Printed =8-PIFA for Penta-Band WWAN Operation in the Mobile Phone Chih-Hua Chang, Student Member, IEEE, and Kin-Lu Wong, Fellow, IEEE

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1 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 5, MAY Printed =8-PIFA for Penta-Band WWAN Operation in the Mobile Phone Chih-Hua Chang, Student Member, IEEE, and Kin-Lu Wong, Fellow, IEEE Abstract A small-size printed planar inverted-f antenna (PIFA) operated at its one-eighth wavelength ( 8) mode as the fundamental resonant mode for achieving WWAN (wireless wide area network) operation in the mobile phone is presented. The proposed PIFA has a simple structure of comprising two radiating strips of length about 8 at 900 MHz and is fed using a coupling feed. Compared to the traditional PIFA using a direct feed, the coupling feed greatly decreases the very large input impedance seen at the 8 mode for the traditional PIFA and results in successful excitation of the 8 mode for the proposed PIFA. Two 8 modes are generated by the two radiating strips and occur at close frequencies at about 900 MHz to form a wide lower band to cover GSM850/900 operation. The two radiating strips also generate two higher-order modes or 4 modes at about 1900 MHz to form a wide upper band for GSM1800/1900/UMTS operation. Penta-band WWAN operation is hence achieved, yet the proposed PIFA only occupies a small printed area of mm 2 or 465 mm 2 on the system circuit board of the mobile phone, which is about the smallest for the internal uniplanar printed antenna capable of penta-band operation that have been reported. Details of the proposed PIFA are presented. The specific absorption rate (SAR) and hearing aid compatibility (HAC) results for the proposed PIFA are also analyzed. Index Terms Coupling feed, hearing aid compatibility (HAC), internal mobile phone antennas, specific absorption rate (SAR), 8-planar inverted-f antenna (PIFA). I. INTRODUCTION T HE conventional planar inverted-f antennas (PIFAs) that have been applied in the mobile phone as internal mobile phone antennas are mainly formed by mounting a shorted radiating strip or patch above the system ground plane of the mobile phone [1] [4]. This kind of internal antennas shows a three-dimensional (3-D) structure and is usually operated at their quarter-wavelength resonant modes as the antenna s fundamental or lowest-frequency resonant modes. Such conventional internal antennas usually show a high profile of about 6 to 10 mm above the system ground plane or the grounded portion of the system circuit board in order to achieve wide bandwidths for GSM850/900/1800/1900/UMTS operation. When the distance or thickness between the radiating strip and Manuscript received August 11, 2008; revised November 28, Current version published May 06, The authors are with the Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan ( changch@ema.ee. nsysu.edu.tw). Color versions of one or more of the figures in this paper are available online at Digital Object Identifier /TAP the ground plane is reduced, the operating bandwidth of the traditional PIFA is usually decreased quickly and the desired penta-band operation is difficult to be covered [5]. This causes a limitation for their applications in the modern thin-profile mobile phones that recently attract much attention on the market. For applications in thin-profile mobile phones [5] [7], the printed PIFAs with their radiating strips directly printed on the no-ground portion of the system circuit board of the mobile phone can be a promising candidate. In this case, the internal antenna generally shows no thickness above the system circuit board. Further, the fabrication cost of the two-dimensional (2-D) printed PIFA can be reduced to be minimum, as compared to the conventional 3-D PIFA. For this motivation, a simple small-size printed PIFA is proposed in this study. The proposed PIFA has a simple structure of comprising two radiating strips of length about one-eighth wavelength at 900 MHz, and hence requires a small printed area (less than 500 in this study, which is about the smallest for the internal uniplanar printed mobile phone antenna) on the no-ground portion of the system