Frequency Reconfiguration Mechanism of a PIN Diode on a Reconfigurable Antenna for LTE and WLAN Applications

International Journal of Electrical and Computer Engineering (IJECE)
Vol. 8, No. 3, June 2018, pp. 1893~1902
ISSN: 2088-8708, DOI: 10.11591/ijece.v8i3.pp1893-1902  1893
Journal homepage: http://iaescore.com/journals/index.php/IJECE
Frequency Reconfiguration Mechanism of a PIN Diode on a
Reconfigurable Antenna for LTE and WLAN Applications
S. M. Shah1
, M. F. M. Daud2
, Z. Z. Abidin3
, F. C. Seman4
, S. A. Hamzah5
, N. Katiran6
, F. Zubir7
1,2,3,4,5,6
Research Centre for Applied Electromagnetics, Universiti Tun Hussein Onn Malaysia, 86400 Batu Pahat, Johor,
Malaysia
7
Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
Article Info ABSTRACT
Article history:
Received Nov 19, 2017
Revised Apr 12, 2018
Accepted Apr 25, 2018
Microstrip patch antennas are increasingly gaining popularity for usage in
portable wireless system applications due to their light weight, low profile
structure, low cost of production and robust nature. The patch is generally
made of a conducting material such as copper or gold and can take any
possible shapes, but rectangular shapes are generally used to simplify
analysis and performance prediction. Microstrip patch antenna radiates due
to the fringing fields between the patch edge and ground plane. In this work,
a frequency reconfigurable antenna with a BAR63-02V Positive-Intrinsic-
Negative (PIN) diode is designed, simulated and fabricated. The antenna
operates at 2.686GHz for Long-Term Evolution (LTE2500) and 5.164GHz
for Wireless Local Area Network (WLAN) applications. In the OFF state, the
antenna operates at 5.302GHz, which is also suitable for WLAN application.
The proposed antenna is fabricated on a FR-4 substrate with a relative
dielectric constant, εr of 4.5, thickness, h of 1.6mm and loss tangent, tan δ of
0.019. The fabrication process is carried out at the Advanced Printed Circuit
Board (PCB) Design Laboratory in UTHM.
Keyword:
Long-term evolution
Microtrip antenna
PIN Diode
Reconfigurable antenna
Wireless local area network
Copyright © 2018 Institute of Advanced Engineering and Science.
All rights reserved.
Corresponding Author:
Shaharil Mohd Shah,
Research Centre for Applied Electromagnetics,
Universiti Tun Hussein Onn Malaysia,
86400 Batu Pahat, Johor, Malaysia.
E-mail: shaharil@uthm.edu.my
1. INTRODUCTION
There are numerous wireless communication systems in our daily lives such as cellular radio
systems, mobile satellite systems and wireless local area networks. Although it is hard to predict precisely
how the systems will appear in the future, it is clear that there will be a need for new solutions in the field of
antennas. The new solutions are commonly to cater for the need to include the growing number of
communication services in a single mobile device such as Wireless Local Area Network (WLAN),
Worldwide Interoperability for Microwave Access (WiMAX), Long Term Evolution (LTE) and satellite
communication, only to name a few [1]. In this context, there is an evident interest in developing new
reconfigurable antennas, which allow dynamic reconfiguration of parameters such as operating frequency,
radiation pattern and polarization [2].
Reconfigurable antennas have the ability to simultaneously operate in different frequency bands for
different communication services [3]. Therefore, to operate in multiple frequency bands with improved
radiation efficiency, the RF engineers are focusing on designing reconfigurable antenna. There are many
ways of reconfiguring the antennas such as by using active switches and tunable devices. The development of
active components such as PIN diodes, varactor diodes and RF MEMS, has accelerated the rapid evolution of
the reconfigurable antennas [4]. Recently, PIN diodes have been used as the switching elements in the

 ISSN: 2088-8708
Int J Elec & Comp Eng, Vol. 8, No. 3, June 2018 : 1893 – 1902
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reconfigurable antennas for the purpose of multiple frequency bands operation [5]. In addition,
reconfigurable antenna can be a cheaper alternative to traditional adaptive arrays [6].
