The document presents the design of a stacked layer E-shaped microstrip patch antenna intended for WLAN and WiMAX applications, characterized by a wideband operation in the 5-6 GHz frequency range. The antenna, designed using Ansoft HFSS software, exhibits high performance with a maximum gain of 5.5 dB and satisfactory radiation characteristics, making it suitable for high-speed wireless communication systems. Future work includes fabricating the antenna and comparing simulated results with actual measurements.

1. International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 3, May – June (2013), © IAEME
48
MICROSTRIP LINE FED STACKED LAYER E- SHAPED PATCH
ANTENNA FOR WLAN AND WIMAX APPLICATIONS
Uma Shankar Modani 1
, Gajanand Jagrawal2
1
(Govt. Engg. College, Ajmer, Rajasthan, India)
2
(Govt. Engg. College, Ajmer, Rajasthan, India)
ABSTRACT
The design of stacked layer E-shaped microstrip patch antenna for wideband
operation in the 5-6 GHz frequency range has been presented in this paper. The antenna is
Microstrip line feeded. The Roger RO4350 of 1.6 mm height with relative permittivity of
3.66 and dielectric loss tangent of 0.004 has been used as the substrate on which the patch is
placed. An air box of 2mm height has been introduced between substrate and the ground. The
ANSOFT HFSS software has been used for designing the antenna. High performance
characteristics and good impedance matching have been obtained. The antenna is resonating
at 5.36 GHz with a return loss of -56.5 dB. A maximum gain of 5.3 dB has been obtained in
E-plane. The proposed antenna is suitable for WLAN and WiMax applications operating
within 5.15-5.85 GHz frequency band.
Keywords: E- shaped, Line Feed, Stacked Layers, WLAN and WiMax.
I. INTRODUCTION
Due to the inherent advantages of low profile, less weight, low cost, and ease of
integration with microstrip circuits, the Microstrip patch antennas are widely used in wireless
communications [1]. However, the main disadvantage of microstrip antennas is their small
bandwidth. Many methods have been proposed to improve the bandwidth. These include the
use of a thick substrate and cutting slots in the design [2-5]. Improvement of broader
bandwidth becomes an important need for many applications such as for high speed
networks.
High-speed wireless computer networks have attracted the attention of researchers,
especially in the 5-6 GHz band (e. g. WiMax and IEEE 802.11a Indoor and Outdoor WLAN).
These networks have the ability to provide high speed connectivity between notebook
computers, PCs, personal organizers and other wireless digital appliances. Many novel
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antenna designs have been proposed to suit the standards for high-speed wireless computer
networks. Some approaches have resulted in the probe-fed U-slot patch antennas [6-10], the
E- shaped patch antennas [11-17] and many others.
The E-shape has been an attraction for antenna designers. An E-shaped patch antenna
has been presented in [11]. However, this antenna is a coaxial probe fed antenna and covers
the 5-6GHz frequency band. This antenna design is a bit complex and contains many slots in
the patch. In [12], a parametric study of this E-shaped patch antenna has been presented. In
[13], an E-shaped patch antenna which operates at 1.9 GHz and 2.4 GHz frequency bands has
been presented. The E-shaped patch antenna presented in [14] is a coaxial probe feeded
antenna. In this antenna, the substrate material used is having a dielectric constant of 2.2 and
a height of 3.2mm. A microstrip line fed triband E-shaped antenna has been reported in [15].
This is a monopole antenna. In [16], a multilayer substrate microstrip line fed E-shaped
antenna has been reported. This antenna is designed to cover 5 GHz to 6 GHz band.
However, Glass and Silicon are the two substrate materials used as antenna substrate which
are different than the substrates used in proposed antenna.
In this paper, a simple design of E-shaped patch antenna with an air box of 2 mm
inserted between ground plane and the substrate has been presented which can cover the
frequency range of 5.15-5.85 GHz. The same technique of stacked layers structure using an
air box sandwiched between substrate and the ground has been reported in [11], [17-20].
Ansoft HFSS which is the industry standard simulation tool for 3D full-wave electromagnetic
field simulation based on Finite Element Method (FEM) has been used for simulation
purposes [21], [22].
II. ANTENNA DESIGN
The side view of the proposed antenna structure has been shown in Fig. 1. The broad
banding technique of stacked layers is used to improve the bandwidth. An air box of 2 mm
height has been inserted between substrate and the ground. The Roger RO4350 of 1.6 mm
thickness having relative permittivity of 3.66 and dielectric loss tangent of 0.004 has been
used as the substrate. The substrate and ground size has been considered as 47.6mm x
46.6mm. The antenna is feeded by a microstrip line. The feeding method is easy to fabricate
but difficult to model accurately and have low spurious radiation and narrow bandwidth of
impedance matching [23]. The location of the feed element with respect to the patch also
plays a role in the antenna performance. The patch geometry has been shown in Fig. 2. The
corresponding dimensions are listed in Table I. The E-shaped design has been obtained by
removing two rectangular patches of dimensions L1×W1 from one side of the main
rectangular patch of dimensions L×W at W3 distance apart from the two opposite sides. L2
and W2 are the dimensions of the feed of the antenna.
Fig.1. Side view of proposed antenna structure

