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Bowtie Antenna

A bowtie antenna is simulated in FEKO and compared with data from open literature.

This article illustrates that FEKO can be applied to the simulation of planar antennas with bowtie antennas as example.

Antenna on a Dielectric Halfspace

The first example is of a bowtie antenna that was simulated by placing the structure on a dielectric halfspace.  For the sake of validation against open literature the model is based on an antenna presented in [1] for the analysis of gain vs. angle on incidence on the antenna.  Figure 1 shows this antenna with the currents on it simulated at 94 GHz, while Figure 2 shows the comparison between the published data [1] and the result generated with FEKO.  The FEKO result is in excellent agreement with the result published by Compton [1].


Figure 1:  Currents on a bowtie antenna at 94 GHz
Bowtie antenna with currents
Figure 2:  Normalised gain vs incidence for bowtie antenna at 94 GHz
Bowtie gain vs incidence

Figure 3 presents an input impedance comparison of a bowtie antenna at 2 GHz, as the length of one half of the bowtie varies from 0.05 λ0 to 0.5 λ0.  The input impedance is presented on a Smith-chart with the length of the half bowtie labeling the plot points.  All impedance values were normalised to 152 Ω.


Figure 3:  Normalised impedance with varying length for bowtie antenna at 2 GHz
Normalised imepdance

Antenna Raised Above Real Ground

Leat [2] analyzed the same bowtie antenna configuration depicted in Figure 1 as it is raised over a real ground.  Figure 4 presents an input impedance comparison as the antenna is raised higher above ground.  Agreement is good across the entire frequency range, from 50 MHz to 500 MHz.


Figure 4:  Input impedance as a function of height above real ground
(a) Results published in [2]
(b) Result computed with FEKO
Leat published


R. C. Compton, R. C. McPhedran, Z. Popovic, G. M. Rebeiz, P. P. Tong, and D. B. Rutledge, "Bow-tie antennas on a dielectric half-space: theory and experiment," IEEE Trans. on Antennas and Propagation, vol. 35, pp. 622–631, June 1987.
C. J. Leat, "Modelling and design of GPR antennas," PhD dissertation, University of Queensland, 1998.