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  • 1. Abedan Kondori, Farid
    et al.
    Yousefi, Shahrouz
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Li, Haibo
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Direct Head Pose Estimation Using Kinect-type Sensors2014In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911XArticle in journal (Refereed)
  • 2.
    Alayon Glazunov, Andres
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Maximum joint transmit-receive MRC gain with antennas exciting spherical vector wave modes up to order l2012In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 48, no 24, p. 1520-1521Article in journal (Refereed)
    Abstract [en]

    Derived is the maximum joint transmit and receive maximum ratio combining (MRC) diversity gain in arbitrary MIMO (multiple-input multiple-output) wireless propagation channels and the corresponding transmit and receive antenna coefficients. Also provided are numerical examples addressing two generic MIMO channel models based on the Kronecker correlation model with Laplacian angle-of-arrival (AoA) and angle-of-departure (AoD) distributions. In the analysis, spherical vector wave multipole modes of order l are considered, including both TE and TM modes.

  • 3. Alzaher, H. A.
    et al.
    Elwan, H. O.
    Ismail, Mohammed
    CMOS digitally programmable filter for multi-standard wireless receivers2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 2, p. 133-135Article in journal (Refereed)
    Abstract [en]

    A technique for designing digitally programmable CMOS integrated filters for multi-standard wireless receivers is presented. The technique exhibits the wide frequency range of the transconductance amplifier filters while offering improved linearity. It utilises digitally controlled current followers to provide precise frequency characteristics that can be tuned over a wide range. A digitally tuned lowpass filter is designed for implementing the channel-select filter in the baseband chain of a multi-standard CMOS wireless receiver. Simulation and experimental results obtained from a 1.2 mu m chip show a programmable frequency response covering the IS-54, GSM, IS-95 and WCDMA wireless standards.

  • 4. Alzaher, H. A.
    et al.
    Elwan, H. O.
    Ismail, Mohammed
    CMOS fully differential second-generation current conveyor2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 13, p. 1095-1096Article in journal (Refereed)
    Abstract [en]

    The design of a CMOS fully differential second generation current conveyor is presented. The proposed circuit was designed to incorporate the current sensing technique into a fully differential version of a differential difference amplifier (DDA). A low power class AB circuit realisation has been implemented in 1.2 mu m CMOS technology. A variable gain amplifier (VGA) designed to incorporate the circuit has been shown to exhibit constant, low power consumption and constant, wide bandwidth at different gain settings. Experimental results of the proposed circuits are presented.

  • 5. Alzaher, H. A.
    et al.
    Ismail, Mohammed
    Digitally tuned analogue integrated filters using R-2R ladder2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 15, p. 1278-1280Article in journal (Refereed)
    Abstract [en]

    A new technique for designing digitally tuned frequency selective analogue integrated circuits is proposed. The technique incorporates the R-2R ladder as a circuit element into the circuit design to provide precise frequency characteristics that can be tuned over a wide range. Two filters are described to illustrate the proposed approach. The proposed filters are used to implement the channel-select filter of a multi-standard direct conversion wireless receiver and the bandpass filter of a low IF frequency-hopping receiver.

  • 6. Alzaher, H.
    et al.
    Elwan, H.
    Ismail, Mohammed
    CMOS baseband filter for WCDMA integrated wireless receivers2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 18, p. 1515-1516Article in journal (Refereed)
    Abstract [en]

    A new second-order lowpass filter based on a single CMOS fully differential current conveyor is presented. Developed from the Sallen-Key highpass filter, the proposed filter is AC coupled and provides programmable gain. Moreover, the filter exhibits low noise, high linearity and low power, making it suitable for implementing the baseband filter of a WCDMA direct-conversion wireless receiver. A WCDMA filter having a programmable bandwidth around 2.1 MHz, a variable gain rang of 50dB and a DC notch below 2kHz using passive components below 5kW for resistors and 20pF for capacitors is implemented. Experimental and simulation results obtained from fabricated chips are included.

