Coupler

Distribution by Scientific Domains

Kinds of Coupler

  • branch-line coupler
  • hybrid coupler


  • Selected Abstracts


    To compact ring branch-line coupler using nonuniform transmission line

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009
    F. Hosseini
    Abstract A compact ring Branch-Line Coupler (BLC) with size reduction of about 50%(in circuit area) of conventional BLCs at frequency 2 GHz is introduced. The coupler is designed by using nonuniform transmission lines (NTL) instead of Uniform Transmission Lines in each arm. The normalized width w (z)/h function of the NTLs is expanded in a truncated Fourier series. The reduced size couplers are potential building blocks for the growing wireless communication markets. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2679,2682, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24703 [source]


    Azobenzene Liquid-Crystalline Polymer for Optical Switching of Grating Waveguide Couplers with a Flat Surface

    MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2007
    Chong-Uk Bang
    Abstract Grating waveguide couplers with a flat surface were fabricated in an azobenzene liquid-crystalline polymer film by holographic lithography using Ar+ laser beams at 488 nm. When a probe beam at 633 nm was incident to one grating of a grating waveguide coupler, the beam propagated in the waveguide and an output beam came out from the other grating with the throughput coupling efficiency of ,5%. Upon irradiation of the film between two gratings with UV light to cause trans,cis photoisomerization of the azobenzene moiety, the intensity of the output beam was repeatedly switched. It was found that the alternating irradiation at 366 and 436 nm induced reversible changes in the intensity of the guided probe beam. [source]


    Dielectrophoresis microsystem with integrated flow cytometers for on-line monitoring of sorting efficiency

    ELECTROPHORESIS, Issue 24 2006
    Zhenyu Wang
    Abstract Dielectrophoresis (DEP) and flow cytometry are powerful technologies and widely applied in microfluidic systems for handling and measuring cells and particles. Here, we present a novel microchip with a DEP selective filter integrated with two microchip flow cytometers (FCs) for on-line monitoring of cell sorting processes. On the microchip, the DEP filter is integrated in a microfluidic channel network to sort yeast cells by positive DEP. The two FCs detection windows are set upstream and downstream of the DEP filter. When a cell passes through the detection windows, the light scattered by the cell is measured by integrated polymer optical elements (waveguide, lens, and fiber coupler). By comparing the cell counting rates measured by the two FCs, the collection efficiency of the DEP filter can be determined. The chips were used for quantitative determination of the effect of flow rate, applied voltage, conductivity of the sample, and frequency of the electric field on the sorting efficiency. A theoretical model for the capture efficiency was developed and a reasonable agreement with the experimental results observed. Viable and non-viable yeast cells showed different frequency dependencies and were sorted with high efficiency. At 2,MHz, more than 90% of the viable and less than 10% of the non-viable cells were captured on the DEP filter. The presented approach provides quantitative real-time data for sorting a large number of cells and will allow optimization of the conditions for, e.g., collecting cancer cells on a DEP filter while normal cells pass through the system. Furthermore, the microstructure is simple to fabricate and can easily be integrated with other microstructures for lab-on-a-chip applications. [source]


    New Optical Amplifier Placement Schemes for Broadcast Networks

    EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2000
    Jason Iness
    WDM optical broadcast networks (based on the passive-star coupler) may encounter large splitting and attenuation losses that need to be compensated for using optical amplifiers, such as EDFAs. However, optical amplifiers are costly, so their total count in the network should be minimized. This study will examine three different such amplifier-placement schemes. The first approach utilize fewer amplifiers than previous schemes that do not add special hardware to avoid the near-far effect. The second study considers a bidirectionai-link network and it can use fewer amplifiers than a comparable unidirectional-link network. The third study minimizes the number of amplifiers when the amplifiers are equipped with special hardware to avoid the near-far effect, i.e., amplifiers are equipped with attenuators/filters to equalize amplifier input power on different wavelengths. [source]


    Periphyton as alternative food source for the filter-feeding cladoceran Daphnia magna

