Dual-Mode Circular Horn Simulation with the MLFMM
Skobelev et al.  described how a dual-mode horn antenna may be manufactured cost effectively with simple modifications to the geometry of the antenna. This page describes the simulation of a standard dual-mode horn antenna with dimensions comparable to the antennas proposed by Skobelev et al. The simulation is constructed at a 12.5 GHz centre frequency and was simulated using FEKO's Multilevel Fast Multipole Method (MLFMM) implementation.
The dual-mode antenna simulated in this simulation has the following dimension, illustrated in Figure 1:
- Waveguide radius = 0.51 λ0
- Waveguide length = 2 λg
- Transition radius = 0.65 λ0
- Flare radius = 1 λ
- Flare length = 3.05 λ
|Figure 1: Dual-mode antenna geometry
A TE11 mode is excited with with both a pin-feed configuration and a waveguide port, as depicted in Figure 2. The pins are located 10mm from the end of the guide and are 5mm long.
|Figure 2: Dual-Mode Circular Horn Models
Figure 3 presents the results from the MLFMM simulation of the far-field patterns of the horn antenna. Both the maximum gain and the -3dB mainlobe width compares well with the values predicted in  for both the waveguide-fed and pin-fed configurations.
|Figure 3: Far-field radiation patterns
|||S.P. Skobelev, B.-J. Ku, A.V. Shishlov, and D.-S. Ahn, "Optimal Geometry and Performance of a Dual-Mode Horn Modification," IEEE Antennas and Propagation Magazine, Vol. 43, No. 1, February 2001