ISSUE DATE: AUGUST 2008   OPTIONS
Oscillators & Synthesizers

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August 2008 - In This Issue

[Cover Story]
Rohde & Schwarz Celebrates 75 Years
Germany has long been associated with the type of precision engineering that has produced high-quality cameras, fast automobiles, and even the Autobahn roadway to accommodate those higher driving speeds. But this proud country is also home to one of the leading and most innovative test-andmeasurement companies in the world: Rohde & Schwarz GmbH. From its humble beginnings, the firm has grown through the years to now achieve its 75th anniversary, a...  — Ulrich L. Rohde

[News]
Crystal Oscillators Continue To Shrink
Crystal oscillators are also known as clocks, for their importance in keeping system time and frequency. A few decades ago, very high levels of stability required large assemblies with built-in ovens to maintain a narrow range of temperatures for optimum performance. But today’s crystal oscillators, including temperature-compensated crystal oscillators (TCXOs) and oven-controlled crystal oscillators (OCXOs), provide improved performance compared to ...  — Jack Browne

[News]
Millimeter-Wave Bands Support Diverse Uses
Millimeter-wave frequencies are difficult to generate and as difficult to test, but the bands above 30 GHz have long intrigued commercial and military spectrum planners because of their amount of available bandwidth. So named because of having wavelengths in the 1 to 10 mm range, frequencies from 30 to 300 GHz have long been used in military and government applications, but only recently been ...  — Jack Browne

[Design Features]
Use Pulse I-V Testing To Characterize RF Devices
Pulsed current-voltage (I-V) testing is becoming an invaluable method for evaluating the performance and reliability of semiconductor devices. The measurement approach is relatively cost effective and avoids the negative effects of self-heating and transient trapped charges, which can result in misleading test results. And pulsed I-V testing provides the accurate device data needed for improved computeraided- engineering (CAE) software models. ...  — Pete Hulbert

[Design Features]
Digital Predistortion Linearizes Broadband PAs, Part 2
Power amplifiers (PAs) are essential to the transmitter sections of communications systems and in many other RF/microwave applications. As seen last month in Part 1 of this three-part series, the linearity of a power amplifier is often compromised for efficiency, but numerous digital predistortion techniques are available to help improve linearity without sacrificing efficiency. Part 2 of this threepart article series will offer some comparisons of different ...  — Hardik Gandhi

[Design Features]
Design An X-Band Vivaldi Antenna, Part 2
Vivaldi antennas can provide excellent directional propagation at microwave frequencies. As introduced in Part 1 of this article (July Microwaves & RF), the Vivaldi antenna can be a simple design based on a tapered-slot-antenna (TSA) architecture. This concluding installment in this two-part article will compare measurements of a designed and fabricated X-band antenna with simulations from the Advanced Design System (ADS) software from Agilent ...  — Dr. J.S. Mandeep , et al.

[Design Features]
Analyze Antenna Approaches for LTE Wireless Systems
Multiple-input, multiple- output (MIMO) spatial-diversity antenna configurations are specified for emerging 3GPP Long- Term Evolution (LTE) mobile communications systems. In reality, LTE systems specify three types of antenna techniques: MIMO, beamforming, and diversity approaches. The three techniques are considered essential for improving signal robustness and achieving LTE system capacity. Understanding how the different antenna techniques work...  — Moray Rumney , et al.

[Product Technology]
Frequency Synthesizers Fit In Rugged Systems
Military and some commercial systems can benefit from a frequency synthesizer capable of harsh treatment. The Ruggedized Series (RS) of frequency synthesizers from Elcom Technologies are designed for the harsh realm of many military applications at frequencies to 23 GHz. In addition, they are small and sacrifice little in terms of spectral purity compared to much larger frequency synthesizers. Built for altitudes to 60,000 feet and capable of...  — Jack Browne

[Product Technology]
Test Software Simplifies Phase, Power Measurements
Microwave measurements can be made easier with the help of the right software. This was the thinking behind the introduction of two software tools by Anritsu Co. (www.us.anritsu.com) designed to assist with phase-noise and power measurements when using the firm’s MS271xB family of economy spectrum analyzers and its ML2490A series of power meters, respectively. The programs run on a personal...  — Jack Browne

[Product Technology]
New EDA Software Versions Boast Broad Enhancements
Electronic-design-automation (EDA) software tools have become the voltmeter and the slide rule to the modern high-frequency engineer. But unlike those two hardware tools, software can be updated for improved performance, as is the case in recent releases from Applied Wave Research [AWR] for Version 2008 of the firm’s widely used Microwave Office design environment and Version 2008 of the Visual System Simulator (VSS) software tools. Both new software ...  — Jack Browne

[Product Technology]
Tiny Trimmers Target Tunable Requirements
Trimmer capacitors provide the means of adjusting a circuit’s capacitance once all components are assembled onto a printed-circuit board (PCB). For the purpose of experimentation, or even for tuning a circuit’s performance on the production line, a well-chosen trimmer capacitor can provide the necessary capacitance range to adjust the center frequency of filters, oscillators, and other high-frequency components. And while adding a trimmer once...  — Nicholas Perrella

