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Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry
Alexandria Engineering Journal (2017) xxx, xxx–xxx
H O S T E D BY
Alexandria University
Alexandria Engineering Journal www.elsevier.com/locate/aej www.sciencedirect.com
ORIGINAL ARTICLE
Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry Deepanshu Kaushal, T. Shanmuganantham * Dept. of Electronics Engg., School of Engg. and Tech., Pondicherry Central University, Pondicherry 605014, India Received 2 May 2017; revised 20 August 2017; accepted 23 August 2017
KEYWORDS Parametric enhancement; Novel fractal; Coaxial fed; Metamaterial [MTM]; Negative permittivity/permeability; Circular SRR
Abstract The improvement in the performance of a novel microstrip patch antenna through added stages of a fractal geometry and a circular split ring resonator for multiband operation is presented. In its first stage, a coaxial-fed novel shaped patch is developed over a 60 mm 60 mm 1.6 mm FR4 epoxy substrate. The modification of the basic patch structure into a fractal geometry results into the addition of bands along with the parametric enhancement of reflection coefficient, gain and bandwidth. A further stamping of Circular Split Ring Resonator on reverse side of the substrate would result in significantly improved performance. The validation of the simulated results has been done and the measured set of data has been plotted against the simulated results graphically. Ó 2017 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction Over the years, microstrip patch antennas have been fascinatingthe researchers with their inherent characteristics of small size, light weight, low profile, conformability, portability, easy designing, fabrication and integration [1]. All the aforementioned traits supplement the use of these microstrip patch antennas for different applications including the space, military and medical operations. The work on the design of micro-
* Corresponding author. E-mail addresses: [email protected] (D. Kaushal), [email protected] (T. Shanmuganantham). Peer review under responsibility of Faculty of Engineering, Alexandria University.
strip patch antennas for different applications started with the conventionally used rectangular shaped patches [2]. Jaget et al. initially designed a rectangular microstrip patch antenna that offered a single band peak gain of 7.5 dB [2]. Tahsin et al. designed a rectangular microstrip antenna for X band operation that achieved a peak gain of 7.7 dB. The conventional patch structures, however, are limited to single band of operation and have low gain and bandwidth. The use of novel geometries provide for better characteristics [3]. Shanmuganantham et al. proposed a danger shaped microstrip patch antenna for fixed satellite applications that produced dual band peak gains of 1.6 dBi and 4.9 dBi respectively [4]. Deepanshu et al. proposed a novel geometry with an apple shaped patch that produced a peak gain of 4.28 dBi at 4.88 GHz and that of 10.1 dBi at 5.3 GHz. The limitations of low gain and narrow bandwidth can be overcome by the implementa-
http://dx.doi.org/10.1016/j.aej.2017.08.021 1110-0168 Ó 2017 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
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D. Kaushal, T. Shanmuganantham
tion of any or combination of various techniques which include the use of substrate with small dielectric constant, increasing the height of the substrate, use of parasitic elements, stacking, meta-material structures and array of antennas. In a wide range, multiple band resonating modes can be attained by an alteration of the radiating strip/ground flat and by utilization of dissimilar shapes [5]. Syeda et al. designed a novel star shaped fractal design of rectangular patch antenna that produced a single band peak gain of 11.35 dB for the simulated fractal geometry as compared to the simple rectangular patch design that produced a peak gain of 5.47 dB [6,7]. Shanmuganantham et al. designed SRR loaded Periwinkle flower shaped fractal antenna and rose flower shaped antennas respectively for multiband operation [8]. Abha et al. proposed a miniaturized rectangular microstrip patch antenna that produced a peak gain of 1.52 dB on the use of SSRR against the 1.42 dB peak gain that is produced without the use of SSRR [9]. Shanmuganantham et al. designed a SRR loaded Koch star fractal antenna that resonated at five different frequencies and can be utilized for different wireless applications. The use of fractal conception together with an exploitation of metamaterial structures usually restricts the antenna applications owing to decreased complexity and miniaturized antenna dimensions. The design of a Circular SRR loaded novel fractal antenna that offers an improved performance over the initial design stages of a novel microstrip patch antenna structure and the subsequently proposed fractal stage is presented. While the transition from the first stage to the second one offers the multiband feature together with better characteristics of reflection coefficient, gain and bandwidth; an improvement in these characteristics is recorded in the third stage.
Fig. 1
2. Design model This section discusses the three stage design of a Circular SRR loaded novel fractal antenna. The simulation software used is HFSS v-15 [10]. All the stages utilize a 60 mm 60 mm 1.6 mm Flame Retardant-4 substrate with dielectric constant er = 4.4 and dielectric loss tangent of 0.02. The first stage builds up a novel microstrip patch antenna design. The second stage modifies the stage one patch design into a basic fractal geometry by repetitive iteration of a definite pattern of slots. A metamaterial structure that has a circular split ring resonator as the central edifice is stamped on the reverse side of the substrate. 2.1. Stage 1: novel microstrip patch antenna design Fig. 1 shows the configuration of the initially designed coaxial fed novel microstrip patch antenna. The structure of the patch has been formed by the unification of four circular elements of identical radius. The planned proportions of the stage 1 structure are shown in Table 1.
