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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 21, Issue 4, 14 February 1985

Volumes & issues:

Volume 21, Issue 4

14 February 1985

Low-noise HEMT fabricated by MOCVD
  • Author(s): H. Takakuwa ; Y. Kato ; S. Watanabe ; Y. Mori
  • Source: Electronics Letters, Volume 21, Issue 4, p. 125 –126
  • DOI:  10.1049/el:19850088
  • Type: Article
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  • p. 125 –126 (2)
    Low-noise HEMTs with GaAlAs/GaAs heterostructures have been successfully fabricated using metal organic chemical vapour deposition (MOCVD). Hall mobilities of the two-dimensional electron gas at the interface are 8000 and 148 000 cm2/Vs at 300 and 77 K. These are comparable to the best results yet reported using molecular beam epitaxy (MBE). The HEMTs fabricated by MOCVD with a 0.8 μm-long gate have exhibited a noise figure of 1.47 dB with 9 dB associated gain at 12 GHz and transconductance of 190 mS/mm.
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Picosecond semiconductor laser radar with optical amplifier
  • Author(s): A. Alping ; P. Andersson ; S.T. Eng
  • Source: Electronics Letters, Volume 21, Issue 4, p. 126 –127
  • DOI:  10.1049/el:19850089
  • Type: Article
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  • p. 126 –127 (2)
    An optical range finder, which uses the same semiconductor laser as both an optical pulse source and an optical preamplifier of the reflected pulse, is reported. This method has the advantage of reducing the number of optical components that must be aligned, which makes it suitable as a picosecond laser radar in aerospace applications. The device showed a maximum optical gain of 17 dB with a dynamic range of 33 dB, and the obtained resolution was of the order of 1 mm.
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Standard instrument configuration for parametric testing
Single PIN diode X-band phase shifter
Dynamic line broadening of semiconductor lasers modulated at high frequencies
Effects of growth temperature and [PH3]/[In(C2H5)3] on purity of epitaxial InP grown by metalorganic chemical vapour deposition
Cancellation of distortion of any order in integrated active RC filters
Single-mode optical-fibre ribbon cable
Semiconductor-platelet fibre-optic temperature sensor
Digital lattice filters with reduced number of tap-multipliers
Method of simplified analysis of switched-capacitor networks
Low dark current InGaAs PIN photodiodes grown by molecular beam epitaxy
  • Author(s): P. Cinguino ; F. Genova ; C. Rigo ; A. Stano
  • Source: Electronics Letters, Volume 21, Issue 4, p. 139 –140
  • DOI:  10.1049/el:19850099
  • Type: Article
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  • p. 139 –140 (2)
    High-quality InGaAs PIN photodiodes have been made from high-purity layers grown on InP substrate by molecular beam epitaxy. The diodes are top-illuminated mesa-type passivated and planarised by polyimide. The devices exhibit dark current densities as low as 2.3 × 10−5 A/cm2 at −10 V with a breakdown voltage of −80 V. These values are comparable with those obtained by other more conventional growth techniques, and are the best so far reported by MBE.
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Probability density function of amplitude scintillations
  • Author(s): G. Ortgies
  • Source: Electronics Letters, Volume 21, Issue 4, p. 141 –142
  • DOI:  10.1049/el:19850100
  • Type: Article
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  • p. 141 –142 (2)
    The letter reports on amplitude scintillation measurements of the orbital test satellite (OTS) BO carrier beacon carried out from June to December 1983. The scintillations are here characterised by standard deviations of the amplitude fluctuations and by the distribution of amplitude deviations from their mean. It is known that during scintillations log-amplitudes are normally distributed for short time intervals (1 min). The long-term probability density of amplitude scintillations can be calculated using recorded 1 mm standard deviations σ. The probability density function of log ((σ−σN)/dB) can be well approximated by a Gaussian distribution, where σN is the 1 min standard deviation due to thermal noise alone.
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Effect of crystal orientation on plasma-grown oxides of silicon
  • Author(s): K.J. Barlow ; A. Kiermasz ; W. Eccleston
  • Source: Electronics Letters, Volume 21, Issue 4, p. 142 –143
  • DOI:  10.1049/el:19850101
  • Type: Article
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  • p. 142 –143 (2)
    The effects of silicon crystal orientation on the rate of growth and oxide charge of layers grown in a plasma of oxygen with and without chlorine in the gas stream are described. It is shown that plasma oxide growth rate in the initial linear region is orientation-independent and is not, therefore, surface-reaction-rate-limited as with thermal oxidation. Strong orientation effects are seen, however, in the oxide charge, the results being qualitatively similar to those associated with thermal oxidation. The (111) surface is found to have higher oxide charge levels than (100).
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Diurnal and seasonal variations of OTS amplitude scintillations
  • Author(s): G. Ortgies  and  F. Rücker
  • Source: Electronics Letters, Volume 21, Issue 4, p. 143 –145
  • DOI:  10.1049/el:19850102
  • Type: Article
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  • p. 143 –145 (3)
    The letter reports on scintillation measurements of the orbital test satellite (OTS) BO carrier which were carried out from June to December 1983. The scintillations are characterised here by the variance of amplitude deviations from their mean. The diurnal distribution of variances exceeding a certain threshold in summer shows a strong maximum in the early afternoon and a less pronounced one around midnight. In winter these maxima are displaced by 5 and 8 h, respectively. The results on the seasonal variations indicate that stronger fluctuations occurred more frequently in summer than in winter.
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Phase velocity compensation in three-line coupled microstrip structure by using stratified dielectric substrate
Lowpass to highpass transformation in vis switched-capacitor filters
Combined michelson and polarimetric fibre-optic interferometric sensor
  • Author(s): M. Corke ; J.D.C. Jones ; A.D. Kersey ; D.A. Jackson
