Industry News

IEEE Starts Work on New 802.15 Standards

The IEEE has approved the start of work on four projects concerning IEEE 802.15™ wireless personal area network (WPAN) standards. These projects involve a wireless mesh topology standard for WPAN devices and alterations to the high rate WPAN standard so it supports new wireless multimedia uses more effectively. Two...
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The Book End

World Wide Wi-Fi Technological Trends and Business Strategies Teik-Kheong (TK) Tan and Benny Bing Wiley-Interscience 217 pages; $62.95 ISBN: 0-471-46356-6 IEEE 802.11 wireless local area networks (LAN) are becoming ubiquitous and increasingly relied upon. The demand for wireless access to a LAN is fueled by the growth of mobile...
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High Frequency Circuit Materials to Meet the Needs of Today’s Complex Military and High Reliability Designs

The introduction of RT/duroid®6002 high frequency circuit material, manufactured by Rogers Corp. in the late 1980s, changed entirely what RF/microwave engineers could select for circuit board materials. Up until that time, designers seeking options of high frequency materials could select laminates with low or high dielectric constant, based on...
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Potential Applications of PBG Engineered Structures in Microwave Engineering: Part I

Electromagnetic bandgap (EBG) materials are periodic structures that exhibit wide bandpass and band rejection properties at microwave frequencies. Introducing periodic perturbations such as dielectric rods, holes and patterns in waveguides and PCB substrates forms photonic bandgap (PBG) materials. As in a photonic crystal (PC), photon propagation is impeded by...
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Design of a 3.5 W S-band Power Amplifier Based on Small-signal S-parameter Analysis

Large-signal device S-parameters are usually used in power amplifier (PA) designs to obtain the desired output power. The large-signal characteristics of a power transistor can be accurately extracted from load-pull measurements as described in the lit...
In the design of high frequency power amplifiers, the goal is to achieve the power gain and output power at the desired frequency in order to achieve high PAE. Large-signal S-parameters of power devices are normally not provided by the manufacturer. One of the methods to characterize the device...
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A Novel Power Combining Network for Doherty Amplifiers

This article proposes a new type of power combining network for a Doherty amplifier based on the use of short transmission lines and lumped capacitors. Compared with the conventional combining network, which consists of λ/4 transmission lines, thi...
Modern mobile communication systems use band-limited linear modulation schemes, such as multi-level quadrature amplitude modulation (QAM) and quadrature phase shift keying (QPSK), which have high peak-to-average power ratio characteristics. For these systems, linear power amplifiers are needed to prevent adjacent channel interference. A power amplifier operated sufficiently below the...
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