Microstrip patch antennas are increasingly gaining popularity for use in portable wireless system
applications due to their light weight, low profile structure, low cost of production and robust nature [7]. In
its most basic form, a microstrip patch antenna consists of a radiating patch on one side of a dielectric
substrate and a ground plane on the other side. The patch is generally made of a conducting material such as
copper or gold and can take any possible shape, but regular shapes are generally used to simplify analysis and
performance prediction [8]. The radiating patch and the feed lines are usually photo-etched on the dielectric
substrate. Microstrip patch radiate due to the fringing fields between the patch edge and ground plane.
In this work, a frequency reconfigurable antenna with a PIN diode will be designed, simulated and
fabricated. PIN diodes have been used for RF switching of reconfigurable antennas in many applications such
as mobile and satellite communications, cellular radio system and radar application. PIN diodes is a current
controlled device that operates as a variable resistor in the RF switching operation. PIN diodes have many
advantages such as small in size, high switching speed, low distortion, low insertion loss, good isolation with
low power handling and low in cost [9]. The operation of PIN diode is based on the ON or OFF states of the
PIN diodes. The antenna will operate at WLAN frequency (5.15GHz–5.825GHz) and LTE2500 frequency
(2.5GHz – 2.69GHz). The Computer Simulation Technology Microwave Studio (CST MWS) software is
used to design and simulate the reconfigurable antenna. The proposed antenna is fabricated on a FR-4
substrate with a relative dielectric constant, εr of 4.5, thickness, h of 1.6 mm and loss tangent, tan of 0.019.
The fabrication process is carried out at the Advanced Printed Circuit Board (PCB) Design Laboratory.
2. RESEARCH METHODOLOGY
2.1. Antenna design and configuration
The design and simulation processes are done by using CST MWS® software. The simulation result
is optimized to achieve the best performance of antenna. Then, In order to achieve the required
reconfiguration, the antenna is designed in an orderly manner which involved two stages. Firstly, the
proposed antenna comprises of only the main radiating plane which is fed by a microstrip line with a stub for
impedance matching. Secondly, an additional radiating plane is added on top of the main radiating plane that
is connected by the BAR63-02V PIN diode. The main reason to introduce the additional radiating plane is to
alter the length of current travelled across the antenna which will in return also reconfigure the resonant
frequencies. Figure 1 shows the structure of the reconfigurable antenna. The dimensions of the antenna are
listed in Table 1.
(a) (b)
Figure 1. Reconfigurable antenna with a BAR63-02V PIN diode: (a) With only the main radiation plane
(b) With the main and an additional radiating planes

Int J Elec & Comp Eng ISSN: 2088-8708 
Frequency Reconfiguration Mechanism (S.M. Shah)
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Table 1. Dimensions of the Reconfigurable Antenna with a BAR63-02V PIN diode
Parameter Value (mm)
𝑾 𝒈 50
𝑳 𝒈 50
W 12
L 23.9
𝑾 𝟏 4
𝑳 𝟏 4
𝑾 𝟐 5.5
𝑳 𝟐 15.9
Parameter Value (mm)
𝑾 𝒔 4
𝑳 𝒔 2
𝑳 𝒇 10.8
𝑾 𝟑 15.5
𝑳 𝟑 3
𝑾 𝟒 15
𝑳 𝟒 8
𝑳 𝟓 11.9
2.2. Antenna Simulation
In the reconfigurable antenna design, a BAR63-02V PIN diode from Infineon Technologies is used
as a switch since it has a very low capacitance which provides high isolation. The PIN diode is modeled by
using the equivalent circuit model in CST MWS® software. Figure 2(a) shows the discrete port in CST
MWS software which can be modelled by the equivalent circuit model of the PIN diode in the ON and OFF
states. Figure 2(b) and Figure 2(c) show the equivalent circuit model in the ON and OFF states of the
BAR63-02V PIN diode.
