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ISSUE DATE: OCTOBER 2005 | |
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October 2005 - In This Issue [Cover Story] NLTLs Push Sampler Products Past 100 GHz Sampling technology has evolved into a powerful tool for microwave engineers. Effective sampling circuitry requires knowledge of time-domain and broadband techniques, both of which have been advanced at Picosecond Pulse Labs (Boulder, CO) in support of several product lines, including pulse generators, comb generators, and high-speed sampling modules. The firm has succeeded in pushing microwave sampling technology beyond 100 GHz with the help of its innovative nonlinear-transmission-line... — Steven H. Pepper , et al. [News] Passive Components Benefit From Materials Advances Passive components would appear at first to embody some of the more mature of microwave technologies. After all, passive component functions such as dividing and coupling power, filtering, switching, attenuating, and terminating high-frequency signals have been in existence for more than half a century. But surprisingly, passive components have enjoyed their share of technological advances in recent years as demands for lower cost, smaller size, and higher integration drive the latest... — Jack Browne [Design Features] Overlay Inductor Aids Power Amplifier Match Shrinking cell phones have required shrinking components, including the power amplifier (PA). In just the last four years, the PA module in GSM cellular handsets has shrunk from 10 × 10 mm to a mere 5 × 5 mm (a model TQM7M4006 from TriQuint Semiconductor, for example). But in spite of the size reduction, performance must also improve, requiring clever design strategies. For example, to maintain high power-added efficiency (PAE) losses in the PA's output matching network should be... — Tarun Juneja , et al. [Design Features] Characterize Balanced Devices With A VNA Differential (balanced) topologies are very often used in RF and microwave circuits, and particularly in integrated circuits (ICs), such as MMICs and single-chip receivers. Such circuits are usually impedance matched at the input at a single carrier or local-oscillator (LO) frequency. Unfortunately, manufacturers' data sheets do not always provide the required differential input impedance of the device at the frequency of interest. In such a case, it is necessary to characterize the... — Olivier Chevalerias , et al. [Design Features] Design And Verify A 50-W Power Amp Power-amplifier (PA) design, especially for wireless communications systems, often involves the trade-off between linearity and efficiency. Fortunately, modern computer-aided-engineering (CAE) tools can help to decide on the best approach to making such trade-offs quickly and efficiently. As an example, consider some requirements for a PA. For this project, these requirements include RF output power level of 50 W peak envelope power (PEP) at 760 MHz with input drive level of 1 W,... — Wilfredo Rivas-Torres [Product Technology] Test Cables’ "Memory" Saves Component Stress Microwave test cables often lead a stressful life. The seemingly tranquil benchtop environment can harbor many hazards, including engineers and technicians who over-flex cable assemblies, over-torque their connectors, and cram cables into drawers. To withstand these stresses, test cables are manufactured for ruggedness, while maintaining low loss as well as good phase and amplitude stability. Unfortunately, some flexibility is often sacrificed when trying to build cables to meet these other... — John Lewis [Product Technology] Rotary Attenuators Step 110 dB To 4.5 GHz Rotary step attenuators are invaluable when performing measurements where signal levels, such as the output of a signal generator, must be controlled in precisely known increments. Although such components are often associated with high cost and limited reliability, a patented design developed by Trilithic (Indianapolis, IN) delivers high attenuation accuracy at competitive costs. The firm's RSA series of rotary step attenuators includes 16 members with as much as 110 dB attenuation from DC... — Mark Burton [Product Technology] Eight-Port VNA Aids Production Testing Increasing numbers of multiport and balanced devices have increased the complexity of RF/microwave testing. Since balanced (differential) components and multiport devices require more test channels, conventional four-port vector network analyzers (VNAs) must literally work double-time to perform the necessary measurements on these components. One way to simplify and speed the measurements is to add more test channels, and this is the direct approach taken in the industry's first eight-port... — Jack Browne [Editorial] Downsizing The Passive Component Passive components are those taken-for-granted building blocks that make sophisticated military and commercial systems work. While they may lack the luster of their active counterparts, they are as essential. And although the advances in semiconductors may be more visible, advances in passive components over the last decade have been no less impressive. The efforts at miniaturizing established passive components, such as baluns, hybrid couplers, directional couplers, and power... — Jack Browne [White Paper] White Paper: "Disruptive" Ceramic Technology Enables Spectrum Management (Part 1) Frequency management is an essential goal of modern high-frequency design, whether for avoiding interference in cellular communications systems or ensuring security in military electronic systems. But generating and maintaining stable signals, especially at RF and microwave frequencies, is not a trivial task. Time alone can cause the designed frequencies of some circuit materials to drift, not to mention the deleterious effects of temperature, vibration, environmental... — Michael P. Busse |
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