Tri-Band Cactus Shaped Printed Monopole

Chio Saephan, Haider Khaleel, Ben Valdovinos Department of Engineering Science

Sonoma State University Rohnert Park, California, USA

khaleel@sonoma.edu

Ayman Isaac, Ayad Bihnam Department of Systems Engineering

University of Arkansas at Little Rock Little Rock, Arkansas, USA

axabbosh@ualr.edu

Abstract— This paper presents a printed multi-band monopole antenna for use in wireless systems. The antenna is designed to operate at 2.4 GHz, 3.6 GHz, and 5.6 GHz under the maximum return loss of 10 dB. CST Microwave Studio was used for the design process. Chemical etching was used in the fabrication process. The resulting frequency bands cover 2.13-2.48 GHz, 3.51-3.88 GHz, and 5.56-6.70 GHz.

I. INTRODUCTION

In recent years, wireless communication systems have increased rapidly. It is believed by many that wireless is the dominant technology of the future. A variety of services are offered throughout the frequency spectrum: GPS, WiFi, WiMax, GSM, cellular telephones, satellite television, and Wireless USB. To obtain the benefits of wireless communication, one needs to be able to access more than one frequency band. Microstrip antennas are widely used due to their many advantages, such as their low profile, light weight, compactness, conformity, and ease of fabrication. They are extremely useful because they can be printed directly on a printed circuit board (PCB) [1]. A plethora of antenna designs for the abovementioned applications have been reported [2]–[9]. However, the requirements of antennas to be small, low-cost, and have relatively omnidirectional patterns over multiple bandwidths are not always attainable. In this paper, a simple tri-band antenna is printed on a low-cost laminate. It is worth mentioning that the frequency bands could be adjusted by modifying the lengths of the monopole branches.

II. ANTENNA DESIGN

The idea behind this design is basic. The first techniques of receiving and transmitting wireless signals taught to many people are the dipole and monopole antennas. The length of the radiating element determines the center operating frequency. This idea was adapted to have an antenna operating on three frequency bands. This design has three branches, each to handle a different band. The antenna is printed on one side of an FR4 substrate with a square ground-plane on the other side. A 50-Ω SMA connector is used as the feeding port to the antenna.

A. Antenna Geometry

This antenna is printed on one side of an FR4 substrate with a square ground-plane. The FR4 properties are (t = 1.5 mm, l = 80 mm, w = 45 mm) with an approximate dielectric constant of 4.4. A cactus formation was chosen as the design of our

resonating arms. An iterative process was done to optimize the dimensions of the antenna.

Fig. 1. Geometry of the proposed antenna.

TABLE I. EXAMPLE OF A TABLE CAPTION.

Dimension Antenna Geometry Variables

Value Units Description

W 45 mm Width of substrate

L 80 mm Length of substrate

Hm 24 mm Length of middle branch

Hr 7.2 mm Length of right branch

Hl 11 mm Length of left branch

wr 1.5 mm Width of right branch from center

wl 4 mm Width of left branch from center

wf 2.4 mm Width of feed line

lg 44 mm Length of ground plane

Wp 2.75 mm Width of radiating poles

B. Simulation

Simulation was done using CST Microwave Studio which is based on the finite integration technique. S11 and return loss are

1704978-1-4799-3540-6/14/$31.00 ©2014 IEEE AP-S 2014

calculated using time-domain techniques. As stated earlier, an iterative process was done to alter the design of the antenna to attain the desired frequencies. The desired frequency ranges are presented in Figure 2.

E-plane (YZ cut) and H-plane (XZ cut) far-field radiation patterns at 2.45 GHz are shown in Figure 14. It can be seen that the radiation power is omni-directional. The antenna achieved a gain of 1.7 dBi at 2.45 GHz.

Fig.2. Simulated S11 of the proposed tri-band antenna.

Fig.3 Measured S11 of the proposed tri-band antenna.

Fig.4. E and H Plane Radiation Patterns for the proposed tri-band antenna.

III. FABRICATION AND MEASUREMENT

The antenna was fabricated using the traditional photolithography method by etching a double sided FR4 substrate. An Agilent network analyzer was used to measure the S11 of the antenna. Using a -10 dB return loss factor, the measured frequency ranges from 2.13 - 2.48 GHz, 3.51 - 3.88 GHz, and 5.56 - 6.70 GHz. Return loss values are as follows: -16.0dB at 6.12GHz, -17.65dB at 3.69GHz, and -13.964dB at 2.31GHz.

IV. CONCLUSION

A cost-effective printed tri-band printed monopole antenna is proposed in this paper for WLAN applications. The antenna is designed to operate at 2.4 GHz, 3.6 GHz, and 5.6 GHz under the maximum return loss of 10 dB. Simulation and measurement results are in good agreement which suggests that the antenna is a reasonable candidate for the targeted application.

REFERENCES [1] H. R. Khaleel, H. Al-Rizzo, D. Rucker, and S. Mohan, "A Compact

Polyimide-Based UWB Antenna for Flexible Electronics," IEEE Antennas and Wireless Propagation Letters, vol.11, no., pp.564-567, May 2012.

[2] M. N. Srifi, S. K. Podilchak, M. Essaaidi, and Y. M. M. Antar, “Compact Disc Monopole Antennas for Current and Future Ultrawideband (UWB) Applications,” IEEE Trans. On Antennas and Propagation, vol. 59, no. 12, pp. 4470–4480, December 2011.

[3] H. R. Khaleel, H. Al-Rizzo, and D. Rucker, Y. Al-Naiemy, "Flexible Printed Monopole Antennas for WLAN Applications," 2011 IEEE International Symposium on Antennas and Propagation (APSURSI), pp.1334–1337, July 2011.

[4] P. Salonen, Jaehoon Kim, and Y. Rahmat-Samii, “Dual-band E-shaped patch wearable textile antenna,” IEEE Antennas and Propagation Society Symposium, vol. 1 , pp. 466– 469, July 2005.

[5] H. R. Raad, A. Abbosh, H. Al-Rizzo, and D. Rucker, “Flexible and Compact AMC Based Antenna for Telemedicine Applications,” IEEE Trans. on Antennas and Propagation, 61 (2), pp. 524–531, February 2013.

[6] H.R. Khaleel, H. Al-Rizzo, D. Rucker, "Compact Polyimide-Based Antennas for Flexible Displays," IEEE Journal of Display Technology, vol.8, no.2, pp.91-97, February 2012.

[7] D. Anagnostou, A. Gheethan, A. Amert, K. Whites, "A Direct-Write Printed Antenna on Paper-Based Organic Substrate for Flexible Displays and WLAN Applications,” IEEE Journal of Display Technology, vol. 6, no. 11, pp. 558–564, November 2010.

[8] G. DeJean, R. Bairavasubramanian, D. Thompson, G. Ponchak, M. Tentzeris, J. Papapolymerou, "Liquid Crystal polymer (LCP): a new organic material for the development of multilayer dual-frequency/dual-polarization flexible antenna arrays," IEEE Antennas and Wireless Propagation Letters, vol.4, no., pp. 22–26, March 2005.

[9] Kirsch, N.J.; Vacirca, N.A.; Kurzweg, T.P.; Fontecchio, A.K.; Dandekar, K.R.; , "Performance of transparent conductive polymer antennas in a MIMO ad-hoc network," 2010 IEEE 6th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), vol., no., pp.9-14, 11-13 October 2010.

1705