July 2008 Digital Predistortion Linearizes Broadband PAs Power amplifier (PA) linearity and efficiency are often two parameters that must be traded off in a wireless system. Fortunately, a Volterra-based adaptive digital-predistortion (DPD) linearizer circuit can enable RF PAs in wireless systems to achieve high efficiency with good linearity. This adaptive digital predistortion solution extends the linear range of power amplifiers and, in combination with crest factor reduction, enables RF PAs to be ... — Hardik Gandhi July 2008 Planar Resonators Arm Tunable Oscillators Last month, Part 1 of this article introduced novel self-injection- locked compact-coupled-planar-resonator (CCPR) oscillators. Part 2 concludes this article with more details on CCPR technology and some product examples. Edward5 proposed a novel, compact, high-Q multilayer integrable printed helical resonator that offers an optimum ratio of loaded quality factor to unloaded quality factor (QL/Q0 ) for minimum phase noise for a given VCO topology.... — Ajay Kumar Poddar , et al. July 2008 CSP Technology Shrinks RF Component Size Components and integrated circuits for RF/microwave applications have traditionally been small in size, although the limit on miniaturization has often been the package. With the announcement of its unique WaferCap chipscale- packaging (CSP) technology, however, Avago Technologies (San Jose, CA) has dramatically shrunk the size of microelectronic packaging, but also the losses that such packaging can inflict on high-frequency circuits. Avago’s ... — Jack Browne June 16, 2008 GaN HEMT Transistors Designed For 5-GHz WiMAX Applications Two new gallium nitride (GaN) HEMT transistors from Cree Inc. are for use in WiMAX applications covering the 4.9- to 5.8-GHz frequency band. The new CGH55015F and CGH55030F transistors, which are in sample release, are specified to operate at up to 5.8 GHz — Lisa Maliniak June 16, 2008 Low-Capacitance Varistors Protect Antennas, Data Lines The AntennaGuard Series of low-capacitance multilayer varistors (MLVs) has been expanded to include a sub-1-pF version. Designed to provide a one-chip means of protecting high-speed digital interfaces, RF antennas, and RF amplifier circuits against — Lisa Maliniak June 2008 Coupled Stubs Support Microstrip Bandbass Filter Filters are essential in separating and sorting signals in communications systems. Filters are essentially two-port networks that can modify the frequency response of a communications system. In some applications, such as communications satellites and mobile communications devices, it is critical that filters be designed with small size and light weight. Planar filter geometries are well suited for meeting these requirements. The approach presented... — N. Nagachenchaiah , et al. June 2008 Planar Resonators Arm Tunable Oscillators Communication systems rely on low-phase-noise signal sources such as tunable oscillators or phase-lock-loop (PLL) synthesizers for reliable voice communications and to ensure transmitted data integrity. Challenges still remain in achieving reasonable trade offs in low phase noise, low thermal drift, low power consumption, low cost, and potential for integration in integrated-circuit (IC) processes, however.1-38 With ever- increasing demands... — Ajay Kumar Poddar , et al. June 2008 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... — Nancy Friedrich June 2008 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... — Nancy Friedrich June 2008 Cables And Connectors Deliver Robust Signals Cables and connectors are among the most overlooked components in any high-frequency system. Since they must deliver signals from one point to the next, without altering those signals, these transmission-line components are generally only noticed when they fail. In spite of the low profile, however, manufacturers continue to invest in these components in the quest of improved performance and reliability, to ensure that their cables and connectors ... — Jack Browne May 2008 Modular GPIB Switches Connect Test Applications Switching signals among test sources and devices under test (DUT) in a measurement setup can be cumbersome and time-consuming. Fortunately, the GPIB series 8000 modular switch assemblies help simplify complex test assemblies with reliable electromechanical microwave switches mounted in their own rugged enclosures. The switch assemblies are designed for applications from DC to 18 GHz... — Jack Browne May 19, 2008 RF Power Transistor Targets LDMOS Base Stations NXP Semiconductors recently introduced the BLC7G22L(S)-130 base station power transistor optimized for high power use and Doherty amplifier applications. This is the first of its products to feature the company’s Gen7 LDMOS technology... — Lisa Maliniak May 19, 2008 Broadband Linear Power Amplifier Delivers +39 dBm OIP3 A new QFN packaged GaAs MMIC linear power amplifier from Mimix Broadband features +39 dBm OIP3 and 26 dB small-signal gain... — Lisa Maliniak May 19, 2008 Solid-State Switch Boasts Less Than 100-ns Speed Trilithic’s RF and Microwave Components division has released a solid-state non-reflective RF switch with a 1-MHz to 4.2-GHz frequency range... — Lisa Maliniak May 2008 Chip-Scale Packaging Approach Cuts Losses Chip-scale packaging (CSP) offers great promise for shrinking the size and cost of certain semiconductor devices. With customer pressures to reduce the size, weight, and cost of commercial semiconductors for wireless handsets, infrastructure equipment, and other commercial electronic applications, semiconductor manufacturers have sought ways to reduce the impact of packaging on their chips. Avago Technologies (... — Jack Browne May 2008 Multilayer Microstrip Forms Tunable Bandstop Filters Tunable bandstop filters are useful for a wide range of applications in eliminating unwanted signals and interference. Designing such filters can be greatly simplified with a new structure fabricated on multilayer microstrip substrates with a metallic diaphragm. This new structure overcomes the limitations of traditional tunable bandstop filter designs and supports simple, low-cost manufacturing processes.1 The new tunable filter... — Yamina Bekri , et al. May 2008 VCOs Offer Linear Tuning Through 10.9 GHz Linear tuning is essential for a wide range of applications requiring frequency precision over time and temperature. The latest series of voltagetuned oscillators from Synergy Microwave (www.synergymwave.com) provide outstanding tuning linearity at frequencies through 10.9 GHz. The first three models in the DCO and DXO families of voltage-tuned oscillators provide frequency coverage of 4730 to 5420... — Jack Browne May 2008 Custom Synthesizers Range 144 To 4500 MHz Frequency synthesizers provide the fixed and tunable signals for local oscillators (LOs) in a wide range of commercial and military communications systems, including in wireless base stations. Technologies for creating frequency synthesizers are diverse, from traditional analog methods using phase-locked loops (PLLs) to direct digital synthesizers (DDSs) that rely on high-speed digital-to-analog converters (DACs) to transform digital input words into... — Jack Browne May 2008 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,... — Nancy Friedrich May 2008 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... — Nancy Friedrich |
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