Image NRD Guide-Fed Dielectric Rod Antenna for Millimeter-Wave Applications

Ally Yahaya SIMBA  Manabu YAMAMOTO  Toshio NOJIMA  Kiyohiko ITOH  

IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.9   pp.1405-1411
Publication Date: 2004/09/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Wave Technologies for Wireless and Optical Communications)
Category: Antennas, Circuits and Receivers
dielectric rod antenna,  image NRD guide,  millimeter-wave,  transition,  FDTD,  

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An image NRD guide-fed dielectric rod antenna, which is suitable for use at millimeter-wave frequencies, is presented in this paper. The antenna is composed of a linearly tapered dielectric rod connected to the image NRD guide. First, radiation characteristics of the dielectric rod antenna directly protruded from the end of the image NRD guide are investigated by FDTD analysis and measurements at 30 GHz band. For this case, the degradation of the radiation pattern and the decrease of the gain, which are due to the strong radiation from the guide-to-antenna discontinuity, are observed. In order to minimize this radiation and to realize reasonable radiation characteristics, a transition from the image NRD guide-to-rod antenna is proposed. A simple procedure to determine the optimum dimensions of the transition is described. This procedure is based on parametric study of the transition's dimensions, and is performed using FDTD analysis. Based on the results, the dielectric rod antenna having a length of 10 λ0 is designed, and its performance is analyzed and measured. The results show that radiation patterns with the half power beamwidth of 22, sidelobe level of -21 dB and reasonable gain of 18.5 dBi can be realized by employing the transition having the optimum dimensions.