circuit board. With such a small occupied area, successful excitation of the modes, different from the conventional modes, as the antenna s fundamental resonant modes has been achieved. This behavior is obtained owing to the use of a coupling feed in the proposed PIFA, which greatly decreases the very large input impedance observed at about the mode for the conventional PIFA and hence results in successful excitation of the mode for the proposed PIFA. Effects of the coupling feed in this study are different from the coupling-feed techniques that have been reported [8], [9], in which the applied coupling feed results in dual-resonance excitation in the 900 MHz band for bandwidth enhancement, and however, the studied antenna is still operated at its mode as the fundamental mode. In addition, the proposed smallsize PIFA can generate two wide operating bands at about 900 and 1900 MHz to cover GSM850/900 and GSM1800/1900/UMTS operations; that is, penta-band operation for WWAN (wireless wide area network) communication is obtained. Details of the proposed small-size printed PIFA are described in the paper, and results of the fabricated prototype are presented and discussed. The SAR [10] [12] results of the proposed PIFA that are required to meet the limit of 1.6 W/kg for the 1-g head tissue or 2.0 W/kg for the 10-g head tissue [13] are also analyzed. In addition, the proposed PIFA is tested for the HAC standard ANSI C for hearing aid compatibility of the X/$ IEEE

2 1374 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 5, MAY 2009 Fig. 2. (a) Measured and simulated return loss for the proposed PIFA. (b) Simulated return loss for the proposed PIFA and the two cases with strip 1 only and strip 2 only. Fig. 1. (a) Geometry of the printed =8-PIFA for GSM850/900/1800/1900/ UMTS operation in the mobile phone. (b) Dimensions of the metal pattern of the proposed PIFA. wireless communication device [14] [17]. Obtained SAR and HAC results are presented and studied. II. PROPOSED COUPLED-FED -PIFA Fig. 1(a) shows the geometry of the proposed printed -PIFA with a coupling feed for WWAN operation in the mobile phone. The proposed PIFA has a uniplanar structure and is printed on a small area of on the no-ground portion of the system circuit board of the mobile phone. Detailed dimensions of the metal pattern of the proposed PIFA are given in Fig. 1(b). In this study, a 0.8-mm thick FR4 substrate of relative permittivity 4.4 and size is used to simulate the system circuit board; on its back side, a system ground plane of size is printed. These dimensions are reasonable for practical mobile phones on the market. Note that on the no-ground portion, there is an unoccupied space of, which can be used to accommodate the associated electronic elements such as the lens of the embedded digital camera [18], [19], the speaker [20], [21] and so on. That is, with the proposed small-size antenna, compact integration of the internal WWAN antenna and the possible electronic elements inside the mobile phone can be obtained. Further, to simulate the mobile phone casing, a plastic casing (thickness 1 mm, relative permittivity 3.5, and loss tangent 0.06) is made to enclose the proposed PIFA including the system ground plane as shown in the figure. The proposed PIFA has a simple structure and mainly comprises two folded radiating strips and a coupling-feed portion. The two radiating strips (strip 1 and 2 in the figure) are of the same narrow width 0.5 mm, except that (1 mm) of the 4.5-mm long section in the central part, which is short-circuited to the top edge of the system ground plane at point B (a via-hole and the shorting point) through an inverted-l shorting strip of length 20 mm (section BF). The two radiating strips are slightly different in length; the lengths of strip 1 (section CD) and strip 2 (section CE) are 35 and 33 mm, respectively, which are both close to at 900 MHz. By exciting the two strips using the coupling feed in the proposed PIFA, two modes and two modes can be easily generated at about 900 and 1900 MHz, respectively. The two modes form a wide lower band for the proposed PIFA to cover GSM850/900 operation. While the two modes form the desired