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Design Features

283 results found for Design Features, displaying items 1 - 20

December 2008 [Communications]
UWB Antenna Assists Ground-Penetrating Radar
Landmines are buried and forgotten, so often that an estimated total of 110 million landmines are buried in over 60 countries around the world. Statistics show that hidden and forgotten landmines kill or injure approximately 70 people each day, resulting in over 25,000 deaths or injuries per year. Unfortunately, there is little international effort to detect and clear the landmines due to shortage of funding. Before they can be removed, they must be located... — Boon-Kuan Chung , et al.

December 2008 [Test & Measurement]
Test Radio Receivers With Recorded Signals
Channel impairments can be disruptive on RF-based communications devices. Impairments such as fading and multipath, which are often unpredictable, can hinder wireless communications. Because channel impairments are often unpredictable and not repeatable, many engineers face the challenge of supplying a prototype receiver with a reliable model of the real-world signal environment. Fortunately, by understanding the causes of these impairments through... — Dominique Fortin , et al.

December 2008 [Components]
Equalize RF Amplifiers With Bandpass Filters
Filters and amplifiers can make a powerful combination, especially when the filter is used to equalize the amplifier. What follows is an approach to apply the complementary response characteristics of a bandpass filter to flatten the amplitude response of a transmit amplifier. The filter consists of a pair of asymmetric slow-wave open-loop resonators. It reduced ripple in a transmitter’s passband from 3.3 dB before equalization to 0.5 dB after... — Wei Hong , et al.

November 20, 2008 [Test & Measurement]
Assess Quadrature-Demodulator Noise Figure Using Vector Signal Analysis
In a direct-conversion signal chain, it is often difficult to accurately predict the noise-figure impact due to an in-phase/quadrature (IQ) demodulator. Typically, the noise figure is measured using a noise-figure meter. Yet those meters do not operate at low enough frequencies to capture representative noise data at baseband frequencies... — Eric Newman , et al.

November 2008 [Computer-Aided Engineering]
Perform Fast Optimization Of Tapered WG Transformers
Waveguide tapers are often necessary when making a transition between two different types of waveguide transmission lines, such as singleridge waveguide and double-ridge waveguide. While three-dimensional electromagnetic (EM) analysis programs can help achieve good performance for such waveguide tapers, they also depend on a fairly close starting point in terms of the geometric dimensions for the transition. Fortunately, the author has developed a... — Zelman Harbater

November 2008 [Applications]
UWB GPR Receiver Detects Waterpipe Leaks
Ground-penetrating-radar (GPR) systems based on ultrawideband (UWB) generation and reception of reflected signals are often associated with military applications such as land-mine detection. But because of aging waterpipe infrastructure in many major cities within the European Union (EU), a UWB-based GPR system also has application for detecting leaks in underground waterpipes. The cost of replacing these aging waterpipe systems, if left to deteriorate beyond a... — Anastasios Garetsos , et al.

November 2008 [Communications]
Antenna Tuning Approach Aids Cellular Handsets
Shrinking wireless and mobile electronic devices are impacting antenna design and performance. Portable device designers must work with miniature antennas covering 824 to 2170 MHz or more, different modulation schemes, and high data rates. With shrinking handsets, the area for the antenna is limited, often with the antenna wrapped around peripheral functions in the handset. Such a solution often makes the antenna more susceptible to detuning by... — Rodd Novak , et al.

October 2008 [Test & Measurement]
Measure The Range Of Sensor Networks
Wireless sensor networks (WSNs) provide invaluable services with their short-range communications capabilities. But their limited operating power can impose restrictions on the maximum allowable distance between the sensors and the base station.1,2 Due to this limitation, direct communications between a sensor and its base station is not always possible, especially in a difficult radio environment with strong attenuation. To overcome this... — R.A. Abd-Alhameed , et al.

October 2008 [Communications]
Analyze Interference In Compact Wireless Designs
Portable wireless transceivers have proliferated rapidly in recent years, for a wide range of applications including transmission and reception of voice, data, and video. One of the key requirements for wireless equipment is that the electronic circuits operate in the vicinity of other high-frequency radio transmitters, such as Bluetooth devices. Previous studies on interference have considered any source as a far-field effect and focused on... — Don LaFontaine

October 2008 [Devices & ICs]
Setting Strategies For Transmission Lines
Last month, the first part of this article made recommendations for choosing the physical dimensions of stripline. A large height, H, ensures high power-handling capability. Smaller H requires a smaller strip for the same impedance, leading to higher losses. The thickness, h, of the suspended stripline dielectric substrate should be as small to minimize losses and parasitic inductance of vias, as well as to reduce cost. For slotline, the... — Leo G. Maloratsky

October 2008 [Devices & ICs]
Two-Stage LDMOS RFIC Drives WiMAX
Power amplifiers (PAs) for modern communications systems are generally designed by cascading and paralleling multiple RF transistors to achieve the required solid-state gain and power. With their wide range of impedancematching, optimization, and architectural options, single-stage discrete RF transistors offer a great deal of flexibility for power-amplifier designers, although with some loss of printedcircuit- board (PCB) space compared to RF... — Cedric Cassan , et al.