3. International Journal of Electronics and Communication Engineering & Technology (IJECET),
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Fig.2. E-shaped patch geometry with line feed
TABLE I
DIMENSIONS OF THE PATCH AND FEED
Parameters Dimensions (mm)
L 38
W 37
L1 17.5
W1 15.5
L2 4.8
W2 11
W3 2
III. RESULTS AND DISCUSSION
Fig. 3 shows the return loss plot of the proposed antenna. The antenna is resonating at
5.43 GHz with a return loss of -58.2 dB. The lower -10 dB frequency at 4.96 GHz and upper
-10 dB frequencies at 5.95 GHz have been obtained which covers the entire range of WiMax
and WLAN applications. Fig. 4 presents the E-plane and H-plane radiation patterns which are
almost omnidirectional in shape. The maximum gain of 5.5 dB has been obtained in the E-
plane. The smith chart has been shown in Fig. 5 which presents the impedance characteristics
of the antenna at the entire observing frequency range of 3.5 GHz to 8 GHz. Fig. 6 presents
the 3D polar plot obtained at 5.5 GHz. Fig. 7 shows the variations in the gain with respect to
frequency. Fig. 8 and Fig. 9 are showing the E-field and H-field respectively. It has revealed
that the gain performance of the proposed antenna is satisfactory within the desired frequency
range. The other parameters such as peak directivity, peak gain and radiation efficiency are
shown in Table II.

4. International Journal of Electronics and Communication Engineering & Technology (IJECET),
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Fig.3. Return loss plot
Fig.4. E and H plane radiations patterns
Fig.5. Smith chart

5. International Journal of Electronics and Communication Engineering & Technology (IJECET),
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Fig.6. Polar plot
Fig.7. Gain v/s frequency curve
Fig.8. E-field distribution on the patch

6. International Journal of Electronics and Communication Engineering & Technology (IJECET),
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Fig.9. H-field distribution on the patch
TABLE III
OTHER SIMULATED RESULTS
Parameters Simulated Results
Peak Directivity 3.4859
Peak Gain 3.4399
Radiation Efficiency 0.98682
IV. CONCLUSION AND FUTURE SCOPE
A simple stacked layers E-shaped microstrip patch antenna fed with microstrip line
has been designed for WiMax, WLAN and other high-speed wireless communication systems
operating within 5.15 GHz to 5.85 GHz frequency band. The simulated results have shown
satisfactory radiation performance of the antenna across the entire operating frequency range.
These features are very useful for worldwide portability of wireless communication
equipments. The proposed antenna design will be helpful for antenna design engineers to
design and optimize the antennas for other wireless applications. The future works include
fabrication of the antenna, measurements of antenna performance parameters with the
industry standard equipments and comparison of simulated and measured results.
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