Yuta Saito - Academia.edu (original) (raw)

Papers by Yuta Saito

IEICE Technical Report; IEICE Tech. Rep., Jul 19, 2017

Proceedings of the School of Engineering of Tokai University, Sep 1, 2013

International Symposium on Antennas and Propagation, Oct 1, 2018

In this paper, we propose the configuration inserted a semi-rigid cable monopole antenna into a 6... more In this paper, we propose the configuration inserted a semi-rigid cable monopole antenna into a 60GHz band oscillator chip for one of low-loss connection between a RF circuit and an antenna. The inner conductor is connected with a RF pad of the oscillator chip by a gold wire and the outer conductor inserted in the chip prevents leakage of an electromagnetic wave into silicon. We measure radiation power and radiation pattern. The measured radiation power is estimated to be 18.6 dBm by a reverberation chamber while he directly measured output power from the RF pad by a prober is in a range of -13.5dBm-12.0dBm. The designed and the measured patterns have good agreement. We confirm the radiation to the circuit side is small.

IEEE Access, 2020

In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array a... more In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array antenna loaded with dipoles is proposed. The antenna is composed of a feeding circuit, radiating slots on radiating waveguides, and dipoles for polarization conversion. By integrating the feeding circuit and the radiating waveguides into a single dielectric layer, the total number of dielectric layers is reduced to two which greatly increases ease of mass production. The feeding circuit divides power into two and feeds the two radiating waveguides from their center. 8 × 2 radiating elements are composed of a slot and a dipole placed on the radiating waveguides. The elements are designed by standing-wave excitation. The antenna is fabricated by printed circuit board technology and its dimensions are 44.5 × 20.0 × 2.16 mm 3. The measured results show a 2.1-dB axial ratio, 15.6-dBi gain, and 57.2% efficiency at 61.5 GHz. The proposed antenna realizes a circular polarized array antenna with the minimum number of dielectric layers and electric performance comparable to conventional antennas. INDEX TERMS Circular polarization, waveguide slot array antenna, post-wall waveguide, substrate integrated waveguide, 60-GHz band.

Transactions-Materials Research Society of Japan, 2007

Atomic Energy Society of Japan, Feb 13, 2014

IEICE Technical Report; IEICE Tech. Rep., Mar 7, 2019

Transactions of the Materials Research Society of Japan, 2007

The syntheses of novel graft copolyamides containing both of poly(ethylene oxide) (PEO) and polyd... more The syntheses of novel graft copolyamides containing both of poly(ethylene oxide) (PEO) and polydimethylsiloxane (PDMS) in the side chains were carried out by a macromonomer method, in order to develop a new functional membrane material which were expected to possess the high permeability of PDMS and the functionality of PEO-metal complex. For this purpose, 3,5-bis(4-carboxyphenyloxy)phenyloxy-terminated PEO (BCPP-PEO) and 3,5-bis(4aminophenoxy)benzyloxypropyl-terminated PDMS (BAPB-PDMS) were synthesized as macromonomers. The polycondensations of BCPP-PEO and BAPB-PDMS yielded the desired PDMS/PEO alternately grafted aromatic polyamide (P A-g-SE). Copolymer membranes were prepared by solvent casting method, and the gas permeability of these membranes was evaluated. As a result, P A-g-SE membrane exhibited the higher gas permeability than PEO-grafted polyamide membrane (P A-g-PEO). Furthermore, the selectivity of olefin gas through the membrane was effectively advanced by the addition of Ag ion to the copolymer membrane.

Novel graft copolymers, which consisted of polyamide or polyimide backbone attached with polydime... more Novel graft copolymers, which consisted of polyamide or polyimide backbone attached with polydimethylsiloxane (PDMS)/poly(ethylene oxide) (PEO) block segments, were prepared by the polycondensation of diamino-terminated PEO/PDMS macromonomers with terephthaloyl chloride or 2,2-bis(3,4-anhydrodicarboxyphenyl)hexafluoropropane. Then, the effect of the composition on the physical properties of graft copolymers was investigated. The obtained copolymers were soluble in THF and some solvents, and the self-standing membranes could be prepared by a solvent-casting method. Gas permeability and ethanol permselectivity in pervaporation of ethanol/water mixture decreased with the increase of the PEO component in the side chain. In addition, the protein adhesion on the membrane surface increased with the decrease of the PEO component in the side chain. Therefore, it was revealed that the PEO component was effective for reducing the protein adhesion, although the trade-off relation was observed b...

