RADIATION CHARACTERISTICS OF SHORT BACKFIRE ANTENNA APPLICABLE TO MOBILE COMMUNICATIONS

Short backfire (SBF) antenna developed by H. W. Ehrenspeck is experimentally well-known to have high efficiency radiation characteristics in spite of its small size so far. Therefore this antenna is expected to be one of the candidates of single antennas and an element of array antennas for several types of communications. For example, this antenna has been proposed for shipborne antenna of INMARSAT-M system for maritime satellite communications. Although many efforts to analize and/or optimize this antenna has been made mainly experimentally, rigorous design procedure has not been almost established even now because of its complex configuration. In 1980, an approach to analyze this antenna was tried by Kawakami, H. and et al. which was the first attempt to obtain the theoretical characteristics by more rigorous process, however, from the view points of practical designing, the calculated values in their paper were insufficient because of the lack of strict numerical consideration. Upon the above circumferences, analysis of SBF antenna is performed in this paper by using method of moment with wire-grid model from the view points of establishing the design technique. This paper presents the analytical results of the radiation characteristics of this antenna and also the comparison with the experimental results. From this study, it can be noticed that the radiation characteristics of this antenna can be almost exactly analyzed and also there exists the good agreements between the theoretical and experimental results.