  • 7.
    Asplund, Carl
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Sundgren, Petrus
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mogg, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hammar, Mattias
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Christiansson, Ulf
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Oscarsson, V.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Runnström, C.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Odling, E.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Malmquist, J.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    1260 nm InGaAs vertical-cavity lasers2002In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 38, no 13, p. 635-636Article in journal (Refereed)
    Abstract [en]

     The fabrication and performance of highly strained double-quantum well InGaAs/GaAs vertical-cavity lasers with record-long emission wavelength of 1260 nm at room temperature is reported. Depending on device diameter, the minimum threshold current is in the low mA-regime while the maximum output power exceeds 1 mW. The devices work continuous-wave over a wide temperature range of at least 10-120degrees C.

  • 8. Barrios, C. A.
    et al.
    Messmer, E. R.
    Risberg, A.
    Carlsson, C.
    Halonen, J.
    Ghisoni, M.
    Larsson, A.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    GaAs/AlGaAs buried-heterostructure vertical-cavity surface-emitting laser with semi-insulating GalnP: Fe regrowth2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 18, p. 1542-1544Article in journal (Refereed)
    Abstract [en]

    The authors report the first results of a GaAs/AlGaAs buried-heterostructure vertical-cavity surface-emitting laser (VCSEL) with semi-insulating Ga0.51In0.49P:Fe (SI-GaInP:Fe) as the burying layer. Regrowth of SI-GaInP:Fe around 15 mu m diameter and 8 mu m tall VCSEL mesas was carried out by hydride vapour phase epitaxy (HVPE). Under room temperature continuous wave (CW) operation. the device exhibited a threshold current of 3.5mA, a differential quantum efficency of 33% and a light output power of 4.2mW. CW operation at temperatures up to 97 degrees C is also demonstrated.

  • 9.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Dual polarised multibeam antenna1999In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 35, no 25, p. 2158-2160Article in journal (Refereed)
    Abstract [en]

    A dual polarised four-beam antenna array for the 1850-1990 MHz frequency band is presented. The polarisations are ±45° to vertical. The antenna has eight inputs corresponding to two orthogonal polarisations and four beams. The return loss and cross-polar isolation for a single Butler beam exceeds 15 and 22 dB, respectively. The radiation pattern is similar to an ideal Butler pattern and the cross-polarisation level is <-21 dB in the beams

  • 10.
    Ben Slimane, Slimane
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Bandwidth efficiency of MC-CDMA Systems1999In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 35, no 21, p. 1797-1798Article in journal (Refereed)
    Abstract [en]

    The bandwidth efiiciency of MGCDMA signals is evaluated and Compared to that of DS-CDMA signals. For the same available bandwidth, the achievable processing gain of the two systems with and without Sdtetering is evaluated and then Compared.

  • 11.
    Bjurshagen, Stefan
    et al.
    KTH, Superseded Departments, Physics.
    Evekull, D.
    Acreo AB, Kista.
    Koch, R.
    Acreo AB, Kista.
    Generation of blue light at 469 nm by efficient frequency doubling of a diode-pumped Nd:YAG laser2002In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 38, no 7, p. 324-325Article in journal (Refereed)
    Abstract [en]

    Efficient operation of a diode-pumped Nd: YAG laser at 938.5 nm is reported. A continuous wave output power of 3.9 W is obtained. Single-pass frequency doubling in periodically poled KTP delivered a power of 88 mW at 469 nm. By intracavity frequency doubling an output of 200 mW in the blue region is achieved.

  • 12.
    Björkqvist, Oskar
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Zetterström, Oskar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Quevedo-Teruel, Oscar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Additive manufactured dielectric Gutman lens2019In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 55, no 25, p. 1318-1320Article in journal (Refereed)
    Abstract [en]

    In this Letter, the design of a 3D printed fully dielectric Gutman lens is presented. The authors demonstrate the feasibility of using highly accessible and cheap additive manufacturing technology to produce a compact and high performing antenna lens. The lens is designed to operate at Ku band and utilises a flat feed surface that approximates the focal sphere. The flat feed surface allows for beam steering that requires only translational movement of the feed. The lens has a measured realised gain of 20 dBi with 3 dB scan loss at +45°. The lens finds applications in systems that require high gain antennas, such as the new generation of satellite and 5G communications and radar technology.