    FRESHWATER BIOLOGY, Issue 1 2009
    SILVANA SIEHOFF
    Summary 1., Daphnia magna, a well-studied primary consumer, is mainly known as a filter feeder. In this study, we investigated the ability of D. magna to use periphyton as an alternative food source to phytoplankton. We examined the development of laboratory populations fed with different food sources (Desmodesmus subspicatus and/or periphyton or neither) over a period of 42 days, and observed the behaviour of the daphnids. 2.,The addition of periphyton to phytoplankton food led to an increase of daphnid population biomass. When fed with periphyton as the only food source, a small but stable D. magna population developed. 3.,The behaviour of daphnids fed with both food sources revealed a preference for feeding on D. subspicatus. Only below a concentration of D. subspicatus of approximately 0.05 mg C L,1 (0.4 107 cells L,1) did D. magna use periphyton as an alternative food source. 4.,Periphyton showed distinct reactions to grazing by D. magna. The thickness of the periphyton layer was reduced from about 4 to 1 mm and we observed a change in species composition due to grazing. 5.,The ability of D. magna to graze on periphyton could serve to stabilize its population density and reinforce its competitive advantage over other cladocerans. By switching between food sources, D. magna can act as a coupler between pelagic and benthic habitats and food webs. [source]


    Frequency reconfigurable RF circuits using photoconducting switches

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2010
    D. Draskovic
    Abstract Designs for a frequency switchable dual-band branch-line coupler and a reconfigurable S-band power amplifier input matching network with photoconducting switches are presented. Frequency switching is achieved by increasing the power of the laser applied to the highly resistive silicon wafer and changing the properties of silicon under optical illumination. The advantages of this approach are high-speed switching, electromagnetic transparency (no interference), and thermal and electrical isolation between the device and the control circuit. A branch-line coupler frequency shift of 35% and 10% has been achieved from all switches off to all switches on in lower (900 MHz) and upper (1800 MHz) frequency bands, respectively. Frequency switchable class AB power amplifier with silicon switch in the input matching circuit has obtained the frequency tuning range of 2.5,3.5 GHz with no significant loss in efficiency and linearity. 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source]


    Design and measurement of microstrip ferrite coupled line circulators

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 3 2001
    C. S. Teoh
    Abstract The design of microstrip ferrite coupled line (MFCL) circulators using normal mode theory and the first proof-of-principle experiments are described. The longitudinally magnetized ferrite slab is positioned on top of a pair of microstrip lines to form the FCL and this is used with a T -junction and a novel hybrid coupler to form a three-port and a four-port circulator, respectively. The results show MFCL circulator behavior for the first time, and impedance levels and discontinuities are discussed. 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 121,130, 2001 [source]


    Formulation and characterization of radio-opaque conjugated in situ gelling materials,

    JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2010
    Brandon Blakely
    Abstract X-ray visibility is an integral design component of in situ gelling embolization systems for neurovascular treatment. The goals of this project included the synthesis and characterization of a unique intrinsically radio-opaque in situ gelling material for neurovascular embolization. The gels formed using Michael-Type Addition between pentaerythritol tetrakis 3-mercaptopropionate (QT) thiols and poly(propylene glycol) diacrylate (PPODA) with the addition of the new material Iodobenzoyl poly(ethylene glycol) acrylate (IPEGA), a radio-opaque agent, synthesized successfully as confirmed with 1H NMR. The PPODA and IPEGA were mixed using a syringe coupler with QT and buffer at pH 11 for 90 seconds. Gel mixes were weighed to provide equal molar thiols and acrylate groups, changing the present acrylate-bearing compounds wt % ratios from 100 PPODA: 0 IPEGA, 90:10, 80:20, 70:30, 60:40, 50:50, and 0:100. Formulations with 10% and above of IPEGA were X-ray visible. Rheology showed that increasing the amount of IPEGA decreased the storage. Kinetic FT-IR studies indicate that the amphiphilic nature of the PEG backbone increased the reaction rate of the phase segregated reactants. Second order reaction constant modeling showed a change in initial reaction rate from 0.0029 to 0.0187 (M sec),1 from the 10% to 50% IPEGA formulations respectively. 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [source]


    Improved bonding of adhesive resin to sintered porcelain with the combination of acid etching and a two-liquid silane conditioner