upper band to cover GSM1800/1900/UMTS operation. The successful excitation of the modes of the two radiating strips is mainly owing to the coupling feed used in the proposed PIFA, which greatly decreases the very large input impedance observed at the mode for the traditional PIFA with a direct feed. Further, the coupling feed also results in small input impedance (less than 100 ) for the excited modes or higher-order modes of the proposed PIFA. Detailed results will be discussed in the next section with the aid of Figs. 3 and 4. The coupling feed is located in-between the two radiating strips and consists of a feeding strip and a coupling strip (, ), both separated by a coupling gap of. The feeding strip is fixed to

3 CHANG AND WONG: PRINTED 8-PIFA FOR PENTA-BAND WWAN OPERATION IN THE MOBILE PHONE 1375 Fig. 3. Comparison of the simulated return loss of the proposed PIFA and the reference antenna (the corresponding antenna with a direct contact feed). Fig. 5. Simulated return loss as a function of (a) the coupling-gap width g and (b) the coupling-strip length t in the coupling feed. Other dimensions are the same as given in Fig. 1. Fig. 4. Simulated input impedance versus frequency for the proposed PIFA and the reference antenna studied in Fig. 3. have a width 3 mm and a length 12 mm and is connected to the printed 50- microstrip feedline on the front side of the system circuit board. For easy tuning in the proposed design, the dimensions of the feeding strip are fixed in the study, while the length of the coupling strip and the width of the coupling gap are adjusted to fine-tune the effect of the coupling feed on improving the impedance matching of the desired lower band at about 900 MHz and the upper band at about 1900 MHz. The preferred length and width in this study are adjusted to be 12 mm and 0.3 mm, respectively. Detailed effects of varying the two parameters of and are analyzed in Fig. 5 in the next section. Furthermore, effects of the shorting-strip length and the relative permittivity of the FR4 substrate on the antenna performances are also studied in Figs. 6 and 7. III. RESULTS AND DISCUSSION Fig. 2(a) shows the measured and simulated return loss of the proposed PIFA. The simulated results are obtained using Ansoft High Frequency Structure Simulator (HFSS) [22], and good agreement between the simulation and the measurement is obtained. The lower band shows a wide bandwidth of 140 MHz Fig. 6. Simulated return loss as a function of the shorting-strip length s. Other dimensions are the same as given in Fig. 1. Fig. 7. Simulated return loss as a function of the relative permittivity " of the FR4 substrate. Other dimensions are the same as given in Fig. 1. ( MHz), which covers the desired GSM850/900 operation. A wide bandwidth of 472 MHz ( MHz) is also obtained for the upper band centered at about 1900 MHz, which covers the GSM1800/1900/UMTS operation. In Fig. 2(b), a comparison of the simulated return loss for the proposed PIFA and the two cases with strip 1 only and strip 2

4 1376 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 5, MAY 2009 Fig. 8. Measured 3-D and 2-D radiation patterns at (a) 859 MHz and (b) 925 MHz for the proposed PIFA. only is presented. For the case of strip 1 only, there are two resonant modes excited at about 1 and 1.8 GHz; while for the case of strip 2 only, two resonant modes at about 1 and 2.1 GHz are generated. It is then observed that the two modes at about 1 GHz are formed into the desired wide lower band for GSM850/900 operation, and the two modes at about 1.8 and 2.1 GHz are formed into the wide upper band for GSM1800/1900/UMTS operation. A comparison of the simulated return loss of the proposed PIFA and the reference antenna (the corresponding antenna with a direct contact feed) is presented in Fig. 3. Quite different from the obtained two wide bands at about 900 and 1900 MHz for the proposed PIFA, there is only one resonant mode excited at about 1500 MHz for the reference antenna. This behavior is reasonable because the two radiating strips in the reference antenna are of comparable lengths (about 43 mm, starting from point A to each one of the two open ends), which is close to