  • 13. Chen, D.
    et al.
    Fu, H.
    Liu, W.
    Wei, Y.
    He, Sailing
    Dual-wavelength single-longitudinal-mode erbium-doped fibre laser based on fibre Bragg grating pair and its application in microwave signal generation2008In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 44, no 7, p. 459-460Article in journal (Refereed)
    Abstract [en]

    A simple dual-wavelength single-longitudinal-mode erbium-doped fibre laser is proposed by incorporating a fibre Bragg grating pair, which is used as a Fabry-Perot filter with two ultra-narrow (similar to 0.12 pm) transmission bands. Stable dual-wavelength single-longitudinal-mode lasing with a wavelength spacing of similar to 0.08 nm is achieved at room temperature. By beating the dual-wavelengths at a photodetector, a microwave signal at 9.616 GHz is demonstrated with a frequency stability better than 1 MHz and a spectral width less that 10 kHz.

  • 14.
    Chen, Daru
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Qin, Shan
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Gao, Ying
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Gao, Shiming
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wavelength-spacing continuously tunable multiwavelength erbium-doped fibre laser based on DSF and MZI2007In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 43, no 9, p. 524-525Article in journal (Refereed)
    Abstract [en]

    A novel multiwavelength erbium-doped fibre laser is proposed by incorporating a section of dispersion-shifted fibre (DSF) and a Mach-Zehnder interferometer (MZI). The wavelength spacing of the fibre laser can be continuously tuned by adjusting an optical variable delay line in the MZI-based comb filter. Stable multiwavelength lasing at room temperature with the standard ITU (International Telecommunication Union) channel spacing of 0.2 nm (25 GHz), 0.4 nm (50 GHz), 0.8 nm (100 GHz) or 1.6 nm (200 GHz) is demonstrated.

  • 15.
    Chen, Daru
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Yu, Zhangwei
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Qin, S.
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Switchable dual-wavelength Raman erbium-doped fibre laser2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 4, p. 202-204Article in journal (Refereed)
    Abstract [en]

    A fibre Bragg grating feedback fibre laser with both Raman and erbium-doped fibre pumps is proposed. Dual-wavelength switching is achieved by controlling the power of the Raman pump. The characteristics of the dual-wavelength switching are studied experimentally, and the mechanism is explained physically.

  • 16. Claesson, A.
    et al.
    Holm, J.
    Koch, R.
    Olson, M.
    Olsson, A.
    Vieider, C.
    Ahlfeldt, H.
    Laurell, Fredrik
    KTH, Superseded Departments, Physics.
    Diode-pumped miniature lasers using microstructured silicon carriers2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 5, p. 433-434Article in journal (Refereed)
    Abstract [en]

    A new versatile design concept for compact diode-pumped solid-state lasers based on a microstructured silicon carrier with etched V-grooves is presented. The carrier provides efficient thermal management as well as compact integration and alignment of all active acid passive optical components. In initial experiments, an Nd:YAG laser delivered a continuous-wave output of 3W.

  • 17. Dai, D.
    et al.
    He, Sailing
    Low-index-material-based nano-slot waveguide with quasi-Bragg-reflector buffer2008In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 44, no 23, p. 1554-+Article in journal (Refereed)
    Abstract [en]

    A low-index-material-based nano-slot waveguide based on a quasi-Bragg-reflector buffer is presented. This quasi-Bragg-reflector buffer includes alternating low and high refractive index dielectric layers. The thicknesses of these dielectric layers are chosen optimally by using a genetic algorithm so that the leakage loss of the present optical waveguide is minimised. An SiO2-based slot-waveguide is designed as an example and the quasi-Bragg-reflector buffer is formed by using several Si/SiO2 bilayers. The theoretical leakage loss for an SiO2-based slot-waveguide with three optimised Si/SiO2 bilayers is about 0.01 dB/mm (at 1550 nm). The modal analysis with a full-vectorial finite-difference method shows that the present slot waveguide has an enhancement of the field distribution in the nano-slot region.

  • 18. Dai, D.
    et al.
    Liu, Liu
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, L.ech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Design and Fabrication of an Ultrasmall Overlapped AWG Demultiplexers Based on α-Si Nanowire Waveguides2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 7, p. 400-402Article in journal (Refereed)
    Abstract [en]

    A novel layout for an ultra-compact arrayed-waveguide grating (AWG) demultiplexer is presented. The present layout has two overlapped free propagation regions, and is more compact than a conventional layout. Using αSi-on-SiO2 nanowire waveguides, an ultra-small 4×4 AWG (about 40×50 μm2) with channel spacing of 11 nm is fabricated and characterised.

