1.5/2.45GHz 二偏波共用単層アンテナ

摘要

A multi-polarization antenna that can be made by single fed and single layered structure is presented in this paper. The numbers of antennas inside mobile communication devices are getting more as the functions of them are increasing. Interference of two or more antennas being located closely inside the devices has become a serious problem. Multi polarization antennas could be useful for solving the problem. An effective planer antenna that radiates circularly and linearly polarization waves simultaneously has been presented by the authors. It has been able to be used, however, only for the case that the frequency of linearly polarized waves is lower than that of circularly polarized waves. Moreover, the gain and efficiency of linearly polarized waves have been lower than those of circularly polarized waves. In this paper, a new structure of the antenna for radiating linearly polarized waves at higher frequency in comparison with that of circularly polarization waves. The return loss and polarization characteristics of the prototype antenna that can radiate circularly polarized waves at 1.5GHz and linearly polarized wave at 2.45GHz have been shown. The antenna achieved the target performance that the axial ratio at 1.5GHz is 3 dB and cross polarization level relative to co-polarization is -40 dB or less.%昨今の移動体無線通信機器は、多機能化に伴い複数の周波数帯で異なる偏波を送受信できなければならなくなった。その結果、内蔵アンテナの種類や数が増え端末内における配置に苦慮することが多い。このよう問題の解決には共用アンテナが有効である。我々はこれまで完全な単層平面構造でありながら、二つの周波数帯で異なる偏波を放射する偏波共用アンテナを提案してきた。しかし、直線偏波は、共用する円偏波より低い周波数で放射され、また効率も悪いという問題があった。本論文では、これらを解決した、1.5GHz において円偏波、2.45GHz において直線偏波を共用できるアンテナを紹介する。本アンテナは、1.5GHz おいて軸比3dB、2.45GHzにおいて最大交差偏波-40dB を達成している。