Engineering, Technology & Applied Science Research Vol. 8, No. 4, 2018, 3149-3152 3149  
  

www.etasr.com Nelaturi & Sarma: Compact Wideband Microstrip Patch Antenna based on High Impedance Surface 
 

Compact Wideband Microstrip Patch Antenna based 
on High Impedance Surface 

 

Suman Nelaturi 
Department of Electronics and Communication Engineering 

National Institute of Technology Warangal 
Warangal, India 

nelaturi.suman4@gmail.com 

N. V. S. N. Sarma 
Department of Electronics and Communication Engineering 

National Institute of Technology Warangal 
Warangal, India 

sarma@nitw.ac.in 
 

 

Abstract—A compact single probe feed asymmetrical 
semicircular fractal boundary patch antenna based on HIS (high 
impedance surface) is proposed for wide bandwidth at Wi-Fi 
band. Circular polarization operation can be obtained by 
embedding semi-circle fractal curves along the edges of the 
square patch antenna. The 10-dB return loss bandwidth is 
15.13% (2.32GHz-2.70GHz). The 3-dB axial ratio bandwidth is 
4.11% (2.38GHz-2.48GHz). The close relationship between 
simulation results and measured results establishes the antenna 
usefulness. 

Keywords-high impedance surface; circular polarization; semi 
circular fractal  

I. INTRODUCTION 
A microstrip patch antenna (being compact, low profile, 

easy to manufacture and multifunctioning) is the most coveted 
candidate for modern day wireless communication 
applications. Wideband antennas with circular polarization 
operation are mostly used in handheld device applications. 
Orientation mismatch between receiver and transmitter can be 
avoided by using circularly polarized (CP) antennas. CP 
antennas are widely used in WLAN, Wi-Fi and WiMAX 
applications. Metamaterials are a good choice in designing 
novel antennas like compact wide band antennas because of 
their artificial electromagnetic properties [1-10, 12]. 
Metamaterials are classified into single negative materials 
(SNG) [1, 2, 9, 11], double negative materials (DNG) [5-8], 
electromagnetic band gap materials (EBG) [13, 14] and chiral 
materials. EBGs are divided into mushroom EBG structures 
and VIA less EBG structures. Fractals are the self-repetitive 
curves used to design compact antennas [15]. A compact 
microstrip antenna with dual-band operation having both 
unidirectional linear polarization and omni directional circular 
polarization properties based on epsilon negative materials is 
designed in [11]. Dual band patch antenna with unidirectional 
circular Polarization (CP) and omni directional CP based on 
EBG is designed in [14]. In this paper, a compact microstrip 
patch antenna on HIS with semi-circle fractal curves is 
designed and simulated in single frequency with good 10-dB 
return loss bandwidth and 3-dB axial ratio bandwidth. The 
impedance bandwidth of the proposed antenna is 15.13% 
(2.32GHz-2.70GHz). The 3-dB axial ratio bandwidth is 4.11% 

(2.38GHz-2.48GHz). Ansoft HFSS (high frequency structure 
simulator) software tool was used to simulate the antenna.  

II. ANTENNA GEOMETRY 
The semi-circle fractal boundary patch antenna geometry is 

shown in Figure 1 which is also printed on Rogers RT/Duroid 
with dielectric constant 2.2. The presented antenna has two 
substrates (bottom and top), on the top substrate the 
recommended antenna is designed and on the bottom substrate 
the HIS with a planar array of 3x3 fractal mushroom unit cells 
is printed. The circular polarization (CP) operation can be 
obtained by inserting semi-circle curves with IF's Rx and Ry 
along x and y axes respectively. The 10-dB return loss 
bandwidth and axial ratio bandwidth can be improved by 
optimizing IF along each edge of the antenna. The optimized 
dimensions of the proposed antenna are given in Table I. 

