150 MHz Power dividers and combiners are critical to the distribution or combining of microwave signals. The model PD-32-LB3-S, for example, provides for 1 x 32-way inphase power division or combining over the very-small-aperture-terminal (VSAT) extended frequency band, LB3. That band spans 950 to 2150 MHz. The RoHScompliant PD-32-LB3-S boasts a maximum insertion loss of 4.0 dB, an in/out ... — Nancy Friedrich

[Editor's Choice]
Power Amplifier Offers 50 dB Gain From 6 To 18 GHz
Power Amplifier Offers 50 dB Gain From 6 To 18 GHz By taking a monolithic-microwave-integrated- circuit (MMIC) approach, a family of broadband high-power amplifiers is being billed as both economical and reliable. The model AMP6G18-50-33 is a 6-to-18- GHz amplifier. It flaunts more than 50 dB of gain. The amplifier delivers at least 2 W of output power at 1-dB compression. Its noise figure is less than 3.5 dB. Typical current draw is less than 1.5 A from +12 VDC. The... — Nancy Friedrich

[Editor's Choice]
Mini-TCXO Keeps Phase Noise To -155 dBc/Hz
Mini-TCXO Keeps Phase Noise To â??155 dBc/Hz Designers are under pressure to shrink the size, lower the cost, and improve the performance of a variety of components. Oscillators are among the most essential of the components requiring these enhancements. Following this trend, the VTM3 temperature-compensated crystal oscillator (TCXO) offers phase-noise performance that is similar to its predecessorsâ??the VTC4 and VTC1 TCXOsâ??in a 50-percent package smaller ... — Nancy Friedrich