ISSUE DATE: FEBRUARY 2005   OPTIONS
Test & Measurement

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February 2005 - In This Issue

[Cover Story]
Three-Probe Tuner Tackles Multiple Tasks
Electromechanical impedance tuners provide the appealing combination of extremely high VSWR (to 200:1) and high power-handling capability (to 400 W CW). Until now, electromechanical slide screw tuners have been built as wideband models (with two probes of different lengths), as high-VSWR systems (with a prematching stage), or as harmonic rejection tuners, although not with all three characteristics at the same time. The MPT Multi-Purpose Tuners from Focus Microwaves (Montreal, Quebec,...  — Cristos Tsironis

[News]
RLC Components Support Higher-Level Designs
Lumped circuit elements, such as capacitors (C), inductors (L), and resistors (R), are the essential building blocks of tuned active and passive circuits. While the most enduring trends in these passive components have seen shrinking size and packaging suitable for surface-mount applications, performance has also improved with advances in ceramic and other materials, notably in terms of stability with temperature and time. For higher-level designs, this results in more stable filters and...  — Jack Browne

[Design Features]
Surveying Synthetic Instruments For Defense
Synthetic Instruments (SI) became an important issue for test-equipment suppliers as soon as the United States Department of Defense (DoD) announced the award of the ARGCS (Agile Rapid Global Combat Support) contract in September 2004. Although the ARGCS represents only a technology demonstration, it may well foretell the future of high-performance analog and microwave test equipment used in automatic test systems (ATS). What follows is a...  — John Stratton

[Design Features]
Cascading Amp Stages For Higher Gain
Amplifiers are designed for adding signal gain or achieving a target output-power level. As was demonstrated last month, it is possible to design a simple broadband amplifier for relatively flat gain performance from 50 to 1050 MHz. But if higher gain levels are required, it becomes necessary to cascade two or more amplifier stages, and the design becomes more complex. The final installment of this eight-part article series on transistor design addresses the steps that should be taken to...  — Joseph F. White

[Design Features]
Checker Reads Cellular Radiation
Long-term effects of electromagnetic (EM) radiation from cellular and Personal Communications Services (PCS) handsets are still unknown. Prudent practices include the use of measurement tools to detect unusually high levels of EM radiation from, for example, broken gaskets in a cellular handset package. Another safety measure is to measure the radiation levels from wireless handsets using a low-cost radiation checker as proposed in this article. This report will present the design, review...  — Dr. A. Kumar

[Product Technology]
Dividers And Terminations Cut Costs To 8 GHz
Microwave power dividers and terminations may represent simple functions, but achieving broadband performance with such components is never trivial. Doing this while also keeping costs to a minimum requires attention to everything from materials and component choices to fabrication techniques. The 4436 Series power dividers and T-SMA and T-N Series terminations from Narda Microwave-East (Hauppauge, NY) achieve these conflicting goals with low loss and prodigious power-handling...  — Jack Browne

[Product Technology]
Quad Hybrids Serve 450-MHz CDMA Systems
CDMA450 (at 450 MHz) as implemented in Europe and Asia shows great promise for low-cost voice and high-speed fixed and mobile Internet access. As always, competition among base station manufacturers is driving prices down, and RF component manufacturers are asked to respond with cost-effective solutions. Merrimac's (West Caldwell, NJ) response is the Multi-Mix QHD Series 3-dB, 90-deg. hybrid couplers, which provide cost-effective power combining and dividing in CDMA450 base stations....  — Jack Browne

[Product Technology]
Refinements Revitalize Variable Delay Lines
Delay lines in the PDL Series from Colby Instruments (Bellevue, WA) brought precision delays to analog and digital testing from DC to 18 GHz almost two decades ago. Although capable of accurately adjusting delay lengths as long as 625 ps, this first generation of instruments was at times difficult to program and operate. Fortunately, the 2005 version of the PDL series is easier to use, with increased precision and range, a Windows-based user interface, TCP/IP Ethernet capability, and an...  — Victor Chinn

[Editorial]
The Evolution Of Test Equipment
Test equipment represents that last barrier between a design concept and a shipped product. Reliable test gear can keep production lines running and ensure that a customer is satisfied with the performance of those products. In the research and development (R & D) laboratory, the test instruments provide invaluable insight into the performance characteristics of a design, allowing engineers to refine and optimize. The essential nature of test equipment to microwave engineering has...  — Jack Browne