Design of a small and thin PIFA antenna for handheld devices covering several cellular communication bands such as UMTS, Bluetooth, WiMAX, 4G LTE, WLAN. Ground plane of the antenna is used as a radiator along with the main patch.

1. IJECT Vol. 4, Issue 2, April - June 2013
w w w.ijec t.org International Journal of Electronics & Communication Technology 399
ISSN : 2230-7109 (Online) | ISSN : 2230-9543 (Print)
A Compact Planar Inverted-F Antenna
With Slotted Ground Plane
1
Naveen Kumar, 2
Garima Saini
1,2
Dept. of ECE, NIT Teachers’ Training & Research (NITTTR), Chandigarh, India
Abstract
The ground plane of an antenna in a mobile phone has significant
role in improving the performance of the entire antenna structure.
In this paper, a slotted ground plane configuration to design a very
small and thin Planar Inverted-FAntenna (PIFA) is proposed. By
using the ground plane as a radiator along with PIFA’s main patch
situated above the ground plane, the height of PIFAcan be reduced
to a great extent, thus resulting in reduction of overall mobile
phone thickness. In this paper proposed antenna has volume as
25 x 15 x 3.8 mm3
and it is simulated & analyzed using HFSS
software. It is designed to cover UMTS, Bluetooth, 4G LTE,
m-WiMAX, 5 GHz WLAN bands. The simulated results show
that the performance parameters of the antenna are satisfying the
requirements of advanced wireless communication devices.
Keywords
Slotted, Planar Inverted-FAntenna (PIFA), HFSS, Radiator, LTE,
m-WiMAX, Ground Plane
I. Introduction
Planar Inverted-F Antennas (PIFAs) are widely used for mobile
phone applications and other communication systems due to
easy integration, light weight, low profile, low SAR values, &
good gain [1-4]. In last few years mobile phones evolved rapidly
and they are becoming thinner and thinner with more and more
technologiessupportedbythemsuchasGPS,Wi-Fi,3G,WiMAX,
4G LTE, GLONASS etc [2]. For such mobile phones, number of
PIFAdesigns having different structures and configurations have
been implemented to achieve single and multiband operation.
While designing a PIFA structure the main objective is to cover
the required operating bandwidth, because of this requirement
the height of PIFA is generally taken in the range of 7-12 mm
abovegroundplane.Butthislargeantennaheightresultsinthicker
phones although the battery is very thin [3]. So, the height of PIFA
can be taken as small as 4mm which reduces phone thickness, but
this reduction in the antenna height results in narrow bandwidth
coverage [4].
PIFA structure consists of a ground plane, a radiating element
i.e. a patch, a feed wire or strip & one or more shorting pins or
plates to connect the top patch and the ground plane. Fig. 1 shows
a simple PIFA structure which is fed at the base by a feed wire.
In a PIFA structure there are several design variables which can
be varied and the performance of the desired antenna is achieved
[3-4]. Some of the design variables are width, length and height
of the top radiating patch, width and position of shorting pin or
plate, location of the feed point, dimensions of the ground plane.
The ground plane of PIFA antenna is very significant if it is used
as a radiator along with the main patch [5]. The performance of
the antenna can be enhanced by varying ground plane length.
Optimum length of the ground plane is 0.4λ at the operating
frequency [6]. In several designs, position of the antenna on the
dielectric substrate is important as enhancement in the operating
bandwidth can be achieved to few more percentage.
L
W
Ground Plane
Radiating Patch
Feed point
h
Lp
Wp
Fig. 1: Simple PIFA Structure
The basic formula to estimate the resonant frequency at which
PIFA structure resonates is as given below
(1)
Where c is the speed of light,
Wp
and Lp
are the width and length of the top patch,
fr
is the resonant frequency
II. Proposed Antenna
The structure of the proposed PIFA antenna with slotted ground
plane is shown in fig. 2. The proposed PIFA antenna consists
of main radiating patch, a rectangular slot on the ground plane,
a shorting plate, coaxial feed and a ground plane. The antenna
is designed using a dielectric material as FR-4 which has loss
tangent, δ=0.02, dielectric constant, εr
= 4.4 and substrate height,
h = 1.6 mm.
FR-4
Substrate
Radiating
Patch
Shorting
Plate
Ground
Plane Slot
Ground
Plane
Lg
Wg
h
Feed
Pin
Wp
Lp
Fig. 2: 3-D view of Proposed Antenna Structure
Feeding point source simultaneously excites both the upper patch
and ground plane slot. Total dimensions of the radiating parts of
the antenna are 25.5 x 15 x 4 mm3 and that of ground plane are
58 x 39 x 4 mm3
. It can be observed that radiating parts covers
small portion of the total size of the antenna leaving more space
available for other electronic components [7]. To make the design
suitable for real handset applications, the slot on the ground plane
is situated under the top patch [8], which is an area away from
other components of the handset such as battery, RF components,

