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Software & CAD

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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A Measurement-based Behavioral Model for I/Q RF Modulators

This article describes a nonlinear behavioral modeling technique for application to I/Q modulated communication channels. The model data was gathered by independent measurements of an I/Q modulator and amplifier, using vector signal generators and anal...
The W-CDMA standard expresses transmit quality in terms of EVM and ACLR, and receive quality in bit error ratio (BER). These quality measurements are simple scalar numbers representing a very complicated system. Modern communications channels (still) consist of a number of concatenated functions such as baseband (BB) processor, DAC,...
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A Fast and Flexible Circuit Board Plotter

When employing circuit board plotters for product development the main requirement is for fast, efficient and flexible operation. Consequently, the high costs incurred by the long waiting periods inherent when externally procuring circuit board prototypes, particularly those with RF substrates, can be avoided. The ProtoMat 95s/II meets these requirements,...
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Active Multipliers and Dividers to Simplify Synthesizers

A new family of active frequency multipliers and dividers is featured this month
Modern frequency synthesis uses a combination of frequency multiplication and frequency division to generate the required data and carrier signals for microwave radio and radar applications. Frequency multiplication increases the carrier frequency while increasing the phase noise of the carrier by 20log(N), where N is the multiplication factor. Conversely,...
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Practical Design Consideration of a Modified Structure for a Planar Multiport Power Divider at 2 GHz

This article proposes a modified structure at 2 GHz of IMT-2000 for the planar multiport power divider published in the literature.<sup>8-10</sup> Design parameters for the practical realization of the structure have also been investigated using HFSS (...
A power divider is a basic microwave and millimeter-wave circuit dividing the input RF power by an arbitrary ratio. This circuit has a wide range of applications such as antenna systems, power amplifiers, power oscillators, balanced mixers and so on. Multiport power dividers/combiners have been used in power amplifiers...
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Using Load Pull Analysis and Device Model Validation to Improve MMIC Power Amplifier Design Methodologies

This article describes a methodology for the design of a 2 GHz monolithic microwave integrated circuit (MMIC) power amplifier (PA) using a heterojunction bipolar transistor (HBT) process. It is based on the use of modern software tools and advanced loa...
There is certainly no shortage of information about designing power amplifiers these days, and several books address the subject quite admirably. 1-6 However, as well as these books cover the theory and underlying logic of such designs, they do not tell the reader precisely how to do it. As...
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Considerations in Capacitor-pairing to Obtain Nonstandard Part Values

Series- and parallel-combining of surface-mount capacitors is a standard approach to realize semi-arbitrary capacitance when designing a printed circuit board layout. This pairing of components is often necessary as surface-mount parts are available in only a limited number of fixed values, such as 0.5, 1.0, 2.0 pF. This article...
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Balancing the Budgets: The Importance of Dedicated Software for System Design

The International Telecommunication Union (ITU) standard Wideband Code-Division Multiple Access (WCDMA) was derived from code-division multiple access (CDMA), and is officially known today as IMT-2000 direct spread. It is a third-generation (3G) mobile wireless technology offering much higher data speeds to mobile and portable wireless devices than commonly offered...
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