  • 19.
    Ellgardt, Anders
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Computing return loss for arbitrary scan directions using limited scan codes for infinite phase arrays2009In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 45, no 13, p. 660-662Article in journal (Refereed)
    Abstract [en]

    Analyzing large phased array antennas using time domain codes is favourable when looking into wideband solutions. This is often done by assuming an infinite array, i.e. a unit cell approach is used. Unfortunately, unit cell based time domain codes using time shifts between cell boundaries have a disadvantage of only being able of analyzing phase shifts corresponding to a beam scanned in the visible space. However, in order to fully characterize the infinite array antenna it is sometimes necessary to compute the active reflection coefficient also for scan directions/phase shifts corresponding to invisible space. Presented in this letter is a new approach on how to do this in a simple manner using unit cell based time domain codes. By extending the size of the computational domain, and include more than one element, phase shifts corresponding to invisible space are included.

  • 20. Elwan, H.
    et al.
    Gao, W.
    Sadkowski, R.
    Ismail, Mohammed
    CMOS low-voltage class-AB operational transconductance amplifier2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 17, p. 1439-1440Article in journal (Refereed)
    Abstract [en]

    The authors present a new low-voltage class-AB opt rational transconductance amplifier (OTA). The proposed OTA achieves a fast non slew-rate limited settling time with low power consumption. The circuit is power efficient when driving large capacitive loads. The OTA circuit is well suited For low-voltage low-power switched capacitor applications. Experimental results of the proposed circuit are included.

  • 21.
    Evekull, D.
    et al.
    Acreo AB, Kista.
    Johansson, Sandra
    KTH, Superseded Departments, Physics.
    Bjurshagen, Stefan
    Acreo AB, Kista.
    Olson, M.
    Acreo AB, Kista.
    Koch, R.
    Acreo AB, Kista.
    Laurell, Fredirk
    KTH, Superseded Departments, Physics.
    Polymer encapsulated miniature Nd:YAG lasers2003In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 39, no 20, p. 1446-1448Article in journal (Refereed)
    Abstract [en]

    A continuation of the previously introduced microstructured silicon carrier concept for diode-pumped solid-state lasers is presented, using novel heat-conducting polymers as a carrier. The most prominent features of the silicon carrier concept are maintained, adding to the mass production possibilities of the inexpensive polymers. The first experiments, using a continuous wave Nd:YAG microchip laser, have given an output power of 2 W at 1064 nm, showing the potential of this new approach.

  • 22.
    Fang, Zequn
    et al.
    Southwest Jiaotong Univ, Prov Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Ma, Zheng
    Southwest Jiaotong Univ, Prov Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Karagiannidis, George K.
    Aristotle Univ Thessaloniki, Elect & Comp Engn Dept, Thessaloniki, Greece..
    Xiao, Ming
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Fan, Pingzhi
    Southwest Jiaotong Univ, Prov Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Low complexity decoding of Reed-Solomon codes over magnetic recording channels2019In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 55, no 3, p. 159-160Article in journal (Refereed)
    Abstract [en]

    A low complexity soft-decision decoding technique is presented for Reed-Solomon codes, over magnetic recording channels (MRC), by considering symbol and bit reliability, jointly. A symbol detection scheme for burst error scenarios has been put forward for the iterative error-and-erasure decoding algorithm (IEED), which is based on multiple trials, and is a combination of the generalised minimum distance and Chase-2 decoding schemes. In order to decrease complexity, the decoding test patterns are used in a certain order, while the stopping criteria is also discussed. Simulations show that the proposed algorithms can achieve almost the same performance as that of IEED for the additive white Gaussian noise channel and slightly better performance in MRC, but with significantly less complexity.

  • 23.
    Ferrer Coll, Javier
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Ängskog, Per
    Chilo, Jose
    Stenumgaard, Peter
    Characterization of electromagneticproperties in iron-mine production tunnels2012In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 48, no 2, p. 62-63Article in journal (Refereed)
    Abstract [en]

    Modern underground mines require reliable wireless communication for transmitting voice data, operating surveillance cameras, and monitoring mining equipment such as heavy vehicles. The electromagnetic characteristics of mines therefore have to be considered when determining the type of wireless technology for such critical applications. In this reported work, measurements of radio interference levels, path loss, and multipath propagation are performed in the world's now largest iron ore mine, situated in Sweden, to determine a suitable wireless technology for this mine.

