Motofumi Yamaguchi

Wall-Hanging Type of Self-Complementary Spiral Patch Antenna for Indoor Reception of Digital Terrestrial Broadcasting

A printed spiral antenna with a self-complimentary configuration was developed. This antenna consists of spiral shaped metal strips and slots provided on ground planes as their counterparts. For balanced and unbalanced feeds, two types of antenna configurations such as single and twin spirals were fabricated and their antenna performances were investigated. From evaluation of carrier noise ratio of digital terrestrial broadcasting channels at UHF band, it was confirmed that the presented self-complimentary spiral antenna has capability to apply into an indoor terrestrial broadcasting TV antenna

Giga-bit class ultra high speed signal wireless distribution by using NRD guide technology at 60GHz

A giga-bit class ultra high speed data distribution has been successfully demonstrated at 60GHz by using the nonradiative dielectric waveguide (NRD guide) technologies. An emphasis is placed on a high speed performance of an ASK modulator and a stability of a Gunn oscillator. By assembling these circuit components, ultra high speed NRD guide transmitter and receiver have been fabricated, and it was confirmed that these NRD guide front ends have great advantage of high speed operation capacity beyond 1Gb/s. Moreover, an SDI (Serial/Digital Interface) signal with a bit rate of 1.48 Gb/s was distributed successfully to drive a high resolution HDTV display at 60GHz.

Experimental Verification of Mode Coupling Phenomenon in High Permittivity NRD Guide with Small Remaining Asymmetrically Air Gap

It is known that a high permittivity NRD guide suffers from irregular transmission phenomena. In this study, we clarified that this problem is caused by a mode coupling phenomenon between the operating and parasitic modes due to a small remaining asymmetrically air gap between the metal plates and high permittivity dielectric materials.

Mode coupling phenomenon in high permittivity NRD guide with asymmetrically remained small air gap

It is known that a high permittivity NRD (nonradiative dielectric) guide, where an LSM01 mode mainly propagates, suffers from irregular transmission phenomena. Since high permittivity materials such as ceramics and alumina have rough and hard surfaces, we assumed that this problem was caused by an asymmetric remaining small air gap between the metal plates and the high permittivity dielectric materials in the NRD guide. From the theoretical and experimental investigations, it is clear that the LSM01 mode is liable to couple with an unwanted mode, while an LSE01 mode, being another nonradiating mode, is hard to couple with such a mode.

Design and fabrication of square shaped ceramic resonator filter, for NRD guide integrated circuit at 60GHz

Cylindrical ceramic resonators with TE/sub 0n/spl delta// resonant modes are usually used at centimeter frequencies due to their low loss natures. However they have a difficulty in making wide-band band-pass filters in the millimeter-wave region because of the poor coupling factors between the resonators and input/output waveguides. Having this fact in mind, we propose the use of square shaped ceramic resonators. From the theoretical and experimental investigations, it is confirmed that the coupling factor of the square shaped ceramic resonator with EH/sub 12/spl delta// resonant mode is larger than that of the cylindrical one.

Theoretical Study on Square Ceramic Resonator Loaded NRD Guide Band-Pass Filters at 60GHz

Cylindrical ceramic resonators with TE0n¿ resonant modes are usually used at centimeter frequencies due to their low loss natures. However they have a difficulty in making wide-band band-pass filters in the millimeter-wave region because of the poor coupling factors between the resonators and input/output waveguides. Having this fact in mind, we propose the use of square shaped ceramic resonators. From the theoretical investigations based on the high frequency structure simulator, it is confirmed that the coupling factor of the square shaped ceramic resonator with EH12¿ resonant mode is larger than that of the cylindrical one.

New type of millimeter wave antenna by using the high permittivity LSE NRD guide

A technique for construction of a millimeter-wave antenna has been developed based on high permittivity LSE-NRD guide technology. The novelty of the present technique lies in the use of a simple radiator, which consists of tapered dielectric strip with the length of about a guided wavelength and a broad radiation pattern. A new type of fan beam antenna for marine radar use has been fabricated by locating the radiator in the focal point of the cylindrical parabolic reflector. A good fan beam pattern with half-power beam widths of 4 in the horizontal plane and 38 in the vertical plane can be obtained.

Folded Planar Antenna Fed by LSE-NRD Guide at 60GHz

A technique for construction of a millimeter-wave antenna has been developed based on the high permittivity LSE-NRD guide technology. The novelty of the present technique lies in use of a simple radiator, which consists of tapered dielectric strip with the length of about a guided wavelength and has the broad radiation pattern. The folded planar antenna for the wireless LAN systems and car warning sensers has been fabricated by locating the radiator in the focal point of the cylindrical parabolic reflector. A pencil beam pattern with the half-power beam widths of 2° in H-plane and 7° in E-plane can be obtained.