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Dual-Mode Circular Horn Simulation with the MLFMM

A dual-mode circular horn antenna is simulated with the MLFMM and far-fields are extracted.

Skobelev et al. [1] 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.

Geometry

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
 

 

Feed mechanism

A TE11 mode is excited with a pin-feed configuration as depicted in Figure 2.  The pins are located 10mm from the end of the guide and are 5mm long.

 

Figure 2: Feed pins for a TE11 excitation
 

 

 

Results

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 [1].

 

 

Figure 3:  Far-field radiation patterns
(a) 2D mainlobe characterisation
 (b) 3D mainlobe with aperture near-field
 

 

 

 

 

References

[1] 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