T. Kikkawa

Hiroshima University, Hirosima, Hiroshima, Japan

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Publications (213)163.63 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Interchip data transmission was demonstrated using impulse radio ultrawideband complementary metal-oxide–semiconductor (CMOS) transmitter integrate circuits withon-chip dipole antennas. A differential pseudorandom binary sequence of (2^{7}) data of Gaussian monocycle pulse (GMP) was formed by 65-nm CMOS logic circuits using up- and down-pulses with certain gate delays. The CMOS transmitter generated 5-Gb/s GMP with the center frequency of 10 GHz. To improve transmission gains, an interposer with the high dielectric constant ( (varepsilon _{textrm r} =38)) and optimized thickness was inserted under the CMOS chips as a dielectric slab waveguide. 2-Gb/s GMP signals were transmitted and received in the distance of 10 mm by use of the CMOS on-chip antennas and the high- (kappa ) interposer.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 07/2014; 4(7):1193-1200. · 1.24 Impact Factor
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    ABSTRACT: High-performance low-temperature poly-Si thin film transistor (LTPS-TFT) with one-dimensionally elongated long crystal grains have been developed. In the LTPS TFTs, the carrier mobility is enhanced, however the off-leakage current also increase. This is because, grain boundary become longer, and bridge the distance between source and drain, and the grain boundary bridge become a current-leakage path. In this paper, we suggest a novel ozone radical treatment for reducing the off-leakage current.
    2014 21st International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD); 07/2014
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    ABSTRACT: The variability in measurements of complex permittivities of tumor tissues between multiple samples could be attributed to the volume fraction of cancer cells in the excised tumor tissue. By the use of a digital photomicrograph image and hematoxylin-eosin staining, it was found that the malignant tumor tissue was not fully occupied by the cancer cells, but the cells were distributed locally in the stroma cells depending on the growth of cancer. The results showed that the volume fraction of cancer cells in the tumor tissue had a correlation to the measured conductivity and dielectric constant in the frequency range from 1 GHz to 6 GHz. It introduces a method to understand and gauge variability in measurements between different tumors.
    Applied Physics Letters 06/2014; 104(25):253702-253702-5. · 3.52 Impact Factor
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    ABSTRACT: A time-domain reflectometry breast cancer detection system was developed, which was composed of a Gaussian monocycle pulse (GMP) transmitter circuit fabricated by complementary metal oxide semiconductor (CMOS) 65 nm technology and an ultra wide-band (UWB) planar slot antenna array. The center frequency and bandwidth of the antenna were 6 and 9.2 GHz, respectively. The GMP train having the pulse width of 160 ps was generated by the 65 nm CMOS logic circuit with a core area of 0.0017 mm2 and was emitted by the 4 × 4 planar slot antenna array. The fabricated planar 4 × 4 antenna array with the matching layer could resolve the two separate 5 × 5 × 5 mm3 breast tumor phantoms, which were located at the depth of 22 mm with the spacing of 8 mm.
    Japanese Journal of Applied Physics 03/2014; 53(4S):04EL03. · 1.06 Impact Factor
  • Li Xu, Xia Xiao, Takamaro Kikkawa
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    ABSTRACT: Ultra-wide band (UWB) microwave imaging is a promising method for the breast cancer detection based on the large contrast of electric parameters between the malignant tumor and its surrounded normal organisms. In this paper, a two-dimensional model of the breast organisms is numerically carried by the finite difference time domain (FDTD) method. The dispersion characteristics of the breast media are taken into account by single pole Debye model to approach the actual properties of the breast organism. In this method, a tumor is assumed in the model with two cases. The standard Capon beamforming (SCB) and doubly constrained robust Capon beamforming (DCRCB) algorithm performed to reconstruct the image is described in detail. The tumor can be detected and localized using the proposed algorithm and the result demonstrates a good stability of DCRCB algorithm.
    Journal of Circuits System and Computers 01/2014; 22(10). · 0.33 Impact Factor
  • Xia Xiao, Xingmeng Shan, Ye Tao, Yuan Sun, Takamaro Kikkawa
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    ABSTRACT: Surface acoustic waves (SAWs) technique is a promising method to determine the mechanical properties of thin low dielectric constant (low-k) dielectrics by matching the experimental dispersion curve with the theoretical dispersion curves. However, it is difficult to calculate the dispersion curves when SAWs propagate along patterned structure. In this paper, finite element method (FEM) is applied to obtain the numerical dispersion results of SAWs propagating on patterned film. Periodic boundary condition and plane-strain model is used to improve the computation speed. Four structures of bulk silicon, single layered low-k film, two layered Cu and SiO2 film, and patterned film, are simulated in this paper. The dispersion curves of single low-k films derived from the FEM simulation agree very well with those calculated by traditional method, which verifies the correct employment of the FEM approach. Dispersion curves of two patterned film structure of Cu and SiO2 with difference metal wire width are obtained. Effective Young's moduli are achieved by fitting the FEM simulated results with those of traditional theoretical calculation through least square error method.
