Yoshihiko Wagatsuma

New applications of millimeter-wave incoherent imaging

A compact wideband millimeter wave detection element for the 35 GHz band has been developed mainly for passive imaging technologies. Using this element, fruit, timber, and foods in cardboard boxes have been observed nondestructively. The thermal radiation emitted from fruit changes as it is ripening, timber with knots and/or damages by white ants, and food temperature in cardboard box can be detected through incoherent passive imaging.

Millimeter-Wave Imaging Technologies and Their Applications

A compact wideband millimeter wave detection element for the 35 GHz band has been developed mainly for passive imaging technologies. Applications of this element include security areas as well as food industry areas. Human bodies can be detected through fire flame, the thermal radiation emitted from fruit changes as it is ripening. Timber with knots and/or damages by white ants, and food temperature in cardboard box can be detected through passive mm-wave imaging.

Distance estimation at 60 GHz band

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. Main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 times 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than 0.7 m.

Broadband FDTD design of Fermi antenna for passive millimeter wave imaging

The broadband FDTD analysis of the Fermi antenna as a receiving element of passive millimeter-wave imaging is presented. The Fermi antenna is a type of the tapered slot antennas (TSA) and has a taper profile expressed by Fermi-Dirac function as well as a corrugation on the side of the substrate. A design of Fermi antenna with the axially symmetric radiation pattern was already reported in our previous paper at 35 GHz. In this paper, the radiation pattern with changing the parameters of a Fermi antenna is investigated in a broad frequency range of 30-50 GHz. A design of Fermi antenna which has an axially symmetric radiation pattern in a broad frequency range is presented

Development of 35GHz band passive imaging systems and their applications to medical and bio-objects imaging

A compact passive millimeter wave imaging element fabricated on a single substrate has been developed. Using this element several medical and bio-objects were imaged. The results suggest that passive millimeter wave imaging would be a useful tool for medical and agricultural areas.

Planar millimeter-wave car warning radar using NRD-guide

The development of a 60 GHz FM-CW car warning radar by integrating NRD-guide front-end with the planar slot array antenna is described. The structure of the radar-head is planar with 150 mm in vertical length, 140 mm in width and 19 mm in thickness. The results of experiments show that the measured distance error is less than 0.7 m for the target distance between 5 m to 120 m, satisfying the car radar specifications issued by the Ministry of Posts and Telecommunications.

A new leaky NRD guide based on a grating structure

Analysis and experiment of a new leaky nrd guide based on a grating structure is described. Analysis employs a mode coupling procedure which yields highly accurate results while presenting the advantage of simplicity and ease of manipulation. Numerical values for the phase and leakage constants are presented and the role of each grating parameter is assessed. Theoretical results are compared with experimental data for different geometric and constitutive parameters and reasonable agreement between them is obtained.RésuméL’article décrit l’analyse et les expé riences conduites à l’aide d’un tel guide. L’analyse utilise une procé dure à couplage de modes qui conduit à des résultats précis avec l’avantage d’être simple et facile à mettre en æuvre. Les valeurs numériques du coefficient de fuite et du déphasage linéique sont obtenues et le rôle de chaque paramètre est déterminé. Les ré sultats thé oriques et expé rimentaux obtenus pour diffé rents paramètres géométriques et constitutifs sont comparables.

60 GHz FM-CWR Using NRD guide for distance estimation

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. The main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by a leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 times 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than a distance of 0.7 m.

Distance estimation at 60 GHz

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. Main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 /spl times/ 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than a distance of 0.7 m.

Development of passive millimeter-wave imaging systems and its applications to medical- and bio-objects imaging

Passive millimeter wave (PMMW) imaging systems have been developed at Ka-band using imaging elements with Fermi tapered slot antennas (TSA) with corrugation. The imaging elements were installed in a focal-plane imaging system and a Fresnel (close)-distance imaging system to obtain medical and bio-object images.