Planar monopole antenna with offset square split

ring resonator

Murtala Aminu-Baba1, Mohammad Kamal A Rahim1, Farid Zubir1, Mohd Fairus Mohd Yusoff1, 1Osman Ayop, Noor Asmawati Samsuri1

1Advanced RF & Microwave Research Group,

School of Electrical Engineering Universiti Teknologi Malaysia, (UTM), 81300 Skudai, Johor Bahru, Malaysia Corresponding author, e-mail: limaminkobi@yahoo.com; mkamal@fke.utm.my; faridzubir@utm.my; fairus@fke.utm.my,

asmawati@fke.utm.my)

Abstract – A low cost, low profile dual band metamaterial

monopole antenna is proposed in this paper. These bands are achieved when a Square Split Ring Resonator (S-SRR) is added on the ground plane; a narrow band covering WiMAX and standard ultrawideband (UWB) with a patch antenna dimension of 10.17 x 15 mm2. In order to realize the bandwidth enhancement, parametric studies of the S-SRR and gaps position were performed. The antenna design was performed on the low cost FR4 substrate using CST Microwave Studio. The proposed antenna is suitable for UWB systems covering WLAN/WiMAX for high data rate, interference mitigation and signal quality improvement.

Index Terms — Monopole antennas, S-SRR, UWB.

1. Introduction

Due to the recent development in the wireless and

communication technology, various communication system

can operate in more than one frequency band such as

wireless LANs (WLANs), WiMAX, satellite navigation

systems, ultrawide-band (UWB) or combination of them, [1-

3]. Thus, a single antenna with compact size that has the

capcity to cover multiple bands is required for limited space

environment. Among the numerous advantages of UWB

antennas such as strong protection to multipath fading, high

data rate, low interference and high channel capacity, great

research interests have aroused in the last few decades.

Various types of UWB antennas have been reported in [4-8].

Monopole antennas as reported in [8] have been widely used

due to their low profile, low cost and ease of fabrication.

Moreover, different techniques have been used to improve

the bandwidth of the monopole antenna, include the feed,

radiator or ground modification [1], [9], applying fractal

elements to the patch [8], and by the introduction of

metamaterial structure [10]. The authors in [10] presented an

UWB monopole antenna with flexible AMC for gain

bandwidth enhancement. However, the design approach is

quite complex as it requires extra circuitries for

implementation.

In this paper, a simple technique using metamaterial

structure is proposed for bandwidth enhancement, gain

improvement and additional band generation. Fig. 1 shows

the rectangular monopole antenna microstrip line with the

SRR on the back plane fed by a 50 Ω.

2. Antenna Design and Simulation

(i) Monopole Antenna

Fig. 1. shows the structure of the proposed antenna with

the labeled designed parameters. The monopole antenna is

comprised of a microstrip feed structure and rectangular

radiator with partial ground plane. The antenna is designed

and simulated using CST Microwave Studio and printed on

FR4 substrate with a thickness of 0.8 mm and permitivity of

4.4. The layout of the structure and the parameters are shown

in Fig. 1. Fig. 2 depicts the reflection coefficient of the

monopole antenna.

top view Bottom view

Fig. 1 Structure of the proposed metamaterial monopole antenna geometry. L

= W= 43mm, hf = 15.9, Lp = 15, Wp = 10.17, Zo = 4, g = 0.5, Z = 1, j = 7.2, f

= 6.15

Fig. 2. Simulated results for the proosed metamaterial antenna reflection

coefficent, with and without R-SRR.

2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea

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(ii) Monopole Antenna with R-SRR

It can be seen in fig. 2 that, by addition of the SRR on the

ground plane of the monopole antenna, the impedance

bandwidth is improved from (3.1303 ~ 4.5748) – (9.49 ~

13.6520) to an UWB (3.1414 ~ 13.2180) and also generates

additional narrowband of (2.5627 ~ 2.7597). The first and

second resonant frequencies of the monopole antenna are

shifted to higher and upper and lower frequencies from 3.66

~ 9.61 GHz respectively, thereby leading to a bandwidth

from (3.1414 ~ 13.2180) GHz. Thus, it can be concluded that

SRR additional band and improve a wideband that results in

an UWB bandwidth.

3. Results and Discussion

The simulated reflection coefficient for the proposed

antenna with and without the SRR are shown in Fig. 2. It can

be compared and verified that the use of SRR improves the

impedance bandwidth and creates additional band. Based on

the presented results in terms of the operating frequency,

bandwidth and antenna gain are shown in table I. Fig. 3

shows the 3D radiation pattern of the antenna at various

frequencies. Monopole antenna with SRR has a better gain at

the higher than the simple monopole antenna.