IEEE Access, 2020

In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array a... more In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array antenna loaded with dipoles is proposed. The antenna is composed of a feeding circuit, radiating slots on radiating waveguides, and dipoles for polarization conversion. By integrating the feeding circuit and the radiating waveguides into a single dielectric layer, the total number of dielectric layers is reduced to two which greatly increases ease of mass production. The feeding circuit divides power into two and feeds the two radiating waveguides from their center. 8 × 2 radiating elements are composed of a slot and a dipole placed on the radiating waveguides. The elements are designed by standing-wave excitation. The antenna is fabricated by printed circuit board technology and its dimensions are 44.5 × 20.0 × 2.16 mm 3. The measured results show a 2.1-dB axial ratio, 15.6-dBi gain, and 57.2% efficiency at 61.5 GHz. The proposed antenna realizes a circular polarized array antenna with the minimum number of dielectric layers and electric performance comparable to conventional antennas. INDEX TERMS Circular polarization, waveguide slot array antenna, post-wall waveguide, substrate integrated waveguide, 60-GHz band.

Transactions of the Materials Research Society of Japan, 2008

The syntheses of siloxane-grafted polyamides were carried out by a macromonomer method, in order ... more The syntheses of siloxane-grafted polyamides were carried out by a macromonomer method, in order to develop a highly permeable and durable membrane material for pervaporation. A novel compounds, 3 ,5-bis(4-aminophenoxy)benzyloxypropyl-terminated polydimethylsiloxane (BAPB-PDMS), and 3,5-bis(4-amino-3-methylphenoxy)benzyloxypropyl-terminated polydimethylsiloxane (BAMPB-PDMS), were synthesized as macromonomers, which consisted of different PDMS segment lengths. The polycondensation of BAPB-PDMSs or BAMPB-PDMSs with terephthaloyl chloride yielded the desired siloxane-grafted polyamide copolymers, PA-g-PDMS and MPA-g-PDMS, respectively. The copolymer membranes were prepared by solvent casting method, and the gas permeability and pervaporation property of these membranes were evaluated. PA-g-PDMS was insoluble in any solvents after the copolymer was dried in vacuo, however, MPA-g-PDMS was soluble in solvents, such as tetrahydrofuran, chloroform and dichloromethane. Therefore, MPA-g-PDMS exhibited the higher processability than PA-g-PDMS. The gas permeability coefficients of these copolymer membranes were increased as increase of PDMS segment length, and these values of MPA-g-PDMS were slightly higher than those of PA-g-PDMS containing the same PDMS segment length. From the results of pervaporations of the dilute aqueous solutions of organic solvents, it was found that both of PA-g-PDMS and MPA-g-PDMS exhibited the excellent permselectivity toward several organic solvents, such as alcohols, acetone, tetrahydrofuran, chloroform, dichloromethane and benzene with a high and stable permeation.

Journal of Nuclear Fuel Cycle and Environment, 2015

VTC Spring 2009 - IEEE 69th Vehicular Technology Conference, 2009

ABSTRACT

Transactions of the Materials Research Society of Japan, 2009

Graft copolyamides containing amphiphilic components in the side chains, alternately grafted arom... more Graft copolyamides containing amphiphilic components in the side chains, alternately grafted aromatic polyamides containing polydimethylsiloxane (PDMS) and poly(ethylene oxide) (PEO) segments (PA-g-SEa), were prepared by a macromonomer method, which exhibited the high permeability of PDMS segment and the biocompatibility derived from the amphiphilic components. PA-g-SEa membranes were prepared by solvent casting method, and the gas permeability, the pervaporation property, the surface property and the biocompatibility of the obtained polymer membranes were investigated. From the results of permeation examinations of gases and aqueous ethanol solutions, PA-g-SEa membranes indicated the high permeability for most gases and liquids. In addition, the organic permselectivity was enhanced with the increase of PDMS segment length of these polymers. Furthermore, the amount of adhered platelets on PA-g-SEa membranes was much smaller than that on only PDMS grafted aromatic polyamide (PA-g-PDMS) membranes, which would be due to the effect of amphiphilic side chains.

