 Proceedings of Engineering and Technology Innovation , vol. 4, 2016, pp. 31 - 33 31 Multi-band Slot Antenna Tsang-Yen Hsieh * , Jyh-Liang Wang, Mei-Hui Wang Department of Electronic Engineering, Ming Chi University of Technology, New Taipei City, Taiwan . Received 01 February 2016; received in revised form 08 March 2016; accept ed 03 April 2016 Abstract A small-size printed antenna is developed for the application of mobile phones . The ar- chitecture of antenna bases on the concept of coplanar waveguide (CPW) feeding with slot design. The antenna is planned by an inverted triangular monopole structure with the overall size of 50 mm× 120 mm (shown in Fig. 1). The proposed antenna was fabricated on PCB with FR4 d ielectric substrate. The substrate thickness is 1.6 mm with the relative permittiv ity of ~ 4.45. The slots are added to adjust resonance fre- quency and achieve characteristic of mu lti-band, which may cover the applications of GPS, GSM (Global System for Mobile Co mmunications), UMTS (Universal Mobile Te lecommun ications System), and LT E (Long Term Evolution). By the trial of simulat ion to tune the design of slots , an optimu m design of antenna can be obtained. Fig.2 presents the s imu lated and measured re- turn loss of the antenna. Even though, there are few minor differences between the simulation and measured data. The measured and simulated results still can agree with each other. The achieved bandwidths are 0.54 to 1.01 GHz, 1.34 to 2.28 GHz, and 2.55 to 2.90 GHz, wh ile the return loss ( 11S ) is limited more than 6 d B. Th is antenna is well suitable for the using of mobile phone applications. Ke ywor ds : mult i-band, coplanar waveguide (CPW), printed circuit board (PCB), return loss , slot antenna 1. Introduction The rapid development of wire less commu- nication leads to the more de mands of the types, speed, and quality of wire less communication. The transmission and receiving antennas are the essential parts of wireless communicat ion sys- tems (such as GSM, GPS, UMT S, ISM , LT E, etc.). Therefore , the quality of antenna will greatly affect the emission and reception per- formances of system. In recent years , a lmost all the mob ile devices are equipped with mu lti -band applications, so it requires multiple frequency characteristics of the antenna to transceiver the communication signals [1-2]. 2. Method A small-size printed antenna was designed for the mult i-band require ments of mobile phones. The construction of antenna bases on the concept of coplanar waveguide (CPW) feeding with slot design. The antenna is planned by an inverted triangular monopole structure with the overall dimensions of 50 mm× 120 mm (shown in Fig. 1). The proposed antenna was fabricated on PCB with FR4 d ielectric substrate. The sub- strate thickness is 1.6 mm with the re lative permittivity of ~ 4.45. Fig. 1 Multi-band slot antenna The origina l triangular structure of the an- tenna having a wideband characteristic, coupled with the use of the slots will destroy the wide band characteristic of the triangular structure, and then presenting a mu lti-frequency antenna characteristic. The slots were added to adjust * Corresponding aut hor. Email: t yhsieh@mail.mcut.edu.tw Proceedings of Engineering and Technology Innovation , vol. 4, 2016, pp. 31 - 33 32 Copyright © TAETI resonance frequency and achieve characteristic of multi-band, which may cover the applications of GPS, GSM (Global System for Mobile Co mmunicat ions), UMTS (Universal Mobile Teleco mmunications System), and LT E (Long Term Evolution). We used an electromagnetic simu lation software to predict various important parameters of this proposed antenna. An actual sample of this antenna was fabricated based on the simu- lation results. Moreover, the measured data and simu lated results of this proposed antenna was compared. 3. Simulation and Result Fig. 2 The measured and simulated data of S11 of the multi-band slot antenna Fig. 3 The measured smith chart of the mul- ti-band slot antenna Fig. 2 shows the measured and simulated data of 11S of the mu lti-band slot antenna. There are few minor differences between the simu lation and measured data. The measured and simulated results still can agree with each other. The achieved bandwidths are 0.54 to 1.01 GHz, 1.34 to 2.28 GHz, and 2.55 to 2.90 GHz, while the return loss 11 S is limited more than 6 dB. The measured smith chart of the multi-band slot antenna is presented in Fig. 3. Fro m wh ich it is apparent that the impedances of this antenna at 0.7, 1.8, and 2.6GHz band are very close to 50 ohms . The test results of bandwidths, ga ins and radiat ion e ffic ienc ies a re listed in Tab le 1. The values of acco mp lished bandwidths are those we ment ioned be fore. Via para mete r ad jus t- ment, the ga in o f slot antenna was g reater than -2.54d Bi, rad iation efficiency was highe r than 25%. Table 1 The test results of bandwidths, gains and radiation efficiencies of the mu l- ti-band slot antenna Operat ing Freq. (GHz) 0.8GHz Band (0.7-0.96) 1.9GHz Band (1.7-2.17 ) 2.6GHz Band (2.56-2.7 ) Simulat ed BW (GH z ) (S11 < -6dB) 0.69 - 0.97 1.64 - 2.14 2.52 - 3.0 Measured BW (GH z ) (S11 < -6dB) 0.54 - 1.01 1.34 - 2.28 2.55 - 2.9 Gain (dBi) -2.5 - -0.3 2.3 - 3.9 1.8 - 3 Efficiency (%) 25.2 - 46.9 52.5 - 77.5 44.8 - 47.3 4. Conclusions A slot antenna used in 2G, 3G, 4G and GPS frequency band is proposed. The Applicat ions bands of the slot antenna cover GPS, GSM 850 / 900/ 1800/ 1900, UMT S, LT E700 / 800/ 850/ 900 and LT E 1700/ 1800/1900/2100/2600. The antenna was planned by an inverted t riangula r monopole structure with the design of slots , and the overall size is 50 mm× 120 mm. This an - tenna was fabricated on PCB with FR4 d ie lec - tric substrate. The substrate thic kness is 1.6 mm with the re lat ive permitt iv ity of ~ 4.45. The achieved bandwidths are 0.54 to 1.01 GHz, 1.34 to 2.28 GHz, and 2.55 to 2.90 GHz, wh ile the return loss 11S is limited mo re than 6 d B. Via pa ra mete r ad justment, the ga in of slot a n - tenna was greater than -2.54d Bi, rad iat ion ef- fic iency was highe r than 25%. This antenna is we ll suitab le for the using of mob ile phone applications . Proceedings of Engineering and Technology Innovation , vol. 4, 2016, pp. 31 - 33 33 Copyright © TAETI References [1] G. Park, M. Kim, T. Yang, J. Byun, and A. S. Kim, “The compact quad-band mobile handset antenna for the LTE700 MIMO ap- plication,” Antennas and Propagation Soci- ety International Symposium, (APSURSI '09), IEEE press , pp. 1-4, June 2009. [2] C. J. Park, D. H. Park, K. S. M in, J. W . Kim, and I. H. kim, “Measure ment char- acteristics of LT E-MIM O antenna fo r 4 G mob ile handy te rmina l,” Inte rnationa l Sy mposiu m on Antennas and Propagation (ISAP), pp. 523-526, 2012.