Takaharu Hiraoka

Equivalent network for rectangular-waveguide H-plane step discontinuity-multi-transmission line and multi-port ideal transformer

Equivalent network for H-plane step is derived from modal analysis and expressed by multi-port ideal transformer or vector notation. Vector notation of equivalent network for waveguide was proposed. Then, whole equivalent network for step discontinuity is given. These conclusions are consistent with conventional results and help one to understand mode behavior at step. Finally, an equivalent network for various H-plane waveguide circuits is derived.

Electric field distributions in microwave planar circuits by small coaxial probe and comparison with FDTD method

A detailed investigation of the 2D electric field distributions in bandpass filter elements that consist of microwave planar structures such as microstrip and coplanar waveguide is very useful for physical understanding, accurate and high-speed filter design and studies of electromagnetic coupling effects. By using a small electric coaxial probe, two dimensional electric field distributions for filter elements are measured. The proposed measurement system is very simple, wideband and accurate and does not required complicated system. Comparing the FDTD calculated results with measured results, the agreement is good. The upper limit of the operating frequency and the spatial resolution for the measurement system is clarified.

Two Dimensional Electric Field Measurement in Microstrip-Line Circuits by Coaxial-Type Probe

A detailed investigation of the electromagnetic field distributions in high frequency printed circuits and high-speed interconnects is very useful for physical understanding, studies of electromagnetic coupling effects for EMC and EMI and for optimization of electromagnetic circuit designs. The aim of this paper is to show how to measure the electric field distributions in electromagnetic circuits. An electromagnetic analysis for microstrip-line circuits is carried out by using a finite-difference time domain technique and its measurement is carried out by using a small probe antenna. The measurement results are in fairly good agreement with those of the numerical analysis using the FDTD method. Thus, the measurement system offers a valid means for predictions in the theoretical analysis of more complicated discontinuity problems.

Calculation of Foster-type equivalent network for stripline 45 degrees bend based on novel calculation method of the eigenmode

Foster-type equivalent network for stripline 45 degrees bend of equal or different stripline width is derived based on eigenmode method. The key step is how to calculate eigenmodes of the planar junction of 45/spl deg/ bend up to necessary mode number with exactness. We propose a new idea of three stage cascade-connected stripline configuration and double symmetry with magnetic wall, which is practically carried out with success. The derived equivalent network is applied to the calculation of frequency characteristics and field distribution under the operating.

Analysis of eigenmode for 3-D optical waveguide based on planar circuit equations and lateral equivalent network

Exact calculation of eigenvalues and eigenmodes for 3-D optical waveguide are important for rigorous analysis/design of optical waveguide circuit. Based on planar circuit equations and mode expansion method, equivalent network for 3-D optical waveguide in lateral direction is derived and applied to the analysis of practical 3-D optical waveguide with success.

Equivalent Network Approach for Field Analysis of 3-D Optical Waveguide Step Discontinuity and their Dynamic Behavior

Exact analysis of step discontinuity of 3-D optical waveguide is important for exact design of optical integrated circuit. Mode theory is introduced to derive the equivalent network in lateral direction and that in waveguide direction. The former is used to calculate waveguide propagation mode, which leads to the equivalent network along waveguide direction. The latter is used for field analysis of step discontinuity of 3-D optical waveguide. Two kinds of so far derived equivalent network are used to give reasonable analytical results with success.

Analysis of Propagation Eigenmode for Stripline based on Planar Circuit Equations and Lateral Equivalent Network

Stripline/microstrip line is an important waveguide component for MIC. Theoretical treatment of propagation eigenmode for stripline/microstrip line of infinitesimally thin strip has been established. However, theory for thick strip line is not yet established. In order to treat propagation eigenmode of stripline/ microstrip line with thick strip, rigorous equivalent network in the lateral direction is derived based on mode analysis and planar circuit theory. Derived equivalent network is practically applied to the analysis of propagation eigenmode for stripline of any thickness with success

Computation and measurement of microwave metallic photonic crystal point-defect-cavity

By changing the radius of the rod in the center of a point-defect-cavity (PDC) based on metallic photonic crystals (M-PhCs), a novel type of microwave cavity with an adjustable resonant-frequency is proposed and studied. After the illustration of the band structure of M-PhCs, the first 3 resonant modes of the point-defect-cavity (PDC) are computed by supper-cell methods, whereas the relation between the convergence of calculated resonant frequencies of PDC and the number of rods considered in a single cell is focused. Moreover, a PDC is then fabricated and experimentally measured. The measured resonant frequencies and Q-factors, reported at the first time, are compared to the calculated ones to validate our computation and show its properties. Finally, a PDC-based filter is designed to show its potential applications in microwave regime.

Analysis and Design of Double-mitered Right-angle Bend based on Planar Circuit Model and Rigorous Equivalent Network

Strip-line right-angle bend is a key component for MIC. It has been demonstrated that right-angle bend with proper cut can improve the frequency characteristics of no-cut right-angle bend. However their characteristics are deteriorated with frequency, which can be improved again by double-mitered structure. In this paper how to analyze the double-mitered right-angle bend is explained based on 2-D planar circuit model and rigorous equivalent network. The analysis demonstrates the mechanism of no reflection and guideline for design. Also effective equivalent network of 45 degree planar junction for dominant mode will work well for analysis and design of the double-mitered structure. Finally dynamic behavior of 2-D field distribution is calculated and shown, which will help to understand the operation of double-mitered bend.

Calculation of Propagation Eigenmode for Stripline with Finite Thickness based on Equivalent Network along Horizontal or Vertical Direction

Exact propagation eigenmode for stripline with finite thickness is important for practical design of MIC. So far propagation eigenmode for stripline with zero thickness is given exactly by conformal transformation method, but not for that with finite thickness. In order to treat this problem analytically, lateral equivalent network in general is derived and applied to obtain equivalent network of stripline structure along horizontal or vertical direction. Equivalent network for two direction are different, but gives same propagation eigenmode, which demonstrate the usefulness of the derived lateral equivalent network.