about at 1500 MHz and hence results in the excitation of the mode as the general PIFA or shorted monopole does. This behavior can be seen more clearly from the simulated input impedance versus frequency for the proposed PIFA and the reference antenna studied in Fig. 4. It is seen that owing to the presence of the coupling feed, the very large input impedance seen at about 900 MHz is greatly decreased. This explains the successful excitation of the desired lower band at about 900 MHz seen in Fig. 3 for the proposed PIFA, although the lengths of the two radiating strips (strip 1 and 2) are only about at 900 MHz. This indicates that the modes are excited as the fundamental resonant mode of the proposed PIFA. Also, it is seen that two higher-order resonant modes or modes with good input impedance levels are generated at about 1900 MHz. This explains the successful excitation of the two resonant modes which form the desired upper band as seen in Fig. 3. Fig. 5 shows the simulated return loss as a function of the coupling-gap width and the coupling-strip length in the coupling feed. In Fig. 5(a), the results for the width varied from 0.1 to 0.5 mm are shown; other dimensions of the antenna are the same as given in Fig. 1. Strong effects on the excited resonant modes in both the lower and upper bands are seen, indicating that proper selection of the width is important in the coupling feed of the proposed PIFA. In this design, the preferred width is determined to be 0.3 mm from the obtained results. Fig. 5(b) shows the results for the coupling-strip length varied from 6 to 12 mm. Although the effect on the excited resonant modes is seen to be smaller than that in Fig. 5(a), the impedance matching for frequencies in the lower and upper bands can be adjusted by varying the length, and the preferred length is chosen to be 12 mm in this study. Effects of the lengths of the shorting strip (section BF) on the antenna performances are also studied. The simulated results of three different lengths of, 20 and 22 mm are presented in Fig. 6, and other dimensions of the antenna are the same as given in Fig. 1. For the three cases, the obtained bandwidth of the antenna s upper band is slightly varied and can all cover the desired GSM1800/1900/UMTS operation. While for the lower

5 CHANG AND WONG: PRINTED 8-PIFA FOR PENTA-BAND WWAN OPERATION IN THE MOBILE PHONE 1377 Fig. 9. Measured 3-D and 2-D radiation patterns at (a) 1795 MHz, (b) 1920 MHz and (c) 2045 MHz for the proposed PIFA. band, it is seen to be shifted to lower frequencies when a larger length is selected. The obtained bandwidth of the lower band is also varied. For the length selected to be 22 mm, however, the obtained bandwidth cannot cover the desired GSM850/900 MHz operation. For this reason, the length is selected to be 20 mm for the prototype studied in Fig. 2. To study the effects of the relative permittivity of the FR4 substrate on the antenna performances, simulated results of varied from 4.2 to 4.6 are presented in Fig. 7, with other dimensions of the antenna the same as given in Fig. 1. Very small variations on the excited resonant modes in the lower band are seen. In the upper band, relatively larger effects on the excited resonant modes are observed. However, please note that the obtained bandwidth of the upper band can still easily cover GSM1800/1900/UMTS operation by adjusting the lengths of strip 1 and 2 to fine-tune the excited resonant modes at about 1.8 and 2.1 GHz to compensate for the variations in. Fig. 8 plots the measured 3-D and 2-D radiation patterns at 859 and 925 MHz for the proposed PIFA. Dipole-like radiation patterns for both the two frequencies are seen, which are similar to those observed for the conventional internal mobile phone antennas in the 900 MHz band [1]. The measured radiation patterns at 1795, 1920, and 2045 MHz are plotted in Fig. 9. More variations in the radiation patterns are seen, as compared to those in Fig. 8. This is mainly owing to the excited surface current nulls in the system ground plane for the operating frequencies in the upper band. The observed radiation patterns also show no special distinctions as compared to those of the conven-

