Mikio Fujii

Bio: Mikio Fujii is an academic researcher from Kyocera. The author has contributed to research in topics: Microstrip & Insertion loss. The author has an hindex of 8, co-authored 13 publications receiving 683 citations.

Development of a "laminated waveguide"

Abstract: A waveguide of new structure has been developed for millimeter-wave applications. The dielectric waveguide is constructed with sidewalls consisting of lined via-holes and edges of metallized planes. This structure can be manufactured by lamination techniques, so we refer to the waveguide as a "laminated waveguide". The laminated waveguide can be embedded in a substrate and is able to be wired in three dimensions. The transmission characteristics are evaluated using a glass-ceramic substrate of dielectric constant, /spl epsiv//sub r/=5, and loss, tan /spl delta/=0.0008. Insertion loss per unit length of the guide is estimated to be less than 0.5 dB/cm at 83 GHz. Furthermore, it was confirmed that the laminated waveguide is suitable to feeding lines for a small sized plane array antenna. By electromagnetic simulation, it has been confirmed that fundamental structures, such as bends, branches, power dividers, and interconnections between upper and lower layers can be realized with sufficient performances.

High-frequency package

Abstract: A high-frequency package comprising a dielectric substrate, a high-frequency element that operates in a high-frequency region and is mounted in a cavity formed on said dielectric substrate, and a microstrip line formed on the surface or in an inner portion of said dielectric substrate and electrically connected to said high-frequency element, wherein a signal transmission passage of a waveguide is connected to a linear conducting passage or to a ground layer constituting the microstrip line. In the junction portion of the waveguide, for example, an end of the linear conducting passage is electromagnetically opened, so that the end portion works as a monopole antenna inside the waveguide that is connected. The high-frequency package makes it possible to connect the waveguide without adversely affecting the sealing of the high-frequency element and to transmit high-frequency signals with a low loss.

Development of the "laminated waveguide"

Abstract: A new waveguide structure for millimeter wave has been developed. It is a dielectric waveguide, with conductor walls consisting of two lined via-holes, herein referred to as the "laminated waveguide." Applications for the laminated waveguide include antenna feed lines.

High-frequency semiconductor device and mounted structure thereof

Abstract: A high-frequency semiconductor device contains a semiconductor element in a cavity formed by a dielectric board and a cap. A first high-frequency transmission line connected to the semiconductor element is formed on the surface of said dielectric board in said cavity and a second high-frequency transmission line is formed on the bottom surface of said dielectric board, so that said first high-frequency transmission line and said second high-frequency transmission line are electromagnetically coupled together. In this semiconductor devise in which the first transmission line and the second transmission line are electromagnetically coupled together, the transmission lines need not be passed over the side wall of the cap, and neigther reflection loss or radiation loss takes place on the side wall. Besides, transmission loss of high-frequency signals is caused by neigther through-holes or via-holes, and is effectively suppressed.

77-GHz-band surface mountable ceramic package

Abstract: The authors have developed a surface mount-type ceramic package for 77-GHz millimeter-wave application. The package has a new terminal structure for surface mount and a feedthrough of electromagnetic coupling. The authors have adopted a coplanar structure for the surface mount terminal. The structure for the electromagnetic coupling consists of microstrip line/slot/microstrip line (MSL/SLOT/MSL). Total transmission loss between the signal line on board and the RF input-output terminal inside the package was 1.0 dB at 77 GHz Standard deviation of the insertion loss was 0.08 dB (n = 57) The authors have confirmed that the surface mountable package shows high transmission characteristics as well as high reliability.

Review of substrate-integrated waveguide circuits and antennas

Abstract: Substrate-integrated waveguide (SIW) technology represents an emerging and very promising candidate for the development of circuits and components operating in the microwave and millimetre-wave region. SIW structures are generally fabricated by using two rows of conducting cylinders or slots embedded in a dielectric substrate that connects two parallel metal plates, and permit the implementation of classical rectangular waveguide components in planar form, along with printed circuitry, active devices and antennas. This study aims to provide an overview of the recent advances in the modelling, design and technological implementation of SIW structures and components.

Dielectric Resonator Antennas

Abstract: Linearly and circularly polarized conformal strip-fed dielectric resonator antennas (DRAs) are studied in this article. In the latter case, a parasitic patch is used to excite a nearly degenerate mode. The hemispherical DRA, excited in its fundamental broadside TE111 mode, is used for the demonstration. In the analysis, the mode-matching method is used to obtain the Green's functions, whereas the method of moments is used to solve for the unknown strip currents. In order to solve the singularity problem of the Green's functions, a recurrence technique is used to evaluate the impedance integrals. This greatly increases the numerical efficiency. Measurements were carried out to verify the calculations, with good results. Keywords: circularly polarized antenna; dielectric antennas; mode-matching methods; moment methods; parasitic antennas; resonance

Single-substrate integration technique of planar circuits and waveguide filters

Abstract: The integrated planar technique has been considered as a reliable candidate for low-cost mass production of millimeter-wave circuits and systems. This paper presents new concepts that allow for a complete integration of planar circuits and waveguide filters synthesized on a single substrate by means of metallized post (or via-hole) arrays. Analysis of the synthesized integrated waveguide and design criteria are presented for the post pitch and diameter. A filter design method derived from a synthesis technique using inductive post is presented. An experimental three-pole Chebyshev filter having 1-dB insertion loss and return loss better than 17 dB is demonstrated. Integrating such planar and nonplanar circuits on a substrate can significantly reduce size, weight, and cost, and greatly enhance manufacturing repeatability and reliability.

Simulation and experiment on SIW slot array antennas

Abstract: By etching longitudinal slots on the top metallic surface of the substrate integrated waveguide (SIW), an integrated slot-array antenna is proposed in this letter. The whole antenna and feeding system are fabricated on a single substrate, which takes the advantage of small size, low profile, and low cost, etc. The design process and experimental results of a four-by-four SIW slot array antenna at X-band are presented.

Planar Slot Antenna Backed by Substrate Integrated Waveguide Cavity

Abstract: A novel design method of low profile cavity backed planar slot antenna has been described in this paper. The whole antenna including backed cavity and feeding element is completely constructed at a single substrate by using substrate integrated waveguide technique and grounded coplanar waveguide. An example with 1.7% bandwidth has been presented, which has 5.4 dBi gain, 16.1 dB front-to-back ratio and -19 dB maximum cross polarized radiation level with its total thickness less than lambda0/50. The proposed antenna keeps good radiation performance of conventional cavity backed antenna and has advantages of conventional planar antenna including low profile, light weight, easy fabrication with low cost and convenient integration with planar circuit.