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Industry News

Efficiency Comparison of a Digitally Predistorted and a Feed-forward Linearized Doherty Amplifier with Crest Factor Reduction

This article provides a direct performance comparison between a Doherty digital predistorted (DPD) amplifier and a Doherty feed-forward linearized power amplifier (DFFLPA) under various crest factor reduction levels. Based on experimental results at an...
The increasing importance of spectral efficiency in mobile communication services, such as wideband code division multiple access (WCDMA) and orthogonal frequency division multiplexing (OFDM), has resulted in a fluctuating signal envelope. The large peak-to-average power ratio (PAPR) of these modulations requires base station power amplifiers to have a high...
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An Adaptive Baseband Digital Predistortion System for an RF Power Amplifier

In this article, a baseband digital predistortion (DPD) radio frequency (RF) power amplifier (PA), based on the complex gain compensation and adaptive algorithm, is investigated. First, the nonlinear characters of the power amplifier are described. Nex...
With the rapid growth of modern wireless communication technologies and markets, higher spectrum efficiency is required for higher data rates and larger capacity. As a result, high order digital modulations with high peak-to-average ratio are usually adopted to meet these requirements. Therefore, the dynamic range and linearity of the...
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100 W GaN HEMT Modeling

Recent improvements in GaN HEMT device technology have enabled unprecedented power levels for solid-state amplification. Devices are now capable of exceeding 100 W in a single package.<sup>1</sup> The need for accurate models for these devices has beco...
GaN devices now operate at much higher bias conditions than traditional PHEMTs or HBTs, and also dissipate DC power and generate RF power at much higher densities. Due to high RF and DC power levels, it was found that conventional CW device characterization and modeling techniques are no longer...
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An Adaptive WiMAX Antenna for Indoor Use

A four-sector switchable WiMAX antenna, for indoor use in the 2.6 and 3.4 GHz frequency bands, is presented. The prototype antenna was designed to provide the highest possible gain in a defined amount of space. Furthermore, the radiation beam is electr...
The Worldwide Interoperability for Microwave Access (WiMAX) system 1 is becoming quite popular in allowing broadband wireless Internet access for private and business users. WiMAX is based on the IEEE 802.16 family of standards. 2 Currently, the first system implementations, based on the 802.16-2004 specifications intended for fixed wireless...
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A Printed Heart Monopole Antenna with Band-rejected Characteristics for IEEE 802.16a and UWB Applications

A novel design of a printed heart-shaped monopole antenna, with a ring-section slot for IEEE 802.16a and ultra-wideband (UWB) applications, is proposed where the 5.150 to 5.825 GHz frequency band has been rejected. The measured bandwidth ranges, for a ...
Many various configurations and various substrate materials for ultra-wideband (UWB) applications have been investigated. Many printed broadband monopole configurations, 1–3 such as circular, semi-circular and square shapes, can achieve ultra-wideband characteristics, omni-directional radiation patterns, simple structures, light weight and low cost. The IEEE 802.15.3a standard 4 specifies the 3.1...
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High Q Ceramic-loaded Tunable RF Cavity Filters

Ceramic-loaded resonators are used in the realization of small size, high performance, RF and microwave filters that require extended stop band characteristics. The higher insertion loss usually found from using a loaded resonator can be overcome by ca...
A ceramic-loaded resonator is a transmission line with one end shorted and the other “open” end connected to a capacitor to ground, as shown in Figure 1 . This shortens the length of the line needed to resonate at a particular frequency. The ceramic-loading capacitor overcomes the drawbacks of...
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Ask Harlan: Question of the Month - May 2007

Published May 7, 2007 In an effort to better combine the editorial content of our magazine with our newly developed and retooled on-line presence, we have decided to expand Harlan's RF and microwave engineering advice into a monthly feature that appears in Microwave Journal. Harlan has selected one question...
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TriQuint Semiconductor Bolsters European Sales Force

<B>TriQuint Semiconductor</B>, a leading RF product manufacturer and foundry services provider, announced that it is restructuring its sales coverage and product distribution across Europe.
TriQuint Semiconductor , a leading RF product manufacturer and foundry services provider, announced that it is restructuring its sales coverage and product distribution across Europe. This reorganization is designed to streamline European support to meet growing customer needs for cost-efficient, highly-integrated RF solutions that reduce manufacturing time. Redtree Solutions...
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Solid Growth in Global Semiconductor Market to Continue Through 2008

After five consecutive years of revenue growth that brought worldwide semiconductor revenue to a record $247.7 B in 2006.
After five consecutive years of revenue growth that brought worldwide semiconductor revenue to a record $247.7 B in 2006, the cyclic history of the industry would suggest a reversal is overdue, reports In-Stat. But with an extended period of above average worldwide GDP growth ahead, continued semiconductor revenue growth...
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