Table 1 Fig. 1.
Dimensions of initial stage design in
Parameters
Value [mm]
W/L/R
60/60/15
Stage 1 of coaxial fed novel microstrip patch antenna [Top] and ground [Bottom].
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
Parametric enhancement of a novel microstrip patch antenna 2.2. Stage 2: modification of stage 1 design into fractal geometry Fig. 2 shows the fractal geometry formed out of the stage 1 design by introducing repetitive iteration of a definite pattern of circular and triangular slots. The planned proportions of the stage 2 structure are shown in Table 2 and the fabricated prototype is shown in Fig. 3.
Fig. 2
Fig. 3
3 Table 2 Dimensions of second stage fractal design in Fig. 2. Parameters
Value [mm]
W/L W0 /L0 /W00 /L00 r0 /r00
60/60/15 6/6/4/4 3.16/2
Novel fractal antenna top and flipside view.
Snap of the fabricated novel fractal antenna top and flipside view.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
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D. Kaushal, T. Shanmuganantham
2.3. Stage 3: loading of Circular SRR into reverse side of the fractal geometry on substrate Fig. 4 shows the patch represented by the fractal geometry and a Circular SRR loaded into the substrate at its reverse side (fabricated structure in Fig. 5). The corresponding dimensions have been listed in Table 3.
Fig. 4
Fig. 5
Table 3 Dimensions of third stage Circular SRR Loaded Fractal Design in Fig. 4. Parameters
Value [mm]
R1/R2/R3/R4 d1/d2
20.6/17/14/10 3/3
Circular SRR Loaded Novel Fractal antenna top and flipside view.
Snap of Fabricated Circular SRR Loaded Novel Fractal antenna top and flipside view.
3. Results and discussion The parametric results of the stages of a Circular SRR loaded novel fractal antenna design are discussed. These parametric results include the reflection coefficient, bandwidth, radiation pattern, gain and VSWR. The reflection coefficient and VSWR parameters have been tested on Rhode & Schwarz ZVA 40 Vector Network Analyser [11] operating in a frequency range
of 10 MHz to 40 GHz. Using the received set of data values, the measured data has been plotted against the simulated data for each case. Fig. 6 shows the comparative plot of reflection coefficient of the three stages. The stage 1 simulated design of a novel microstrip patch antenna resonates at the two frequencies of 2 GHz and 3.1 GHz with the respective reflection coefficients and bandwidths of 11.28 dB and 10 MHz; 11.2 dB and
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
Parametric enhancement of a novel microstrip patch antenna
Fig. 6
5
Comparative plot of reflection coefficient for the three stage design.
Fig. 7 Radiation pattern plot for (a) simulated stage 1 design (b) simulated stage 2 design (c) fabricated stage 2 design (d) simulated final stage design and (e) fabricated final stage design.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
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D. Kaushal, T. Shanmuganantham
30 MHz. The introduction of slots as a part of fractal based geometry in the stage 2 design introduces additional bands with an improved parametric performance. The stage 2 design resonates at 3.18 GHz with reflection coefficient and bandwidth pairs of (11.6 dB, 110 MHz), at 4.28 GHz with a pair of (13.3 dB, 140 MHz), at 6.96 GHz with a pair of (16.09 dB, 118 MHz), at 7.49 GHz with a pair of (13.93 dB, 113 MHz) and at 10.08 GHz with a pair of (20.98 dB, 118 MHz). The stage 2 fabricated prototype shows close agreement of results and resonates at 3.18 GHz with a pair of (13.25 dB, 140 MHz), at 4.34 GHz with a pair of (23.11 dB, 142 MHz), at 5.1 GHz with a pair of (10.71 dB, 25 MHz), at 7.04 GHz with a pair of (24.13 dB, 120 MHz), at 7.71 GHz with a pair of (23.51 dB, 120 MHz), at 9.3 GHz with a pair of (15.26 dB, 135 MHz) and at 10.12 GHz with that of (20.99 dB, 121 MHz). An improvement in the parametric performance in the terms of reflection coefficient and bandwidth is observed in the case of stage 2 fabricated prototype. Also, the