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ABSTRACT: We report a SDH/SONET multi-rate SFP module with a gain selectable transimpedance amplifier (TIA) and a dual-loop APC based on top and bottom level hold. With compliance to SDH (STM-1/4/16) and SONET (OC-3/12/48) specifications even without an additional cost requirement, multi-bit rate operation with higher received sensitivity, fully dual-loop APC operation up to 3 Gbit/s and dynamically rate selecting operation are firstly demonstrated.
Electronic Components and Technology Conference, 2007. ECTC '07. Proceedings. 57th; 07/2007
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ABSTRACT: We have proposed an ultra-small and low-cost wireless 3-dimentional system-in-package that includes 60-GHz-band radio frequency (RF) components. 60-GHz-band integrated circuits (ICs) of a 60-GHz-band transmission (TX) module were mounted onto an any layer interstitial via hole (ALIVH) substrate using stud bump bonding (SBB) technology. A mixer using antiparallel diode pair, power amplifier and driver amplifier ICs were fabricated on GaAs substrates. The characteristics of the fabricated TX module in a package were measured. The measured conversion gain and output power at 1-dB gain compression point of the TX module using a single balance mixer were 13 dB and 12 dBm, respectively. The 3-dB bandwidth at lower-side-band (LSB) output was found to be 3 GHz. The measured conversion gain and output power at 1-dB gain compression point of the TX module using a double balance mixer were 11 dB and 10.5 dBm, respectively. The 3-dB bandwidth at LSB output was found to be 3.6 GHz. The measurement results showed sufficient performance for a 60-GHz-band TX module.
Electronics Packaging Technology Conference, 2006. EPTC '06. 8th; 01/2007
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ABSTRACT: Pairing-based cryptosystems (PBC) have been attracted by researchers in cryptography. Some implementations show that PBC are relatively slower than the standard public key crypto systems. We present an efficient implementation for computing Tate pairing on a mobile phone using Java. We implemented the n<sub>T</sub> pairing (a recent efficient variation of Duursma-Lee algorithm) over some finite fields of characteristic 3 with extension degree m = {97,167,193, 239}. Our optimized implementation for m = 97 achieved about 0.5 seconds for computing Tate pairing over FOMA SH90US, NTT DoCoMo. Then our implementation of Tate pairing is compared in the same platform with other Java program of the standard cryptosystems, i.e., RSA cryptosystem and elliptic curve cryptosystem (ECC). The computation speed of Tate pairing is comparable to that of RSA or ECC on the same mobile device
Computational Intelligence and Security, 2006 International Conference on; 12/2006
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ABSTRACT: Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuels. Wind energy is not constant and windmill output is proportional to the cube of wind speed, which causes fluctuating power of wind turbine generator (WTG). In order to reduce the fluctuating power of WTG, this paper presents an output power leveling technique of WTG by pitch angle control using H<sub>infin </sub> control, and the control input of WTG linear model is separated from the disturbance. The simulation results using actual detailed model for WTG show the effectiveness of the proposed method
Power Systems Conference and Exposition, 2006. PSCE '06. 2006 IEEE PES; 12/2006
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ABSTRACT: We have proposed the current-source energy capacitor system (CS-ECS) in our previous work, which consists of an electric double-layer capacitor (EDLC), current-source inverter, and bi-directional DC-DC converter (four-quadrant DC-DC converter). However, this system has low efficiency due to hard-switching losses. Improvements of efficiency and performance are indispensable to implement the proposed system. This paper proposes the soft-switched four-quadrant DC-DC converter with an simple L-C resonant circuit for CS-ECS. High efficiency of the proposed system is achieved based on zero-current switching (ZCS) since a insulated gate bipolar transistors (IGBTs) of that converter softly turns on and turns off by using current-mode resonance. In order to illustrate the operating principle of the proposed system, we analyze in detail through a theoretical approach and computer simulations with MATLAB/SIMULINK
Power Electronics Specialists Conference, 2006. PESC '06. 37th IEEE; 07/2006
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ABSTRACT: We propose a new efficiency enhancement method of Doherty power amplifiers (PAs) using virtual open stub techniques. In this method, we consider a peak amplifier's output line as a virtual capacitive open stub only seen at low power level. Using this method, we can transform the low power load impedance seen from the carrier amplifier into higher than the impedance of classical Doherty PA (>100ohm). The relations of the load impedance and the length of the virtual open stub are derived analytically. The developed UHF-band 250W 2-way Doherty PA has been achieved a drain efficiency of 42.1% and an intermodulation (IM) distortion of -27.3dBc at an output power of 44.1dBm (10dB output backed-off) under an integrated services digital broadcasting-terrestrial (ISDB-T) OFDM signal. To the best of our knowledge, these results are the highest backed-off efficiency ever reported among the over 40dBm saturation high power Doherty amplifiers
Microwave Symposium Digest, 2006. IEEE MTT-S International; 07/2006
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ABSTRACT: In order to deposit a uniform film using plasma enhanced chemical vapor deposition (PECVD), it is required to design an RF discharge antenna to produce and control the plasma in a large area. In this paper, a 25-element array of folded monopole antennas is introduced to deposit a-Si film on a large area glass substrate of 1.6 m×1.2 m using a frequency of 85 MHz. In order to obtain a uniform deposition rate distribution, the feed-phases of the array have been controlled in both the experiment and FDTD analysis. Also, investigated is the correlation between the electromagnetic field distribution and the deposition rate distribution.