September 2008 [Test & Measurement]
Design A Scanning RSSI Receiver For WiMAX Measurements
WiMAX broadband wireless technology offers the promise of untethered, highspeed Internet access in supported service areas. Based on the IEEE 802.16 standard, WiMAX is specified for use in a wide range of frequencies through 66 GHz, with a variety of operational profiles differentiated by frequency band, channel bandwidth, and duplexing mode.1-3 WiMAX has been developed rapidly from inception to deployment. According to a recent (January 2008)... — Zhengbo Jiang , et al.

September 2008 [Test & Measurement]
Achieving Amplitude Accuracy In Modern Spectrum Analyzers
Spectrum analyzers are among the most versatile of RF/microwave measurement tools, with signal power among the most common measurement made with the instruments. Traditionally, the combination of a power meter and power sensor has been the measurement tool of choice for its well-characterized traceability path back to reference standards at national standards laboratories. But modern spectrum analyzers have made dramatic improvements in amplitude... — Joe Gorin

September 2008 [Systems & Subsystems]
Setting Strategies for Transmission Lines
Transmission lines are often taken for granted in the design of high-frequency circuits and integrated circuits (ICs), since the focus is often on getting signals into and from an active device. But by understanding the capabilities of different microwave/RF transmission lines and how to optimize them, design iterations, time, and unnecessary cost can be saved from a project. Part 1 of this two-part article will show how a careful design process should... — Leo G. Maloratsky

September 2008 [Components]
Uneven DGS Cells Construct Compact LPF
Defected-ground-structure (DGS) cells can serve as effective building blocks for high-performance, high-frequency filters. Microstrip filters are widely used in microwave and millimeterwave systems and, in particular, low-pass filters (LPFs) are essential components in modern communications systems.1 The increasingly challenging requirements of such systems calls for LPFs with increasingly improved performance for in-band and out-of-band ... — Xiao Qun Chen , et al.

August 2008 [Test & Measurement]
Use Pulse I-V Testing To Characterize RF Devices
Pulsed current-voltage (I-V) testing is becoming an invaluable method for evaluating the performance and reliability of semiconductor devices. The measurement approach is relatively cost effective and avoids the negative effects of self-heating and transient trapped charges, which can result in misleading test results. And pulsed I-V testing provides the accurate device data needed for improved computeraided- engineering (CAE) software models. ... — Pete Hulbert

August 2008 [Devices & ICs]
Digital Predistortion Linearizes Broadband PAs, Part 2
Power amplifiers (PAs) are essential to the transmitter sections of communications systems and in many other RF/microwave applications. As seen last month in Part 1 of this three-part series, the linearity of a power amplifier is often compromised for efficiency, but numerous digital predistortion techniques are available to help improve linearity without sacrificing efficiency. Part 2 of this threepart article series will offer some comparisons of different ... — Hardik Gandhi

August 2008 [Test & Measurement]
Design An X-Band Vivaldi Antenna, Part 2
Vivaldi antennas can provide excellent directional propagation at microwave frequencies. As introduced in Part 1 of this article (July Microwaves & RF), the Vivaldi antenna can be a simple design based on a tapered-slot-antenna (TSA) architecture. This concluding installment in this two-part article will compare measurements of a designed and fabricated X-band antenna with simulations from the Advanced Design System (ADS) software from Agilent ... — Dr. J.S. Mandeep , et al.

August 2008 [Test & Measurement]
Analyze Antenna Approaches for LTE Wireless Systems
Multiple-input, multiple- output (MIMO) spatial-diversity antenna configurations are specified for emerging 3GPP Long- Term Evolution (LTE) mobile communications systems. In reality, LTE systems specify three types of antenna techniques: MIMO, beamforming, and diversity approaches. The three techniques are considered essential for improving signal robustness and achieving LTE system capacity. Understanding how the different antenna techniques work... — Moray Rumney , et al.

July 2008 [Communications]
Design An X-Band Vivaldi Antenna
Antennas are essential to highfrequency communications and electronic systems for radiating or receiving electromagnetic (EM) energy. Although there are many types of antennas, they all operate according to the same basic EM principles. The basic behavior of an antenna can be described by its wave field strength, polarization, and direction of propagation.1 Key requirements in applications such as airborne radar and communications systems... — Dr. J.S. Mandeep , et al.