Development of analytical methods for cross-polarization components in electromagnetic wave propagation in random media

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K04187
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21030:Measurement engineering-related
• Research Institution: Ariake National College of Technology
• Principal Investigator: Nanbu Yukihisa 有明工業高等専門学校, 創造工学科, 教授 (00228115)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 不規則媒質 / 偏波特性の劣化 / 電波伝搬 / 多重散乱理論

Outline of Final Research Achievements

In this study, the evaluation method of the phenomenon that the main polarization component of the electromagnetic wave propagating in the random medium is slightly attenuated is investigated. The attenuation of this main polarization component is very small. When this attenuation can be known quantitatively, the effective medium constant of a random medium can be obtained, which is useful for remote sensing and meteorological measurement. Therefore, the cross-polarization component caused by the attenuation of the main polarization component was obtained using the perturbation method based on the forward multiple scattering approximation. The 0th-order perturbation solution was analytically determined as the main polarization component, and the 1st-order perturbation solution as the cross-polarization component. The results are useful for quantitative analysis of cross-polarized waves slightly generated from main polarized waves.

Free Research Field

電磁界理論

Academic Significance and Societal Importance of the Research Achievements

雨滴の存在する降雨空間や積乱雲の中などのランダム媒質中を通過した電磁波は，主偏波成分が僅かに減少することが知られている。本研究は，この主偏波成分の僅かな減少と同時に生じる交差偏波成分を解析するために，ランダム媒質中を伝播する電磁波を前方多重散乱理論に基づいて定式化し，波動方程式の導出を行った。そして摂動法を適用し，第0次摂動解（主偏波成分）と第1次摂動解（交差偏波成分）を解析的に求め，交差偏波成分の一次モーメント（コヒーレント界)とその電力を表す二次モーメントを得た。今後は，主偏波成分と交差偏波成分の間の量的な関係について調べる予定である。