    JOURNAL OF ORAL REHABILITATION, Issue 1 2001
    H. Kato
    This study determined the bond strengths of adhesive resins joined to a feldspathic porcelain (VMK 68) for the purpose of developing the most durable surface preparation for the porcelain. Three porcelain surfaces,ground, air-abraded with alumina, and etched with hydrofluoric acid,were prepared. A two-liquid porcelain conditioner that contained both 4-methacryloyloxyethyl trimellitate anhydride (4-META) and a silane coupler (Porcelain Liner M) was used as the priming agent. Each of the two liquid components of the conditioner was also used individually in order to examine the effects of the respective chemical ingredients on adhesive bonding. Two methyl methacrylate (MMA)-based resins initiated with tri- n -butylborane (TBB) either with or without 4-META (MMA-TBB and 4-META/MMA-TBB resins) were used as the luting agents. Shear bond strengths were determined both before and after thermocycling. Shear testing results indicated that thermocycling was effective for disclosing poor bonding systems, and that both mechanical and chemical retention were indispensable for bonding the porcelain. Of the combinations assessed, etching with hydrofluoric acid followed by two-liquid priming with the Porcelain Liner M material generated the most durable bond strength (333 MPa) for the porcelain bonded with the 4-META/MMA-TBB resin (Super-Bond C&B). [source]


    Diode-pumped doubly passively Q-switched Nd:LuVO4 laser with Cr4+:YAG saturable absorber and GaAs output coupler

    LASER PHYSICS LETTERS, Issue 10 2009
    K. Cheng
    Abstract A diode-pumped doubly passively Q-switched Nd:LuVO4 laser with Cr4+:YAG saturable absorber and GaAs output coupler is realized. This laser can generate a shorter and more symmetric pulse profile when compared with pure GaAs. By using two Cr4+:YAG saturable absorbers with different small-signal transmissions T0 = 0.71 and T0 = 0.81, the maximum average output power are 1.15 W and 1.31 W at the incident pump power of 11.23 W, corresponding to optical conversion efficiencies of 10.2% and 11.7%. At the same incident pump power, the minimum pulse widths of 4.18 ns and 5.42 ns can be obtained at T0 = 0.71 and T0 = 0.81, respectively. The pulse repetition rate and the single-pulse peak power of the laser are also measured. ( 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


    A linear cavity Brillouin fiber laser with multiple wavelengths output

    LASER PHYSICS LETTERS, Issue 5 2008
    M.R. Shirazi
    Abstract A linear cavity Brillouin fiber laser (BFL) is proposed and demonstrated for multi-wavelength operation. The BFL uses a single mode fiber (SMF) as a non-linear gain medium and an optical circulator to generate a linear cavity resonator. Two couplers are used to inject the Brillouin Pump (BP) and tap the BFL output respectively. The effect of the coupler ratio on the BFL performance is studied by keeping constant the ratio of the first coupler and varying the ratio of the second coupler. 11 simultaneous lines with a line spacing of 0.8 nm are obtained at a BP of 11.7 dBm and a coupler ratio of 95:5. The laser output is stable at room temperature with 5 lines obtained at above , 30 dBm, and has the largest signal to noise ratio observed at the remaining lines. The proposed BFL has the advantage of being able to operate at any wavelength and is only dependent on the available BP wavelength. ( 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


    Single-stage gain-clamped L-band EDFA with C-band ASE self-oscillation in ring cavity

    LASER PHYSICS LETTERS, Issue 2 2008
    M.A. Mahdi
    Abstract We demonstrate single-stage gain-clamped L-band Er3+ -doped fiber amplifier (EDFA) utilizing self-oscillation modes as the control light. The amplifier structure exploits the characteristics of C/L-band coupler to isolate between lasing modes and L-band signal. The self-lasing cavity modes are obtained without any tunable bandpass filter in the loop and generated from the amplified spontaneous emission in the C-band region. The amplifier configuration has lower noise figures as opposed to a dual-stage partially gain-clamped amplifier. The gain and noise figure fluctuations are less than 0.4 dB in the gainclamping region. The transient analysis confirms that the maximum power excursion is less than 0.3 dB for 10-dB add/drop. ( 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