[Product Technology]
Software Tools Simplify GPS Testing
Global Positioning System (GPS) receivers have been guiding travelers for some time, and now they are guiding drivers of many new cars and even pedestrians by means of embedded circuits in cellular telephones. Of course, with this rapid spread of GPS receivers comes a corresponding need for efficient testing of both stand-alone GPS receivers and units embedded into other devices. For that purpose, the NI GPS Toolkit for Labview from National Instruments (...  — Jack Browne

[Editorial]
Software Has Become A Large Part Of The Job
Software is now an essential part of our lives. Unless one is still plying a time-honored craft such as handrolling cigars, the chances are that each working day involves the use of software somewhere along the line. In an RF/microwave electronics house, for example, it may be on the production line, embedded within a pick-and-place machine that has to be supervised from time to time...  — Jack Browne

[Feedback]
Feedback
Dear Nancy: I read wIth Interest your editorial, “students abroad also spurn science.” For many decades, the US has acted as a colonial power, not reaping benefits from physical colonies, but by fishing for talent, taking the world's best and brightest. This is often justified in the US as being open minded and giving such talent a place to develop, but much of that...  — Various Readers

[The Front End]
Local Designers Drive Chinese IC Market Growth
CHINA—According to iSuppli Corp., sales of semiconductor chips designed in China are surging at a double-digit clip helping to offset slower growth in the country’s previously red-hot IC market as OEMs focus on customizing products for the local market. Led by demand from the wireless communications equipment sector, China’s consumption of semiconductors designed in the country is forecast to rise more than 60 percent by 2012 to $42.1 billion from $25.8 billion ...  — Dawn Hightower

[The Front End]
AVX Honored By Arrow At EDS 2008
MYRTLE BEACH SC—AVX Corporation, an international supplier of advanced electronic components, received two awards from Arrow Electronics at the 2008 Electronic Distribution Show (EDS). AVX was presented with the 2007 Largest Passives Supplier Award and the 2007 Largest Dollar Growth in Passives Award. “AVX’s broad product portfolio and outstanding customer service provided the foundation for excellent sales in 2007. We are pleased to honor AVX with the...  — Dawn Hightower

[The Front End]
Worldwide BWA/WiMAX Subscriber Base Closes On 2 Million
MONTREAL, CANADA—The global BWA/ WiMAX subscriber base increased by 260,246 in the first quarter of 2008, reaching a total of 1,988,246 subscribers, according to the fourth issue of the WiMAXCounts Quarterly Report from Maravedis. “Even with an increase of more than 19% in WiMAX subscribers in the first quarter of 2008, operators are still waiting for the tipping point that will lead to acceleration of WiMAX adoption and deployments,” said...  — Dawn Hightower

[The Front End]
Kudos
HILLSBORO, OR—TriQuint Semiconductor, Inc. an RF frontend product manufacturer and foundry services provider, received the “Northwest 100” award for 2008. The Seattle Times award recognizes the top 100 publicly held companies in the Pacific Northwest by measuring four dimensions of performance over the previous two fiscal years. According to the Seattle Times, to come out on top, a company has to do well on all four factors. DURHAM,...  — Dawn Hightower

[Financial News]
Financial News
ANSOFT CORPORATION, a global provider of Electronic Design Automation (EDA) software, announced that at the company’s special meeting of stockholders held on July 23, 2008 in Pittsburgh, PA, that the company’s stockholders voted to adopt and approve the merger agreement providing for the acquisition of Ansoft by ANSYS, Inc. Ansoft also announced that the conditions to ANSYS’ obligations contained in Section 7.2 of the merger agreement have been satisfied....  — Dawn Hightower

[Company News]
Company News
ViaSat—Has signed a 10-year agreement with KVH Industries Inc., to establish a global Ku-band mobile broadband network using ViaSat-patented ArcLight technology. The agreement includes an initial purchase by KVH of three ArcLight hubs with options for more hubs as the network expands. The contract will enable network expansion that builds on the satellite networks serving business jets, maritime vessels, and ground vehicles in North America, the Caribbean, the North...  — Dawn Hightower

[People]
People
Ansoft Chairman/CTO Receives IEEE Award DR. ZOLTAN CENDES, Ansoft Corporation founder, chairman and chief technology officer, has received the Institute of Electrical and Electronics Engineers (IEEE) Antennas and Propagation Society (AP-S) Distinguished Achievement Award. Cendes earned the award for his “contributions to the widespread use of user-friendly software tools for electromagnetic analysis and design.” The award recognizes outstanding...  — Dawn Hightower

[Educational Meetings]
Educational Meetings
Short courses Besser Associates Short Courses RF Transceiver Architecture, Design and Evaluation Nov.17-21, 2008 (Dallas, TX) Applied RF Techniques for Modern Radio Design Nov. 17-21, 2008 (Dallas, TX ) Wireless System Design and Simulation Dec. 8-12, 2008 (San Jose, CA) Short Range Coexistence...  — Dawn Hightower

