Analysis of electromagnetic radiation from shaped-end radiators using the finite difference time domain method

The finite difference time domain (FDTD) technique is a popular method for analyzing electromagnetic scattering, radiation, and penetration problems. Several authors have recently applied the FDTD method to antenna radiation problems. To date, the antenna structures considered have been wire and conical monopole antennas, rectangular waveguides, pyramidal horn antennas, and microstrip antennas. Results from these analysis have been in the form of normalized field patterns and no results showing absolute gain have been presented. The article demonstrates the first staircased application of the FDTD method to the analysis of radiation from circular waveguides and other shaped-end radiators. Results of absolute gain versus angle are shown for a straight-cut circular waveguide and for two different shaped-end radiators. All FDTD analyses are full three-dimensional computations and are compared in each case with measured data.<
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