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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 17, Issue 20, 1 October 1981

Volumes & issues:

Volume 17, Issue 20

1 October 1981

Production of single-mode fibres with negligible intrinsic birefringence and polarisation mode dispersion
Mn as a p-type dopant in In0.53Ga0.47As on InP substrates
New optical heterodyne detector with integrated diffraction grating
Planar antennas on a dielectric surface
VAD single-mode fibres with high Δn values
Method for improving microstrip coupler directivity
  • Author(s): K. Shibata ; H. Yanagisawa ; Y. Torimura ; K. Hatori
  • Source: Electronics Letters, Volume 17, Issue 20, p. 732 –733
  • DOI:  10.1049/el:19810514
  • Type: Article
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  • p. 732 –733 (2)
    This letter describes a method for improving the directivity of the edge-coupled microstrip couplers; the coupler is made up of the suspended microstrip lines. The gap between the dielectric substrate and the ground plane is adjusted to get equal mode velocities under perfect matching conditions. Design data for optimum structure and experimental results are presented and discussed.
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Efficient real-time interpolation for D/A conversion
Comment: New technique for determination of static emitter and collector series resistances of bipolar transistors
Efficiency of loaded conical log-spiral antenna
Optimum directivity of elliptic loop antennas
GaAs power MESFETs prepared by metalorganic chemical vapour deposition
  • Author(s): T. Shino ; S. Yanagawa ; Y. Yamada ; K. Arai ; K. Kamei ; T. Chigira ; T. Nakanisi
  • Source: Electronics Letters, Volume 17, Issue 20, p. 738 –739
  • DOI:  10.1049/el:19810519
  • Type: Article
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  • p. 738 –739 (2)
    GaAs power MESFETs have been developed by using MOCVD wafers. The saturation current of 7.2 mm-wide MESFET chips fabricated on a 6 cm2 wafer has been found to have a standard deviation of 6.8%, which is nearly a half of that observed for MESFETs fabricated on a conventional VPE wafer of the same size. The two-chip device with a gate width of 14.4 mm delivered 4 W at 7.8 GHz with 3 dB gain. The output power of 4 W at 7.8 GHz is the state-of-the-art performance of the GaAs power MESFETs prepared by the MOCVD technique.
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Wideband tunable mm-wave Gunn oscillator design
Bistable operation of semiconductor lasers by optical injection
  • Author(s): H. Kawaguchi
  • Source: Electronics Letters, Volume 17, Issue 20, p. 741 –742
  • DOI:  10.1049/el:19810521
  • Type: Article
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  • p. 741 –742 (2)
    Bistable operation in InP/InGaAsP DH lasers by optical injection is reported for the first time. An incident optical beam, generated by a conventional DH semiconductor laser, was injected into the semiconductor laser with inhomogeneous excitation. Bistability has been achieved in the relation between input intensity of the incident beam and the optical output intensity of the inhomogeneously excited laser. The bistable laser also acts as an optical limiter, i.e. the optical output completely saturates above the laser threshold level.
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High-resolution measurement of diameter variations in optical fibres by the backscatter method
High-efficiency millimetre-wave silicon impatt oscillators
  • Author(s): H.S. Gokgor ; I. Davies ; A.M. Howard ; D.M. Brookbanks
  • Source: Electronics Letters, Volume 17, Issue 20, p. 744 –745
  • DOI:  10.1049/el:19810523
  • Type: Article
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  • p. 744 –745 (2)
    High-efficiency impatt devices and oscillators have been fabricated from epitaxially grown silicon for operation in the frequency range 40–140 GHz. These devices have produced world state-of-the-art efficiencies and demonstrated the expected relative frequency insensitivity of silicon. Single drift devices have given efficiencies of approximately 8%; and double drift device efficiencies as high as 13.5% at 50 GHz and 12% at 90 GHz. Initial measurements show that the sideband phase noise levels follow a constant deviation law.
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Numerical simulation of solar cell open circuit voltage decay
Determination of an initial mesh for computer simulation of H-abrupt devices
Improved conditional runlength codes based on two composite states
Cross-spectral densities of array elements for folded dipole and loop antennas
  • Author(s): T.S.M. Maclean ; S.P.S. Saini ; Z. Barboza
  • Source: Electronics Letters, Volume 17, Issue 20, p. 749 –751
  • DOI:  10.1049/el:19810527
  • Type: Article
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  • p. 749 –751 (3)
