| JaLCDOI | 10.18926/47029 |
|---|---|
| FullText URL | mfe_36_2_083_089.pdf |
| Author | Watanabe, Tetsushi| Wada, Osami| Koga, Ryuji| Toyota, Yoshitaka| Miyashita, Takuya| |
| Abstract | Suppression of common-mode current is important to achieve electromagnetic compatibility of high-speed and high-density electronic circuits. The authors have focused on the common mode current flowing on a printed circuit board (PCB) to explain the excitation mechanism. A narrow ground pattern in microstrip structure excites common-mode current. In the previous paper, the authors explained the mechanism of common mode generation by means of "current division factor" for simple PCBs. The estimated radiation from a simple PCB agreed well with measured one. In this paper, the authors extend the theory to be applied to generalize ground structure. The validity of the theory is confirmed by comparing the measured radiation and the estimated value using the common-mode model for a test PCB. The estimated radiation agrees well with the measured one within 3 dB up to 900 MHz. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-03 |
| Volume | volume36 |
| Issue | issue2 |
| Start Page | 83 |
| End Page | 89 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003497051 |
| JaLCDOI | 10.18926/47028 |
|---|---|
| FullText URL | mfe_36_2_073_082.pdf |
| Author | Hidayat, Iip Syarif| Toyota, Yoshitaka| Torigoe, Osamu| Wada, Osami| Koga, Ryuji| |
| Abstract | A multi-path ring-resonator (MPRR) was proposed to extend FSR of ring resonator. However, it is complicated to analyze the MPRR by using well-known analysis techniques such as scattering matrix or other numerical methods. This paper describes procedure for deriving transfer matrix by means of signal flow-chart to analyze the MPRR. We do not need complicated calculation for steady state analysis because transfer matrix elements are formulated clearly. As a result, The calcultaion time in this method can be reduced 1/3 to 1/20 times compared with using scattering matirx method. Furthermore, a transmittance characteristics of the MPRR at FSR extension-factor of 10 will also be shown. This suggests that analysis of other types of the MPRR by using this method can be performed simply and take a shorter time. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-03 |
| Volume | volume36 |
| Issue | issue2 |
| Start Page | 73 |
| End Page | 82 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003497050 |
| JaLCDOI | 10.18926/46983 |
|---|---|
| FullText URL | mfe_37_2_089_097.pdf |
| Author | Iokibe, Kengo| Toyota, Yoshitaka| Wada, Osami| Koga, Ryuji| |
| Abstract | Aerosol extinction coefficients of clouds and dust were continuously measured in the year of 2002 with a polarized Mie-scattering lidar controlled by an automatic and remotely operating system utilizing internet services. Measured cloud extinctions were greater than 1.0 km(-1) below the altitude 6 km, 0.17 - 1.0 km(-1) between 6 and 10 km, and 0.091 - 0.3 km(-1) beyond 10km. Extinction of dust were 0.10 and 0.20 km(-1) for Asian dust and 0.057 km(-1) for urban dust. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2003-03 |
| Volume | volume37 |
| Issue | issue2 |
| Start Page | 89 |
| End Page | 97 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003457336 |
| JaLCDOI | 10.18926/46972 |
|---|---|
| FullText URL | mfe_37_1_051_060.pdf |
| Author | Namba, Akihiro| Toyota, Yoshitaka| Wada, Osami| Koga, Ryuji| |
| Abstract | This paper presents pulse timing control method to reduce electromagnetic emission from multiple signal interconnections. Pulse timing control gives intentional skew between signals. Higher order harmonics are canceled because of the difference of the phase between the signals. Using this property, pulse timing control can reduce the EMI in wide frequency range. In this paper, we show that radiated electromagnetic field from multiple signal lines reduces its intensity to the same level of the field from one line by using pulse timing control. The result of measurement shows that EMI from four differential transmission lines can be reduced more than 9 dB in the 200 MHz to 800 MHz frequency range. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-11 |
| Volume | volume37 |
| Issue | issue1 |
| Start Page | 51 |
| End Page | 60 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80015683518 |
| Author | Wang, Zhi Liang| Wada, Osami| Toyota, Yoshitaka| Koga, Ryuji| |
|---|---|
| Published Date | 2005-2 |
| Publication Title | Electromagnetic Compatibility |
| Volume | volume47 |
| Issue | issue1 |
| Content Type | Journal Article |
| Author | Wang, Zhi Liang| Wada, Osami| Toyota, Yoshitaka| Koga, Ryuji| |
|---|---|
| Published Date | 2003-11 |
| Publication Title | Environmental Electromagnetics |
| Content Type | Journal Article |
| Author | Wang, Zhi Liang| Wada, Osami| Toyota, Yoshitaka| Koga, Ryuji| |
|---|---|
| Published Date | 2002-5 |
| Publication Title | Electromagnetic Compatibility |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/15360 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_34_27.pdf |
| Author | Wei, He| Koga, Ryuji| Iokibe, Kengo| Wada, Osami| Toyota, Yoshitaka| |
| Abstract | In spring of 1998, Asian dust was observed with a Mie LIDAR in Okayama University, which can measure depolarization ratio. Three events of intense Asian dust were occurred in the period and medially detailed structure of atmosphere was found after examining records. Asian dust was distinguished from water droplets and the possibility to study three dimensional dynamic structure of atmosphere were demonstrated. |
| Keywords | Mie lidar Asian dust (KOSA) depolarization ratio backscattering ratio range normalized |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2000-03-27 |
| Volume | volume34 |
| Issue | issue1-2 |
| Start Page | 27 |
| End Page | 37 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307539 |
| JaLCDOI | 10.18926/14158 |
|---|---|
| FullText URL | Mem_Fac_Eng_39_1_93.pdf |
| Author | Iokibe, Kengo| Toyota, Yoshitaka| Wada, Osami| Koga, Ryuji| |
| Abstract | The optical properties of clouds were measured with a polarization Mie lidar during April, 2004 and investigated to categorize the particles detected by the lidar. The cloud layers were categorized into five types according to the depolarization ratios, as follows: (I) constant and small (less than 5%); increasing with height (II) nearly from 0% and (III) from about 50%; (IV) large and varying with the backscattering coefficient; and (V) sharply decreasing. This categorization of clouds enabled us to separate aerosols from clouds in a lidar signal. Comparison of the backscattering coefficients between clouds of types (I) and (II) suggested that the depolarization ratio induced by multiple scattering in dense clouds does not depend on the particle density. Estimation of the particle phase for the five cloud categories was also examined. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2005-01 |
| Volume | volume39 |
| Issue | issue1 |
| Start Page | 93 |
| End Page | 101 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002308479 |