fabricated structure is yielding two extra band of frequencies that remain unaccounted. The reflection coefficient and the bandwidth pairs for the simulated design in the third stage include (15.26 dB, 111 MHz) at 3.14 GHz, (13.5 dB, 145 MHz) at 4.28 GHz, (12.2 dB, 30 MHz) at 5.1 GHz, (38.13 dB, 121 MHz) at 6.91 GHz and (34.55 dB, 138 MHz) at 9.66 GHz. The fabricated prototype upon testing yields reflection coefficient and bandwidth pairs of (14.21 dB, 108 MHz) at 3.18 GHz, (13.6 dB, 142 MHz) at 4.31 GHz, (26.51 dB, 112 MHz) at 6.42 GHz, (19.96 dB, 108 MHz) at 7.58 GHz, (12.91 dB, 8 MHz) at 11.28 GHz and (22.64 dB, 36 MHz) at 12.64 GHz. The fabricated design in the final stage yields the respective reflection coefficient and bandwidth pairs of degraded value than the simulated case. Apart from the appearance of two extra bands, the fabricated structure also has cases of resonant frequencies different from the simulated structure. It may also be noted that the final fabricated structure exhibits a positive peak at around 9.5 GHz. The reason for such a unusual behaviour in case of fabricated prototype remains unaccounted. While the stage 1 was only simulated, the stages 2 and 3 were fabricated and tested over the anechoic chamber [12] for the gain values. The gains achieved at different stages of the design are shown in Fig. 7. The simulated design of the
Fig. 8
stage 1 achieves a peak gain of 2.02 dBi at 2 GHz and 4.47 dBi at 3.1 GHz respectively. The simulated design in stage 2 achieves a peak gain of 5.17dBi at 3.15 GHz, 11.01 dBi at 4.28 GHz, 3.33 dBi at 6.96 GHz, 6.28 dBi at 7.49 GHz and 10.88 dBi at 10.01 GHz. The fabricated design on the other hand achieves a peak gain of 1.9 dBi at 3.18 GHz, 10.9 dBi at 4.34 GHz, 1.89 dBi at 5.1 GHz, 6.28 dBi at 7.01 GHz, again 5.79 dBi at 7.71 GHz, 9.88 dBi at 9.3 GHz and 4.16 dBi at 10.12 GHz. The stage 3 simulated design yields a peak gain of 4.91 dB at 3.14 GHz, 2.08 dBi at 4.28 GHz, 5.33 dBi at 5.1 GHz, 15.45 dBi at 6.91 GHz and 8.33 dBi at 9.66 GHz. The fabricated prototype of the third stage, on the other hand, yields a peak gain of 2.32 dBi at 3.18 GHz, 1.25 dBi at 4.39 GHz, 3.89 dBi at 6.42 GHz, 4.1 dBi at 7.58 GHz, 11.54 dBi at 11.28 GHz and 19.31 dBi at 12.64 GHz. The fabricated designs of the two stages have been tested over VNA. Fig. 8 shows the comparative VSWR plot of the three design stages. The VSWR values corresponding to the stage 1 resonant frequencies of 2 GHz and 3.1 GHz include 1.88 and 1.97, the stage 2 simulated design yields that of 1.81 at 3.15 GHz, 1.53 at 4.28 GHz, 1.34 at 6.96 GHz, 1.21 at 7.49 GHz and 1.03 at 10.08 GHz. The fabricated prototype yielded VSWR values of 1.77, 1.48, 1.35, 1.24, 1.09, 1.44 and 1.32 at 3.18 GHz, 4.34 GHz, 5.1 GHz, 7.04 GHz, 7.71 GHz, 9.3 GHz and 10.12 GHz respectively. The VSWR values of 1.68, 1.71, 1.29, 1.28 and 1.41 are achieved at 3.14 GHz, 4.28 GHz, 5.1 GHz, 6.91 GHz and 9.66 GHz respectively in case of the simulated design of the stage 3. The fabricated design of the stage 3, on the other hand, yields VSWR values of 1.51, 1.66, 1.27, 1.18, 1.35 and 1.28 at 3.18 GHz, 4.31 GHz, 6.42 GHz, 7.58 GHz, 11.28 GHz and 12.64 GHz respectively. Table 4 below summarizes the parametric results of each design stage. The simulated results of stage 2 design clearly exhibit an improved performance over stage 1 simulated results. The fabricated structure yields additional bands in comparison to its simulated counterpart. The improved performance of stage 2 fabricated structure over the simulated counterpart is unaccounted. Both the structures however offer the much needed better parametric performance over the initial stage design. The insertion of Circular SRR at the bottom of the fractal geometry results into improved reflection coefficient, gain
Comparative VSWR plot of the three design stages.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
Parametric enhancement of a novel microstrip patch antenna Table 4
7
Parametric results for different design stages.
