{"title":"WPT by a pair of short helical dipoles","authors":"T. Uesaka, H. Arai","doi":"10.1109/IMWS.2012.6215819","DOIUrl":"https://doi.org/10.1109/IMWS.2012.6215819","url":null,"abstract":"Wireless power transmission (WPT) by two short helical dipoles arrayed orthogonally is presented. For the electric resonance coupling WPT system, the short dipoles need for a matching circuit due to cancel its large capacitance at the operating frequency. In the proposed method, the loss is reduced by using the helical structure instead of matching circuit. Its power transmission characteristics are shown in experiments. The measured results are agreed with the calculated results of a pair of dipoles with a matching circuit. In the orthogonal arrangement, the WPT is possible in the wide range expect for the angle θ = 0 between the antennas. At θ = π/4, the coupling coefficient becomes the maximum, and the WPT is enabled for the longest distance.","PeriodicalId":6308,"journal":{"name":"2012 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications","volume":"17 1","pages":"57-60"},"PeriodicalIF":0.0,"publicationDate":"2012-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86784842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Transferred power and efficiency of a coupled-resonator WPT system","authors":"I. Awai, T. Ishizaki","doi":"10.1109/IMWS.2012.6215770","DOIUrl":"https://doi.org/10.1109/IMWS.2012.6215770","url":null,"abstract":"A coupled-resonator WPT system is analyzed in terms of transferred power and transfer efficiency. Quality factor (fm) of the coupled resonators is defined by the product of the coupling coefficient (k) and unloaded Q (Q1, Q2) of the resonators. Though it is well known that the maximum value of transfer efficiency is determined only by fm, its condition has been unrealistic. The present paper gives a new expression that is not only far more realistic but also physically acceptable. In addition, the operating frequency selection method for the case of double peak response due to the over-coupling is proposed. A widely accepted method of the peak preference is criticized.","PeriodicalId":6308,"journal":{"name":"2012 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications","volume":"85 1","pages":"105-108"},"PeriodicalIF":0.0,"publicationDate":"2012-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88390408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}