Keycom Corporation

Tokyo, Japan

Keycom Corporation

Tokyo, Japan
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Osipov A.,German Aerospace Center | Kobayashi H.,Niigata University | Suzuki H.,KEYCOM Corporation
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2010

An improved approach to determination of radar cross section (RCS) of electrically large targets from the scattered field measured with a monostatic radar over a circle in the near-field of the targets is presented. The frequency- and azimuth-domain scattering data are used to calculate a reflectivity map (radar image) of the target, from which RCS of the target is determined. The characteristic features of the proposed version of Near-Field-to-Far-Field Transformation (NFFFT) are the use of the calibrated signal from the network analyzer as the input data in the transformation and an improved focusing operator for producing reflectivity maps. The combination of these features is expected to result in a practical and more accurate approach to the analysis of scattering properties of electrically large targets. © 2010 IEICE Institute of Electronics Informati.


Kobayashi H.,Niigata University | Osipov A.,German Aerospace Center | Suzuki H.,KEYCOM Corporation
2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011 | Year: 2011

An improved image-based circular near-field-to-far-field transformation (NFFFT) developed recently by the authors for smaller measurement facilities and for targets with pronounced scattering centers offset from the center of the imaging area is extended to a cylindrical scanning surface. Scanning over a surface instead of a circle permits RCS estimations for targets whose size in the direction perpendicular to the measurement plane is comparable to their extension in the measurement plane. The approach consists in near-field imaging of the target, followed by integration of the image. The focusing operator, which is used to generate the image, is built in such a way so that the image of an electrically small PEC sphere is exactly the delta function. The paper describes the effect of various transformation parameters such the sampling rates in the input data and in the image domain on the quality of RCS estimations. © 2011 IEEE.


Osipov A.,German Aerospace Center | Kobayashi H.,Niigata University | Suzuki H.,KEYCOM Corporation
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2012

An improved version of the cylindrical near-field-to-far-field transformation (NFFFT) with computational complexity comparable to that of the circular NFFFT is described. Instead of producing a 3D radar image the proposed approach generates a 2D projection of the image on the plane, in which the radar cross section is to be determined. The imaging operator is modified so as to allow probes with directivity patterns and scanning surfaces of smaller radii. © 2012 IEEE.


Osipov A.,German Aerospace Center | Kobayashi H.,Niigata University | Suzuki H.,Keycom Corporation
IEEE Transactions on Antennas and Propagation | Year: 2013

An improved version of the near-field-to-far-field transformation (NFFFT) for determining the radar cross section (RCS) of electrically large targets from the scattered field measured with a monostatic radar over a circle in the near field of the targets is presented. The characteristic feature of the proposed NFFFT is an improved imaging operator which is derived by requiring that the integral transformations involved in the NFFFT scheme be self-consistent for every electrically small scatterer. The presented NFFFT version is expected to lead to more accurate RCS values for strongly asymmetric targets measured at smaller facilities. © 2012 IEEE.


Suzuki H.,KEYCOM Corporation | Hotchi T.,KEYCOM Corporation | Nojima T.,Hokkaido University
IEEE Transactions on Instrumentation and Measurement | Year: 2012

The relative dielectric constant ε r is calculated by quasi-static and frequency-dependent hybrid-mode analysis of two layers of dielectric materials (a sample material and a resonator base material) after measuring the rate of change of the resonating frequency of a sheet material under test sandwiched between a sheet metal and a calibrated stripline resonator. This method corrects the fringing effect of the resonator by using two resonators that have slightly different resonating frequencies. In the present study, tan δ is calculated by balancing the conductor loss. The features of this method are as follows. 1) Measurement of ε r and tan δ is accurate. 2) Measurement can occur at several frequencies simultaneously. 3) Measurement can be made of ε r and δ in the E direction perpendicular to the sheet material, e.g., a printed circuit board. 4) A metal pattern is not required. Only the sheet material under test is necessary. 5) Measurement provides accurate data since there is no radiation loss. This method is useful for measurement in the 0.5-14-GHz range, calculated at multiple frequencies. Fully automatic calculation can be achieved by computer analysis through connection to a network analyzer. © 1963-2012 IEEE.