Design stage
Number of bands
Resonant frequencies (GHz)
Reflection coefficient (dB), Bandwidth (MHz)
Gain (dBi)
VSWR
1 2
2 5
Fabricated
7
(11.28, 10)/(11.2, 30) (11.6, 110)/(13.3, 140)/(16.09, 118) (13.93, 113)/ (20.98,118) (10.71, 25)/(13.25,140)/(23.11, 142)/(24.13,120)/ (23.5120)/(15.26, 135)/(20.99, 121)
3
5
Fabricated
6
2/3.1 3.15/4.28/6.96/ 7.49/10.08 3.18/4.34/5.1/ 7.04/7.71/9.3/ 10.12 3.14/4.28/5.1/ 6.91/9.66 3.18/4.31/6.42/ 7.58/11.28/12.64
2.02/4.47 5.17/11.01/3.33/ 6.28/10.88 1.9/10.9/1.89/ 6.28/5.79/9.88/ 4.16 4.91/2.08/5.33/ 15.45/8.33 2.32/1.25/3.89/ 4.1/11.54/19.31
1.88/1.97 1. 81/1.53/1.34/ 1.21/1.03 1.77/1.48/1.35/ 1.24/1.09/1.44/ 1.32 1.68/1.71/1.29/ 1.28/1.41 1.51/1.66/1.27/ 1.18/1.35/1.28
Table 5
(15.26, 111)/(13.5, 145) (12.2, 30)/(14.21, 108)/(13.6, 142)/(26.5, 112)/(19.96, 108)/(12.91, 8)/(22.64, 36) (14.21, 108)/(19.96, 108)/(13.6, 142)/(26.51, 112)/ (12.91, 8)/(22.64, 36)
Comparison of Different Existing Fractal MM antenna’s.
S. No
References
Antenna size [mm2]
Frequency [GHz] enclosed by antenna
Antenna nature
1 2 3 4 5
[7] [8] [9] [10] Proposed
12 14 28 26 40 40 25.5 25.5 60 60
1.88/6.54/7.88/12.2/15.08 2.6/4.8 2.5/5.5 2.45/5.50 3.14/4.28/5.1/6.91/9.66
Multi-band Dual-band Dual-band Dual-Band Multiband
and bandwidth parameters for most resonant frequencies and the prototype thus offers an improved performance when compared to structures in the reviewed literatures(see Table 5). 4. Conclusion In this article, the improvement in the performance of a novel microstrip patch antenna through added stages of a fractal geometry and a circular split ring resonator for multiband operation is presented. The validation of the simulated results has been done and the measured set of data has been plotted against the simulated results graphically. While the simulated transition from the basic novel patch geometry to the fractal geometry indicates improved parametric performance together with the addition of bands, the measured results lie in close agreement. The introduction of Circular SRR at the rear side of the substrate over the software shows further improvement in the parametric performance. The measured results, however, show degraded performance for the fabricated prototype of the final stage. This is mainly accounted to the faults in fabrication. References [1] Deepanshu Kaushal, T. Shanmuganantham, A vinayak slotted rectangular microstrip patch antenna design for C-band applications, John Wiley-Microwave Opt. Technol. Lett. 59 (8) (2017) 1833–1837. [2] Jaget Singh, Tejwinder Singh, B.S. Sohi, Design of Slit Loaded Rectangular Microstrip Patch Antenna, RAECS UIET, Punjab University, Chandigarh, 2015.
[3] Deepanshu Kaushal, T. Shanmuganantham, Danger microstrip patch antenna for fixed satellite applications, in: IEEE International Conference on Emerging Trends in Technology (ICETT), Kollam, India, 2016. [4] Deepanshu Kaushal, T. Shanmuganantham, Design of compact microstrip apple patch antenna for space applications, in: IEEE Antennas and Propagation Symposium (APSYM), Cochin University of Science and Technology (CUSAT), Cochin, India, 2016. [5] Syeda Fizzah Jilani, Hamood-Ur-Rahman, Muhammad Naeem Iqbal, Novel Star-shaped Fractal Design of Rectangular Patch Antenna for Improved Gain and Bandwidth, IEEE, 2013. [6] Abha R. Karade, P.L. Zade, A miniaturized rectangular microstrip patch antenna using SSRR for WLAN applications, in: IEEE ICCSP Conference, 2015. [7] C. Elavarasi, T. Shanmuganantham, SRR loaded periwinkle flower shaped fractal antenna for multiband applications, Microwave Opt. Technol. Lett. 59 (10) (2017) 2518–2525. [8] C. Elavarasi, T. Shanmuganantham, SRR loaded CPW–fed multiple band rose flower-shaped fractal antenna, Microwave Opt. Technol. Lett. 59 (7) (2017) 1720–1724. [9] C. Elavarasi, T. Shanmuganantham, Multiband SRR loaded koch star fractal antenna, Alexandria Eng. J. (2017) (in press). [10] Deepanshu Kaushal, T. Shanmuganantham, Microstrip slotted caterpillar patch antenna for S, Ku and K-band applications, J. Mater. Today, in press. [11] Deepanshu Kaushal, T. Shanmuganantham, A novel microstrip flower patch antenna design for multiband operation, J. Mater. Today, in press. [12] Deepanshu Kaushal, T. Shanmuganantham, Design of a compact and novel microstrip patch antenna for multiband satellite applications, J. Mater. Today, in press.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
H O S T E D BY
Alexandria University
Alexandria Engineering Journal www.elsevier.com/locate/aej www.sciencedirect.com
ORIGINAL ARTICLE
Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry Deepanshu Kaushal, T. Shanmuganantham * Dept. of Electronics Engg., School of Engg. and Tech., Pondicherry Central University, Pondicherry 605014, India Received 2 May 2017; revised 20 August 2017; accepted 23 August 2017
KEYWORDS Parametric enhancement; Novel fractal; Coaxial fed; Metamaterial [MTM]; Negative permittivity/permeability; Circular SRR