  • 24. Fu, J. J.
    et al.
    Liu, W. S.
    Chen, D.
    He, Sailing
    Ultra-long-distance FBG sensor system based on spectrum-limited Fourier domain modelocking fibre laser with Raman pumps2008In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 44, no 16, p. 961-963Article in journal (Refereed)
    Abstract [en]

    A novel ultra-long-distance (up to 76 km) fibre Bragg grating (FBG) sensor system based on a spectrum-limited Fourier domain modelocking fibre laser is proposed. Raman pumps are employed to form a Raman amplifier to compensate the transmission loss of the long fibre and ensure ultra-long-distance sensing. Strain sensing based on such an ultra-long-distance FBG sensor system is demonstrated with a signal-to-noise ratio over 22 dB and a sensitivity of 1.03 pm/mu epsilon in the wavelength domain or 18.3 ns/mu epsilon in the time domain.

  • 25. Gao, S.
    et al.
    Gao, Y.
    He, Sailing
    Photonic generation of tunable multi-frequency microwave source2010In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 46, no 3, p. 236-237Article in journal (Refereed)
    Abstract [en]

    A flexibly tunable multi-frequency microwave source is presented based on optical heterodyning between the intensity-modulated optical carrier (incorporated four-wave mixing equalisation and stabilisation) and the frequency-shifted Stokes light generated by fibre stimulated Brillouin scattering. About 20 microwave frequencies centred at 10.77 or 21.62 GHz are experimentally observed. The central frequency and the frequency spacing of the multi-frequency microwave source can be freely tuned by changing the frequency shift of the beating optical waves and the driving frequency on the modulator.

  • 26. Gao, S.
    et al.
    Gao, Yonghong
    Fu, Hongyan
    Chen, D.
    He, Sailing
    Microwave frequency up/downconversion based on dual-wavelength fibre laser2009In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 45, no 18, p. 932-933Article in journal (Refereed)
    Abstract [en]

    A novel method of microwave frequency up/downconversion is proposed for microwave/millimetre-wave-based radio-over-fibre (RoF) systems. The uplink and downlink are both based on dual-wavelength single-longitudinal-mode fibre laser modulation and heterodyning, which provides the possibility to realise bidirectional RoF transmissions.

  • 27. Garcia, FC
    et al.
    Fokine, Mikael
    KTH, Superseded Departments, Physics.
    Margulis, Walter
    KTH, Superseded Departments, Physics.
    Kashyap, Raman
    Mach-Zehnder interferometer using single standard telecommunication optical fibre2001In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 37, no 24, p. 1440-1442Article in journal (Refereed)
    Abstract [en]

    It is demonstrated that a single, short-length, standard telecommunications optical fibre can function as an interferometer when subjected to hydroxyl-flooding. The interferometer is based on the mode beating effect arising from the induced-refractive index change.

  • 28. Gerschutz, F.
    et al.
    Fischer, M.
    Koeth, J.
    Chacinski, M.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Kovsh, A.
    Krestnikov, I.
    Forchel, A.
    Temperature insensitive 1.3 mu m InGaAs/GaAs quantum dot distributed feedback lasers for 10 Gbit/s transmission over 21 km2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 25, p. 1457-1458Article in journal (Refereed)
    Abstract [en]

    Long wavelength monomode InGaAs/GaAs quantum dot (QD) distributed feedback (DFB) lasers with emission wavelength around 1325 ran are presented. Threshold currents below 19 mA for operating temperatures up to 70 degrees C and Output powers of 10 mW at 25 degrees C (6 mW at 70 degrees C) are observed. Error-free 10 Gbit/s transmission over 21 kin fibre with an extinction ratio of 8.5 dB at room temperature (5.1 dB at 70 degrees C) is demonstrated. The low threshold, low temperature sensitivity and high modulation speed were realised using complex coupled DFB lasers with ten stacks of self-organised MBE-grown QD layers and p-type modulation doping.