    Journal of Nanoscience and Nanotechnology 02/2013; 13(2):1602-6. · 1.34 Impact Factor
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    ABSTRACT: A compact 4 × 4 planar ultrawideband (UWB) antenna array with the total size of 44 × 52.4 mm was developed for radar-based breast cancer detection system. The center frequency and the bandwidth of the antenna were 6 and 12.5 GHz, respectively. The breast phantom materials were developed to fit the characteristics of the measured human breast tissues. A quasi-three-dimensional confocal imaging was performed using the breast phantoms. It was confirmed that the compact 4 × 4 antenna array could detect a 5 × 5 × 5-mm3 tumor phantom in an inhomogeneous structure with a glandular phantom and resolve the two separate tumor phantoms, which were located at the depth of 23 mm with the spacing of 10 mm.
    IEEE Antennas and Wireless Propagation Letters 01/2013; 12:733-736. · 1.95 Impact Factor
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    ABSTRACT: A radar-based breast cancer detection system was developed using a CMOS impulse transmitter circuit and an ultra-wideband (UWB) antenna array. The center frequency and the bandwidth of the antenna were 6 GHz and 12.5 GHz, respectively. A 198 ps Gaussian monocycle pulse (GMP) was generated by the CMOS circuit and emitted by 4x4 planar slot antenna array. The three-dimensional image of a 10 mm x 10 mm tumor phantom buried at the depth of 20 mm in the breast adipose phantom was reconstructed by confocal imaging algorithm.
    Electromagnetic Theory (EMTS), Proceedings of 2013 URSI International Symposium on; 01/2013
  • K. Sogo, A. Toya, T. Kikkawa
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    ABSTRACT: This paper presents a ring voltage-controlledoscillator (ring-VCO)-based sub-sampling phase locked loop(PLL) CMOS circuit with low phase noise and low jitter. A 2.08 GHz PLL is developed by use of 65 nm CMOS technology. The in-band phase noise is -119.1 dBc/Hz at 1 MHz and the output jitter integrated from 1 kHz to 10 MHz is 0.73 ps (rms) with the power consumpition 20.4 mW. The normalized jitter-power product is -229.7 dB.
    Design Automation Conference (ASP-DAC), 2013 18th Asia and South Pacific; 01/2013
  • T. Kikkawa, T. Sugitani
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    ABSTRACT: A 4×4 planar ultra-wideband (UWB) antenna array was developed for radar-based breast cancer detection system in the supine position. The the center frequency and the bandwidth of the antenna were 6 GHz and 12.5 GHz, respectively. The size of an antenna element was 11 mm × 13.1 mm. Confocal imaging was perfomed using breast phantoms whose characteristics were close to those of measured tumors, glandular and adipose tissues. The three-dimensional breast tumor images were reconstructed.
    Antennas and Propagation (EuCAP), 2013 7th European Conference on; 01/2013
  • K. Sogo, A. Toya, T. Kikkawa
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    ABSTRACT: This paper presents a ring-voltage-controlled-oscillator (ring-VCO)-based sub-sampling phase locked loop (PLL) CMOS circuit with low phase noise and low jitter. A 2.08 GHz PLL is designed and fabricated in 65 nm CMOS technology. The PLL consumes 20.4 mW while the in-band phase noise is -119.1 dBc/Hz at 1.4 MHz and the output jitter integrated from 1 kHz to 10 MHz is 0.73 ps (rms). The figure of merit (FOM) is -229.7 dB, which is the best data ever reported.
    ESSCIRC (ESSCIRC), 2012 Proceedings of the; 01/2012
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    ABSTRACT: Impulse radio ultra-wide-band complementary metal oxide semiconductor (IR-UWB-CMOS) integrated circuits have been developed for breast cancer detection. The circuits consist of Gaussian monocycle pulse (GMP) generator and transmitter, low noise amplifier (LNA), equivalent time sampling circuits and analog to digital converter. The GMP with the center frequency of 6 GHz was digitally generated and transmitted by use of off-chip UWB antennas. The received signals were digitized by equivalent time sampling technique and were transformed to the two-dimensional pixels by confocal imaging algorism.