Abstract The improvement in the performance of a novel microstrip patch antenna through added stages of a fractal geometry and a circular split ring resonator for multiband operation is presented. In its first stage, a coaxial-fed novel shaped patch is developed over a 60 mm 60 mm 1.6 mm FR4 epoxy substrate. The modification of the basic patch structure into a fractal geometry results into the addition of bands along with the parametric enhancement of reflection coefficient, gain and bandwidth. A further stamping of Circular Split Ring Resonator on reverse side of the substrate would result in significantly improved performance. The validation of the simulated results has been done and the measured set of data has been plotted against the simulated results graphically. Ó 2017 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction Over the years, microstrip patch antennas have been fascinatingthe researchers with their inherent characteristics of small size, light weight, low profile, conformability, portability, easy designing, fabrication and integration [1]. All the aforementioned traits supplement the use of these microstrip patch antennas for different applications including the space, military and medical operations. The work on the design of micro-
* Corresponding author. E-mail addresses: [email protected] (D. Kaushal), [email protected] (T. Shanmuganantham). Peer review under responsibility of Faculty of Engineering, Alexandria University.
strip patch antennas for different applications started with the conventionally used rectangular shaped patches [2]. Jaget et al. initially designed a rectangular microstrip patch antenna that offered a single band peak gain of 7.5 dB [2]. Tahsin et al. designed a rectangular microstrip antenna for X band operation that achieved a peak gain of 7.7 dB. The conventional patch structures, however, are limited to single band of operation and have low gain and bandwidth. The use of novel geometries provide for better characteristics [3]. Shanmuganantham et al. proposed a danger shaped microstrip patch antenna for fixed satellite applications that produced dual band peak gains of 1.6 dBi and 4.9 dBi respectively [4]. Deepanshu et al. proposed a novel geometry with an apple shaped patch that produced a peak gain of 4.28 dBi at 4.88 GHz and that of 10.1 dBi at 5.3 GHz. The limitations of low gain and narrow bandwidth can be overcome by the implementa-
http://dx.doi.org/10.1016/j.aej.2017.08.021 1110-0168 Ó 2017 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
2
D. Kaushal, T. Shanmuganantham
tion of any or combination of various techniques which include the use of substrate with small dielectric constant, increasing the height of the substrate, use of parasitic elements, stacking, meta-material structures and array of antennas. In a wide range, multiple band resonating modes can be attained by an alteration of the radiating strip/ground flat and by utilization of dissimilar shapes [5]. Syeda et al. designed a novel star shaped fractal design of rectangular patch antenna that produced a single band peak gain of 11.35 dB for the simulated fractal geometry as compared to the simple rectangular patch design that produced a peak gain of 5.47 dB [6,7]. Shanmuganantham et al. designed SRR loaded Periwinkle flower shaped fractal antenna and rose flower shaped antennas respectively for multiband operation [8]. Abha et al. proposed a miniaturized rectangular microstrip patch antenna that produced a peak gain of 1.52 dB on the use of SSRR against the 1.42 dB peak gain that is produced without the use of SSRR [9]. Shanmuganantham et al. designed a SRR loaded Koch star fractal antenna that resonated at five different frequencies and can be utilized for different wireless applications. The use of fractal conception together with an exploitation of metamaterial structures usually restricts the antenna applications owing to decreased complexity and miniaturized antenna dimensions. The design of a Circular SRR loaded novel fractal antenna that offers an improved performance over the initial design stages of a novel microstrip patch antenna structure and the subsequently proposed fractal stage is presented. While the transition from the first stage to the second one offers the multiband feature together with better characteristics of reflection coefficient, gain and bandwidth; an improvement in these characteristics is recorded in the third stage.
Fig. 1
2. Design model This section discusses the three stage design of a Circular SRR loaded novel fractal antenna. The simulation software used is HFSS v-15 [10]. All the stages utilize a 60 mm 60 mm 1.6 mm Flame Retardant-4 substrate with dielectric constant er = 4.4 and dielectric loss tangent of 0.02. The first stage builds up a novel microstrip patch antenna design. The second stage modifies the stage one patch design into a basic fractal geometry by repetitive iteration of a definite pattern of slots. A metamaterial structure that has a circular split ring resonator as the central edifice is stamped on the reverse side of the substrate. 2.1. Stage 1: novel microstrip patch antenna design Fig. 1 shows the configuration of the initially designed coaxial fed novel microstrip patch antenna. The structure of the patch has been formed by the unification of four circular elements of identical radius. The planned proportions of the stage 1 structure are shown in Table 1.