2. IJECT Vol. 4, Issue 2, April - June 2013 ISSN : 2230-7109 (Online) | ISSN : 2230-9543 (Print)
w w w.ijec t.org400 International Journal of Electronics & Communication Technology
displays, speakers etc.
Fig. 3 shows the detailed dimensions of the proposed antenna
having a rectangular slot on ground plane near feeding point and
also the distance of the slot from edges of the ground plane and
that of shorting plate from the edge.
TABLE 1: Detailed Dimensions of Proposed Antenna
Parameter Value (mm) Parameter Value (mm)
Lg
58 H 1.6
Wg
40 Lgs
14
Lp
25 Wgs
1.5
Wp
15 L1
36
Ls
4 L2
21.9
Ws
3.4 L3
15.6
III. Simulated Results
The simulation and analysis of the proposed antenna is done
usingHighFrequencyStructureSimulator(HFSS).Thesimulated
reflection coefficient (S11) also known as return loss is presented
in fig. 4. It can be observed from S11 plot that there are three
frequencies at which resonance is achieved by the antenna
structure.
Wp
Ls
Lg
h
Wgs
L2
L1
Wg
Ws
L3
Lp
Lgs
Fig. 3: Detailed Dimensions of Proposed Antenna (a) Top view,
(b) Side View
Fig. 4: The Simulated S11 (dB) of Proposed PIFA
These three frequencies are 2.16 GHz, 2.96 GHz and 4.24 GHz
withreturnlossof-11.29dB,-12.60dBand-17.47dBrespectively.
ThecellularbandscoveredbyproposedantennaareUMTS(1920-
2170 MHz), 4G LTE {(2300-2400 MHz), Bluetooth (2400-2480
MHz), WLAN 802.11 {(2400-2485 MHz), (5170 - 5825 MHz)},
m-WiMAX (3400-3600 MHz). Comparing the overall size of
radiating parts of the proposed antenna with the design discussed
in [7] shows that there is 35% reduction in the volume of proposed
antenna as size of PIFA in [7] was 26 x 25.6 x 3.57 mm3
. As the
main objective of this research work is to propose a small antenna
having thin structure, the height of PIFA selected is 2.4mm from
the FR-4 substrate and 4 mm from the ground plane. With these
dimensions selected for the antenna, the structure can operate at
UMTS, LTE, Bluetooth, m-WiMAX, WLAN bands with good
enough bandwidth to serve for these applications.
IV. Conclusion
In this paper, a multi-band planar inverted-F antenna (PIFA)
using an open ended slot on ground plane is designed.The ground
plane of the antenna is used as a radiator and helped in improving
operating bandwidth and resonance of the antenna. Use of slot
in ground plane also reduced volume of the antenna making it
suitable for use in today’s slim handsets.
References
[1] Hang Wong, Kwai-Man Luk, Chi Hou Chan, Quan Xue,
Kwok Kan So, Hau Wah Lai,“Small antennas in Wireless
Communications”, Proceedings of the IEEE Journal, Vol.
100, No. 7, pp. 2109 – 2121, July 2012.
[2] Kin-LuWong,“PlanarAntennasforWirelessCommunication”,
Published by JohnWiley & Sons, Inc., Chapter: 2, pp. 26-65,
2003.
[3] Ray J.A, Chaudhuri S.R.B.,“Areview of PIFAtechnology”,
IEEE Indian Antenna week (IAW), pp. 1 – 4, Dec. 2011.
[4] Belhadef,Y., Boukli Hacene, N.,“PIFAS antennas design for
mobile communications”, 7th IEEE International Workshop
on Systems, Signal Processing and their Applications
(WOSSPA), pp. 119 – 122, May 2011.
[5] SinhyungJeon,HyengcheulChoi,HyeongdongKim,“Hybrid
PlanarInverted-FAntennawithaT-shapedslotontheground
plane”, ETRI Journal, Vol. 31, No. 5, pp. 616-618, October
2009.
[6] C. Picher, J. Angueral, A. Andújar, C. Puente1, S. Kahng,
“Analysis of the Human Head Interaction in Handset
Antennas with Slotted Ground Planes”, IEEE Antennas and
Propagation Magazine, Vol. 54, No. 2, pp. 36 – 56, April
2012.
[7] Hattan F. AbuTarboush, R. Nilavalan, T. Peter, S. W.
Chuang,“SmallandThinInverted-FAntennawithInsensitive
Ground Plane for Mobile Handsets”, IEEE Loughborough
Antennas and Propagation Conference (LAPC), pp. 109 –
112, November 2010.
[8] Wen Xing Li, Xing Liu, Si Li,“Design of A Broadband and
Multiband Planar Inverted-F Antenna”, IEEE
[9] International Conference on Communications and Mobile
Computing, pp. 90 – 93, April 2010.

3. IJECT Vol. 4, Issue 2, April - June 2013
w w w.ijec t.org International Journal of Electronics & Communication Technology 401
ISSN : 2230-7109 (Online) | ISSN : 2230-9543 (Print)
Naveen Kumar is pursuing M.E.
from National Institute of Technical
Teachers’ Training & Research,
Chandigarh, India. He has completed
B.Tech in E.C.E. from SVIET, Mohali
(Punjab), India in the year 2009. He has
2 years of academic experience. His
areas of interest are Wireless & Mobile
Communication and Antennas.
Garima Saini is currently working
as an Assistant Professor at National
Institute of Technical Teachers’
Training & Research, Chandigarh,
India. She has completed her M.E.
from PTU, Jalandhar, India and B.Tech
from JMIT, Radaur, India. She has 12
years of academic experience. She has
authored research papers in reputed
International Journals, National and
International conferences. Her areas of interest are Advanced
Digital Communication, Wireless & Mobile Communication and
Antennas.