    A new configuration of multi-wavelength Brillouin fiber laser

    LASER PHYSICS LETTERS, Issue 1 2008
    S.W. Harun
    Abstract A multi-wavelength laser is demonstrated using stimulated Brillouin scattering in a single-mode fiber with a feedback loop using two couplers and an optical circulator. This Brillouin fiber laser can operate at any wavelength depending on the Brillouin pump (BP) wavelength used. With a BP of 14 dBm, approximately 8 to 10 BFL lines are obtained in both forward and backward directions respectively with a line spacing of 0.16 nm. The use of the 99/1 coupler and 50/50 coupler gives the highest power and number of lines for the forward and backward outputs respectively. The maximum Stokes power obtained is approximately 8.0 dBm. The anti-Stokes lines are also obtained due to four wave mixing and bidirectional operation. The combination of forward and backward output can generate a larger number of lines with channel spacing of 0.08 nm. ( 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


    Near-field probing of photonic crystal directional couplers

    LASER PHYSICS LETTERS, Issue 6 2006
    V. S. Volkov
    Abstract We report the design, fabrication and characterization of a photonic crystal directional coupler with a size of ,20 20 m2 fabricated in silicon-on-insulator material. Using a scanning near-field optical microscope we demonstrate a high coupling efficiency for TM polarized light at telecom wavelengths. By comparing the near-field optical images recorded in and after the directional coupler area, the features of light distribution are analyzed. Finally, the scanning near-field optical microscope observations are found to be in agreement with the transmission measurements conducted with the same sample. ( 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


    Temperature-tuning Yb:YAG microchip lasers

    LASER PHYSICS LETTERS, Issue 9 2005
    Jun Dong
    Abstract Based on the quasi-three-level system, a theoretical model of diode-laser end-pumped fundamental continuous-wave (CW) Yb3+:YAG microchip lasers is proposed. The fluorescence concentration quenching effect, the temperature dependent mechanical and optical properties and the absorption efficiency of the host have been taken into account in the model. The theoretical results of the numerical calculations are in good agreement with those of experiments. The effects of the concentration of the Yb3+:YAG crystal, the thickness of the Yb3+:YAG crystal, the temperature and the transmission of the output coupler on the laser performance (threshold and output power) are addressed. The optimization of the concentration and the thickness for the Yb3+:YAG crystal microchip laser is presented. The effects of the temperature and the pump power intensity on the optical-tooptical efficiency are discussed. The output power can be scaled by increase the working area of the laser gain medium. This modeling is not only applicable to Yb3+:YAG crystal microchip laser but also to other quasi-three-level microchip lasers. ( 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


    Azobenzene Liquid-Crystalline Polymer for Optical Switching of Grating Waveguide Couplers with a Flat Surface

    MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2007
    Chong-Uk Bang
    Abstract Grating waveguide couplers with a flat surface were fabricated in an azobenzene liquid-crystalline polymer film by holographic lithography using Ar+ laser beams at 488 nm. When a probe beam at 633 nm was incident to one grating of a grating waveguide coupler, the beam propagated in the waveguide and an output beam came out from the other grating with the throughput coupling efficiency of ,5%. Upon irradiation of the film between two gratings with UV light to cause trans,cis photoisomerization of the azobenzene moiety, the intensity of the output beam was repeatedly switched. It was found that the alternating irradiation at 366 and 436 nm induced reversible changes in the intensity of the guided probe beam. [source]


    Delayed removal of 3M vein coupler does not disturb the anastomosis,

    MICROSURGERY, Issue 6 2009
    Stuart Hilliard M.D.
    [source]


    Size-reduced defected ground microstrip directional coupler

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2010
    Ashraf S. Mohra
    Abstract In this article, size reduction and harmonic suppression in coupled-lines microstrip directional couplers is attained using dumbbell, and reshaped dumbbell slots, as defected patterns, specifically placed under the metering position in the ground plane. Quantitative investigation of the performance of the directional coupler as controlled by the variations of the DGS rectangular slots height, DGS gap length, and the DGS reshaped rectangular slot height is presented. This concept is further illustrated experimentally for a 12 dB coupler realized on RT/Duroid 5880 substrate. The proposed DGS design confers size reduction because of the shift of the operating frequency to lower values. The measurements are in a good agreement with the simulated results and emphasize the size reduction and the harmonics suppression of the DGS coupled-lines microstrip directional coupler. 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1933,1937, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25410 [source]