(b)
(a) (c)
Figure 2. The reconfigurable antenna with a BAR63-02V PIN diode: (a) The discrete port to connect the
main radiation plane to the additional plane (b) Equivalent circuit model of the BAR63-02V PIN diode in
the ON state (c) Equivalent circuit model of the BAR63-02V PIN diode in the OFF state
2.3 Antenna fabrication
The fabrication process is performed at the Advanced Printed Circuit Board (PCB) Design
Laboratory. The outcomes of the fabrication process can be viewed in Figure 3. The antennas are fabricated
on a FR-4 substrate with a relative dielectric constant, 𝜀 𝑟 of 4.5, thickness, h of 1.6mm and loss tangent, tan
of 0.019. Figure 4 shows the final prototype of the reconfigurable antenna with a BAR63-02V PIN diode and
the biasing circuit.

 ISSN: 2088-8708
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(a) (b)
Figure 3. The fabricated reconfigurable antenna with a BAR63-02V PIN diode: (a) With only the main
radiating plane (b) With the main and an additional radiating planes
Figure 4. The reconfigurable antenna with a BAR63-02V PIN diode and the biasing circuit
3. RESULTS AND ANALYSIS
3.1. Reconfigurable antenna with the main radiating plane
The simulation results of reflection coefficient and bandwidth of the antenna and the comparison
with the measurement results are shown in Figure 5. From the simulation results, the proposed antenna
operates at 5.206GHz with a reflection coefficient, S11 of -25.51dB and bandwidth, BW of 99.1MHz. The
measurement results, on the other hand, show that the S11 is the greatest at 5.26GHz at -21.48dB. There is a
slight shift in the measurement result with the simulation result of 5.206 GHz, which can be attributed to the
fabrication losses.
Figure 5. Reflection coefficients of the reconfigurable antenna with only the main radiating plane
-30
-25
-20
-15
-10
-5
0
1 2 3 4 5 6
ReflectionCoefficient(dB)
Frequency (GHz)
Measured
Simulated

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-30
-25
-20
-15
-10
-5
0
1 2 3 4 5 6
Frequency (GHz)
Measured
Simulated
Figure 6 shows the surface current distribution on the main radiating plane. From the figure, the
maximum surface current is seen to be concentrated in the middle and around the edges of the radiating
plane.
Figure 6. Simulated surface current of the reconfigurable antenna with only the main radiating plane
3.2. Reconfigurable antenna with the main and additional radiating planes
The simulation and measurement results of the reflection coefficient and bandwidth of the antenna
can be viewed in Figure 7. From the simulation results, it is observed that the antenna is operating at the
resonant frequency of 5.302GHz with the S11 of -25.385dB and BW of 99.4MHz. The measured S11 of the
antenna is the greatest at 5.35GHz at -21.52dB. There is a slight difference between the simulation result of
5.302GHz, which can be attributed to the fabrication losses. In addition, it is also shown that the existence of
the additional radiating plane has further increased the resonant frequency to 5.302GHz from 5.206GHz.
Figure 7. Reflection coefficients of the reconfigurable antenna with two radiating planes
The surface current distribution of the reconfigurable antenna with the main and additional radiating
planes can be viewed in Figure 8. Even though there is an additional radiating plane, but there is no current
flow between the main and the additional radiating plane since there is no physical connection between the
two planes. Therefore, that explains the occurrence of only a single frequency band from the antenna.