TABLE I.  PARAMETER VALUES 
Parameter Value in mm 

L1 38 
L2 30 
a1 8 
a2 13 
h1 1.6 
h2 1.6 

Rx1=Rx2=Rx 2 
Ry1=Ry2=Ry 5 

III. SEMI-CIRCLE FRACTAL CURVES AND SIMULATION 
RESULTS 

Equal indentation radii (Rx1=Rx2=Ry1=Ry2) along the 
four sides of the square patch antenna result in linear 
polarization. Circular polarization radiation can be obtained by 
loading different indentation radii along each side of the patch 
(Rx1≠Rx2≠Ry1≠Ry2) or (Rx1=Rx2=Rx≠Ry1=Ry2=Ry) or 
(Rx1≠Rx2≠Ry1≠Ry2). High bandwidth can be obtained when 
the indentation radii along the same axis are equal and at the 
same time are not equal along the perpendicular axis 
(Rx1=Rx2=Rx≠Ry1=Ry2=Ry). Operation of the proposed 
antenna can be understood by considering an evolution of patch 
antenna design shown in Figure 2. Square patch Ant1 on single 
substrate is chosen as reference which is resonating at 3.05GHz 



Engineering, Technology & Applied Science Research Vol. 8, No. 4, 2018, 3149-3152 3150  
  

www.etasr.com Nelaturi & Sarma: Compact Wideband Microstrip Patch Antenna based on High Impedance Surface 
 

with linear polarization. The semi-circle fractal curves with 
different indentation radii are inserted into Ant1 to get antennas 
Ant2 to Ant11, which results in single band of operation with 
less 10-dB return loss bandwidth and axial ratio bandwidth. 
The 10-dB return loss characteristics of all simulated antennas 
on single substrate are shown in Figure 3. The impedance 
bandwidth of each antenna is listed in Table II.  

 

L1
L2

patch

mushroom
Co ax feedground

h1
h2

 
(a) 

 
(b) 

Ry2

Ry1

Rx1 Rx2

(x,y)

 
(c) 

Fig. 1.  (a) Geometry of the proposed antenna (b) top view of the HIS (c) 
top view of the patch 

 
Fig. 2.  Evaluation of the proposed antenna on single substrate 

 
Fig. 3.  Simulated return loss characteristics of antennas Ant1 -Ant11 

TABLE II.  IMPEDANCE BANDWITH OF EACH ANTENNA 

Antenna 
IRs (in mm) 

Impedance Bandwidth 
Rx Ry 

Ant1 -- -- (3.13-3.25) 3.76% 
Ant2 1 2 (3.11-3.23) 3.78% 
Ant3 1 3 (3.03-3.27) 7.61% 
Ant4 2 3 (3.05-3.19) 4.56% 
Ant5 1 4 (2.98-3.27) 9.29% 
Ant6 2 4 (3.01-3.19) 5.80% 
Ant7 3 4 (2.94-3.13) 6.27% 
Ant8 1 5 (2.80-2.86) 2.12% 
Ant9 2 5 (2.82-2.88) 2.10% 
Ant10 3 5 (2.92-3.23) 10.26% 
Ant11 4 5 (2.94-3.13) 6.27% 

 

To get widened impedance bandwidth with circular 
polarization at Wi-Fi band the same antenna is implemented on 
HIS (Figure 4). HIS is made of planar array of 3x3 fractal 
mushroom unit cells. Each unit cell has 8x8mm2 square patch 
and 0.5mm radius VIA where all unit cells connected to ground 
through VIAs. The semi-circle fractal curves are inserted into 
each square mushroom unit cell to make required HIS. Finally 
Ant20 is the proposed antenna with good wide bandwidth. The 
10-dB return loss characteristics of all simulated antennas on 
fractal mushroom HIS are shown in Figure 5 and the 
impedance bandwidth of each antenna is listed in Table III. The 
simulated current distribution of the proposed antenna at 
2.4GHz is shown in Figure 6. The simulated radiation 
efficiency of the proposed antenna is shown in Figure 7. The 
efficiency is good at 2.4GHz (98%). 

