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Software & CAD

Memory Effect Reduction for LDMOS Bias Circuits

Memory effects have taken a very important role in today's design of base station power amplifiers. For example, they are responsible for limiting the cancellation when pre-distortion is applied to a power amplifier system.<sup>1</sup> This study show...
Electrical memory effects are defined as changes in amplitude and phase of distortion components caused by modulation frequency. There are several ways of measuring memory effects. One of the most common is to plot the phase and amplitude of the distortion parameters with respect to the tone spacing in...
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A Low Noise Wideband Microwave Oscillator Using a Tunable Microstrip Combline Filter

In RF measurement equipment, microwave synthesized signal sources, broadband digital satellite receivers and many other applications, broadband and low phase noise oscillators are becoming more and more important. A wide tuning range and good phase noi...
Typical oscillator designs use a common-base or common-collector circuit for generating a negative resistance at one port, which is usually terminated with a parallel or series LC-resonant circuit. The main problems in this design are the bandwidth of the negative resistance, which cannot be easily extended over one frequency...
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Effects of Grounding and Bias Circuit on the Performance of High Frequency Linear Amplifiers

The design of a high frequency amplifier is normally based on the S-parameters supplied by the manufacturer of the active device. However, in a practical design, these parameters are affected by the DC bias network and the grounding of the active devic...
In the design of high frequency power amplifiers, one of the parameters is the stability of the active device. The stability of the active device is determined by the Rollet stability factor K. If K > 1, then the active device is unconditionally stable and the design of the...
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Hybrid Synthesizer Tutorial

Use of a variety of synthesis blocks to create frequency synthesis systems with enhanced performance characteristics
Frequency synthesizers are used in a variety of communications and timing systems. Phase-locked loops (PLL) have been the "workhorse" of the majority of traditional synthesizers and clock generation circuits. However, there are other types of synthesis blocks available such as direct digital synthesizers (DDS), mixers, frequency doublers and dividers...
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HFSS Software for Next-generation Design

When HFSS™ was introduced in February 1990, it created a new era in microwave design. Prior to this event, microwave design was limited to simple analyses and cut-and-try methods. With HFSS, engineers could conveniently build, analyze and refine three-dimensional (3D) microwave prototypes using their computers. For the first time,...
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New Enhancements for the GENESYS Software Suite

All 15 modules of the GENESYS RF/microwave design software suite have recently been enhanced. For 17 years, Eagleware has worked with thousands of customers worldwide to continuously upgrade its suite of synthesis, simulation and design environment tools. Major enhancements in the current release include new models, an antenna pattern...
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A 2.4 GHz CMOS Power Amplifier with 20 dBm Output Power for Bluetooth and WLAN Applications

This article presents a 2.4 GHz CMOS power amplifier (PA) with an output power of 20 dBm using a 0.25 µm 1P5M standard CMOS process. The PA uses a diode connected NMOS transistor functioning as a diode linearizer. It is believed that this is the first ...
Due to the fast development of wireless communications, a low cost, high performance, high integration technology is needed for system on a chip (SOC) implementation. The CMOS technology provides a good solution for SOC integration. 1 Recent improvements of the standard CMOS process make it possible to implement RF...
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An RF Module Design for a Multi-mode Handset

This article describes a novel design of an RF module for a multi-mode handset and presents an example of an RF module for a W-CDMA/GSM/DCS tri-band and dual-mode handset. The entire module, including a direct modulation transmitter and a superheterody...
The number of mobile users is predicted to reach 1.7 billion by the year 2010. More than 45 percent of them will use high data speed services. W-CDMA, proposed by IMT2000, has become the most practical and important system for the development of new wireless communications. Nevertheless, second generation...
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Interactive Interdigital Filter Design Using MMICAD Software

Successful microwave circuit realization requires flexible circuit analysis tools that allow engineers to prototype, analyze and verify their circuits. Today, available software tools offer standard features such as frequency analysis, tuning and optimization, but are differentiated by their model libraries and special customization capabilities. This article describes the design...
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High Efficiency Class B, E and F Power Amplifiers: The Magic of Parallel Circuits

Modern commercial and military communication systems require high efficiency, long term operating conditions. For this purpose, the power amplifiers, as final and highly current-consuming transmitter elements, are developed using the high efficiency class B, F or E modes of operation, depending on the technical requirements. In class B operation,...
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