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December 2011 Etching Alternative Emerges For RFID Antennas Traditionally, RF-identification (RFID) antennas have been produced by etching conductive layers on substrates. — March 2011 Metamaterials Set Spacecraft Antennas On New Path MANY NAYSAYERS have doubted the potential of metamaterials, pointing to issues like narrow bandwidth and high loss. Recently, however, Lockheed Martin collaborated with Pennsylvania State University to develop a material that will improve the performance of spacecraft antennas. They have successfully designed metamaterials that enhance standard horn antennas by more than an octave bandwidth with negligible loss. This electromagnetic (EM)... — February 2011 Picking Materials For Multilayer PCBs Multilayer printed-circuit boards (PCBs) offer an opportunity to save space by stacking circuits. once associated more with digital circuit cards, multilayer PCBs are now commonly used in commercial, military, and test applications requiring a large amount of functionality in a small space. With those tightly packed circuits, however, come some stiff requirements for the circuitboard materials—such as laminates and prepregs—used in building the... — Jack Browne November 2010 Selecting Optimal Microwave Substrates Microwave substrates are often compared to building materials. They are available at many levels of quality and cost, but cutting corners can set limits on the overall performance possible for a circuit. Most dielectric materials’ data sheets list the key parameters to consider when choosing a printed-circuit-board (PCB) material for a microwave application. These include dielectric constant, dissipation factor, coefficient of thermal expansion... — Jack Browne October 2010 Lasers Carve MM-Wave Circuits Millimeter-wave frequencies represent largely uncharted bandwidth. Hoping to explore the region further, Germany’s Fraunhofer Institute for Applied Solid State Physics, named after Joseph von Fraunhofer who investigated the properties of visible light as early as 1820, has enlisted the aid of a ProtoLaser S system from laser-machining specialist LPKF... — Stephan Schmidt August 12, 2010 Rogers Develops Matched 6.15-Dk Multilayer System Solution Rogers Corp. has developed the RO4460prepregs to match its RO4360 laminates. Both materials feature consistent dielectric constant (Dk) of 6.15 ± 0.15 and low dielectric loss of 0.003 at 2.5 GHz. — The Editors of Microwaves & RF March 2010 Suppliers Enhance Substrate Performance Electronic substrate materials are like the foundation in a building: rarely noticed, but critical to the overall architecture. For RF/microwave circuits, the printed-circuitboard (PCB) substrate or laminate material is an essential building block that must be stable over time and temperature with low signal losses at microwave frequencies. Although PTFE has long been a substrate of choice at microwave frequencies, pure PTFE tends to suffer... — Jack Browne February 2010 Partnership Results In High-Permeability Magnetic Shielding Tubing WARWICK, RI—A.T. Wall Company has partnered with the MuShield Company to develop the M Shield seamless, high-permeability magnetic shielding tubing that ranges to 20 feet in length. Depending on the welding method used, this tubing’s shielding capability promises to be 20 to 30 percent better than a formed and welded product. The tubing can hold outside and inside diameters to +/-0.002 inches along with wall thicknesses within 0.002 inches. The seamless ... — Dawn Hightower January 2010 EMI Shielding Maintains Strength In Harsh Conditions TO MAINTAIN STRENGTH at elevated temperatures and under cryogenic conditions, new tubular braided electromagnetic-interference (EMI) shielding combines the conductivity of an outer metal coating with the strength, light weight, and flexibility of genuine KEVLAR fibers. Dubbed ARACON, it comes in standard inner-diameter sizes ranging from 0.62 to 2.00 in. When braided into a shield, it vows to provide impressive performance against EM and RF interference. The conductors of... — Nancy Friedrich December 2009 Microwave Materials Lay Foundation For PAs Power-amplifier designers typically create a circuit based on specific active devices for the output stage. While the choice of transistor determines the ultimate performance of an amplifier, printed-circuit-board (PCB) materials can also play a major role in an amplifier design. Selecting optimum substrate materials for an amplifier can improve gain and stability, and enable the maximum output power possible