Antennas and Propagation Society International Symposium, 2004. IEEE; 07/2004
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ABSTRACT: A look up table (LUT) type adaptive digital pre-distortion (ADPD) using a weight divided adaptive algorithm is presented. In this algorithm, an output signal of the power amplifier (PA) is used as a reference signal. Additionally, reference signal is divided by the coefficient of the LUT, so that the characteristics of the PA, such as temperature dependence, do not have influence on the convergence performances. The proposed algorithm is presented and the convergence condition is derived analytically. From the ADPD simulation, we present that the proposed algorithm is more stable than the conventional normalized least mean square (NLMS) algorithm. The developed UHF-band ADPD power amplifier achieved the intermodulation (IM) distortion of -50dBc and the PA efficiency of 18% at output power of 54.8dBm under an integrated services digital broadcasting for terrestrial television broadcasting (ISDB-T) OFDM signal.
Microwave Symposium Digest, 2004 IEEE MTT-S International; 07/2004
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ABSTRACT: Numerical computations are made of axisymmetric laminar hydrogen diffusion flames, focusing on the unsteady behavior under microgravity and the effects of magnetic field. In the microgravity without magnetic field, it is revealed that combustion products remain around the diffusion flame because of the lack of convection, and the amount of O<sub>2</sub> diffusion to the flame region becomes retarded. When a gradient magnetic field is added, convection is induced around the diffusion flame by the magnetic field which induces magnetic buoyancy force due to the inhomogeneity of magnetic susceptibility. The flow configuration formed by the magnetic force under microgravity is similar to that under the normal gravity without the magnetic field.
IEEE Transactions on Appiled Superconductivity 07/2004; · 1.04 Impact Factor
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ABSTRACT: This paper describes research on crack shape reconstruction in ferromagnetic materials using a novel fast numerical simulation method. The fast numerical method developed here, which can treat ferromagnetic materials, is an extension of a precomputed database approach based on the reduced magnetic vector potential method. It provides a fast forward simulator that is about 80 times faster than a conventional one, even in the case of ferromagnetic materials, without losing accuracy. The fast simulator is applied to the inverse problem of eddy current testing (ECT), crack shape reconstruction, and results of some electric discharge machining (EDM) cracks on a ferromagnetic plate are shown.
IEEE Transactions on Magnetics 04/2004; · 1.36 Impact Factor
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ABSTRACT: This paper describes a module-based behavior selection architecture for a personal robot intended for a real world environment. We adopt the Emotional GrOunded architecture for a basis, and define and describe a behavior module and an associated tree structure for controlling many behavior modules. Also we discuss the requirements and approach for controlling the behavior module tree. Through experimentation and implementation on QRIO SDR4X-II, we confirm the feasibility and design of the behavior selection system.
Robotics and Automation, 2004. Proceedings. ICRA '04. 2004 IEEE International Conference on; 01/2004
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ABSTRACT: The implanted device discussed here is an artificial sphincter that utilizes shape memory alloy (SMA). To provide an independent evacuation for the patients using artificial anus, this device is implanted into their body. It receives driving energy by a transcutaneous energy transmission system using an electromagnetic coupling of a coil pair. This artificial sphincter operates according to the phase transformation of the SMA. Temperature control in the living body is necessary in order to heat the SMA to its phase transformation completion temperature. Taking advantage of the needless of a power supply for the temperature control circuit, we examined the way of controlling electric power to be transmitted by the transformer consisting of thermosensitive magnetic ferrite core. The SMA temperature is controlled by using the Curie-point of the ferrite attached to SMA as a reference temperature. Phase transformation completion temperature of the SMA that we used is 55°C. The purpose of this system is to automatically prevent overheating of the SMA above 55°C. Actually, because the electric power transmitted through the transformer decreases smoothly as the temperature rises to the Curie-point, the temperature of the SMA becomes stable to a point at which the heat conduction of the SMA balances the heat generated by the heater.
IEEE Transactions on Magnetics 10/2003; · 1.36 Impact Factor
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ABSTRACT: A low phase noise 19 GHz-band VCO is presented in this paper. The VCO has a novel tuning circuit consisting of two resonators which have a different resonant frequency. With these two resonators, the Q factor of the tuning circuit of the VCO is improved, and low phase noise can be achieved. The measurement results of the developed VCO show phase noise from -120 dBc/Hz to -122 dBc/Hz at 1 MHz from the carrier over a 290 MHz tuning bandwidth in the 19 GHz-band. This VCO achieves one of the lowest recorded values of phase noise at K-band.