    Dual-band hybrid coupler with extended bandwidth

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2010
    King Yin Cheung
    Abstract A dual-band branch-line quadrature coupler with extended bandwidth using simple three-section branch line is presented. This proposed design exhibits larger bandwidth than existing dual-band designs reported in previous literature. A dual-band branch-line coupler was designed and measured to give 34.5 and 16.4% bandwidth in the lower band and upper band, respectively, for an amplitude imbalance less than 1 dB. The achieved bandwidth is wide enough to cover wireless local area network and wideband code division multiple access applications. 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2095,2098, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25405 [source]


    A highly integrated Ka-band transceiver module with two channels

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2010
    Zhigang Wang
    Abstract A compact Ka-band square-wave modulation transceiver module with two receiving and transmitting channels is presented. This module consists of 15 monolithic microwave integrated circuits, two dielectric resonator oscillators, a E-plane waveguide filter, a coupler, two power dividers, and over 200 components, and works at two Ka-band operating frequency points. The developed Ka-band transceiver module is fabricated using advanced packages techniques, which has a compact size of 120 mm 60 mm 20 mm and exhibits greater than 500 mw output power with amplitude imbalance of two output ports less than 30 mw, switch rise time and fall time less than 4 ns, isolation of transmitting two channels more than 63 dB, and voltage standing wave ratio of receiving ports better than 1.3. 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 615,618, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25005 [source]


    Compact rat-race ring coupler with capacitor loading

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010
    Wei Shao
    Abstract A simple compact microstrip rat-race ring coupler with capacitor loading is presented in this letter. The new coupler not only effectively reduces the occupied area to 15% of the conventional one at 1.0 GHz, but also has high harmonic suppression performance over a wide band. Furthermore, the new structure has only two variable parameters and can be easily designed. The design is validated both by simulation and measurement. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 7,9, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24823 [source]


    Application of a rat-race coupler in low-cost load and source pull transistor amplifier design

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009
    Slawomir Gruszczy
    Abstract A method for load and source pull is proposed in which rat-race couplers with sections of shorted transmission lines are used. It is shown that the connection of a rat-race coupler with two shorted transmission lines allows for realization of any desired impedance, thus, allowing for effective transistor matching and, therefore, achieving maximum output power. Both theoretical analysis and experimental results are presented showing usefulness of the proposed technique. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2537,2541, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24668 [source]


    To compact ring branch-line coupler using nonuniform transmission line

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009
    F. Hosseini
    Abstract A compact ring Branch-Line Coupler (BLC) with size reduction of about 50%(in circuit area) of conventional BLCs at frequency 2 GHz is introduced. The coupler is designed by using nonuniform transmission lines (NTL) instead of Uniform Transmission Lines in each arm. The normalized width w (z)/h function of the NTLs is expanded in a truncated Fourier series. The reduced size couplers are potential building blocks for the growing wireless communication markets. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2679,2682, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24703 [source]


    DOP-tunable semiconductor fiber ring laser

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009
    Nian Fang
    Abstract A novel laser with tunable and stable degree of polarization (DOP) is introduced. It consists of a polarization beam splitter (PBS) and a bidirectional semiconductor fiber ring, which is composed of a semiconductor optical amplifier (SOA), a polarization controller (PC) and a 2 2 wideband fiber coupler. By adjusting the PC or the injected current of the SOA, the time averaged DOP of the laser output varies optionally from 0.16 to 99%. Employing the bidirectional ring structure and PBS polarization combination method, DOP of the laser can be kept stable at any level in that range. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1669,1671, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24403 [source]


