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ISSUE DATE: JULY 2006 | |
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July 2006 - In This Issue [Cover Story] Surface-Mount Amps Span 0.1 To 40.0 GHz Broadband amplifiers serve an endless list of applications, from amplitude adjustment in commercial and military systems to signal driving signals in test equipment. Adding an amplifier to an application usually requires a trade-off between size and effort: The simplicity of using a connectorized amplifier is offset by its large package size, while the small size of a chip-and-wire amplifier is balanced by the labor involved with this approach. Fortunately, MITEQ... — Don Neuf , et al. [News] High-Power Transistors Surf GaN Wave Transistors are workhorses in both analog and digital circuits. In modern high-power applications, they have almost completely replaced the vacuum tube. Since the transistor was invented in the middle of the 20th century, these devices have continuously evolved. Today, for example, many high-power-transistor makers are making the switch to gallium nitride (GaN). Compared to more traditional technologies, such as silicon LDMOS and gallium arsenide (GaAs), GaN transistors... — Nancy Friedrich [News] Crosstalk: An Interview With Digital Fountain’s Charlie Oppenheimer MRF: What attracted you to join this company? Oppenheimer: There are two things you look for in an entrepreneurial situation. One is a very big profit. Big markets are where big opportunities are made. The other is some distinguishing characteristics in the company. And this company had both of those in place. This technology can be used in some many different systems: cellular, Internet, defense communications. It is limitless. The technology at its core... — Jack Browne [News] Plethora Of Patents Fuels Licensing Foray Technological advances often earn patents for their inventors. For large companies, such as IBM or Agilent Technologies, it is not unusual for multiple patents to be granted in a single year. But what makes the growing collection of US and overseas patents so unusual for Synergy Microwave (Paterson, NJ) is the relatively small size of the company in proportion to the number of patents pending and received in the past few years. With just over 100 employees, the ... — Jack Browne [Design Features] Establish Test Procedures For WiMAX Transceivers Data-intensive wireless applications have sped the development of multicarrier modulation techniques, such as orthogonal frequency-division multiplexing (OFDM). OFDM can overcome many problems that arise with high-bit-rate communications, such as time dispersion.1-4 Because OFDM is becoming so widespread, with applications in European Hiperlan, US wireless local-area networks (WLANs, such as IEEE 802.11a/g standards), in wireless metropolitan-area... — Huseyin Arslan , et al. [Design Features] Topology And Technology Drive E-PHEMT Amplifiers Wideband Darlington amplifiers-offer versatile gain for a variety of wireless and wire-line applications, including in base stations, fiber-optic transceivers, cable-television (CATV) systems, and measurement systems. A Darlington feedback amplifier features multi-decade coverage, can be realizedin a small size, and is simple to use with few additional external components. What follows is a report on a Darlington amplifier that makes use an innovative bias topology ... — Kevin W. Kobayashi [Product Technology] System Monitors Satellite Carriers Satellite-communications ( satcom) systems send signals where terrestrial-based wired and wireless systems often fail to go. But monitoring the health and performance of a satcom network requires specialized spectrum-analysis tools with enough accuracy and stability to characterize the quality of satcom carriers. The VC1800 Carrier Monitoring System from Morrow Technologies (St. Petersburg, FL) is such a tool, with a frequency-measurement range of 3 to 1800 MHz and as... — Jack Browne [Editorial] Watching The Sun Set At The MTT-S TRADE SHOWS PROVIDE different industries a chance to assess themselves. There was plenty of assessment taking place at the IEEE Microwave Theory & Techniques Symposium (or International Microwave Symposium, if you prefer), held last month in the Moscone Convention Center (San Francisco, CA). And there was a great deal of looking back. The event didn't lack for the quality of its presentations in the technical sessions or the number of major new product... — Jack Browne [Here's How We Solved It] Stripline Crossover Board Facilitates Planar High-Frequency Microwave Subassemblies One of the challenges in the layout of multifunction microwave assemblies is the crossing of microwave transmission lines while maintaining isolation requirements. In designs of limited complexity, this crossing-over has been done using a vertical transition. The transition comprises RF feedthroughs that are used to route signals to the backside of the housing and back up again in order to maintain the high isolation between signal paths. Although this design ... — Raymond Kaarsberg , et al. [Here's How We Solved It] Advanced Oscillator Technology Conquers Reference Degradation Due To Dynamic Environments The Problem: The sophisticated military electronic systems aboard helicopters, missiles, and unmanned aerial vehicles (UAVs) must provide superior performance while being subjected to severe environmental conditions. The greatest impact on high performance comes from dynamic environments—those that induce degradations while the military platform is in motion accomplishing its intended mission. Of these mobile disturbances, vibration, acceleration, and shock have ... — Olie Mancini [Here's How We Solved It] Microwave Synthesizers Aid Aircraft Tracking Significant advances have been made in Laser Detection and Ranging (LADAR) systems, which also are known as Light Detection and Ranging (LIDAR). These advances provide for a broad range of target imaging and tracking applications. LADAR provides significant advantages over conventional RF RADAR in image resolution, as much shorter wavelengths of the electromagnetic spectrum are used (typically in the ultraviolet, visible, or near infrared). Because image resolution... — Ken Positeri [Here's How We Solved It] SMD Port Discontinuities Are Conquered It was a pesky problem: the highaccuracy EM analysis of circuits with ports placed internal to the circuit (instead of on the edge). These internal ports would be used to connect surface-mount devices (SMDs) or include transistors inside an RF IC. Much of the time, uncalibrated internal port results are "good enough." When measured and calculated, they line up reasonably close. But there was that pesky little bit of difference that occasionally became large and design-disabling. ... — James B. Rautio [Here's How We Solved It] Quick ACPR Analysis Performs Necessary PA Simulations Traditionally, power amplifiers for communication systems have been designed to meet specifications like 1-dB gain-compression output power or third-order intercept point. Such tests can be made with one or two sinusoidal input tones. In reality, however, these power amplifiers are usually required to meet a certain adjacent-channel-power-ratio (ACPR) specification or satisfy a spectral mask at a particular output power. These results may not be obtained by using... — Andy Howard [Here's How We Solved It] Connectors Raise Density And Reduce Footprint A major defense contractor wanted to eliminate the use of cable assemblies for its in-the-box applications. The contractor gave W.L. Gore & Associates the challenge of developing low-profile boardto-board interconnects for its Common Radar Module (CRM) architecture. The requirements for a super-density, push-on interconnect series included the following: center-to-center spacing of 0.085 in. maximum, printed-circuit-board (PCB) -to-PCB stack height of 0.110 in. maximum, lowest possible... — Paul A. Czikora [Here's How We Solved It] Making The Case For Well-Rounded Devices In today's competitive wireless market, success is measured by providing solutions for customers rather than simply delivering " unprecedented performance" in a single area. For example, a new performance benchmark set by an RF power transistor will make great headlines. But it will accomplish little else if it isn't accompanied by attributes that let customers put that performance to work. To be truly useful in a particular system, it must offer more than impressive P1dB or Psat "numbers."... — John McCaffrey [White Paper] White Paper: RF Power Devices Meet Wireless Challenges Head On RF Power Devices Meet Wireless Challenges Head On? The number and types of commercial wireless-communications technologies have exploded in the last 15 years, from comparatively simple systems using FDMA to the higher-order modulation schemes employed in GSM and CDMA and new standards and services such as WiMAX and ZigBee?. For semiconductor manufacturers serving these applications, they represent immense opportunities. For... — John McCaffrey , et al. |
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