1. Performance Comparison of Two Types of
Low-profile Sinuous Antenna in Ultra Wideband Application
M. Vahdani, S. Salemhesari, B. Manouchehrinia
Performance Comparison of Two Types of
Low-profile Sinuous Antenna in Ultra Wideband Application
M. Vahdani, S. Salemhesari, B. Manouchehrinia
 Application
Nowadays planar antennas are widely used in:
• Wireless Communications
• Radar
• Radio-astronomy
Introduction
 Objectives of this work
The performance comparison of two models of sinuous antennas, the Duhamel[3] and
Vahdani’s sinuous antennas[4] over a wide frequency range by comparison between
simulation results in a similar size 5.3 cm×5.3 cm. As essential antenna parameters, Gain,
HPBW, Return loss and Directivity radiation patterns are presented.
Design Antennas
 Duhamel sinuous antenna [3]







N
K
rrk


2
exp0













)Pln(τ
)
PR
r
180.ln(
.SinP.αP1)(φ
4-Directivity
E-Plane
Phi=0
H-Plane
Phi=90
2-Gain
• Duhamel’s type has wider bandwidth with higher input impedance.
• The gain uniformity in Duhamel’s is higher than Vahdani’s but the Vahdani’s type has
approximately higher gain value.
• The comparison of HPBW shows that Vahdani’s type is more directive than Duhamel’s.
• Vahdani's antenna has the advantage of being used in applications requiring high gain
and low input impedance.
 Advantages
The comparison between different types of wideband antennas shows that sinuous
antennas are the best candidates in wideband planar antennas since they have :
• the capability to be designed in compact structure with self-complementary configuration.
• they own constant phase centre.
• Input impedance which is essentially independent of frequency [1].
• A good performance in ultra-wideband.
• An appropriate symmetry in directivityradiation patterns in dual linear polarization [2].
The cells of the sinuous arms are generated from the sinuous curves, which are provided by
Duhamel [3]:
PRr1PR 
P = number of arms

45
75.0

5.22
 220inR
All parameters were designed and optimized for a two arms sinuous antenna operating in
UWB.
 Vahdani sinuous antenna [4]
The major inconvenience of this antenna is its high input impedance due to design
difficulties of feeding system. To achieve a performance with low input impedance, a
different geometry was investigated [4].
The geometry of antenna proposed by Vahdani et al [4] looks like the sinuous of Duhamel
[3] but the configuration of each arm is defined by the idea of log-spiral antenna. The
geometry of an N-arm equiangular spiral is defined by:
N = number of arms
150inR
The best substrate permittivity with widest bandwidth and highest performance is selected
(DiClad880 with thickness 0.762 mm, permittivity 2.17 and tan δ = 0.0009).
Fundamental Parameters
1- Return Loss (S11)
It is shown that the gain of Duhamel’s is more uniform than Vahdani’s one. However in
Vahdani’s model, the gain has higher value which makes it suitable for the applications
requiring the high gain.
3-HPBW in H-plane
Both types have good symmetry radiation patterns with a directive behavior. Moreover, the
feeding system is well matched to the antennas. In addition, in different frequencies there
are no significant changes in radiation patterns. Thus, it can be concluded that both antennas
have a quasi-independent frequency behavior.
[1] K. Mohammad Pour Aghdam, R. Faraji Dana, J. Rashed Mohassel, “The sinuous antenna-a dual polarized feed for reflector-based
searching systems,” Int. J. Electron. Communication (AEÜ), vol.59, pp.392-400. 2005.
[2] M.Vahdani, “ Low-profile, ultra wideband and dual polarized antennas and feeding systems,” PhD thesis, Telecom Paristech, October
2008, p. 24
[3] DuHamel R. H., Dual Polarized Sinuous Antennas, U.S. Patent 4 658 262, Apr. 14, 1987.
[4] M. Vahdani, X. Begaud, “Wideband Integrated Feeding System for a Dual Polarization Sinuous Antenna,” IET Microwaves, Antennas
& Propagation.Vol. 4, issue: 11, pp. 1704 – 1713, 2010.
Duhamel’s sinuous antenna exhibit an ultra-wideband performance better than 10 dB
from 2.5 to 13 GHz and in Vahdani’s sinuous antenna from 3.3 to 10.45 GHz.
Freq (GHz) 2 3 4 5 6 7
Vahdani (dB) 89.06 81.25 77.08 77.08 74.47 56.9
Duhamel(dB) 98.54 82.7 76.56 79.63 73.61 73.13
Freq (GHz) 8 9 10 11 12 13
Vahdani (dB) 67.18 73.32 81.53 128.57 25.52 41.66
Duhamel(dB) 73.13 82.27 81.73 81.73 89.85 86.06
Table shows HPBW comparison of these two antennas. The results illustrate that Vahdani’s
model is approximately more directive than Duhamel’s one. This feature makes it suitable for
many applications in wireless communication .
Mohammad Vahdani :m_vahdani@yahoo.com
Sara Salemhesari :sarasalem2003@gmail.com
Babak Manouchehrinia :eexbm12@nottingham.ac.uk
Conclusion
Refrences