 ISSN: 2088-8708
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Figure 8. Simulated surface current of the reconfigurable antenna with two radiating planes
3.3. Reconfigurable antenna with a BAR63-02V PIN diode
In this work, the PIN diode acts as an active switch and thus, the operations are based on the ON and
OFF states of the PIN diode. Figure 9 shows the simulated S11 and BW of the reconfigurable antenna in the
ON and OFF states. From the figure, the antenna operates at a dual-band frequency of 2.686GHz and
5.164GHz in the ON state. For the frequency of 2.686GHz, the S11 and BW are -12.1dB and 50.6MHz while
for the frequency of 5.164GHz, the S11 and BW are -10.822dB and 32.2MHz, respectively. In the OFF state,
the antenna operates as a single band antenna at a resonant frequency of 5.302GHz with a S11 and BW of
-24.835dB and 99.8MHz. Therefore, it is shown that in the ON state of the PIN diode, the upper resonant
frequency is further reduced to 5.164GHz as compared to 5.302GHz when the PIN diode is not present. This
can be attributed to the fact that the current travels a longer path from the main radiating plane to the
additional plane through the PIN diode that in return, reduces the resonant frequency [10]. It is also shown
that the resonant frequency of the reconfigurable antenna in the OFF state of the PIN diode at 5.302GHz is
almost similar (vary slightly) to the resonant frequency of the antenna without the presence of the PIN diode
(refer Figure 8).
Figure 9. Reflection coefficients of the reconfigurable antenna with a BAR63-02V PIN diode in the ON
and OFF states
The reconfigurable antennas are measured by using the ZVB14 Rohde & Schwarz Vector Network
Analyzer (VNA). Due to the lack of facilities, only the reflection coefficients are measured. The
-30
-25
-20
-15
-10
-5
0
1 2 3 4 5 6
Frequency (GHz)
ON State
OFF State

1899
measurement data retrieved from the VNA also do not reflect the reflection coefficients on display.
Therefore, only the screen display of the reflection coefficients are shown in this paper. The reflection
coefficients of the reconfigurable antenna in the ON and OFF states can be viewed in Figure 10. In the ON
state, a 12V DC voltage is supplied to the antenna to produce a 10mA of current across the PIN diode. The
power supply is switched off in the OFF state. From Figure 10(a), the measured S11 are -11.471dB at
2.504GHz and -20.131dB at 5.210GHz. (The marker at 5.210GHz is not available on the display).
Figure 10(b) shows the measured reflection coefficient of the reconfigurable antenna in the OFF state. From
the figure, it can be seen that the antenna operates at 5.26GHz with a S11 at -22.36dB.
(a) (b)
Figure 10. Measured reflection coefficients of the reconfigurable antenna with a PIN diode in the: (a) ON
state (b) OFF state
Figure 11 shows the surface current distribution of the simulated reconfigurable antenna with the
PIN diode in the ON state. The current is seen to flow across the main radiating plane to the additional plane
that explains the dual-band frequency operation of the antenna at 2.686GHz and 5.164GHz. It is shown from
the figure that the current travels a longer path from the main radiating plane to the additional plane through
the PIN diode in both resonant frequencies. From the previous simulation results, it can be concluded that the
main radiating plane produces the upper resonant frequency at 5.164GHz while the additional radiating
plane, on the other hand, produces the lower resonant frequency at 2.686GHz. The surface current
distribution of the simulated reconfigurable antenna in the OFF state of the PIN diode at 5.302GHz can be
viewed in Figure 12. Since the PIN diode is in the OFF state, there is no current flows through the PIN diode
to the additional radiating plane. Thus, the current travels a shorter path which increases the resonant
frequency.
(a) (b)
Figure 11. Simulated surface current of the reconfigurable antenna with a PIN diode in the ON state at:
(a) 2.686GHz (b) 5.164GHz

 ISSN: 2088-8708
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Figure 12. Simulated surface current of the reconfigurable antenna with a PIN diode in the OFF state at
5.302GHz
4. CONCLUSION
A reconfigurable antenna with a BAR63-02V PIN diode has been designed, simulated, fabricated
and measured in this work. The antenna is fabricated on a FR-4 substrate with a relative dielectric constant,
𝜀 𝑟 of 4.5, thickness, h of 1.6mm and loss tangent, tan of 0.019. The equivalent circuit model of the PIN
diode has been modelled in the ON and OFF states. In order to switch ON the PIN diode, a 12V DC voltage
is supplied to the antenna in order to produce a 10mA of current to pass through the PIN diode while in the
OFF state, the power supply is switched off. Based on the obtained results, the antenna operates at 2.686GHz
and 5.164GHz in the ON state which are suitable for LTE2500 and WLAN applications. On the other hand,
the antenna operates at 5.302GHz in the OFF state for WLAN application. The antenna is measured on the
ZVB14 Rohde & Schwarz Vector Network Analyzer.