for a design. High-frequency amplifier designers have a wide array... — John Coonrod November 2009 Making The Most Of Microwave Materials Microwave materials provide the foundations for highfrequency circuits and packaging. Dielectric circuit materials, often referred to as laminates because of the added copper for etching transmission lines, have made progress in recent years in terms of consistency and stability as well as flexibility, with many suppliers offering a wide range of materials in support of designs from RF through millimeter-wave frequencies. High-frequency... — Jack Browne November 2009 Two-Sided Contacting Reduces RC Parasitics At delft institute of Microsystems and Nanoelectronics (DIMES), RF/microwave silicon devices have been implemented in a process that allows two-sided contacting of the devices. Dubbed the back-wafer-contacted Silicon On Glass (SOG) Substrate Transfer Technology (STT), that process was developed at DIMES. Those implementations were reviewed by Lis K. Nanver, Hugo Schellevis, Tom L.M. Scholtes, Luigi La Spina, Gianpaolo Lorito, Francesco Sarubbi, Victor Gonda,... — Nancy Friedrich October 2009 Form GaAs/InGaAs Lasers On Virtual Ge Reliable GaAs-based optoelectronic devices, such as GaAs/InGaAs quantum well lasers, can be realized on silicon substrates using several advanced techniques. Fabrication involves first forming germanium (Ge) stripes on a silicon dioxide (SiO2) trench-patterned silicon substrate via aspect ratio trapping (ART), where any defects originating from the Ge/Si interface are trapped by laterally confining sidewalls. Defects arising from above the... — J. Bai , et al. June 2009 Launching TM Mode Onto A Single Conductor, Part 2 Last month, the first part of this three-part article series introduced a transversemagnetic (TM) propagation mode that is present with the better-known transverseelectromagnetic (TEM) mode in conventional coaxial transmission line. Put simply, waves move along a conductor having no outer shielding and no insulation or special surface conditioning. Part 2 will describe the TM mode around an unconditioned conductor, backed by models and measurements ... — Glenn Elmore March 27, 2009 High-Frequency Laminates Showcased At CTIA 2009 — Lisa Maliniak March 2009 Microwave Materials Move Beyond Thermal Management Materials are not just tasked with bonding and separating circuit traces and ground lines on circuit boards. They must also channel life-shortening heat away from components. In addition, materials must provide stable foundations for circuits over both time and temperature even as new designs call for higher power and increased thermal stability. To enable future designs, materials are growing increasingly sophisticated and promising increased... — Nancy Friedrich February 2009 Making Manufacturing Choices For X-Band BPFS Bandpass filters help extract desired signals from a portion of frequency spectrum while rejecting unwanted signals. In addition, they can symmetrically or asymmetrically modify the amplitude and/or phase of a signal. They are essential to a host of commercial and military systems and have evolved over the years, so much so that a review of available filter design and materials technologies can aid engineers faced with developing high-performance bandpass filters for X-band... — William Cuviello , et al. February 2009 Form Bandpass Filters On Glass Substrates Glass is good for more than just windows: in recent years, the material has attracted attention for its dielectric properties and cost-effectiveness as a high-frequency-circuit substrate. It features low circuit losses over wide frequency and temperature ranges and is suitable for circuit fabrication using standard integrated-circuit (IC) planar manufacturing methods. When evaluated for several high-frequency filter topologies, the performance of glass-based components has... — D. Balasubramanyam , et al. December 2008 ICP Etching Reduces MM-Wave Substrate Loss FOR GALLIUM-ARSENIDE(GAAS) coplanar passive devices, the design methods used in centimeterwave frequencies have been proven to work for millimeter-wave frequencies up to W-band (75 to 110 GHz). Those same methods can be applied to CMOS coplanar devices at millimeter-wave frequencies. To demonstrate this point, two test third-order, quarter-wavelength, double-shortedstub wideband bandpass coplanar filters have been implemented at E-band by Pen-Li... — Nancy Friedrich December 4, 2008 DVB Library Added To VSS Software Tool — Jack Browne  prev. page
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