This paper studies a circular patch antenna which is fed by using a coaxial pin, which is a suitable antenna design for applications where small size is of importance. Such applications are wearable antenna designs. The main purpose of this paper is to design an antenna with wearable capabilities and adequate radiation characteristics for satellite communications and more specifically for the Iridium satellite constellation. The goals for the radiation characteristics of the antenna are the tuning of the antenna to 1.62GHz which is the Iridium's frequency, maximum boresight gain for this frequency, as well as circular polarization

Cosmas, John P.

Glover, Ian A.

Lazaridis, Pavlos I.

Liu, Bo

Mistry, Keyur K.

Tziris, Emmanouil N.

Zaharis, Zaharias D.

English

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Tziris, E. N., Lazaridis, P. I., Mistry, K. K., Zaharis, Z. D., Cosmas, J. 
P., Liu, B.  and Glover, I. A. (2018) 1.62 GHz Circularly Polarized Pin-Fed 
Notched Circular Patch Antenna. In: 2018 2nd URSI Atlantic Radio 
Science Meeting (AT-RASC), Meloneras, Spain, 28 May - 01 Jun 2018, 
ISBN 9789082598735 (doi:10.23919/URSI-AT-RASC.2018.8471447) 
 
The material cannot be used for any other purpose without further 
permission of the publisher and is for private use only. 
 
There may be differences between this version and the published version. 
You are advised to consult the publisher’s version if you wish to cite from 
it.  
 
 
http://eprints.gla.ac.uk/209556/  
 
 
 
 
 
 
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1.62GHz Circularly Polarized Pin-Fed Notched Circular Patch Antenna 
 
Emmanouil N. Tziris
(1)
, Pavlos I. Lazaridis 
(2)
, Keyur K. Mistry
(2)
,  Zaharias D. Zaharis
(3)
, John P. Cosmas
(1)
, 
Bo Liu
(4)
, and, Ian A. Glover
(2) 
(1) Brunel University, Uxbridge, UK 
(2) University of Huddersfield, Huddersfield, UK 
(3) Aristotle University of Thessaloniki, Thessaloniki, GR 
(4) Wrexham Glyndwr University, Wrexham, UK 
 
 
 
Abstract 
 
This paper studies a circular patch antenna which is fed 
by using a coaxial pin, which is a suitable antenna design 
for applications where small size is of importance. Such 
applications are wearable antenna designs. The main 
purpose of this paper is to design an antenna with 
wearable capabilities and adequate radiation 
characteristics for satellite communications and more 
specifically for the Iridium satellite constellation. The 
goals for the radiation characteristics of the antenna are 
the tuning of the antenna to 1.62GHz which is the 
Iridium's frequency, maximum boresight gain for this 
frequency, as well as circular polarization. 
 
1. Introduction 
 
The Iridium satellite constellation is one of the very well-
known global satellite systems that provide voice and data 
services over the entire surface of the planet. In particular, 
their services are used in military, sea and air transport, 
emergency services as well as in many other industries, 
which suggests that it is used in areas where reliable 
communication is of importance, and thus, for antennas 
used for this purpose, it is significant to demonstrate solid 
radiation characteristics.  
Polarization is one of the fundamental characteristics of 
any antenna and the types of polarization which are 
considered in electromagnetics are the: 1) linear, 2) 
circular, and 3) elliptical. The fundamental advantage of 
circular polarization (CP) is that all reflections change the 
direction of polarization, precluding the usual addition or 
subtraction of main and reflected signals. Therefore, there 
is far less fading and flutter when circular polarization is 
used at each end of the link. The circularly polarized 
wave will radiate energy in the horizontal and vertical 
plane, as well as every plane in between [2].  
There are two directions of propagation that come with 
circular polarization: Right-Hand-Circular-Polarization 
(RHCP) which follows a clockwise pattern, and Left-
Hand-Circular-Polarization (LHCP) which follows a 
counterclockwise pattern. Due to the advantages of 
circular polarization, it makes it ideal for use in satellite 
 
 
 
communications. Figure 1 clearly depicts the components 
of circular polarization. The horizontal component (green) 
in conjunction with the vertical component (blue), 
generate the circular polarization.  
 
 
 
 
 
 
 
 
 
 
 
Figure 1. Analysis of circular polarization [3]. 
 
Microstrip or patch antennas are becoming increasingly 
useful because they can be printed directly onto a circuit 
board. They are low cost, have a low profile and are 
easily fabricated and for that reason they are becoming 
very widespread throughout the whole antenna industry 
[4, 5]. In this paper, a model of a pin-fed notched circular 
patch antenna [6, 7] which was designed in CST 
Microwave Studio is studied, which is designed for 
circular polarization, maximum boresight gain and 
minimum VSWR for the frequency of 1.62GHz (Iridium). 
 
2. Implementation and Results 
 
For the purpose of this paper a model of a pin-fed notched 
circular patch antenna was designed in CST Microwave 
Studio as demonstrated in Figure 2. The patch antenna 
consists of four main components, 1) a dielectric material 
with the same characteristics as FR4 (relative permittivity 
etc.), 2) a ground plane layer, 3) a coaxial feed pin on the 
rear, 4) and a notched circular patch on the front of the 
antenna. By implementing some powerful tools which are 
provided by CST MWS an optimal geometry for the patch 
antenna was developed and Table 1 describes all the 
geometrical elements of the patch antenna. 
 