  • 29.
    Goobar, E.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Gillner, L.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Broberg, B.
    Tanbun-Ek, T.
    Nilsson, S.
    Measurement of a VPE-transported DFB laser with blue-shifted frequency modulation response from DC to 2 GHz1988In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 24, p. 746-747Article in journal (Refereed)
    Abstract [en]

    The frequency modulation characteristics of a VPE-transported 1.53 mu;m wavelength GaInAsP-InP DFB semiconductor diode laser was measured. Below approximately 0.7 mW optical output power per facet, it exhibited a smooth, blue-shifted, frequency modulation response from DC to 2 GHz. In the modulation frequency range of 10 MHz to 100 MHz it exhibited a | Delta;f/ Delta;I| of 0.5-1.8 GHz/mA, depending on the biasing level

  • 30.
    Goobar, E.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Broadband measurements of frequency noise spectrum in two section DBR laser1991In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 27, p. 289-291Article in journal (Refereed)
    Abstract [en]

    The dependence of the frequency noise on the output power, the tuning current and the current modulation has been measured in a two electrode DBR laser from 30 MHz to 8 GHz. The frequency noise spectrum was fairly flat and decreased with increased output power at a rate faster than 1/P. At certain biasing levels, the noise increased and the relaxation peak was shifted towards lower frequencies when current was injected into the passive waveguide. Furthermore, the frequency noise was not affected by the current modulation.

  • 31.
    Goobar, E.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Broberg, B.
    Nilsson, S.
    Pure frequency modulation or intensity modulation with suppressed frequency chirp using active Bragg reflector integrated laser1989In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 25, p. 304-305Article in journal (Refereed)
    Abstract [en]

    The modulation properties of a laser structure which consists of an active Bragg reflector (300 mu m) integrated with an uncorrugated gain region (600 mu m) have been measured. The laser exhibited a flat FM response and very low spurious intensity modulation when modulating the current in the Bragg reflector. Furthermore, broadband intensity modulation with suppressed frequency chirp could also be achieved. An inhomogeneous linewidth enhancement factor alpha caused by the uneven carrier density distribution between the two sections gives a qualitative explanation to our results.

  • 32. Gothenberg, A.
    et al.
    Tenhunen, Hannu
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Improved cascaded sigma-delta noise shaper architecture with reduced sensitivity to circuit nonlinearities2002In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 38, no 14, p. 683-685Article in journal (Refereed)
    Abstract [en]

    An improved cascaded sigma-delta noise shaper with reduced sensitivity to switch and opamp nonlinearities is presented. The architecture can be used for wideband applications, i.e. RF-front ends, at low oversampling ratio, as well as for high-resolution audio applications.

  • 33.
    Gudmundson, Mikael
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Correlation Model for Shadow Fading in Mobile Radio Systems1991In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 27, no 23, p. 2145-2146Article in journal (Refereed)
    Abstract [en]

    A simple autocorrelation model for shadow fading in mobile radio channels is proposed. The model is fitted to both large cells and microcells. Results show that the model fit is good for large to moderate cell sizes. It is however shown that the model does not provide adequate results for microcells.

  • 34. Hansson, B. T.
    et al.
    Friberg, Ari T.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Pulsed 1.55 mu m transmission mode microchip laser using semiconductor modulator2001In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 37, no 4, p. 223-225Article in journal (Refereed)
    Abstract [en]

    A semiconductor saturable absorber modulator is used, for the first time, in a passively Q-switched microchip laser in transmitting mode. The laser has a wavelength of 1.55 mum in a single longitudinal TEM, mode beam and has pulse characteristics that compare favourably with preciously reported data un comparable devices.

  • 35. HELMFRID, S
    et al.
    ARVIDSSON, G
    WEBJORN, J
    LINNARSSON, M
    KTH, School of Information and Communication Technology (ICT).
    PIHL, T
    STIMULATED-EMISSION IN ER-TI-LINBO3 CHANNEL WAVE-GUIDES CLOSE TO 1.53-MU-M TRANSITION1991In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 27, p. 913-914Article in journal (Refereed)
    Abstract [en]

    Fabrication and characterisation of Er:Ti:LiNbO3 channel waveguides is reported. A lifetime of 2.4 +/- 0.2 ms has been measured for the 4I13/2 level. In a pump and probe experiment using a high power InGaAsP laser and a tunable DBR laser, a signal increase of 0.75 dB for a transmitted pump power of 4.8 mW was demonstrated.