Journal of the American Ceramic Society, 1999

Billets of hexagonal boron nitride powders (h-BN) were hot-pressed, varying the alignment of the ... more Billets of hexagonal boron nitride powders (h-BN) were hot-pressed, varying the alignment of the platelike particles and the amount of oxide additives. Increasing either alignment of individual grains or the amount of additives was shown to increase flexural strength, to approximately 120 MPa at ambient temperatures. h-BN was shown to deflect cracks initially propagating normal to its basal planes.

Epidemiology and Infection, 2003

The aims of this descriptive study were to confirm the high incidence of subacute sclerosing pane... more The aims of this descriptive study were to confirm the high incidence of subacute sclerosing panencephalitis (SSPE) previously reported from Papua New Guinea (PNG) and to relate SSPE to previous measles vaccination and measles illness. From February 1997 to April 1999 we diagnosed a total of 55 patients with SSPE at Goroka Base General Hospital in Eastern Highlands Province (EHP) of PNG. The diagnosis was based on high cerebrospinal fluid and serum measles virus antibody titres with progressive neurological disorder and myoclonic jerks. Of these 55 patients 42 were from EHP, including 32 whose onset was in the 2-year period 1997–1998. The annual incidence of SSPE in EHP in these 2 years was 98 per million population under 20 years of age, the highest ever reported. This incidence was more than ten times higher than the highest incidence in the prevaccine era reported from elsewhere. The mean age of onset of SSPE was 7·7 years (range 2·8–14·8 years) and the interval between measles a...

IEICE Technical Report; IEICE Tech. Rep., Jul 19, 2017

Proceedings of the School of Engineering of Tokai University, Sep 1, 2013

International Symposium on Antennas and Propagation, Oct 1, 2018

In this paper, we propose the configuration inserted a semi-rigid cable monopole antenna into a 6... more In this paper, we propose the configuration inserted a semi-rigid cable monopole antenna into a 60GHz band oscillator chip for one of low-loss connection between a RF circuit and an antenna. The inner conductor is connected with a RF pad of the oscillator chip by a gold wire and the outer conductor inserted in the chip prevents leakage of an electromagnetic wave into silicon. We measure radiation power and radiation pattern. The measured radiation power is estimated to be 18.6 dBm by a reverberation chamber while he directly measured output power from the RF pad by a prober is in a range of -13.5dBm-12.0dBm. The designed and the measured patterns have good agreement. We confirm the radiation to the circuit side is small.

IEEE Access, 2020

In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array a... more In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array antenna loaded with dipoles is proposed. The antenna is composed of a feeding circuit, radiating slots on radiating waveguides, and dipoles for polarization conversion. By integrating the feeding circuit and the radiating waveguides into a single dielectric layer, the total number of dielectric layers is reduced to two which greatly increases ease of mass production. The feeding circuit divides power into two and feeds the two radiating waveguides from their center. 8 × 2 radiating elements are composed of a slot and a dipole placed on the radiating waveguides. The elements are designed by standing-wave excitation. The antenna is fabricated by printed circuit board technology and its dimensions are 44.5 × 20.0 × 2.16 mm 3. The measured results show a 2.1-dB axial ratio, 15.6-dBi gain, and 57.2% efficiency at 61.5 GHz. The proposed antenna realizes a circular polarized array antenna with the minimum number of dielectric layers and electric performance comparable to conventional antennas. INDEX TERMS Circular polarization, waveguide slot array antenna, post-wall waveguide, substrate integrated waveguide, 60-GHz band.

