Linearly and curvilinearly tapered cylindrical- dielectric-rod antennas

• Published in: IEEE transactions on antennas and propagation Vol. 53; no. 9; pp. 2827 - 2833
• Main Authors: Ando, T., Isao Ohba, Numata, S., Yamauchi, J., Nakano, H.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna radiation patterns; Antenna theory; Antennas; Antennas and propagation; Apertures; Applied sciences; Conversion; dielectric antennas; dielectric waveguides; Dielectrics; endfire antennas; Exact sciences and technology; Excitation; Feeds; Finite difference method; Finite difference methods; finite-difference time-domain (FDTD) methods; Guidelines; Horn antennas; Horns; Launching; Mathematical analysis; Mathematical models; Radiocommunications; Telecommunications; Telecommunications and information theory; Time domain analysis; Performance evaluation; finite-difference time-domain (FDTD) methods; Antenna theory; endfire antennas; Cylindrical antenna; Finite difference time-domain analysis; Guided wave; Numerical method; Dielectric metal interface; Cylindrical shape; Dielectric antenna; Dielectric waveguides; Wave propagation; dielectric antennas; Radiation pattern; Launching; Mode conversion
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2005.854551

The body-of-revolution finite-difference time-domain (BOR-FDTD) method is applied to the analysis of a tapered cylindrical-dielectric-rod fed by a metallic waveguide with a launching horn. Before evaluating the wave propagating along the tapered rod, we design the launching horn to efficiently excite the fundamental guided-mode of a uniform rod. After confirming the effectiveness of the launching horn, guided-mode conversion properties are evaluated in linearly and curvilinearly tapered rods. As a result, the guided mode excited at the feed end is smoothly converted into that at the free end in a curvilinearly tapered rod. It is numerically revealed that the smooth guided-mode conversion leads to the expansion of the equiphase field region in a terminal aperture with a subsequent increase in the gain. The calculated radiation patterns are in good agreement with experimental data.