 
 
 
 
 
 
 
 
Figure 2. CST MWS model of a pin-fed notched circular 
patch antenna. 
 
Geometrical Element Value 
Notch Length 4.59 mm 
Notch Width 9.19 mm 
Patch Diameter (Ø) 70.79 mm 
Dielectric Length Ø * 3 mm 
Dielectric Width Ø * 3 mm 
Coaxial Pin Diameter Inner 1.80 mm 
(Outer) (Inner/0.43)mm 
Coaxial Pin Offset 11.04 mm 
Coaxial Pin Angular Position -45° 
Coaxial Pin Length λ1.62GHz/10 mm   
Table 1. The geometry of the patch antenna. 
 
The results of the designed geometry of the antenna as it 
is observed in the following figures generates satisfactory 
radiation characteristics for the purpose of satellite 
communication, taking into consideration that it is a small 
form factor patch antenna. As it is observed in Figure 3, 
the antenna is finely tuned for the Iridium frequency 
range.  
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3. Simulated reflection coefficient.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 4. Simulated Axial Ratio vs Theta (Phi = 0) for the 
frequency of 1.62 GHz. 
 
The axial ratio which is shown in Figure 4 demonstrates a 
qualitative circular polarization with values below the 
limit of 3dB across most of the angles, especially at the 
front of the antenna (Phi=0, Theta =0) which implies a 
small cross polarization level. The antenna excites left-
hand CP (LHCP), and the cross polarization is right-hand 
CP (RHCP) as it can be observed in Figure 5 and it attains 
reasonable boresight realized gain for the desired 
frequency of 1.62GHz.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 5. Simulated LHCP and RCHP.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 6. Simulated realized gain. 
 
In Figure 7 a very narrow axial ratio is observed, 
nonetheless, by further optimizing the geometry of the 
designed antenna it is possible to widen the bandwidth of 
the antenna axial ratio as well as all the rest of the antenna 
radiation characteristics. 
 
Symposium, 2005, pp. 271-274 vol. 2A, doi:  
10.1109/APS.2005.1551791. 
 
7. S. L. S. Yang, A. A. Kishk and K. F. Lee, "Wideband 
Circularly Polarized Antenna With L-Shaped Slot," in 
IEEE Transactions on Antennas and Propagation, vol. 56, 
no. 6, pp. 1780-1783, June 2008, doi:  
10.1109/TAP.2008.923340 
 
Figure 7. Axial Ratio vs Frequency (Theta = 0, Phi = 0). 
 
3. Conclusion 
 
A pin-fed notched circular patch antenna was studied for 
satellite communications and small form factor in mind. 
The design demonstrates solid radiation characteristics, 
such as low cross polarization, adequate gain and fine 
tuning for the Iridium central frequency (1.62GHz). 
However, this initial design can be further optimized, and 
performance, such as axial ratio and gain, can be 
improved. 
 
4. References 
 
1. A. K. Sharma and A. Mittal, "Notched circular 1. M. S. 
Shakhirul et al., "1.575 GHz Circular Polarization 
wearable antenna with three different substrate materials," 
2014 IEEE Asia-Pacific Conference on Applied 
Electromagnetics (APACE), Johor Bahru, 2014, pp. 43-
46, doi: 10.1109/APACE.2014.7043807. 
 
2. M. S. Shakhirul, M. Jusoh, A. H. Ismail, M. I. Jais, M. 
R. Kamarudin and M. N. Osman, "Analysis of circular 
polarization textile antenna in bending condition," 2015 
International Conference on Computer, Communications, 
and Control Technology (I4CT), Kuching, 2015, pp. 360-
363, doi: 10.1109/I4CT.2015.7219598. 
 
3. M. Akbari, M. Farahani, A. R. Sebak and T. A. 
Denidni, "Ka-Band Linear to Circular Polarization 
Converter Based on Multilayer Slab With Broadband 
Performance," in IEEE Access, vol. 5, pp. 17927-17937, 
2017, doi: 10.1109/ACCESS.2017.2746800 
 
4. P. Sharma and K. Gupta, "Analysis and optimized 
design of single feed circularly polarized microstrip 
antennas," in IEEE Transactions on Antennas and 
Propagation, vol. 31, no. 6, pp. 949-955, November 1983, 
doi: 10.1109/TAP.1983.1143162. 
 
5. H. Iwasaki, "A circularly polarized small-size 
microstrip antenna with a cross slot," in IEEE 
Transactions on Antennas and Propagation, vol. 44, no. 
10, pp. 1399-1401, Oct 1996, doi: 10.1109/8.537335. 
 
6. A. K. Sharma and A. Mittal, "Notched circular 
microstrip patch antennas with bow tie shaped aperture 
coupling for improved axial ratio bandwidth," 2005 IEEE 
Antennas and Propagation Society International 
 
 
 
 
 
 


1.62 GHz Circularly Polarized Pin-Fed Notched Circular Patch Antenna

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1.62 GHz Circularly Polarized Pin-Fed Notched Circular Patch Antenna

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