    An extremely miniaturized microstrip branch-line coupler

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2009
    Mehdi Nosrati
    Abstract In this letter, an extremely miniaturized branch-line coupler (BLC) operating at 0.9 GHz is analyzed, designed, and introduced to enhance the bandwidth accompanied by highly size reduction without via-holes, multilayered technique, and air-bridged. A combination of a simple low-pass and band-stop filters is proposed to increase isolation between BLC's ports. This model is equaled by a quarter-wavelength line and necessary equations are obtained using even and odd modes analysis. A compact BLC is designed and tested using this technique. It is shown that the proposed BLC works as well as conventional ones though with size reduction of about 74% and 4.5% enhancement in bandwidth in analogy with recent branch-line coupler. The measurement results are in good agreement with the theoretical. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1403,1406, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24365 [source]


    A low local oscillator power K-band mixer based on tunneling diodes

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009
    Iacopo Magrini
    Abstract In this article, we will demonstrate a low local oscillator (LO) power K-band mixer based on a tunneling diode technology. Due to its unique diode characteristics, no DC supply is needed, whereas an LO power as low as ,2 dBm is required for nominal functionality. The energy-efficient MMIC prototype integrates a pair of heterojunction interband tunnel diodes and a 90 coplanar broadband coupler. The prototype is optimized within the 19,26 GHz band, with an IF ranging from zero to 7 GHz. In addition, when compared with other mixers, it has the lowest LO power requirement with a conversion loss ranging from 6 to 10 dB, an input compression point of ,3 dBm and an intercept 2nd and 3rd order intermodulation point of 22 and 12 dBm, respectively. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1140,1143, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24228 [source]


    An X-band 185 CMOS phase shifter MMIC for multiple-antenna systems

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2009
    Chien-San Lin
    Abstract The design and implementation of an X-band phase shifter MMIC using the standard 0.18-,m CMOS process is presented. A transformed doublet varactor load is analyzed and applied to a 3-dB quadrature coupler to exhibit large phase shift tuning range and low insertion loss with minimal variation. By using the derived design equations, the implemented CMOS reflection-type phase shifter demonstrates a continuous phase shift tuning range greater than 185, an average insertion loss of 5.2 dB with 0.4 dB variation, and return losses better than 13 dB in 9,11 GHz. The total chip size including I/O pads is 0.76 0.79 mm2. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 645,648, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24131 [source]


    Wavelength tuning using an arrayed waveguide gratings demultiplexer

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2009
    Gaozhi Xiao
    Abstract A novel wavelength tuning method using a specially designed arrayed waveguide gratings (AWG) demultiplexer was demonstrated. It was found that the transmission wavelengths of the AWG channels change linearly with the scanning of the input fiber along the facet of the input coupler of the AWG device. Initial results showed that more than 35 nm tuning range can be achieved at resolution of picometer. Optical spectra measurement using this novel wavelength tuning method is also reported. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 693,696, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24145 [source]


    Fully embedded lumped LC-quadrature hybrid coupler into organic packaging substrate for power sampling

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2009
    Yi Jae Lee
    Abstract In this article, fully embedded lumped LC-quadrature hybrid coupler are designed, fabricated, and characterized into multilayered organic packaging substrate. This embedded device comprised high Q MIM capacitors and circular spiral stacked inductors. For realizing fully embedded high Q capacitor, barium titanate (BaTiO3) composite high dielectric film was utilized. The measured return loss and isolation were better than 25 dB. Measured insertion loss was about 0.38,0.42 dB at the frequencies ranged from 824 to 894 MHz. The coupler exhibited a coupling loss of 23.3,24 dB. The phase error between through and coupling ports was 1.2,2.4. It has a size of 2.8 mm 2.95 mm 0.77 mm (height), which is the smallest one in the couplers developed onto the packaging substrate. The measured performance characteristics were also well matched with the 3D EM simulated ones. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 845,848, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24173 [source]


    A reduced-size branch-line coupler for improved LDMOS balanced power amplifiers

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009
    Drasko Draskovic
    Abstract This article discusses the application of a reduced-size branch-line coupler in the design of a LDMOS class-AB balanced power amplifier at a center frequency of 2.14 GHz. In the proposed balanced configuration, at center frequency a size reduction, improved intermodulation distortion level by 7 dB, and power added efficiency by 5% are achieved, comparing with the balanced configuration with Wilkinson couplers. 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 445,448, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24058 [source]