IEICE Transactions on Electronics
Online ISSN : 1745-1353
Print ISSN : 0916-8524
Volume E101.C, Issue 6
Displaying 1-3 of 3 articles from this issue
Regular Section
  • Hideki ONO, Takasi SIMOYAMA, Shigekazu OKUMURA, Masahiko IMAI, Hiroki ...
    Article type: PAPER
    Subject area: Optoelectronics
    2018 Volume E101.C Issue 6 Pages 409-415
    Published: June 01, 2018
    Released on J-STAGE: June 01, 2018
    JOURNAL RESTRICTED ACCESS

    We report good responsivity at the wavelength of 1600nm in a Ge photodetector which had lateral p-i-n structure and butt-joint coupling structure based on conventional normal complementary metal oxide semiconductor processes. We experimentally verified the responsivity of 0.82A/W and 0.71A/W on the best and the worst polarizations, respectively. The butt joint lateral p-i-n structure is found to be polarization independent as compared with vertical ones. Although cut-off frequency was 2.3-2.4GHz at reverse bias 3V, clearly open eye diagram at 10Gbps was obtained with reverse bias over 12V. These results are promising as optical photodetectors to receive long wavelengths downstream signal wavelengths required for next-generation optical access network systems.

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  • Mitsuyoshi KISHIHARA, Masaya TAKEUCHI, Akinobu YAMAGUCHI, Yuichi UTSUM ...
    Article type: PAPER
    Subject area: Microwaves, Millimeter-Waves
    2018 Volume E101.C Issue 6 Pages 416-422
    Published: June 01, 2018
    Released on J-STAGE: June 01, 2018
    JOURNAL RESTRICTED ACCESS

    The microfabrication technique based on SR (Synchrotron Radiation) direct etching process has recently been applied to construct PTFE microstructures. This paper attempts to fabricate an integrated PTFE-filled waveguide Butler matrix for short millimeter-wave by SR direct etching. First, a cruciform 3-dB directional coupler and an intersection circuit (0-dB coupler) are designed at 180 GHz. Then, a 4×4 Butler matrix with horn antennas is designed and fabricated. Finally, the measured radiation patterns of the Butler matrix are shown.

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  • Takashi OHSAWA
    Article type: PAPER
    Subject area: Electronic Circuits
    2018 Volume E101.C Issue 6 Pages 423-429
    Published: June 01, 2018
    Released on J-STAGE: June 01, 2018
    JOURNAL RESTRICTED ACCESS

    Several new memories are being studied as candidates of future DRAM that seems difficult to be scaled. However, the read signal in these new memories needs to be amplified in a single-end manner with reference signal supplied if they are aimed for being applied to the high-density main memory. This scheme, which is fortunately not necessary in DRAM's 1/2Vdd pre-charge sense amp, can become a serious bottleneck in the new memory development, because the device electrical parameters in these new memory cells are prone to large cell-to-cell variations without exception. Furthermore, the extent to which the parameter fluctuates in data “1” is generally not the same as in data “0”. In these situations, a new sensing scheme is proposed that can minimize the sensing error rate for high-density single-end emerging memories like STT-MRAM, ReRAM and PCRAM. The scheme is based on averaging multiple dummy cell pairs that are written “1” and “0” in a weighted manner according to the fluctuation unbalance between “1” and “0”. A detailed analysis shows that this scheme is effective in designing 128Mb 1T1MTJ STT-MRAM with the results that the required TMR ratio of an MTJ can be relaxed from 130% to 90% for the fluctuation of 6% sigma-to-average ratio of MTJ resistance in a 16 pair-dummy cell averaging case by using this technology when compared with the arithmetic averaging method.

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