Transactions-Materials Research Society of Japan, 2007

Atomic Energy Society of Japan, Feb 13, 2014

IEICE Technical Report; IEICE Tech. Rep., Mar 7, 2019

Transactions of the Materials Research Society of Japan, 2007

The syntheses of novel graft copolyamides containing both of poly(ethylene oxide) (PEO) and polyd... more The syntheses of novel graft copolyamides containing both of poly(ethylene oxide) (PEO) and polydimethylsiloxane (PDMS) in the side chains were carried out by a macromonomer method, in order to develop a new functional membrane material which were expected to possess the high permeability of PDMS and the functionality of PEO-metal complex. For this purpose, 3,5-bis(4-carboxyphenyloxy)phenyloxy-terminated PEO (BCPP-PEO) and 3,5-bis(4aminophenoxy)benzyloxypropyl-terminated PDMS (BAPB-PDMS) were synthesized as macromonomers. The polycondensations of BCPP-PEO and BAPB-PDMS yielded the desired PDMS/PEO alternately grafted aromatic polyamide (P A-g-SE). Copolymer membranes were prepared by solvent casting method, and the gas permeability of these membranes was evaluated. As a result, P A-g-SE membrane exhibited the higher gas permeability than PEO-grafted polyamide membrane (P A-g-PEO). Furthermore, the selectivity of olefin gas through the membrane was effectively advanced by the addition of Ag ion to the copolymer membrane.

Novel graft copolymers, which consisted of polyamide or polyimide backbone attached with polydime... more Novel graft copolymers, which consisted of polyamide or polyimide backbone attached with polydimethylsiloxane (PDMS)/poly(ethylene oxide) (PEO) block segments, were prepared by the polycondensation of diamino-terminated PEO/PDMS macromonomers with terephthaloyl chloride or 2,2-bis(3,4-anhydrodicarboxyphenyl)hexafluoropropane. Then, the effect of the composition on the physical properties of graft copolymers was investigated. The obtained copolymers were soluble in THF and some solvents, and the self-standing membranes could be prepared by a solvent-casting method. Gas permeability and ethanol permselectivity in pervaporation of ethanol/water mixture decreased with the increase of the PEO component in the side chain. In addition, the protein adhesion on the membrane surface increased with the decrease of the PEO component in the side chain. Therefore, it was revealed that the PEO component was effective for reducing the protein adhesion, although the trade-off relation was observed b...

IEEE Access, 2020

In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array a... more In this paper, an 8 × 2-element 60-GHz band circularly polarized post-wall waveguide slot array antenna loaded with dipoles is proposed. The antenna is composed of a feeding circuit, radiating slots on radiating waveguides, and dipoles for polarization conversion. By integrating the feeding circuit and the radiating waveguides into a single dielectric layer, the total number of dielectric layers is reduced to two which greatly increases ease of mass production. The feeding circuit divides power into two and feeds the two radiating waveguides from their center. 8 × 2 radiating elements are composed of a slot and a dipole placed on the radiating waveguides. The elements are designed by standing-wave excitation. The antenna is fabricated by printed circuit board technology and its dimensions are 44.5 × 20.0 × 2.16 mm 3. The measured results show a 2.1-dB axial ratio, 15.6-dBi gain, and 57.2% efficiency at 61.5 GHz. The proposed antenna realizes a circular polarized array antenna with the minimum number of dielectric layers and electric performance comparable to conventional antennas. INDEX TERMS Circular polarization, waveguide slot array antenna, post-wall waveguide, substrate integrated waveguide, 60-GHz band.

