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Industry News

High Efficiency Power Amplifier Driving Methods and Circuits: Part II

May 19, 2004
Part I of this article 1 analyzed the driving circuits and methods for power amplifiers, using a low frequency approximation. This second part deals with the driving problem at high frequencies. Using a simple yet effective (for this purpose) active device model, the influence of the intrinsic feedback capacitance...
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Thin Film Barium Strontium Titanate (BST) for a New Class of Tunable RF Components

Thin film ferroelectrics (TFFE) are receiving increased attention because of their potential in producing tunable RF and microwave circuits. Tunable circuits, including filters, matching networks and phase shifters offer the flexibility to adapt to cha...
May 19, 2004
RF and microwave applications benefit greatly from the use of tunable devices and circuits. With components that can be tuned over a broad range, filters can be made to tune over multiple frequency bands of operation, impedance matching networks can be adjusted for amplifier power level or antenna impedance...
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Comparison of Coaxial Dipole Antennas for Applications in the Near-field and Far-field Regions

Coaxial antennas with properties similar to those of a two-wire dipole antenna are presented and analyzed. Since coaxial antennas extend along a straight line and can have almost any radius, they may be easily inserted into confined spaces that require...
May 19, 2004
Coaxial antennas with properties similar to those of a two-wire dipole antenna are developed and analyzed in this article. In order to simulate the characteristics of a two-wire dipole antenna with a 50 Ω coaxial line, the inner and outer conductors of the coaxial line are altered in specific...
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Predicting the EVM Performance of WLAN Power Amplifiers with OFDM Signals

This article details a method of predicting the error vector magnitude (EVM) of wireless local area network (WLAN) power amplifiers (PA). It starts with a definition and explanation of EVM, and explains the EVM specification as defined by the IEEE 802....
May 19, 2004
The 802.11a/g WLAN standards stipulate the use of orthogonal frequency division multiplexing (OFDM) signals with M-QAM symbols modulation, where M can be as high as 64. These wideband digital modulations demand PAs with high linearity, due to the inherent high peak-to-average ratio (PAR) of these signals. This article describes...
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S-band High Power Solid-state Amplifier Design and Development

The design and development of a 230 W power amplifier operating at S-band (2.35 to 2.45 GHz) is described. The motivation behind this development is the need for a microwave driver amplifier to be used in the linear accelerator facility at the Institut...
May 19, 2004
The starting point for the design of the S-band high power amplifier was that it had to meet the specifications given in Table 1 . These specifications are dictated by the actual operating conditions of the magnetron, which the amplifier is going to feed with microwave power. Solid-state technology...
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Design of a Novel Balun for a Star Configuration Double-balanced Mixer at S-band

A double-balanced mixer (DBM) has some advantages over other types of mixers. Ring and star configurations are available for the construction of a DBM. Between the two, the star configuration is preferred for high frequency operation. The star configur...
May 19, 2004
The merits of a doubly balanced mixer (DBM) include high dynamic range, good port-to-port isolation and rejection of even-order spurious responses. 1 The ring configuration, using two trifilar wound ferrite transformers, is most commonly used for DBMs at low frequencies. The application of a transformer DBM is, however, limited...
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Leading-edge SAW Filters for Short Range Devices

May 19, 2004
The last few years have seen the manufacturers of chips for short range devices (SRD) operating in the ISM frequency bands (315, 433, 869 and 915 MHz) significantly improving their products. Alongside this, SAW device manufacturers have been endeavoring to develop products offering the best solutions in terms of...
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A Unique New Technology for RF Budget Analysis

May 17, 2004
The primary motivation for using a system simulator is to establish the right system architecture and formulate suitable specifications for each of the underlying components. Accomplishing this goal helps companies to reduce time-to-market by eliminating iterations and rework, and to reduce system cost by ensuring that components are not...
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A Low Profile Switch Filter Bank

May 17, 2004
Switch filter banks or integrated filter assemblies have been primarily built as large high profile block type structures that consume a large portion of available design space. This has primarily been driven by the physical limitations of the RF filters, switches and control circuitry. The Lorch Microwave model 4IFA-1600/22-300-MP...
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Two Cards to Convert a Microwave Receiver into a State-of-the-Art ELINT System

May 17, 2004
Once again the global market for capable electronic intelligence gathering systems is heating up in the wake of increased investments supporting homeland defense both in the US and overseas. Companies that already develop and produce microwave receivers capable of covering the UHF thorough millimeter-wave bands may already have products...
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