TABLE III.  IMPEDANCE BANDWITH OF EACH ANTENNA 

Antenna IRs (in mm) Impedance Bandwidth 
Rx Ry

Ant12 -- -- (2.40-2.56) 6.45% 
Ant13 1 2 (2.42-2.56) 5.60% 
Ant14 1 3 (2.40-2.58) 7.22% 
Ant15 2 3 (2.42-2.58) 6.45% 
Ant16 1 4 (2.30-2.58) 11.47% 
Ant17 2 4 (2.34-2.56) 8.90% 
Ant18 3 4 (2.40-2.56) 6.45% 
Ant19 1 5 (2.28-2.70) 16.86% 
Ant20 2 5 (2.32-2.70) 15.13% 
Ant21 3 5 (2.30-2.60) 12.24% 
Ant22 4 5 (2.36-2.54) 7.34% 



Engineering, Technology & Applied Science Research Vol. 8, No. 4, 2018, 3149-3152 3151  
  

www.etasr.com Nelaturi & Sarma: Compact Wideband Microstrip Patch Antenna based on High Impedance Surface 
 

 
Fig. 4.  Evaluation of the proposed antenna on HIS 

 

 
Fig. 5.  Return loss characteristics of HIS antennas 

 

 

 

Fig. 6.  Simulated current distribution of proposed antenna at 2.4GHz 

 
Fig. 7.  Radiation efficiency of the proposed antenna 

IV. MEASURED RESULTS AND DISCUSSION 
The proposed antenna (Ant20) is fabricated on Rogers 

RT/Duroid substrate (Figure 8). Fractal mushroom HIS and 
fractal patch antenna are individually fabricated. HIS is printed 
on bottom substrate and the patch antenna is placed on top 
substrate without ground. The VIAs are fabricated with the 
help of through hole copper plating technique. Both substrates 
are attached with the help of paper tape. The dimensions of 
both substrates are 38x38x1.6mm3. The return loss 
characteristics are measured using Agilent 8719A microwave 
network analyzer. Radiation pattern measurements are taken in 
an anechoic chamber having physical dimensions 
22.5x12.5x11.5m3. The operating frequency range of the 
anechoic chamber is 400MHz to 18GHz. The input power 
given to transmitter is -40dBm. 

 

 
(a) 

 
(b) 

Fig. 8.  Photos of fabricated Ant20: (a) top view (b) bottom view 

The measured return loss characteristics along with 
simulated data are given in Figure 9. Measured results are in 
close agreement with simulated results. The discontinuity at 
patch mode band indicates possibility of circular polarization 
radiation. The axial ratio characteristics are given in Figure 10. 
While the impedance bandwidth is 15.13% (2.32GHz-
2.70GHz), 3-dB axial ratio bandwidth is 4.11% (2.38GHz-
2.48GHz). The minimum axial ratio value of 0.5 dB occurred 
at the center frequency. The radiation patterns of the proposed 
antenna are depicted in Figure 11. The measured and simulated 
gains are given in Figure 12. 

V. CONCLUSION 
A compact single probe feed semi-circle fractal boundary 

microstrip patch antenna based on fractal mushroom HIS is 
proposed and studied experimentally for wide impedance and 
axial ratio bandwidths. The 10-dB return loss bandwidth is 



Engineering, Technology & Applied Science Research Vol. 8, No. 4, 2018, 3149-3152 3152  
  

www.etasr.com Nelaturi & Sarma: Compact Wideband Microstrip Patch Antenna based on High Impedance Surface 
 

15.13%. The 3-dB axial ratio bandwidth is 4.11%. The 
proposed antenna covers WLAN (2.4GHz) band.  

 

Fig. 9.  Simulated and measured return loss characteristics of Ant20 

 

Fig. 10.  Simulated and measured axial ratio characteristics of Ant20 

 
(a) 

 
(b) 

Fig. 11.  Simulated and measured radiation patterns at 2.4 GHz 
(a) E Plane (b) H Plane 

 

Fig. 12.  Simulated and measured gain of the proposed antenna 

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