Table 1 Fig. 1.
Dimensions of initial stage design in
Parameters
Value [mm]
W/L/R
60/60/15
Stage 1 of coaxial fed novel microstrip patch antenna [Top] and ground [Bottom].
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
Parametric enhancement of a novel microstrip patch antenna 2.2. Stage 2: modification of stage 1 design into fractal geometry Fig. 2 shows the fractal geometry formed out of the stage 1 design by introducing repetitive iteration of a definite pattern of circular and triangular slots. The planned proportions of the stage 2 structure are shown in Table 2 and the fabricated prototype is shown in Fig. 3.
Fig. 2
Fig. 3
3 Table 2 Dimensions of second stage fractal design in Fig. 2. Parameters
Value [mm]
W/L W0 /L0 /W00 /L00 r0 /r00
60/60/15 6/6/4/4 3.16/2
Novel fractal antenna top and flipside view.
Snap of the fabricated novel fractal antenna top and flipside view.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
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D. Kaushal, T. Shanmuganantham
2.3. Stage 3: loading of Circular SRR into reverse side of the fractal geometry on substrate Fig. 4 shows the patch represented by the fractal geometry and a Circular SRR loaded into the substrate at its reverse side (fabricated structure in Fig. 5). The corresponding dimensions have been listed in Table 3.
Fig. 4
Fig. 5
Table 3 Dimensions of third stage Circular SRR Loaded Fractal Design in Fig. 4. Parameters
Value [mm]
R1/R2/R3/R4 d1/d2
20.6/17/14/10 3/3
Circular SRR Loaded Novel Fractal antenna top and flipside view.
Snap of Fabricated Circular SRR Loaded Novel Fractal antenna top and flipside view.
3. Results and discussion The parametric results of the stages of a Circular SRR loaded novel fractal antenna design are discussed. These parametric results include the reflection coefficient, bandwidth, radiation pattern, gain and VSWR. The reflection coefficient and VSWR parameters have been tested on Rhode & Schwarz ZVA 40 Vector Network Analyser [11] operating in a frequency range
of 10 MHz to 40 GHz. Using the received set of data values, the measured data has been plotted against the simulated data for each case. Fig. 6 shows the comparative plot of reflection coefficient of the three stages. The stage 1 simulated design of a novel microstrip patch antenna resonates at the two frequencies of 2 GHz and 3.1 GHz with the respective reflection coefficients and bandwidths of 11.28 dB and 10 MHz; 11.2 dB and
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
Parametric enhancement of a novel microstrip patch antenna
Fig. 6
5
Comparative plot of reflection coefficient for the three stage design.
Fig. 7 Radiation pattern plot for (a) simulated stage 1 design (b) simulated stage 2 design (c) fabricated stage 2 design (d) simulated final stage design and (e) fabricated final stage design.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
6
D. Kaushal, T. Shanmuganantham
30 MHz. The introduction of slots as a part of fractal based geometry in the stage 2 design introduces additional bands with an improved parametric performance. The stage 2 design resonates at 3.18 GHz with reflection coefficient and bandwidth pairs of (11.6 dB, 110 MHz), at 4.28 GHz with a pair of (13.3 dB, 140 MHz), at 6.96 GHz with a pair of (16.09 dB, 118 MHz), at 7.49 GHz with a pair of (13.93 dB, 113 MHz) and at 10.08 GHz with a pair of (20.98 dB, 118 MHz). The stage 2 fabricated prototype shows close agreement of results and resonates at 3.18 GHz with a pair of (13.25 dB, 140 MHz), at 4.34 GHz with a pair of (23.11 dB, 142 MHz), at 5.1 GHz with a pair of (10.71 dB, 25 MHz), at 7.04 GHz with a pair of (24.13 dB, 120 MHz), at 7.71 GHz with a pair of (23.51 dB, 120 MHz), at 9.3 GHz with a pair of (15.26 dB, 135 MHz) and at 10.12 GHz with that of (20.99 dB, 121 MHz). An improvement in the parametric performance in the terms of reflection coefficient and bandwidth is observed in the case of stage 2 fabricated prototype. Also, the fabricated structure