ACKNOWLEDGEMENTS
The author would like to acknowledge Universiti Tun Hussein Onn Malaysia for financial assistance.
REFERENCES
[1] Boutejdar, A., Mohammad, A., Bennani, S. D., & El Hani, S, (2017), “Design of Compact Monopole Antenna
Using double U-DMS resonators for WLAN, LTE, and WiMAX applications”, TELKOMNIKA
(Telecommunication Computing Electronics and Control), vol. 15, no. 4.
[2] Debogovic, T, (2010), “Perspectives of Reconfigurable Antennas in Modern Wireless Communication and Sensing
Systems”, http:/www. fer. hr/_download/repository/Debogovic_kvalifikac ijski. pdf.
[3] Hsieh, H. W., Lee, Y. C., Tiong, K. K., & Sun, J. S., (2009), “Design of a Multiband Antenna for Mobile Handset
Operations”, IEEE Antennas and Wireless Propagation Letters, 8, pp. 200-203.
[4] El Maleky, O., Abdelouahab, F. B., Essaaidi, M., & Abdelfatah, N., (2017), “Miniature design of T-Shaped
frequency Reconfigurable antenna for S-Band Application using Switching Technique”, International Journal of
Electrical and Computer Engineering (IJECE), vol. 7, no. 5, pp. 2426-2433.
[5] Ismail, M. F., Rahim, M. K. A., & Majid, H. A., (2011, December), “The Investigation of PIN Diode Switch on
Reconfigurable Antenna”, In RF and Microwave Conference (RFM), 2011 IEEE International, pp. 234-237, IEEE.
[6] Razak, A., Rahim, M. K. A., Majid, H. A., & Murad, N. A., (2017), “Frequency Reconfigurable Epsilon Negative
Metamaterial Antenna”, International Journal of Electrical and Computer Engineering (IJECE), vol. 7, no. 3.
[7] Constantine, A. B., (2005), Antenna theory: Analysis and Design, MICROSTRIP ANTENNAS, Third Edition,
John Wiley & Sons.
[8] Kumar, G., & Ray, K. P., (2003), Broadband Microstrip Antennas, Artech House.
[9] Haupt, R. L., & Lanagan, M., (2013), “Reconfigurable Antennas”, IEEE Antennas and Propagation Magazine,
pp. 55, no. 1, pp. 49-61.
[10] Yang, F., & Rahmat-Samii, Y., (2005), “Patch Antennas with Switchable Slots (PASS) in Wireless
Communications: Concepts, Designs, and Applications”, IEEE Antennas and Propagation Magazine, vol. 47,
no. 2, pp. 13-29.

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BIOGRAPHIES OF AUTHORS
Shaharil Mohd Shah obtained his B. Eng in Microwave and Communication from Multimedia
University (MMU) in 2002. He received his M.Sc in Microwave Engineering and Wireless
Subsystems Design from the University of Surrey, UK in 2004 and pursuing his Ph.D in
Communication Engineering from the University of Birmingham, UK before graduating in 2016.
He is currently a senior lecturer in the Department of Communication Engineering, Faculty of
Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia (UTHM). His area of
research includes, but not limited to, design of microwave devices, active antennas measurement
and nonlinear characterisation of active devices.