    When a loop or folded dipole antenna is placed in a noise field the resultant mean-square noise current is a function of the cross-spectral densities between the different segments of the antenna. Earlier work on the evaluation of cross-spectral densities between the collinear segments of a dipole placed in an isotropic noise field is here extended to include the parallel and orthogonal segments of rectangular loop and folded dipole antennas.
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Multichannel photon-counting backscatter measurements on monomode fibre
Amorphisation and low temperature recrystallisation of InP
  • Author(s): V.L. Wrick ; W.J. Choyke ; C.F. Tzeng
  • Source: Electronics Letters, Volume 17, Issue 20, p. 752 –754
  • DOI:  10.1049/el:19810529
  • Type: Article
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  • p. 752 –754 (3)
    Fe-doped semi-insulating samples of InP have been implanted at room temperature and liquid nitrogen temperature at 200 KV with phosphorous. A fluence of 5 × 1014/cm2 was sufficient to render the lattice amorphous as determined by Rutherford backscattering techniques. Successful reconstruction of the damaged lattice was achieved using a 400°C anneal for 24 h on samples implanted at liquid nitrogen temperatures.
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Symbolic analysis of circuits containing active elements
Temperature dependence of the transferred electron threshold current in In1−xGaxAsyP1−y
Effects of heat treatment on noise spectrum in Au-InP Schottky barriers
  • Author(s): J.M. Peransin ; M. Mesbah ; E. Groubert
  • Source: Electronics Letters, Volume 17, Issue 20, p. 757 –758
  • DOI:  10.1049/el:19810532
  • Type: Article
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  • p. 757 –758 (2)
    Measurements are reported on low frequency noise in Au-InP Schottky diodes after heating cycles. An 1/f noise component was dominant in annealing time range before 80 min. Observation of G-R noise spectra are achieved for long-term operations. Noise measurements between 77 K and 300 K have given the time constants and the activation energies of five trapping levels. The G-R processes are attributed to traps due to gold contamination in the depletion region.
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Efficient fundamental frequency oscillation from millimetre-wave indium phosphide n+-n-n+ transferred electron oscillators
  • Author(s): I.G. Eddison ; I. Davies ; P.L. Giles ; D.M. Brookbanks
  • Source: Electronics Letters, Volume 17, Issue 20, p. 758 –760
  • DOI:  10.1049/el:19810533
  • Type: Article
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  • p. 758 –760 (3)
    The letter describes the development of CW indium phosphide, transferred-electron oscillators (TEOs) with emphasis being place on the achievement of efficient operation in the millimetre-wave frequency range. Reasons are given for the choice of the n+-n-n+ epitaxial structure used, together with relevant material growth and characterisation details. A brief outline of the device fabrication technology is given before discussing oscillator performances. Results are presented for operating frequencies from 30 to 110 GHz which show that the three-layer indium phosphide device is capable of much higher conversion efficiencies than the equivalent gallium arsenide structure at frequencies above 40 GHz. From these figures it is concluded that indium phosphide will supplant gallium arsenide as a mm-wave TEO material.
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Temperature effect on low threshold voltage ion-implanted GaAs MESFETs
Interface states in MOSFETs due to hot-electron injection determined by the charge pumping technique
GaAs digital integrated circuits for very high-speed frequency division
  • Author(s): M. Gloanec ; J. Jarry ; G. Nuzillat
  • Source: Electronics Letters, Volume 17, Issue 20, p. 763 –765
  • DOI:  10.1049/el:19810536
  • Type: Article
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  • p. 763 –765 (3)
    Dual- and single-clocked frequency dividers, consisting of normally-on GaAs MESFET integrated circuits, with maximum toggle frequency of 5.7 GHz, were fabricated. The gate length was 0.8 μm and an E-beam direct writing processing technology was used. Some improvements, such as reduction of the gate length and adoption of a double pinchoff voltage technology, would make possible the implementation of a counter family with a maximum operating frequency in the range 5–7 GHz.
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Design of two-dimensional recursive digital filters to a specified stability margin
Leaky-mode channel-guide injection lasers
Materials dispersion zero in glass mixtures
Reduction of shot noise by the influence of space charge
Erratum: Encryption with keyed random permutations

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