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June 2008 [Editorial] Students Abroad Also Spurn Science It is widely acknowledged that US engineering companies are attracting more international than homegrown talent. The problem is that less and less US-born students are going into engineering-related fields. In fact, they are less inclined to study mathematics and science in general. This issue has largely been blamed on our education system. When it was recognized decades ago that fewer students were continuing in math and science, many argued that there should have... June 2008 [Communications] Disparate Solutions Work To Fill Communications Gap More than seven years have passed since the Sept. 11, 2001 terrorist attacks. Since that time, the world has witnessed the subway bombings in the UK, the train bombings in Spain, and multiple other attacks. Government agencies have boosted their resources to gather more intelligence and prevent such attacks. In addition, they continue to emphasize the need for interoperable communications. Problems with communications continue to arise during... June 2008 [Research & Development] Dielectric-Resonator Antenna Serves As Filter THE TREND TOWARD BUNDLING multiple components into a single module for wireless communications has researchers eying a dual-function DRA that can simultaneously act as the antenna and packaging cover. The problem is that the DRA’s quality (Q) factor tends to be low to enhance both radiation and bandwidth. In contrast, the Q-factor of the dielectric-resonator filter (DRF) is usually high to reduce insertion loss. It is therefore contradictory to... June 2008 [Research & Development] Microwave Approach Detects Lymphatic Disease LYMPHATIC FILARIASIS (LF) is a parasitic infection spread by mosquitoes. This disabling and disfiguring disease is caused by thread-like parasitic worms. To accomplish the earlier detection of LF, a microwave method has been presented by Anil Lonappan, Vinu Thomas, G. Bindu, Joe Jacob, and K.T. Mathew from the Department of Electronics, Microwave Tomography, and Materials Research Laboratory at India’s Cochin University of Science and Technology... June 2008 [Research & Development] Define Lightwave Antennas For Measurement Systems COMPARED TO MICROWAVE ANTENNAS, lightwave antennas have different measurement characteristics because of their use of shorter wavelengths. This aspect makes it difficult to design lightwave antennas according to each application system. A technique for measuring the far-field radiation pattern (FFP), gain, and transmissivity of each portion of an aperture has been described by Yasushi Munemasa, Tadashi Takano, and Makoto Mita from Tokyo University... June 2008 [Devices & ICs] Single-Chip MIMO Transceiver Covers 2.3 To 2.7 GHz TO MAKE IT EASIER to build in mobile-WiMAX support, a single-chip, 2.3-to-2.7-GHz, multiple-inputmultiple- output (MIMO) RF transceiver has emerged. By using a dual-receiver architecture to mitigate RF channel fading, the MAX2839 is vowing to improve receiver signal-to-noise ratio (SNR) by 10 dB compared to a single-receiver architecture. The transceiver’s two receivers feature a low noise figure at 2.3 dB and –81-dBm sensitivity for a ... June 2008 [Components] Pulse Modulators Switch In Under 500 ns A COMPACT LINE of magnetron pulse modulators has been spawned to replace tube-based pulsers for highpower- radar transmitters delivering peak RF powers of 3 to 50 kW. The DTI PowerMod solid-state pulse modulators provide over 99 percent switching efficiency. Depending upon load, pulse frequencies range up to 100 kHz. The modulators feature adjustable pulse widths from sub-microseconds to DC pulse to pulse. Under typical performance, the modules vow to... June 2008 [Components] Chip Resistors Are Optimized For 50-Ohm Impedance BY USING SPECIAL MANUFACTURING techniques to reduce voltage standing wave ratio (VSWR), a family of chip resistors has been optimized for 50-O characteristic impedance. Power ratings for the resistors range from 50 mW up to 200 W and a low return loss to 20 GHz. In addition to the standard and MIL-PRF-55342 case sizes, the new components are available in 14 standard case sizes: 0402 thru 3838. The resistors are available with single-surface or wrap-around terminations and a... June 2008 [Test & Measurement] Cable Kit Checks WiFi And Broadband Infrastructure Cable Kit Checks WiFi And Broadband Infrastructure FOR BOTH WIFI and broadband infrastructure installation, cables are needed for RF and data throughput. With the variety of connectors available today and the popularity of reverse-polarity styles, it has become quite difficult to test these cable assemblies in the field. The RFA-4028-WIFI kit was created to simplify this task. The kit contains a Unidapt RF cable tester (RFA-4018-20) with an assortment of 30... June 2008 [Applications] Wireless Medical Devices Eye Three Core Standards RECENTLY, INTEREST HAS GROWN in the potential of wireless technologies to enable a new generation of mobile personal-healthcare devices. These efforts are summarized in a white paper by EZURiO titled, “Wireless Connectivity – the Key to Enabling Personal Medical Technology.” The seven-page document explains that three wireless standards— Bluetooth, Wibree, and WiFi—will most likely dominate the majority of medical applications. Four primary parameters... June 2008 [Applications] WiMAX and WiFi