Suzuki H.,KEYCOM Corporation | Saito K.,KEYCOM Corporation
European Microwave Week 2013, EuMW 2013 - Conference Proceedings; EuRAD 2013: 10th European Radar Conference | Year: 2013

Driving safety awareness has led to the need for pre-crash safety systems installed on passenger cars and long-haul trucks. In developing radars for pre-crash safety systems or automatic brake systems for automobiles equipped with such radars, tests have been traditionally performed with actual car models traveling toward the radar under test from a distance of about 150 m to approximately 1 m. However, for both technical and safety reasons, it has always been a challenge to stop the model as close to the radar under test as the industry-demanded distance of 0.2 m. We therefore developed a moving collision target simulation system using a dielectric waveguide. The system consists of a cylindrical measurement device with a diameter of 0.4 m that simulates the target of the radar under test moving from a distance of 20 m to 0.2 m at a maximum speed of 30 km/h. The newly developed system allows for indoor testing of radars and radar-based automatic brake systems. © 2013 EMA.


Suzuki H.,Keycom Corporation | Inoue M.,Keycom Corporation
IEEE MTT-S International Microwave Symposium Digest | Year: 2012

An improved complex permittivity measurement method is shown that uses a resonator composed of two circular disks of different radii, where (1) the effective radius of each disk due to the fringing field is estimated by comparing two resonance frequencies and (2) the disks of different radii are used to cancel out conductor loss. The method utilizes a balanced-type circular disk resonator excited at its center through coaxial cables. The basic features of the proposed method are that (1) the perpendicular E-field complex permittivity of a dielectric sheet is measured, (2) only TM 0m0 modes having different integer values are selectively excited and (3) multiple frequencies are measured. By using the proposed method, the complex permittivity of polytetrafluoroethylene, polyimide and fiber-reinforced epoxy sheets are measured from 5 GHz to 30 GHz. © 2012 IEEE.


Suzuki H.,KEYCOM Corporation | Shinbo K.,KEYCOM Corporation | Tamukai K.,KEYCOM Corporation | Saito K.,KEYCOM Corporation
20th ITS World Congress Tokyo 2013 | Year: 2013

For testing radar-based safety systems, we have developed an indoor system that simulates the multilane driving behavior of multiple lead vehicles, including slowing down, accelerating, and changing lanes. The original model was designed for 76.5 GHz radars, but support for 24 GHz and 79 GHz radars was added in subsequent models. This compact 3 × 3 m system can be easily installed in a typical 10 × 10 m room.


Takeda S.,Magnontech Ltd. | Motomura S.,KEYCOM Corporation | Hotchi T.,KEYCOM Corporation | Suzuki H.,KEYCOM Corporation
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2014

The wideband measurement system of permeability for magnetic thin slab was proposed for up to 10GHz, using the all shielded shorted microstrip lines. In order to analyze this configuration, the reference plane was set on the other end of specimen where the LC parallel resonant circuit was assumed. The permeability was derived from the measurement of S11 by VNA (Vector Network Analyzer) comparing between with strong static magnetic field parallel to rf magnetic field and without it. The shorted microstrip line was calibrated by the standard sample of rectangular shape NSS (Noise Suppression Sheet) comparing with the results of toroidal core measured by the shorted coaxial line. © 2014, Journal of the Japan Society of Powder and Powder Metallurgy. All rights reserved.


Suzuki H.,Keycom Corporation | Kobayashi T.,Keycom Corporation | Takino H.,Keycom Corporation | Nojima T.,Hokkaido University
Conference Record - IEEE Instrumentation and Measurement Technology Conference | Year: 2011

This paper presents a method for measuring the complex permittivity (relative dielectric constant ε′r and dielectric loss tangent tan δ) of sheet materials in the 1-15 MHz range, as part of efforts to achieve low dielectric loss. We were able to measure tan δ of 2×10 -4 at low frequency by employing the following procedure. (1) The coil is immersed in liquid nitrogen, LN 2. (2) Coupling of the resonating coil to the input-output coil is decreased to less than -30 dB. (3) A network analyzer is used to measure frequency and Q value. (4) Low-loss material is used as the standard to calibrate the capacitance of the measurement circuit. (5) A Litz wire coil is used to measure permittivity. © 2011 IEEE.

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