  • 36. Huang, Tianyu
    et al.
    Ma, Linhua
    Hu, Xing
    Huang, Shaocheng
    KTH, School of Electrical Engineering (EES), Information Science and Engineering.
    Liu, Shiping
    2D autoregressive model-based dynamic correlated massive MU-MIMO channel simulator2017In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 53, no 17Article in journal (Refereed)
    Abstract [en]

    To design a dynamic correlated channel simulator which can precisely depict the space-time correlation properties and be suitable for the massive multi-user multiple-input multiple-output (MU-MIMO) system, a 2D autoregressive (2D AR) model-based method is proposed. Specifically, by exploiting stationarity in space-time domain, the authors use 2D AR method to create the space-time channel matrices of every user separately. In this way, the space-time dimension of the simulated channel can be modified flexibly without rebuilding the 2D AR model, and spatial correlation matrix with excessively big size is not necessary to guarantee the accuracy of the proposed simulator, making it suitable for massive MU-MIMO system. Simulation results verify the advantages of the proposed simulator.

  • 37.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Compensation for saturation effects in FIR-NLMS system identification1998In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 34, no 4, p. 411-412Article in journal (Refereed)
    Abstract [en]

    An adaptive scheme is derived to be used in combination with the normalised least mean squares algorithm for finite impulse response models (FIR-NLMS), to combat nonlinear imperfections of the plant to be identified. The scheme is shown to outperform FIR-NLMS when a test system that consists of a variable static nonlinearity in cascade with a linear filter is identified.

  • 38.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Prasad, Sathyaveer
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Maximum likelihood estimation of reverberation chamber direct-to-scattered ratio2009In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 45, no 25, p. 1285-U24Article in journal (Refereed)
    Abstract [en]

    The exact maximum likelihood estimator of the direct-to-scattered ratio of the Rician channel in a reverberation chamber is derived and its performance analysed. It is shown that the estimator obeys a non-central F-distribution, the mean value and variance of which are derived. For well stirred chambers, it is shown that the systematic error in the estimated ratio may be significant.

  • 39.
    Janssen, Gerard J. M.
    et al.
    Telecommunication and Traffic-Control Systems Group, Department of Information Technology and Systems, Delft University of Technology, 2600 GA Delft, The Netherlands.
    Ben Slimane, Slimane
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Symbol error probability of M-PSK multiuser detector using successive cancellation2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 25, p. 2103-2105Article in journal (Refereed)
    Abstract [en]

    A narrowband multiuser receiver based on successive signal detection and subtraction is proposed. The symbol error probability (SEP) for M-PSK modulated signals is analysed and approximations for the SEP of the individual signals are presented and compared to results obtained from simulations for the AWGN channel.

  • 40.
    Jonsson, Fredrik
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Olsson, Håkan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    RF detector for on-chip amplitude measurements2004In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 40, no 20, p. 1239-1241Article in journal (Refereed)
    Abstract [en]

    A novel on-chip amplitude detector that allows for efficient debugging of complex RF circuits is proposed. The simplicity, low power consumption, flat frequency response, minimal loading of the tested circuit and possibility of multiplexing makes this detector suitable for on-chip RF amplitude measurements. Simulations and measurements confirm the detector operation.

  • 41.
    Jorswieck, Eduard
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Lack of duality between SISO Gaussian MAC and BC with statistical CSIT2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 25, p. 1466-1468Article in journal (Refereed)
    Abstract [en]

    Recently, the duality between capacity regions of certain single and multiple antenna MAC with SIC and BC with DPC was proved under the assumption of perfect CSI at the transmitter as well as the receiver. Considered is the case in which the transmitter has only statistical CSI.. It is shown that the average rate region of the SISO BC is a subset of the average rate region of the SISO MAC and that there is a lack of duality between the MAC and BC.

  • 42. Josefsson, L
    et al.
    Persson, Patrik
    KTH, Superseded Departments, Electromagnetic Theory.
    Conformal array synthesis including mutual coupling1999In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 35, no 8, p. 625-627Article in journal (Refereed)
    Abstract [en]

    A pattern synthesis technique for a conformal array antenna on a cylinder is presented using the method of alternate projections. Both the sidelobe region and the shape of the main beam are controlled. The method includes the effect of the mutual coupling in the synthesis. It is shown that if mutual coupling is neglected, then poor results are obtained, especially in the shaped beam region.

