Industry News

The Book End

Microwave Filters for Communication Systems: Fundamentals, Design and Applications R.J. Cameron, C.M. Kudsia and R.R. Mansour Wiley Interscience • 802 pages; $135 ISBN: 978-0-471-45022-1 This book captures the fundamentals and practical aspects of modern microwave filter design. Chapter 1 is devoted to an overview of communication systems. The principles...
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Around the Circuit

Industry News John Dunbabin , owner and president of Connecting Devices Inc. (CDI), passed away on September 8, 2007, from pancreatic cancer. A graduate of Cal Poly, San Luis Obispo, with degrees in mechanical engineering and business, John went to work for CDI. In 1975, he and his partners,...
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An Enabling New 3D Architecture for Microwave Components and Systems

How would you like to design circuits with perfectly shielded, low-loss, purely TEM broadband transmission lines, which could be stacked next to and on top of each other with no coupling? The lines can be tens of centimeters long, cross at multiple levels and at any angle, and holes...
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Design of a Microwave Group Delay Time Adjuster and Its Application to a Feedforward Power Amplifier

This article presents a design method for a microwave group delay time adjuster (GDTA) and its application to a feedforward (FFW) power amplifier (PA). The GDTA consists of a variable capacitor and a variable equivalent inductor. The variable equivalen...
As linear modulation and demodulation is adopted in communication systems for spectrum efficiency, the system performance is limited due to nonlinearity, particularly in the power amplifier. The nonlinearity of a system can be explained as AM-AM, AM-PM, intermodulation distortion (IMD) and adjacent channel leakage ratio (ACLR). Several linearizing techniques...
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High Efficiency Broadband Power Amplifiers

This article is devoted to the design of broadband high efficiency power amplifiers for microwave and RF applications through the synthesis of the load impedance (or load admittance) required by power transistors at fundamental and harmonic frequencies...
The technical definition of an amplification class is not obvious. Patents are among the best documents to explain and define what an amplification class is. 1,2 Reviewing the claims sections of those documents is an interesting exercise in understanding the inherent complexity of an amplification class definition. From a...
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Design of a CPW-fed Printed Antenna for Ultra-wideband Applications

This article describes a compact and simple coplanar waveguide monopole antenna for ultra-wideband (UWB) applications. The overall size of the printed antenna is 26 x 35 x 1.6 mm, which is very compact, low profile and can be integrated in an ultra-wid...
In recent years, wireless communications have progressed very rapidly. Broadband antenna design has become very important for wireless applications. UWB is a high data-rate and short-range wireless technology, utilizing the unlicensed radio spectrum from 3.1 to 10.6 GHz. The UWB antenna is one of the major components of UWB...
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A 5 GHz RFIC Single Chip Solution in GaInP/GaAs HBT Technology

Several high performance GaInP/GaAs heterojunction bipolar transistor (HBT) radio frequency integrated circuits (RFIC) implemented by our research group are reviewed in this article. These demonstrated RFICs include source inductively degenerated casco...
Commercially available 5 GHz WLAN transceivers—with the exception of power amplifiers (PA)—have recently been using advanced CMOS and SiGe BiCMOS technology. 1 It is commonly believed that RFICs made with Si technology, especially CMOS technology, have the lowest cost and can be easily integrated with digital CMOS ICs to...
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Extracting a Nonlinear Electro-thermal Model for a GaN HFET

This article describes the procedure used to extract a nonlinear model for a gallium nitride (GaN) power HFET. The source device is a 2 mm gate-width GaN-on-silicon HFET produced by Nitronex Corp., although the procedure can be applied to many other ty...
The development of GaN technology has brought with it the need for accurate nonlinear active device models that can be easily used in standard design tools. A GaN HEMT model should ideally be scalable with gate width and should be able to predict the performance of the device over...
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CMOS AGC Design Strategies

This article presents seven widely used topologies for the AGC.
The automatic gain control (AGC) circuit is a critical building block in modern wireless transceivers. It is used in both the transmitter (TX) and receiver (RX). In the TX, the AGC is used to regulate the output power level. For example, a well-known issue in a CDMA system is...
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