Industry News

A Modular Switch Filter Bank

A new modular switch filter bank is featured
For many years switch filter banks have been designed as custom RF assemblies with long lead-time, large NRE charges and extreme custom packaging and specifications. A new modular approach to switch filter bank design has been introduced that provides the design engineer with the opportunity to maintain a custom...
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A Small, Low Cost Antenna for WLAN and Bluetooth Applications

Wireless device manufacturers today must fit a growing amount of functionality into continuously decreasing circuit board space. In particular, finding space for the antenna without compromising its performance characteristics has become a major challenge. The AccuWave™ 5800 antenna is an ultra-small tri-band device designed to provide full coverage of...
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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.1 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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A Method to Predict the Level of Intermodulation Products in Broadband Power Amplifiers

This article derives a formula to mathematically predict the level of intermodulation products generated in a broadband, multi-carrier power amplifier. The prediction method uses the level of a harmonic as a reference from which to extrapolate the leve...
Multiple RF exciters feeding a broadband power amplifier and a broadband antenna system has become an increasingly popular form of system architecture throughout the frequency spectrum. This architecture, shown in Figure 1 , has several desirable features, the most popular of which is the reduced real estate requirement. Modern...
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Overcoming Hard Limiter Suppression

For about half a century the suppression effects of bandpass hard limiters on various combinations of signals and interference have attracted widespread interest. 1-4 Certain "rules of thumb" have accreted around a variety of theoretical results. The purpose of this article is to revisit issues of interpretation and to...
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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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Ultra-wideband Radio - The New Part 15

Summary of the possible interactions between ultra-wideband and other wireless communications systems based on newly adopted rules by the Federal Communications Commission
Ultra-wideband (UWB) radio technology enables several important applications, including ground penetrating radar, imaging, location tracking and low cost, short-range communications. With the recent Federal Communications Commission (FCC) approval of rules for operation of UWB devices under Part 15, devices aimed at these, and possibly other, applications will soon be...
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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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