is yielding two extra band of frequencies that remain unaccounted. The reflection coefficient and the bandwidth pairs for the simulated design in the third stage include (15.26 dB, 111 MHz) at 3.14 GHz, (13.5 dB, 145 MHz) at 4.28 GHz, (12.2 dB, 30 MHz) at 5.1 GHz, (38.13 dB, 121 MHz) at 6.91 GHz and (34.55 dB, 138 MHz) at 9.66 GHz. The fabricated prototype upon testing yields reflection coefficient and bandwidth pairs of (14.21 dB, 108 MHz) at 3.18 GHz, (13.6 dB, 142 MHz) at 4.31 GHz, (26.51 dB, 112 MHz) at 6.42 GHz, (19.96 dB, 108 MHz) at 7.58 GHz, (12.91 dB, 8 MHz) at 11.28 GHz and (22.64 dB, 36 MHz) at 12.64 GHz. The fabricated design in the final stage yields the respective reflection coefficient and bandwidth pairs of degraded value than the simulated case. Apart from the appearance of two extra bands, the fabricated structure also has cases of resonant frequencies different from the simulated structure. It may also be noted that the final fabricated structure exhibits a positive peak at around 9.5 GHz. The reason for such a unusual behaviour in case of fabricated prototype remains unaccounted. While the stage 1 was only simulated, the stages 2 and 3 were fabricated and tested over the anechoic chamber [12] for the gain values. The gains achieved at different stages of the design are shown in Fig. 7. The simulated design of the
Fig. 8
stage 1 achieves a peak gain of 2.02 dBi at 2 GHz and 4.47 dBi at 3.1 GHz respectively. The simulated design in stage 2 achieves a peak gain of 5.17dBi at 3.15 GHz, 11.01 dBi at 4.28 GHz, 3.33 dBi at 6.96 GHz, 6.28 dBi at 7.49 GHz and 10.88 dBi at 10.01 GHz. The fabricated design on the other hand achieves a peak gain of 1.9 dBi at 3.18 GHz, 10.9 dBi at 4.34 GHz, 1.89 dBi at 5.1 GHz, 6.28 dBi at 7.01 GHz, again 5.79 dBi at 7.71 GHz, 9.88 dBi at 9.3 GHz and 4.16 dBi at 10.12 GHz. The stage 3 simulated design yields a peak gain of 4.91 dB at 3.14 GHz, 2.08 dBi at 4.28 GHz, 5.33 dBi at 5.1 GHz, 15.45 dBi at 6.91 GHz and 8.33 dBi at 9.66 GHz. The fabricated prototype of the third stage, on the other hand, yields a peak gain of 2.32 dBi at 3.18 GHz, 1.25 dBi at 4.39 GHz, 3.89 dBi at 6.42 GHz, 4.1 dBi at 7.58 GHz, 11.54 dBi at 11.28 GHz and 19.31 dBi at 12.64 GHz. The fabricated designs of the two stages have been tested over VNA. Fig. 8 shows the comparative VSWR plot of the three design stages. The VSWR values corresponding to the stage 1 resonant frequencies of 2 GHz and 3.1 GHz include 1.88 and 1.97, the stage 2 simulated design yields that of 1.81 at 3.15 GHz, 1.53 at 4.28 GHz, 1.34 at 6.96 GHz, 1.21 at 7.49 GHz and 1.03 at 10.08 GHz. The fabricated prototype yielded VSWR values of 1.77, 1.48, 1.35, 1.24, 1.09, 1.44 and 1.32 at 3.18 GHz, 4.34 GHz, 5.1 GHz, 7.04 GHz, 7.71 GHz, 9.3 GHz and 10.12 GHz respectively. The VSWR values of 1.68, 1.71, 1.29, 1.28 and 1.41 are achieved at 3.14 GHz, 4.28 GHz, 5.1 GHz, 6.91 GHz and 9.66 GHz respectively in case of the simulated design of the stage 3. The fabricated design of the stage 3, on the other hand, yields VSWR values of 1.51, 1.66, 1.27, 1.18, 1.35 and 1.28 at 3.18 GHz, 4.31 GHz, 6.42 GHz, 7.58 GHz, 11.28 GHz and 12.64 GHz respectively. Table 4 below summarizes the parametric results of each design stage. The simulated results of stage 2 design clearly exhibit an improved performance over stage 1 simulated results. The fabricated structure yields additional bands in comparison to its simulated counterpart. The improved performance of stage 2 fabricated structure over the simulated counterpart is unaccounted. Both the structures however offer the much needed better parametric performance over the initial stage design. The insertion of Circular SRR at the bottom of the fractal geometry results into improved reflection coefficient, gain
Comparative VSWR plot of the three design stages.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021
Parametric enhancement of a novel microstrip patch antenna Table 4
7
Parametric results for different design stages.