Transactions of the Materials Research Society of Japan, 2008

The syntheses of siloxane-grafted polyamides were carried out by a macromonomer method, in order ... more The syntheses of siloxane-grafted polyamides were carried out by a macromonomer method, in order to develop a highly permeable and durable membrane material for pervaporation. A novel compounds, 3 ,5-bis(4-aminophenoxy)benzyloxypropyl-terminated polydimethylsiloxane (BAPB-PDMS), and 3,5-bis(4-amino-3-methylphenoxy)benzyloxypropyl-terminated polydimethylsiloxane (BAMPB-PDMS), were synthesized as macromonomers, which consisted of different PDMS segment lengths. The polycondensation of BAPB-PDMSs or BAMPB-PDMSs with terephthaloyl chloride yielded the desired siloxane-grafted polyamide copolymers, PA-g-PDMS and MPA-g-PDMS, respectively. The copolymer membranes were prepared by solvent casting method, and the gas permeability and pervaporation property of these membranes were evaluated. PA-g-PDMS was insoluble in any solvents after the copolymer was dried in vacuo, however, MPA-g-PDMS was soluble in solvents, such as tetrahydrofuran, chloroform and dichloromethane. Therefore, MPA-g-PDMS exhibited the higher processability than PA-g-PDMS. The gas permeability coefficients of these copolymer membranes were increased as increase of PDMS segment length, and these values of MPA-g-PDMS were slightly higher than those of PA-g-PDMS containing the same PDMS segment length. From the results of pervaporations of the dilute aqueous solutions of organic solvents, it was found that both of PA-g-PDMS and MPA-g-PDMS exhibited the excellent permselectivity toward several organic solvents, such as alcohols, acetone, tetrahydrofuran, chloroform, dichloromethane and benzene with a high and stable permeation.

Journal of Nuclear Fuel Cycle and Environment, 2015

VTC Spring 2009 - IEEE 69th Vehicular Technology Conference, 2009

ABSTRACT

Transactions of the Materials Research Society of Japan, 2009

Graft copolyamides containing amphiphilic components in the side chains, alternately grafted arom... more Graft copolyamides containing amphiphilic components in the side chains, alternately grafted aromatic polyamides containing polydimethylsiloxane (PDMS) and poly(ethylene oxide) (PEO) segments (PA-g-SEa), were prepared by a macromonomer method, which exhibited the high permeability of PDMS segment and the biocompatibility derived from the amphiphilic components. PA-g-SEa membranes were prepared by solvent casting method, and the gas permeability, the pervaporation property, the surface property and the biocompatibility of the obtained polymer membranes were investigated. From the results of permeation examinations of gases and aqueous ethanol solutions, PA-g-SEa membranes indicated the high permeability for most gases and liquids. In addition, the organic permselectivity was enhanced with the increase of PDMS segment length of these polymers. Furthermore, the amount of adhered platelets on PA-g-SEa membranes was much smaller than that on only PDMS grafted aromatic polyamide (PA-g-PDMS) membranes, which would be due to the effect of amphiphilic side chains.

Journal of the American Ceramic Society, 1999

Billets of hexagonal boron nitride powders (h-BN) were hot-pressed, varying the alignment of the ... more Billets of hexagonal boron nitride powders (h-BN) were hot-pressed, varying the alignment of the platelike particles and the amount of oxide additives. Increasing either alignment of individual grains or the amount of additives was shown to increase flexural strength, to approximately 120 MPa at ambient temperatures. h-BN was shown to deflect cracks initially propagating normal to its basal planes.

Epidemiology and Infection, 2003

The aims of this descriptive study were to confirm the high incidence of subacute sclerosing pane... more The aims of this descriptive study were to confirm the high incidence of subacute sclerosing panencephalitis (SSPE) previously reported from Papua New Guinea (PNG) and to relate SSPE to previous measles vaccination and measles illness. From February 1997 to April 1999 we diagnosed a total of 55 patients with SSPE at Goroka Base General Hospital in Eastern Highlands Province (EHP) of PNG. The diagnosis was based on high cerebrospinal fluid and serum measles virus antibody titres with progressive neurological disorder and myoclonic jerks. Of these 55 patients 42 were from EHP, including 32 whose onset was in the 2-year period 1997–1998. The annual incidence of SSPE in EHP in these 2 years was 98 per million population under 20 years of age, the highest ever reported. This incidence was more than ten times higher than the highest incidence in the prevaccine era reported from elsewhere. The mean age of onset of SSPE was 7·7 years (range 2·8–14·8 years) and the interval between measles a...