[R&D Roundup]
X-Band Oscillator Antenna Targets Phased-Array Systems
Active integrated antennas (AIAs) with one or more active devices and circuits within the radiating element have been garnering quite a bit of attention. They promise to deliver advantages like compact size, low cost, and adaptability to phased-array-antenna systems. Recently, an AIA element was successfully fabricated on a high-dielectric-constant ({? r} = 10.2) microwave laminate that is 0.635 mm thick. The development hails from Carl H. Mueller, Carol...  — Nancy Friedrich

[R&D Roundup]
60-GHz Receiver May Be Realized In CMOS
Wireless communications systems like highspeed personal-area networks and real-time video transmission demand performance that is above the Gigabit-per-second range. As a result, such systems may require the bandwidth provided by a 60-GHz millimeter-wave transceiver. The traditional approach behind such a transceiver is to leverage compoundsemiconductor monolithic microwave integrated circuits (MMICs). Yet, that 60-GHz transceiver may potentially be realized in...  — Nancy Friedrich

[R&D Roundup]
Three-Branch Antenna Serves GPS, UMTS, And ISM Bands
Mobile-phone antennas must become increasingly multiband in order to accomplish their many functions. In response to these trends, researchers have proposed a design method that provides quarter-band operation for the following bands: GPS (1565 to 1585 GHz), UMTS/W-CDMA (1920 to 2170 MHz), Industrial Scientific Medical (ISM; 2400 to 2483.5 MHz), and SDMB (2630 to 2655 MHz). This work is credited to Byung-chan Jang, Che-young Kim, and Jeung-keun Park from the...  — Nancy Friedrich

[Application Notes]
Proper Mounting Ensures Power-Transistor Performance
Achieving performance expectations for highfrequency components requires proper implementation. In the case of RF power transistors, for example, the device-to-heatsink interface establishes the heat transfer path and RF ground. In application note PKG001, “Proper Mounting of RF Power Transistors,” HVVi Semiconductors details the heatsink surface preparation, maximum torque required to tighten the screws, and the proper procedure for connecting leads. ...  — Nancy Friedrich

[Application Notes]
Overcome UWB Test Challenges
Ultra-wideband (Uwb) communications is seen by many as an enabling technology for many short-range applications. Low signal-to-noise transmissions enable it to avoid interference with co-located wireless signals. Specifically, UWB signals must have low spectral densities just above the thermal noise floor. To achieve this goal, the UWB transmitter power is restricted to low levels and spread over wide bandwidths. UWB signals also have redundancy built into them,...  — Nancy Friedrich

[Editor's Choice]
Type-N Connector Performs Through 18 GHz
WITH A WEATHERTIGHT, waterproof, through-panel mount seal, a Type-N connector is targeting rugged RF applications like outdoor antennas and portable test equipment. This new member of the V-Bite RF edgeboard family comprises a coax connector that is engineered with a silicone ring on the inside of the panel or box. This ring creates a robust seal when the nut is tightened from the front. The sealed part boasts a very low profile (one-half the connector’s...  — Nancy Friedrich

[Editor's Choice]
RF Power Detector Boasts 75-dB Dynamic Range
RF POWER-AMPLIFIER control and monitoring are required by a range of wireless systems. To perform these tasks, a monolithic broadband, logarithmic RF power detector promises to provide accurate RF power measurements over the 800-to-900-MHz and 1.7-to-2.2-GHz cellular bands as well as the 2.6- and 3.5-GHz WiMAX bands. The detector exhibits linearity of +/-0.8 dB from -40° to +85°C. The LT5538 is capable of detecting signals as small as -75 dBm to as...  — Nancy Friedrich

[Editor's Choice]
Broadband Solid-State Switch Covers 1 MHz to 4.2 GHz
WITH SWITCHING SPEED of better than 100 ns, a broadband switch is targeting applications like automated switching systems, switch matrices, and manufacturing test systems. The solid-state, non-reflective RF switch, dubbed the model PS-4.2/2S-5V-TTL-R, features a frequency range of 1 MHz to 4.2 GHz. At 4.2 GHz, isolation is greater than 50 dB. Insertion loss is 4.0 dB maximum. Operating-temperature range is 0° to +70°C. The single-pole, double-throw (SPDT)...  — Nancy Friedrich

[Editor's Choice]
170-MHz Signal Generator Fits Benchtop
BY LEVERAGING an internal temperature-controlled crystal oscillator (TCXO), a direct-digital-synthesized (DDS) signal generator provides accuracy of better than +/-2 ppm. Model 2918A contains two synchronized 170-MHz DDS sources that can be individually set to any value between 0.1 Hz and 170 MHz with a resolution of 0.1 Hz. The phase between the channels can be controlled with 14-b resolution. The standard output level is +4 dBm with 10 b programming range....  — Nancy Friedrich