Design stage
Number of bands
Resonant frequencies (GHz)
Reflection coefficient (dB), Bandwidth (MHz)
Gain (dBi)
VSWR
1 2
2 5
Fabricated
7
(11.28, 10)/(11.2, 30) (11.6, 110)/(13.3, 140)/(16.09, 118) (13.93, 113)/ (20.98,118) (10.71, 25)/(13.25,140)/(23.11, 142)/(24.13,120)/ (23.5120)/(15.26, 135)/(20.99, 121)
3
5
Fabricated
6
2/3.1 3.15/4.28/6.96/ 7.49/10.08 3.18/4.34/5.1/ 7.04/7.71/9.3/ 10.12 3.14/4.28/5.1/ 6.91/9.66 3.18/4.31/6.42/ 7.58/11.28/12.64
2.02/4.47 5.17/11.01/3.33/ 6.28/10.88 1.9/10.9/1.89/ 6.28/5.79/9.88/ 4.16 4.91/2.08/5.33/ 15.45/8.33 2.32/1.25/3.89/ 4.1/11.54/19.31
1.88/1.97 1. 81/1.53/1.34/ 1.21/1.03 1.77/1.48/1.35/ 1.24/1.09/1.44/ 1.32 1.68/1.71/1.29/ 1.28/1.41 1.51/1.66/1.27/ 1.18/1.35/1.28
Table 5
(15.26, 111)/(13.5, 145) (12.2, 30)/(14.21, 108)/(13.6, 142)/(26.5, 112)/(19.96, 108)/(12.91, 8)/(22.64, 36) (14.21, 108)/(19.96, 108)/(13.6, 142)/(26.51, 112)/ (12.91, 8)/(22.64, 36)
Comparison of Different Existing Fractal MM antenna’s.
S. No
References
Antenna size [mm2]
Frequency [GHz] enclosed by antenna
Antenna nature
1 2 3 4 5
[7] [8] [9] [10] Proposed
12 14 28 26 40 40 25.5 25.5 60 60
1.88/6.54/7.88/12.2/15.08 2.6/4.8 2.5/5.5 2.45/5.50 3.14/4.28/5.1/6.91/9.66
Multi-band Dual-band Dual-band Dual-Band Multiband
and bandwidth parameters for most resonant frequencies and the prototype thus offers an improved performance when compared to structures in the reviewed literatures(see Table 5). 4. Conclusion In this article, the improvement in the performance of a novel microstrip patch antenna through added stages of a fractal geometry and a circular split ring resonator for multiband operation is presented. The validation of the simulated results has been done and the measured set of data has been plotted against the simulated results graphically. While the simulated transition from the basic novel patch geometry to the fractal geometry indicates improved parametric performance together with the addition of bands, the measured results lie in close agreement. The introduction of Circular SRR at the rear side of the substrate over the software shows further improvement in the parametric performance. The measured results, however, show degraded performance for the fabricated prototype of the final stage. This is mainly accounted to the faults in fabrication. References [1] Deepanshu Kaushal, T. Shanmuganantham, A vinayak slotted rectangular microstrip patch antenna design for C-band applications, John Wiley-Microwave Opt. Technol. Lett. 59 (8) (2017) 1833–1837. [2] Jaget Singh, Tejwinder Singh, B.S. Sohi, Design of Slit Loaded Rectangular Microstrip Patch Antenna, RAECS UIET, Punjab University, Chandigarh, 2015.
[3] Deepanshu Kaushal, T. Shanmuganantham, Danger microstrip patch antenna for fixed satellite applications, in: IEEE International Conference on Emerging Trends in Technology (ICETT), Kollam, India, 2016. [4] Deepanshu Kaushal, T. Shanmuganantham, Design of compact microstrip apple patch antenna for space applications, in: IEEE Antennas and Propagation Symposium (APSYM), Cochin University of Science and Technology (CUSAT), Cochin, India, 2016. [5] Syeda Fizzah Jilani, Hamood-Ur-Rahman, Muhammad Naeem Iqbal, Novel Star-shaped Fractal Design of Rectangular Patch Antenna for Improved Gain and Bandwidth, IEEE, 2013. [6] Abha R. Karade, P.L. Zade, A miniaturized rectangular microstrip patch antenna using SSRR for WLAN applications, in: IEEE ICCSP Conference, 2015. [7] C. Elavarasi, T. Shanmuganantham, SRR loaded periwinkle flower shaped fractal antenna for multiband applications, Microwave Opt. Technol. Lett. 59 (10) (2017) 2518–2525. [8] C. Elavarasi, T. Shanmuganantham, SRR loaded CPW–fed multiple band rose flower-shaped fractal antenna, Microwave Opt. Technol. Lett. 59 (7) (2017) 1720–1724. [9] C. Elavarasi, T. Shanmuganantham, Multiband SRR loaded koch star fractal antenna, Alexandria Eng. J. (2017) (in press). [10] Deepanshu Kaushal, T. Shanmuganantham, Microstrip slotted caterpillar patch antenna for S, Ku and K-band applications, J. Mater. Today, in press. [11] Deepanshu Kaushal, T. Shanmuganantham, A novel microstrip flower patch antenna design for multiband operation, J. Mater. Today, in press. [12] Deepanshu Kaushal, T. Shanmuganantham, Design of a compact and novel microstrip patch antenna for multiband satellite applications, J. Mater. Today, in press.
Please cite this article in press as: D. Kaushal, T. Shanmuganantham, Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.08.021