  • Source: Electronics Letters, Volume 21, Issue 4, p. 148 –149
  • DOI:  10.1049/el:19850105
  • Type: Article
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  • p. 148 –149 (2)
    A fibre-optic interferometric sensor utilising a highly birefringent fibre sensing element has been configured such that both Michelson and polarimetric outputs are simultaneously available. This device therefore offers the high resolution of a Michelson interferometer in conjunction with the increased dynamic range of a polarimetric device. The results of preliminary experiments in which the system was used as a temperature sensor are presented.
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Monolithic integrated 4:1 multiplexer and demultiplexer operating up to 4.8 Gbit/s
  • Author(s): N. Yoshikai ; S. Kawanishi ; M. Suzuki ; S. Konaka
  • Source: Electronics Letters, Volume 21, Issue 4, p. 149 –151
  • DOI:  10.1049/el:19850106
  • Type: Article
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  • p. 149 –151 (3)
    The letter describes the high-speed performance of a 4:1 time-division MSI multiplexer and demultiplexer, which are fabricated using advanced super self-aligned process technology (SST). The maximum operation speed of the multiplexer is 5.02 GHz under 576 mW power dissipation. The system, which is composed of a multiplexer and a demultiplexer, operates at up to 4.80 GHz. The demultiplexer has a power dissipation of 1148 mW. Interchannel interference is also examined.
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11 ps ring oscillators with submicrometre selectively doped heterostructure transistors
  • Author(s): N.J. Shah ; S.S. Pei ; C.W. Tu ; R.H. Hendel ; R.C. Tiberio
  • Source: Electronics Letters, Volume 21, Issue 4, p. 151 –152
  • DOI:  10.1049/el:19850107
  • Type: Article
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  • p. 151 –152 (2)
    Selectively doped AlGaAs/GaAs heterostructure transistor (SDHT) ring oscillators with submicrometre gates have been fabricated using electron beam lithography. Minimum propagation delay of 11.0 ps/gate at 77 K was measured on a 0.4 μm gate-length ring oscillator with a power-delay product of 15 fJ at 1.1 V bias. The processing of these structures is described, as well as the testing of the submicrometre transistors and circuits at 300 K and 77 K.
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New switched-capacitor ladder filters
Enhanced performance of 2 μm N-MOSFETs in doubly recrystallised SOS films
  • Author(s): R.L. Maddox  and  I. Golecki
  • Source: Electronics Letters, Volume 21, Issue 4, p. 154 –155
  • DOI:  10.1049/el:19850109
  • Type: Article
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  • p. 154 –155 (2)
    The field-effect channel electron mobility in 0.5 μm-thick silicon-on-sapphire films is increased by up to 22%, while the back-channel leakage current is decreased 100-fold, following a double recrystallisation by means of Si ion implantation/amorphisation and solid-phase epitaxy. The improved electrical performance correlates with a more than 100-fold reduction in the microtwin density, as measured by X-ray diffraction.
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Low-loss polarisation-maintaining optical fibre with low crosstalk
S-parameter measurements with a single six-port
Novel switched-capacitor generalised integrator
  • Author(s): A. Cichocki  and  R. Unbehauen
  • Source: Electronics Letters, Volume 21, Issue 4, p. 158 –159
  • DOI:  10.1049/el:19850112
  • Type: Article
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  • p. 158 –159 (2)
    A novel circuit arrangement is proposed for a generalised integrator using the switched-capacitor (SC) technique. This generalised integrator (which integrates with respect to a dependent variable) can easily be constructed in IC form using MOS technology. It possesses some attractive features, for instance simplicity and low cost. It can find applications in many analogue systems such as curve-fitting devices, adaptive filters, RMS convertors etc.
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Field test measurement for 920 MHz transmitter diversity
  • Author(s): S. Ogose
  • Source: Electronics Letters, Volume 21, Issue 4, p. 159 –161
  • DOI:  10.1049/el:19850113
  • Type: Article
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  • p. 159 –161 (3)
    Field test measurements on 920 MHz transmitter diversity have been undertaken in the Tokyo metropolitan area. The proposed transmitter diversity provides at least an 8 to 10 dB required receiver input level reduction effect for 10−3 BER under a multipath fading environment. It is confirmed that the transmitter diversity is an effective technique, not only at improving transmission quality, but also at constructing a multitransmitter ‘simulcast’ system.
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High-speed optical-optical logic gate for optical computers
Two-dimensional array of GaInAsP/InP surface-emitting lasers
InGaAsP/InP multiquantum-well structure grown by MOCVD
Anisotropy detection in hot-pressed silicon nitride by acoustic microscopy using the line-focus beam
  • Author(s): K. Yamanaka ; J. Kushibiki ; N. Chubachi
  • Source: Electronics Letters, Volume 21, Issue 4, p. 165 –167
  • DOI:  10.1049/el:19850117
  • Type: Article
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  • p. 165 –167 (3)
    Anisotropy in velocity and attenuation of leaky surface-acoustic waves (leaky SAWs) on hot-pressed silicon nitride was measured by acoustic microscopy using the line-focus beam. On the surface normal to the pressing direction the velocity was 5651 m/s for all propagation directions, whereas on the surface parallel to the pressing direction the velocities varied markedly, depending on the wave propagation direction—typically 5726 m/s along the direction normal to the pressing axis and 5642 m/s along the direction parallel to the pressing axis. Because the fracture toughness KIC, measured by the Vickers indentation technique, also showed an anisotropy on the surface normal to the pressing direction, the anisotropic velocity measurement of the leaky SAWs proved to be useful in the NDE of anisotropic mechanical properties of ceramics products made by hot-pressing.
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Stray-free switched-capacitor building block that realises delay, constant multiplier, or summer circuit

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