TABLE I

Simulated 10-dB band antenna performance for the proposed

metamaterial monopole antenna

(a) (b)

(c) (d)

(e) (f)

Fig. 3. The far field of the monopole antenna with SRR at (a) 2.67 (b)3.50 (c)

3.89 (d) 5.50 (e) 8.20 (f) 10.4 GHz

4. Conclusion

In this paper, a dual band metamaterial monopole antenna

has been presented for WiMAX and standard UWB

applications. The impedance bandwidth of the monopole

antenna is greatly improved from wide bands (3.1303 ~

4.5748) – (9.49 ~ 13.6520) to an UWB (3.1414 ~ 13.2180)

and also generates additional narrowband of (2.5627 ~

2.7597) by loading a SRR in the ground plane. Moreover,

high gain, good radiation characteristics and matching were

obtained at the respective frequencies.

Acknowledgment

The authors would like to thank the Ministry of Higher Education (MOHE)

for supporting the research work, Research Management Centre (RMC),

School of Electrical Engineering, Universiti Teknologi Malaysia (UTM) for

the support of the research under grant no. 14J87, 04G69 and 16H08.

References

[1] R. Zaker and A. Abdipour, "Bandwidth enhancement and

miniaturization of fork-shaped monopole antenna," IEEE

Antennas and Wireless Propagation Letters, vol. 10, pp. 697-700,

2011.

[2] M. A. Baba, M. K. A. Rahim, F. Zubir, and M. F. M. Yusoff,

"Design of Miniaturized Multiband Patch Antenna Using CSRR

for WLAN/WiMAX Applications," TELKOMNIKA

(Telecommunication Computing Electronics and Control), vol.

16, 2018.

[3] M. Aminu-Baba, M. K. A. Rahim, F. Zubir, M. F. M. Yusoff,

and A. B. Shallah, "Microstrip antenna with CSRR ground

structure," in Antennas and Propagation (ISAP), 2017

International Symposium on, 2017, pp. 1-2.

[4] M. S. Alam and A. Abbosh, "Reconfigurable band-rejection

antenna for ultra-wideband applications," IET Microwaves,

Antennas & Propagation, vol. 12, pp. 195-202, 2017.

[5] E. Lopez-Arzate, J. A. Tirado-Mendez, J. Caltenco-Franca, R.

Flores-Leal, H. Aguilar, and M. Peyrot-Solis, "Ultra Wide-Band

Directive Antenna Based on an Inclined Cone Body," IET

Microwaves, Antennas & Propagation, 2017.

[6] J. Yang and A. Kishk, "A novel low-profile compact directional

ultra-wideband antenna: the self-grounded Bow-Tie antenna,"

IEEE Transactions on Antennas and Propagation, vol. 60, pp.

1214-1220, 2012.

[7] J. Wu, Z. Zhao, Z. Nie, and Q.-H. Liu, "A printed UWB Vivaldi

antenna using stepped connection structure between slotline and

tapered patches," IEEE Antennas and Wireless Propagation

Letters, vol. 13, pp. 698-701, 2014.

[8] H. Fallahi and Z. Atlasbaf, "Study of a class of UWB CPW-fed

monopole antenna with fractal elements," IEEE Antennas and

Wireless Propagation Letters, vol. 12, pp. 1484-1487, 2013.

[9] M. Mahdavi, Z. Atlasbaf, and K. Forooraghi, "A very compact

CPW‐FED ultra‐wideband circular monopole antenna,"

Microwave and Optical Technology Letters, vol. 54, pp. 1665-

1668, 2012.

[10] F. Wang and T. Arslan, "A wearable ultra-wideband monopole

antenna with flexible artificial magnetic conductor," in Antennas

& Propagation Conference (LAPC), 2016 Loughborough, 2016,

pp. 1-5.

Antenna

Type

Antenna Performance

Frequency

(GHz) Bandwidth

Antenna

Gain (dB)

Monopole

Antenna

3.65 1.44 GHz (3.1303 ~ 4.5748) 2.15

12.4 4.162 GHz (9.49 ~ 13.6520) 4.96

Monopole

with

CSRR

2.67 197 MHz (2.5627 ~ 2.7597) 1.90

3.50

10.08 GHz (3.1414 ~ 13.2180)

2.18

3.89 2.31

5.50 4.12

8.20 3.56

10.4 5.25

2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea

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