A Highly Compact Triple-Band Microstrip Antenna

for GSM/4G/WLAN Applications

Yadhu Krishnan M K Chetan Desai Milind Fernandes

Department of Electronics and Telecommunication

Goa College of Engineering

Ponda, India

Abstract—A highly compact triple-band microstrip antenna is

proposed that comprises of rectangular monopole with etched out

patterns on two ground plane sections acting as defected ground

planes structures. The proposed antenna generates three separate

impedance bandwidths to cover frequency bands of GSM 1900,

2.6GHz 4G (LTE TDD band) and 5.2GHz WLAN bands. The

realized antenna is highly compact (17 × 20 mm2) and exhibits

good gain and reflection coefficient values over its operating

bands.

Keywords- Triple-band antenna, defected ground plane,

monopole antenna, GSM, 4G, WLAN

I. INTRODUCTION Since the advent of wireless systems in communication,

the demand for incorporating multiple bands into a single system has increased. While covering multiple bands, the antennas used for such systems must also be very compact and cost-effective. The GSM 1900 band is one of the cellular frequencies for operation of GSM mobile phones. Long Term Evolution (LTE)/4G frequency bands are used for wireless communication of high-speed data for mobile phones and data terminals. Wi-Fi/WLAN frequency bands are used in implementing wireless local area networks that allows electronic devices to participate in computer networking. The coverage of all these bands by a single device is a necessity which has driven us to conduct this research.

Monopole antennas have been found to be promising for

use in multiband mobile devices [1]-[2]. Coplanar waveguide

(CPW) fed antennas provide broader bandwidth and allow easy

integration with radio frequency integrated circuits [3]-[4].

Antenna miniaturization and excitation of additional resonance

modes are possible with the use of defected ground structures

(DGS) [5]-[8]. Hence, we have focused our antenna design on

CPW- fed monopole antenna with DGS.

II. ANTENNA DESIGN

The antenna geometry as shown in Fig. 2 consists of a

CPW-fed monopole with two ground plane sections having

etched out patterns (defects) in them. The L and Z slots

imbalance the currents on the two ground planes to generate

additional resonance modes. The antenna was etched on one

side of printed circuit board with dielectric constant of 4.4 and

substrate dimensions 17 × 20 × 1 mm3. The antenna

dimensions and their optimized values are given in Table. 1.

Fig. 2 Antenna geometry

Table.1 Dimensions of the proposed antenna

III. RESULTS AND DISCUSSIONS

The antenna was simulated using the electromagnetic solver FEKO ® as shown in Fig. 1. The graph of simulated reflection coefficients as seen in Fig. 3 shows three impedance bandwidths obtained between 1.890-2.03, 2.57-2.77 and 5.08-5.35 GHz, having respective centre frequencies at 1.95, 2.68 and 5.21GHz with reflection coefficients ≤ -10dB. The bandwidths of 5.2GHz Wi-Fi/WLAN (5.15-5.35 GHz) and 2.6 GHz Long-Term Evolution Time Division Duplex (LTE TDD)/4G (2.57-2.62 GHz) bands are covered, whereas 71.3 % bandwidth of GSM 1900/PCS band is covered. Simulated surface current at 2.56GHz as shown in Fig. 4 illustrates the concentration of currents around the slots, which leads to their imbalance and thus rendering the ground plane as the main radiating element in low frequency ranges. The radiation

Fig. 1 Simulated antenna

patterns as shown in Fig. 6 exhibits typical monopole-like radiation characteristics.

Fig. 3 Reflection coefficient of simulated antenna

Fig. 5 Simulated peak antenna gain across operating bands

The measured peak gain across different operating bands are shown in Fig. 5.. It satisfies gain requirement of most GSM, 4G and WLAN applications.

1.95 GHz - xz plane 1.95 GHz – yz plane

2.68 GHz – xz plane 2.68 GHz – yz plane

5.21 GHz – xz plane 5.21 GHz – yz plane

Fig. 6 Simulated radiation patterns at centre frequencies

IV. CONCLUSION

A highly compact triple-band monopole antenna is

presented. The use of monopole together with DGS, makes it

easy to fabricate the antenna for generating the three bands that

are used in emerging wireless communication technologies.

The future scope includes complete coverage of GSM

1900/PCS band.

REFERENCES [1] Ryu, H.C., et al.: ‘Triple-stacked microstrip patch antenna for multiband

system”, Electron. Lett., 2002, 38, (24), pp. 1496–1497

[2] T. H. Kim and D. C. Park, “Compact dual-band antenna with double L-slits for WLAN operations,” IEEE Antennas Wireless Propag. Lett.,vol. 4, pp. 239–252, 2005.

[3] M. W. Menzel, W. Grabherr “A Microstrip Patch Antenna with Coplanar Feed Line”. IEEE Microwave and Guided Wave Letters, vol.1, no.11, page 340 – 342, November 1991.

[4] S. Chaimool and K. L. Chung, “CPW-fed mirrored-L monopole antenna with distinct triple bands for WiFi and WiMAX applications,” Electron. Lett., vol. 45, no. 18, pp. 928–929, 2009.

[5] Debatosh Guha, Sujoy Biswas and Chandrakanta Kumar, “ Printed Antenna Designs Using Defected Ground Structures: A Review of Fundamentals and State-of-the-Art Developments” FERMAT , vol 2 , April 2014

[6] J.Pei,A.-G.Wang,S.Gao,andW.Leng, “Miniaturized triple-band antenna with a defected ground plane for WLAN/WiMAXApplications,” IEEE Antennas Wireless Propag. Lett., vol. 10, pp. 298–301, 2011.

[7] M. Naser-Moghadasi, R. Sadeghzadeh, L. Asadpor, and B. S.Virdee, “A Small Dual-Band CPW-Fed Monopole Antenna for GSM and WLAN Applications”, IEEE Antennas and Wireless Propagation letters, Vol. 12, 2013

[8] M. A. Antoniades and G. V. Eleftheriades, “A compact multibandmonopole antenna with a defected ground plane,” IEEE Antennas Wireless Propag. Lett., vol. 7, pp. 652–655, 2008.

Fig. 4 Simulated surface current distribution at 2.56 GHz

zzzGHAGH GHz