    Antennas and Propagation (EUCAP), 2012 6th European Conference on; 01/2012
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    ABSTRACT: A quantitative and systematic investigation about the molecular nature of the dielectric and mechanical properties of organic/inorganic hybrid glass film with alkylene bridges was performed. The hybrid glass film was prepared from a sol precursor solution of the mixture of tetraethoxysilane (TEOS) and bis(triethoxysilyl)methane (BTM). The mole fraction of BTM and TEOS was changed in order to control the amount of ≡Si—(CH2)—Si≡. Then, the dielectric constant decreased monotonically from 4.35 to 3.65 with the full replacement of ≡Si—O—Si≡ with ≡Si—(CH2)—Si≡. Young’s modulus also decreased from 48.2 to 36.5 GPa. The same study was also performed about the organosilicate hybrid glass prepared from the mixture of bis(triethoxysilyl)ethane (BTE) and TEOS. Then, the further decreases in the dielectric constant and the Young’s modulus were measured. Molecular bonding structures were analyzed by investigating the atomic composition from Rutherford backscattering spectrometry and complex dielectric function concerning the ionic vibrations from Fourier transform infrared spectrum. Then, it was found that the decrease of the dielectric constant is attributed to the attenuation of ionic vibration strength of siloxane bonding, and the ionic vibration strength is described by a linear function of atomic density of Si and O, which is the same independent of the alkylene bridge length. The Young’s modulus is also well described by a linear function of the sum of the Si and O densities. This result means that the siloxane network is still the most significant factor that determines the Young’s modulus.
    The Journal of Physical Chemistry C 06/2011; 115(26). · 4.84 Impact Factor
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    ABSTRACT: Skeletal siloxane bonding structure of nanocrystalline MEL pure silica zeolite film was investigated. Nanocrystalline zeolite (nc-zeolite) suspension was prepared by the two-stage hydrothermal treatment, and thin film was obtained by spin-coating. After a quantitative analysis of Fourier-transform infrared spectra with the variable incidence angles of light probe, skeletal complex dielectric function concerning the siloxane bond vibration was derived in the 1400–400 cm–1 range. Then, the widening of the AS1-(LO-TO) frequency splitting width and the enhancement of the normalized integrated oscillator strength of AS vibration mode were observed in the nc-zeolite film in comparison with those of sol–gel derived amorphous silica film. Those improvements must be attributed to the increased siloxane network connectivity and the crystal structure of zeolite. The effect of the UV assist anneal was also discussed.
    The Journal of Physical Chemistry C 05/2011; 115(23). · 4.84 Impact Factor
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    ABSTRACT: Young’s moduli of porous silica low-k films with cesium (Cs) doping are determined by surface acoustic waves (SAWs) in this study. Four low-k samples doped with 0–30 ppm wt% Cs in the precursor solution are investigated to check the mechanical promotion of the porous silica films. The SAW determination process is performed on these ultra-thin porous films. The detected signals with the signal-to-noise ratio of 50:1 are achieved in our measurements. The signal process with combination of wavelet and FIR filter is proposed to effectively restrain the high and low frequency noises and the “Gibbs effect” of the detected signals. The smooth experimental dispersive curves with frequency range from 20 to 150 MHz, which is qualified for the data fitting process with the theoretical dispersion curves, are obtained for these detected thin low-k films. The determination results show that the mechanical property is improved with the pretreatment of cesium doping, which confirms that the degree of siloxane cross-linkage of the porous silica film is promoted by cesium doping.
    Microelectronic Engineering 05/2011; 88(5):666-670. · 1.34 Impact Factor
  • Mohiuddin Hafiz, Nobuo Sasaki, Takamaro Kikkawa
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    ABSTRACT: A CMOS detection procedure for ultra-wideband impulse radio (UWB-IR) communication system, employing Bi-Phase Shift Keying (BPSK) modulation scheme, is presented here. The chip, designed and fabricated in a 0.18μm CMOS process, requires a supply voltage of 1.8V and occupies a die area of 0.01mm2. A train of Gaussian monocycle pulses (GMP), modulated by a random data sequence of 800Mb/s, is detected successfully by the detector. The detection scheme employing a very simple architecture with a power consumption of 3mW is well suited for non-coherent wireless communication system.