Zuhairiah Zainal Abidin was born in Kuala Lumpur, Malaysia, in 1978. She received the
B.Eng.from the Universiti Teknologi Malaysia, in 2001, the M. Eng from the Kolej Universiti Tun
Hussein Onn Malaysia, Johor, Malaysia, in 2003, and Ph.D. degree from Bradford University, U.K
in 2011. Currently, she was a Principal Researcher at Applied Electromagnetic Center, Universiti
Tun Hussein Onn Malaysia. She has authored and co-authored numbers of journals and
proceedings, including the IEEE TRANSACTION ON ANTENNA AND PROPAGATION,
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS and IEEE AWPL. Her research interests
include MIMO antenna, printed microstrip antenna, wearable antennas, electromagnetic bandgap
(EBG) for wireless and mobile and high speed digital circuit’s applications.
Fauziahanim Che Seman received the B.Eng. degree in electrical communication from Universiti
Teknologi Malaysia. In 2002, she was awarded M.Eng. degree in communication engineering from
Kolej Universiti Tun Hussein Onn, now known as Universiti Tun Hussein Onn (UTHM). She
received her Ph.D. in electrical engineering Queens University, Belfast, Northern Ireland in 2011.
She serves as academician in Department of Communication Engineering, Faculty of Electrical
Electronic Engineering at Universiti Tun Hussein Onn Malaysia (UTHM) since 2002. She is also a
research fellow in Research Center for Applied Electromagnet (EM-Center). She has authored and
co-authored over 40 referred journal and conference technical papers. Due to her significant
contributions she has been awarded as Top Scopus Index Author by Publisher’s Office, UTHM in
2014. Since 2011, she actively served as an associate reviewer for more than 20 international
conferences. Since 2014, she serves on the IEEE Malaysia AP/MTT/EMC Joint Chapter as
executive committee. She is actively involves with industrial–academia activities and currently has
joint research collaboration with Telekom Malaysia RnD. Her research interests include frequency
selective surfaces, antenna design and applied electromagnetics.
Shipun Anuar Hamzah was born in Perak, Malaysia in 1975. He received the B.Eng. and Ph.D.
in electrical engineering from Universiti Teknologi Malaysia (UTM), Malaysia in 1998 and 2013,
respectively and M.Eng. of Engineering in Communication and Computer System from National
University of Malaysia (UKM), Selangor, Malaysia, in 2000. From 1998 to 2004, he worked as a
lecturer at Kolej UNITI Sdn. Bhd, Malaysia. Since April 2004, he has been working as a Lecturer
at the Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia
(UTHM). He is now a Senior Lecturer with the same institution. His research interests include
active antenna, harmonic suppression antenna, rectifying-antenna and RF propagation.
Norshidah Katiran received her Ph.D in Electrical Engineering from Universiti Teknologi
Malaysia, in 2015, her M.Eng. degree in Communication and Computer Engineering from
Universiti Kebangsaan Malaysia, in 2004, and her B.Eng. degree in Electrical Engineering
(Telecommunications) from Universiti Teknologi Malaysia, in 2001. Currently, she is a Senior
Lecturer in the Department of Communication Engineering at Universiti Tun Hussein Onn
Malaysia. Her major research interests include optimization of resource allocation in cooperative
networks and multiple input multiple output (MIMO) transmissions.
Farid Zubir received the B. Eng. degree in Electrical Engineering majoring in
Telecommunication as well as M. Eng. degree (Communication) from the Universiti Teknologi
Malaysia in 2008 and 2010 respectively. In 2016, he then obtained his Ph.D degree from the
University of Birmingham, UK, for research into direct integration of power amplifiers with
antennas in microwave transmitters. He is currently serves as a Senior Lecturer at the Department
of Communication Engineering, Faculty of Electrical Engineering, Universiti Teknologi Malaysia.
His current research interest and specialization are in the area of RF and Microwave technologies
including Planar Array Antennas, Dielectric Resonator Antennas (DRAs), Active Integrated
Antenna (AIA), Microstrip Reflectarray Antenna (MRA), Millimeter wave Antennas,
Electromagnetic Band Gap (EBG), Artificial Magnetic Conductor (AMC), Full-integrated
Transmitting Amplifiers, Linear PAs, Doherty PAs and Bias Decoupling Circuits. He has
published over 40 articles in journals, book chapters, conference papers and proceedings.

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