This full-text paper was peer-reviewed and accepted to be presented at the IEEE ICCSP 2015 conference.
Design of Compact Ultra-Wideband Microstrip Bandstop Filter using Split Ring Resonator S. Ramya and I. Srinivasa Rao
microstrip technology which offers compact realization of Abstract- This article presents the design of microstrip bandstop filter for ultra-wideband applications using split ring resonator. The emerging interest and ease of design for split ring resonator using microstrip transmission line technology has lead to this research. In this paper, a compact bandstop filter is designed with single and double ring split ring resonator and is
filters. The split ring resonator has stopband performance; hence it can be used for designing a good bandstop filter [9]. With the proper design of SRR, Ultra-Wideband (UWB) can be achieved and used in many commercial applications like High speed WAN/LAN, Tags for intelligent transport
simulated using HFSS, the full wave electromagnetic simulator.
systems radar, Radar, Geo-Iocation and Military applications
This structure gives a wide stopband response. The increase in
like Covert communications and Data links etc. Also, UWB
the number of rings in the split ring resonator gives a sharp cut off improving the stopband performance. Simulation results show that for the bandstop filter using double ring split ring resonator, the sharp cut off is increased to -38.5dB compared to the single ring of -34.8dB and to -23dB from -18.5dB. The microstrip bandstop filter designed using single and double ring split ring
fmds
application
in
the
short
range
ultra-high
speed
communication systems and supports bit rate greater than 100 Mbps for wireless personal area communications within a 10m radius. In UWB, the advantages are low power transmission, less multi-path fading and low power dissipation.
resonator with ultra-wideband of 6GHz can be used for short
The UWB transmissions operate in the frequency range 3.1
range ultra-high speed communications in the frequency range of
to 10.6GHz and additionally it occupies a bandwidth of at least
4.3 to lOAGHz. The compact filter size is 6x6mm excluding the feed.
500MHz [10]. In this article, a compact square shaped single and double ring SRR is used in the design of Microstrip
Index Terms- Bandstop filter, Microstrip lines, Split ring resonator and Ultra-Wideband.
Bandstop Filter (BSF) for ultra-wideband applications which can operate in the frequency range of 4.3 to 10.4GHz. The BSF filter is compact with SRR size of 6x6mm.This paper is organized as follows. Section II, describes the schematics of
I. Metamaterial discovered
in
is
INTRODUCTION an
1967
artificially
by
Victor
microstrip BSF using SRR and the equivalent circuit of SRR.
engineered
Veselago,
with
structure unusual
In Section III, full wave simulations and the results are discussed. Finally, a conclusion is drawn in Section IV.
electromagnetic properties and with many advantages had led to many researches [1]. Pendry worked on an array of Split
II.
Ring Resonators (SRR) and demonstrated that these materials can produce negative permeability over some frequency bands
DESIGN SPECIFICATIONS AND SCHEMATICS
The microstrip bandstop filter is designed on FR4 substrate
[2]. Based on Pendry's work, Smith proved the existence of
material with dielectric constant
metamaterial [3]. These SRR with electromagnetic properties
h=0.5mm
not found in nature had become a great interest in the design of
specifications for the single and double ring SRR are listed in
filters, antennas etc. The complementary SRR and SRR were
Table I. Fig. 1 shows the single ring SRR schematic with the
widely used in the design of low pass filter, band pass filter for its good performance compared to conventional filters [4]-[7]. The SRR structure can be of any shapes like circle, square, rectangle, hexagon etc. Earlier SRR designs were realized by waveguide
technology
[8].
Due
to
their
bulk
size
and
manufacturing difficulties, in this paper, SRR is designed by
and
thickness
t
Sf
= 4.4, tano=0.002, height
=0.018mm.
The
design
gap 'g' denoting gap capacitance and the SRR width 'w'. The equivalent circuit for single ring SRR is shown in Fig. 2 where 'L'
the
inductance,
'R'
the
resistance
and
'C' the gap
capacitance. The full schematics of microstrip single ring SRR BSF is shown in Fig. 3. The 50n feed line is used for excitation and optimization of feed length is done with constant feed width for better performance. The Air box acts as a shielding to the filter and prevents radiation. The Fig. 4 shows double ring SRR schematic and the equivalent circuit is
S. Ramya is with School of Electronics Engineering. VIT University. Veilore I.
-
Srinivasa
Rao
University, Vellore
-
is
with
School
of
Electronics
Engineering,
shown in Fig. 5, where Ll, L2 represents outer and inner ring inductance, Rl,R2 are outer and inner ring resistance, Cl,C2
632014, Tamil Nadu, India (e-mail:
[email protected]). VIT
632014, Tamil Nadu, India (e-mail:
[email protected]).
are outer and inner ring gap capacitance, Cm is the coupling capacitance and n is the transformer ratio.
978-1-4799-8081-9/15/$31.00 © 2015 IEEE
0105
This full-text paper was peer-reviewed and accepted to be presented at the IEEE ICCSP 2015 conference.
The double ring SRR will be equal to single ring SRR when the mutual coupling is very weak. The Fig. 6 is the full schematic of microstrip double ring SRR BSF. The required
IU
BSF performance is achieved by proper tuning of the SRR length, width (w) and gap (g). The filter size is kept compact for less space consumption, low cost and easy fabrication.