    AEU - International Journal of Electronics and Communications 05/2011; 65(5):398-405. · 0.70 Impact Factor
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    ABSTRACT: In this work, we present an ultrawide-band (UWB) complementary metal--oxide--semiconductor (CMOS) low-noise amplifier (LNA) for wireless communication in the upper UWB band, that is, from 5.4--9.2 GHz bandwidth with a wide-band 50 Omega input matching network in front of the LNA. A three-stage cascode-topology-based LNA with high-transconductance MOS transistors, was employed to improve the voltage gain up to 23 dB at 7.5 GHz, with 4.5--9.2 GHz 3 dB bandwidth. The maximum output power S21 was 19.5 dB at 7.3 GHz, with 5.4--9.2 GHz 3 dB bandwidth. The input matching circuit was designed with a reduced number of passive elements, resulting in an input reflection coefficient S11 of less than -10 dB from 4.5--9.2 GHz. The noise figure of the LNA was as low as 3.5 dB and the input-referred third-order intercept point (IIP3) was -8 dBm. The LNA has output reflection coefficient S22 of less than -10 dB from 5--7 GHz and a good reverse isolation, that is, S12 of < -45 dB in the entire UWB, due to a cascode topology. The LNA was fabricated using 180 nm CMOS technology, which consumes 56 mW power at 1.8 V power supply. In this paper, we also demonstrate a wireless communication of 7 GHz Gaussian monocycle pulse (GMP) by horn antennas and the LNA from 20 cm transmission distance.
    Japanese Journal of Applied Physics 04/2011; 50. · 1.06 Impact Factor
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    ABSTRACT: A low-power impulse-radio ultra-wideband (IR-UWB) confocal imaging system was developed using a low-power complementary metal oxide semiconductor (CMOS) equivalent time sampling circuit and UWB slot antennas. The proposed imaging system uses a Gaussian monocycle pulse with 3 GHz center frequency to detect a target. The sampling circuit is fabricated by 65 nm CMOS technology, and it can achieve a high sampling rate of 28.2 GS/s, input bandwidth of 3.3 GHz and PLL RMS jitter of 3.44 ps with a low power consumption of 50.7 mW. The UWB slot antenna having a 1.53--4.80 GHz input bandwidth is developed for the confocal imaging. An aluminum target was detected using a confocal imaging algorithm.
    Japanese Journal of Applied Physics 04/2011; 50(4). · 1.06 Impact Factor
  • A. Toya, N. Sasaki, S. Kubota, T. Kikkawa
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    ABSTRACT: A 32 GS/s ultra-high-speed ultra-wideband (UWB) sampling circuit has been developed by use of a 65 nm CMOS technology. An equivalent time sampling technique was applied using an internal clock generator to achieve its low power consumption and high sampling rate. The generator consists of an eight-stage 2 GHz phase-locked loop, a 16-to-1 multiplexer and a frequency divider. Both a 20 mW low power consumption and a 32 GS/s high sampling rate were achieved. Gaussian monocycle pulse signals with a centre frequency of 450 MHz could be successfully converted to digital codes.
    Electronics Letters 03/2011; · 1.07 Impact Factor
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    ABSTRACT: A simple non-coherent solution to UWB-IR communication has been presented here. An all digital differential transmitter, developed in a 65 nm CMOS technology and a simple receiver, developed in a 180 nm CMOS technology, for detecting the received differential signal are demonstrated in the work. Though the transmitter and the receiver have been developed in two different technologies, the main objective of this paper is to show the effectiveness of such a non-coherent solution for BPSK modulated UWB-IR communication.
    Proceedings of the 16th Asia South Pacific Design Automation Conference, ASP-DAC 2011, Yokohama, Japan, January 25-27, 2011; 01/2011

Publication Stats

830 Citations
163.63 Total Impact Points


  • 1998–2014
    • Hiroshima University
      • Research Institute for Nanodevices and Bio Systems
      Hirosima, Hiroshima, Japan
  • 2004–2013
    • Tianjin University
      • Department of Electronic Information Engineering
      Tianjin, Tianjin Shi, China
  • 2011
    • University of Louisiana at Lafayette
      • Computer Studies, Advanced
      Lafayette, Louisiana, United States
  • 1989–2008
    • NEC Corporation
      Edo, Tōkyō, Japan
  • 2001–2007
    • National Institute of Advanced Industrial Science and Technology
      Tsukuba, Ibaraki, Japan