Make Strong Case For Users OVER TIME, WIMAX is expected to achieve similar attach rates to devices as WiFi. Yet it will not eclipse the usefulness of WiFi. In fact, service providers can bundle WiMAX and WiFi to deliver high-speed Internet connectivity in more places. In a joint paper from Intel and Motorola, the companies focus on the synergies between the IEEE 802.11a/g/n Orthogonal Frequency Division Multiplexing (OFDM) and IEEE 802.16e-2005 OFDM-Access (OFDMA) air interfaces. ... May 2008 [Conferences] IMS Displays Microwave Advances In Atlanta MICROWAVE WEEK has become a true meeting place for members of the highfrequency industry. Part continuing education, part product showcase, and part social networking, this week-long series of events is scheduled for the Georgia World Congress Center in Atlanta, GA from June 15-20, 2008. Organized by members of the IEEE’s Microwave Theory & Techniques Society (MTT-S), it includes the 2008 International Microwave Symposium (IMS), the 2008 radio-frequency-integrated-circuit... May 2008 [Devices & ICs] Novel Approaches Vow To Upset The Status Quo Despite the constant innovation in the microwave industry, many products are rooted in the same technologies. Gallium arsenide (GaAs), for example, is at the heart of many of today’s advanced amplifiers and other active components. Amidst this seeming status quo, however, lurk new innovations that could change the way that many products are made. These “disruptive technologies” can take the form of brand-new, completely novel approaches that have never... May 2008 [Communications] Electrically Tune A Planar Inverted-F Antenna WITH THE PLETHORA of wireless standards being applied to today’s handheld devices, the antennas integrated in those products must often operate in 10 or more frequency bands. For the antenna designer, this translates into the challenge of having to cover a single very wide frequency band or multiple frequency bands while maintaining small size and high efficiency. A novel solution may be to use antennas that have a reconfigurable operating frequency with... May 2008 [Research & Development] Dielectric Blood Measurement Detects HIV/AIDS DESPITE THE FACT THAT HIV/AIDS has grown into a worldwide pandemic, Elisa and Western Blot tests are still the only tests available for detecting it. Yet a new testing method could be based on the measurement of the dielectric properties of blood at microwave frequencies. Behind this proposed method are the efforts of C. Rajasekaran from the Department of Medicine at Medical College (Kerala, India) together with Anil Lonappan, Vinu Thomas, G. Bindu, Joe Jacob,... May 2008 [Commercial] Discrete LNAs Improve Performance Of GPS-Enabled Cell Phones GLOBAL POSITIONING SYSTEM (GPS) functionality is being widely added to cellular phones and other handheld devices. Yet cell-phone manufacturers are still placing restrictive requirements on device size and power consumption. To meet these conflicting demands, GPS receiver/processor integrated circuits (ICs) have been developed that incorporate onboard, low-noise-amplifier (LNA) front ends. The problem is that the noise performance and resultant system sensitivity... May 2008 [Communications] Mobile WiMAX Multi-Antenna Techniques Offer Carriers New Option FOR WIRELESS OPERATORS, the introduction of bandwidth- intensive, rich media applications means that more subscribers will begin to consume increasing amounts of data packets. To conquer the resulting capacity issues, operators can acquire more spectrum channels and deploy more sites. Yet these approaches are both inefficient and costly. In “A Practical Guide to WiMAX Antennas: MIMO and Beamforming Technical Overview,” Motorola asserts that mobile WiMAX—in... May 2008 [Components] FETs Target WiMAX PAs From 2500 To 2700 MHz TWO LDMOS RF power transistors have debuted for wireless-infrastructure applications in the 2.5-GHz-to-2.7- GHz frequency band. By providing peak output power of up to 170 W, these transistors should help designers simplify their RF power-amplifier (PA) designs. Under WiMAX signal conditions, the PTFA260851E/F single-ended, 85-W FET typically features 14 dB gain and 22 percent efficiency at 16 W average output power. Its sibling, the PTFA261702E push-pull,... May 2008 [Systems & Subsystems] 7/16 Panel Receptacle Exhibits –175 dBc IMD Performance LOW INTERMODULATION distortion (IMD) is key to newer wireless systems like WiMAX. Such systems rely on outstanding linearity in both amplifiers and passive components to process the complex modulation schemes needed data rates. By consistently delivering passive-intermodulation (PIM) levels of –175 dBc, a 7/16 panel receptacle is promising to meet this need for connectors. This receptacle exhibits a voltage standing wave ratio (VSWR) of less... May 2008 [Communications] 2.5-GHz, 90-Deg. Antenna Serves WiMAX Base Stations TO TARGET both fixed and mobile WiMAX applications, a new antenna is promising to provide a very predictable pattern and consistent performance. The antenna specifically targets maximal-ratio-combining (MRC), multiple-input-multiple-output (MIMO), and other wireless wide-areanetwork applications. The 2.5-GHz, dual-slant 45-deg., 90-deg. WiMAX base-station antenna is fully compliant with ETSI EN 301.525 CS pattern specifications. It operates across the 2.3-to-2.7-GHz...  prev. page
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