  • 43.
    Kjebon, Olle
    et al.
    KTH, Superseded Departments, Electronics.
    Schatz, Richard
    KTH, Superseded Departments, Electronics.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Electronics.
    Nilsson, Stefan
    KTH, Superseded Departments, Electronics.
    Stålnacke, Björn
    KTH, Superseded Departments, Electronics.
    Bäckbom, Lena
    KTH, Superseded Departments, Electronics.
    30GHz direct modulation bandwidth indetuned loaded InGaAsP DBR lasers at1.55 μm wavelength1997In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 33, p. 488-489Article in journal (Refereed)
    Abstract [en]

    An increased resonance frequency and reduced damping of theresonance peak leading to a record high modulation bandwidth of30GHz were observed in 1.55 mm InGaAsP DBR lasers. Theseresults are attributed to the mechanism of detuned loading.

  • 44.
    Kliewer, J.
    et al.
    University of Kiel.
    Thobaben, Ragnar
    University of Kiel.
    Parallel concatenated joint source-channel coding2003In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 39, no 23, p. 1664-1666Article in journal (Refereed)
    Abstract [en]

    A novel approach for robust source transmission where variable-length source and channel encoding are concatenated in parallel is presented. Simulation results show that for waveform source signals the proposed scheme shows a strong increase in decoding performance compared to the typically applied serially concatenated scheme.

  • 45. Kondori, F. A.
    et al.
    Yousefi, Shahrouz
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Li, Haibo
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Direct three-dimensional head pose estimation from Kinect-type sensors2014In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 50, no 4, p. 268-269Article in journal (Refereed)
    Abstract [en]

    A direct method for recovering three-dimensional (3D) head motion parameters from a sequence of range images acquired by Kinect sensors is presented. Based on the range images, a new version of the optical flow constraint equation is derived, which can be used to directly estimate 3D motion parameters without any need of imposing other constraints. Since all calculations with the new constraint equation are based on the range images, Z(x, y, t), the existing techniques and experiences developed and accumulated on the topic of motion from optical flow can be directly applied simply by treating the range images as normal intensity images I(x, y, t). In this reported work, it is demonstrated how to employ the new optical flow constraint equation to recover the 3D motion of a moving head from the sequences of range images, and furthermore, how to use an old trick to handle the case when the optical flow is large. It is shown, in the end, that the performance of the proposed approach is comparable with that of some of the state-of-the-art approaches that use range data to recover 3D motion parameters.

  • 46. Koo, S. M.
    et al.
    Zetterling, Carl-Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Lee, H. S.
    Östling, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Combination of JFET and MOSFET devices in 4H-SiC for high-temperature stable circuit operation2003In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 39, no 12, p. 933-935Article in journal (Refereed)
    Abstract [en]

    A novel combination of junction-gated and metal-oxide-semiconductor field effect transistor (JMOSFET) has been fabricated and characterised in 4H-SiC. The high-temperature stable operation of JMOSFETs has been explored in terms of constant current levels. The JMOSFETs have shown the feasibility for operating with constant on and off current levels from room temperature up to 300degreesC. Another advantage of this device is the improved current density by accumulation of the MOS n-channel.

  • 47. Krotkus, A.
    et al.
    Pasiskevicius, Valdas
    Electric field probing by picosecond laser pulses1992In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 28, no 12, p. 1137-1138Article in journal (Refereed)
  • 48.
    Krotkus, Arunas
    et al.
    Semiconductor Physics Institute, Vilnius, Lithuania.
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI).
    Electric field probing by picosecond laser pulses1992In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 28, p. 1137-1138Article in journal (Refereed)
  • 49.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Stableblue second-harmonic generation in a KTP waveguide with a diode laser in anexternal cavity1993In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911XArticle in journal (Refereed)
  • 50.
    Laurell, Fredrik
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Karlsson, H.
    Henriksson, P.
    Arvidsson, G.
    Frequencydoubling in periodically poled RbTiOAs41996In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911XArticle in journal (Refereed)
123 1 - 50 of 106
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