TABLE 1
FIg. 4. Double nng SRR.
DESIGN SPECIFICATrONS FOR SRR Parameter
Single ring SRR
Double ring SRR
Substrate
14x 14 mm
14x 14 mm
Outer ring
6mm
6mm
Inner ring
2.5 mm
SRR width (w)
Imm
Imm
SRR gap (g)
0.5 mm
0.5 mm
Feed
4Xlmm
4Xlmm
n
.lw T
C1 Fig. 5. Equivalent circuit for double ring SRR.
r-�\4g Fig. 1. Single ring SRR.
R.
Fig. 6. Microstrip double ring SRR BSF.
III.
Fig. 2. Equivalent circuit for single ring SRR.
RESULTS AND DISCUSSION
In this section, simulation results of the designed filter are given and analyzed. Fig. 7 shows the scattering parameters S11 and S22 for the designed microstrip bandstop filter with single ring SRR simulated by HFSS. These two parameters are the
most
important
to
analyze
about
the
reflected
and
transmitted waves in filters (Two port devices). The SII is the reflection coefficient, the amount of waves reflected back and S21 is the transmission coefficient, the amount of waves transmitted from port 1 to port 2. The simulation result shows an ultra-wideband of 6GHz from the frequency range of 4.3 to lO.3GHz. The simulation result of the double ring SRR BSF is shown in Fig. 8 and the bandwidth is 6GHz in the frequency Fig. 3. Microstrip single ring SRR BSF.
range of 4.4 to 10.4GHz. This ultra-wideband can be used in many real time applications. From simulation results, we can conclude that with increase in the number of rings in SRR structure, the stopband performance is enhanced, a sharp cut is achieved. Fig. 9 shows the electric field distribution of microstrip BSF using SRR.
0106
This full-text paper was peer-reviewed and accepted to be presented at the IEEE ICCSP 2015 conference.
0.00
·S.OO
·10.00 Curve Info dB(S(1,1» Setup1 : SWeep dB(S(2,1)) Setup1 : SWeep -
·1S.00
1
-
>:-20.00
-2S.00
-30.00
-3S.00
-40.00
1. 0
3. 0
6.
0
8.
FreqlGHzl
0
11.00
13. 0
1S.00
13. 0
1S.00
Fig. 7. Scattering parameters for microstrip single ring SRR BSF.
0.00
-S.OO -10.00 -1S.00 >:-20.00
-2S.00 -30.00 -3S.00 -40.00
1. 0
3. 0
6.
0
8.
FreqlGHzl
0
11.00
Fig. 8. Scattering parameters for microstrip double ring SRR BSF.
(b) double ring SRR
(a) Single ring SRR Fig. 9. Electric field distribution for microstrip SRR BSF.
0107
This full-text paper was peer-reviewed and accepted to be presented at the IEEE ICCSP 20IS conference.
[3]
IV.
permittivity," Phys Rev Lett 84,pp. 4184-4187,2001.
The compact microstrip bandstop filter is designed with
[4]
investigated.
The
design parameters
are
optimized
Microstrip
to
achieve good electromagnetic properties. The stopband cut off
"Low
Insertion-Loss,
Low-Pass
Filters,"
Sharp-Rejection
iEEE
Microwave
and
Compact
and
Wireless
components letters,vol. 16,no. II,Nov. 2006. [5]
A. Ali and Z. Hu, "Negative permittivity meta-material microstrip binomial low-pass filter with sharper cut-off and reduced size," iET
for the single ring SRR is -34.8dB and -18.SdB and double ring SRR is -38.SdB and -23dB. It clearly shows that by
Mrinal Kanti MandaI, Priyanka Mondal, Subrata Sanyal, and Ajay Chakrabarty,
split ring resonator of size 6x6mm and the filter performance is
D.R. Smith, W.J. Padilla, D.C. Vier, S.c. Nemat-Nasser, and S. Schultz, "Composite media with simultaneously negative permeability and
CONCLUSION
Microw. Antennas Propagation,pp. 15-18,2008. Deepti Gupta, Prasoon Gupta, Pranjal Chitransh and
P.K. Singhal,
increasing the number of rings in SRR structure, stopband
"Design
Filter
performance is improved. The designed compact microstrip
Metamaterial Ground Structure," iEEE international Conference on
BSF using SRR has a wide bandwidth of 6GHz. Hence, the microstrip bandstop filter can be very effective for ultra wideband
high
speed
communication
applications
in
[6]
Low
Pass
Microwave
Using
Kareem Kasim Abdul Raheem,
"Design
of
Metamaterial
Stepped-Impedance Microwave LPFs," iEEE 2014. [8]
Ferran Martin, Francisco Falcone, Jordi Bonache, Ricardo Marques, and Mario Sorolla, "Miniaturized Coplanar Waveguide Stop Band Filters Based on Multiple Tuned Split Ring Resonators," iEEE Microwave and wireless components letters,vol. 13,no. 12,Dec. 2003.
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J.B. Pendry, AJ. Holden, DJ. Ribbins, and WJ. Stewart, "Magnetism from
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