Microwave Symposium Digest, 2003 IEEE MTT-S International; 07/2003
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ABSTRACT: For many pattern recognition methods, high recognition accuracy is
obtained at very high expense of computational cost. In this paper, a
new algorithm that reduces the computational cost for calculating
discriminant function is proposed. This algorithm consists of two stages
which are feature vector. Division and dimensional reduction. The
processing of feature division is based on characteristic of covariance
matrix. The dimensional reduction in the second stage is done by an
approximation of the Mahalanobis distance. Compared with the well-known
dimensional reduction method of K-L expansion, experimental results show
the proposed algorithm not only reduces the computational cost but also
improves the recognition accuracy
Pattern Recognition, 2000. Proceedings. 15th International Conference on; 02/2000
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M Funada,
K Seino,
K Takita,
Y Itoh,
G Toyoshima, T Takagi,
M Komaru,
H Mizutamari,
H Mineno,
C Ohuchi,
T Nishigaki,
M Takeuchi,
M Nishida,
H Saito
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ABSTRACT: A Ka-Band(21GHz) 20W-class SSPA for the advanced mobile satellite communications system in the COMmunication and broadcasting Engineering Test Satellite (COMETS) has been developed. This SSPA employs MMIC technology to achieve high performance in the Ka-Band region. A maximum output power of 24W with an efficiency of 10.4% including the DC/DC converter has been achieved. This is the best performance ever reported for a Ka-Band SSPA. The qualification-level tests of this SSPA for space use have been completed successfully.
Microwave Conference, 1995. 25th European; 10/1995
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ABSTRACT: A novel amplitude and phase linearizing technique for microwave
power amplifiers has been developed. It employs a series feedback
amplifier with a large source inductance as a predistortion linearizer,
which provides positive amplitude and negative phase deviations for
input power and can compensate for AM-AM and AM-PM distortions of power
amplifiers. Applying this technique to a 1.9 GHz MMIC power amplifier
for use in the Japanese Personal Handy-Phone System (PHS), an
improvement of adjacent channel leakage power (ACP) up to 7 dB has been
achieved when it is used for π/4-shift QPSK signal
Microwave Symposium Digest, 1995., IEEE MTT-S International; 06/1995
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ABSTRACT: A real time human motion recognition method is proposed that uses
fuzzy associative inference. If transforms space time patterns into
state transition patterns, which are then recognized by means of fuzzy
associative inference using associative memories. The tracking data is
given as time series data, from which the characteristic states are
extracted. Each human motion has a specific state transition pattern
that consists of characteristic states. To recognize these motions, the
specific state transition patterns of the motions are defined as fuzzy
rules and these fuzzy rules are implemented in a fuzzy associative
memory system. This method is independent of the person being measured
and the speed of the motion. In real time experiments, this method was
able to recognize three basic tennis motions (forehand stroke, backhand
stroke, and smash) for six unspecified people. The recognition ratio of
the fuzzy associative memory system is better than that of conventional
fuzzy inference and a multilayer perceptron
Fuzzy Systems, 1994. IEEE World Congress on Computational Intelligence., Proceedings of the Third IEEE Conference on; 07/1994
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ABSTRACT: A 4 to 25 GHz 0.5 W monolithic lossy match amplifier has been
developed. It employs a novel constant-resistance network and a parallel
resonant circuit as pre-matching circuits in the design of input and
output networks to make the input and output impedance of FETs purely
resistive. In addition a quarter-wavelength impedance transformer having
a low characteristic impedance is incorporated into the design of
interstage networks to match the output impedance of driver FETs and the
input impedance of power FETs over a wide bandwidth. With the use of
these networks, a two-stage lossy match power amplifier has achieved a
linear gain of 8.3±2.8 dB, a saturated output power of
27.7±2.7 dBm, and a drain efficiency of 15.3±8.3% over 4
to 25 GHz
Microwave Symposium Digest, 1994., IEEE MTT-S International; 06/1994
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ABSTRACT: For vibration analysis of a printed circuit board (PCB) surface
due to operation of mounted electromagnetic relay, the holographic
interferometry measuring technique was applied, in which the time
average method and the stroboscopic method were used and compared, along
with a graphic image processing technique was applied. As the results,
the microscopic displacement of PCB surface could be quantitatively
measured and evaluated from the vibration pattern of the 3-D graphic
image. It is shown that the stroboscopic method is useful in analysis of
the vibration due to impulsive vibration
Instrumentation and Measurement Technology Conference, 1994. IMTC/94. Conference Proceedings. 10th Anniversary. Advanced Technologies in I & M., 1994 IEEE; 06/1994
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ABSTRACT: A 5-10-GHz, 14-W amplifier has been developed. It utilizes a multisectional maximally flat impedance transformer whose length is designed to become a quarter wavelength at the highest frequency of the design band to achieve flat gain and flat power response over a wide bandwidth. Using this transformer, the amplifier has achieved a linear gain of 7+or-1 dB, a 1-dB compressed power of 41.5+or-0.8 dBm, and a power-added efficiency of greater than 25% over 5-10 GHz.
Microwave Symposium Digest, 1993., IEEE MTT-S International; 02/1993