6 1378 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 5, MAY 2009 Fig. 10. Measured antenna gain and radiation efficiency for the proposed PIFA. (a) Lower band for GSM850/900 operation. (b) Upper band for GSM1800/1900/ UMTS operation. Fig. 12. Simulated SAR distributions at 859, 925, 1795, 1920 and 2045 MHz. (a) Antenna at the top position. (b) Antenna at the bottom position. Fig. 11. SAR simulation model (SEMCAD [23]) with the proposed PIFA at the top and bottom positions of the system ground plane. tional internal mobile phone antennas in the 1800 MHz band [1]. Fig. 10 presents the measured antenna gain and radiation efficiency. For the lower band shown in Fig. 10(a), the antenna gain is varied from about 0.5 to 2.1 dbi, while the radiation efficiency is ranged from about 58% to 92%. For the upper band in Fig. 10(b), the antenna gain is in the range of 0.8 to 4.2 dbi, and the radiation efficiency is about 50% to 80%. Acceptable radiation characteristics for practical applications are obtained for the proposed PIFA. The SAR study is given in Figs. 11 and 12. The SAR simulation model (SEMCAD [23]) with the two cases of the proposed PIFA at the top and bottom positions of the system ground plane is shown in Fig. 11. The obtained SAR results in 1 g and 10 g of head tissue from exposure to the antenna radiation are listed in Table I for comparison. For 859 and 925 MHz, the SAR is tested using 24 dbm, while for 1795, 1920 and 2045 MHz, SAR is tested using 21 dbm (both considering a user channel being 1/8 of a time slot only). When the antenna is mounted at the bottom position, large SAR decreases for both 1-g and 10-g cases are seen for frequencies (1795, 1920, and 2045 MHz) in the upper band, as compared to those at the top position. For frequencies (859 and 925 MHz) in the lower band, the SAR value is also decreased comparing the top-position case to the bottom-position case; however, the SAR decrease is relatively much smaller than that for the bottom position. This is largely because the system ground plane plays a more dominant role as a radiator in the lower band than in the upper band [24]. However, it is seen that the 10-g SAR results at all frequencies meet the SAR limit of 2.0 W/kg for both the top and bottom positions. For the case of 1-g head tissue, however, the SAR results at 859 and 925 MHz exceed the SAR limit of 1.6 W/kg, even for the antenna at the bottom position. The simulated SAR distributions in 1-g head tissue at 859, 925, 1795, 1920, and 2045 MHz are shown in Fig. 12. In the figure the square marks represent the local SAR maximum. For higher frequencies (1795, 1920, and 2045 MHz), there are two local SAR maximums for the bottom-position case, while there is only one local SAR maximum for the top-position case. This explains the observed SAR

7 CHANG AND WONG: PRINTED 8-PIFA FOR PENTA-BAND WWAN OPERATION IN THE MOBILE PHONE 1379 TABLE I SIMULATED SAR IN 1-g AND 10-g HEAD TISSUES OBTAINED FROM SEMCAD [23] FOR THE ANTENNA PLACED AT THE TOP AND BOTTOM POSITIONS OF THE MOBILE PHONE WITH THE PRESENCE OF THE USER S HEAD TABLE II SIMULATED NEAR-FIELD STRENGTHS FOR THE HAC SIMULATION MODEL IN FIG. 13. NOTE THAT FOR FREQUENCIES BELOW 960 MHz, THE STRENGTH LEVEL OF THE CATEGORY IS ALLOWED TO BE 10 db STRONGER THAN THAT OF THE SAME CATEGORY AT 1795, 1920 AND 2045 MHz ACCORDING TO THE STANDARD ANSI C [17]. ALSO, THE STRENGTH LEVEL OF THE CATEGORY FOR THE UMTS SYSTEM IS ALLOWED TO BE 2.5 db STRONGER THAN THAT OF THE SAME CATEGORY FOR THE GSM SYSTEM [17] decrease listed in Table I, because the two local SAR maximums indicate that the radiation energy is more uniformly distributed for the bottom-position case, hence resulting in large decreased SAR results. For lower frequencies (859 and 925 MHz), there is only one local SAR maximum for both the top- and bottom-position cases. However, the local SAR maximum is still shifted away from the ear position of phantom head for the bottom-position case; this causes the SAR decrease seen in Table I. Although the SAR results at 859 and 925 MHz exceed the SAR limit of 1.6 W/kg for the bottom-position case, it is still possible that the SAR results can be further decreased for the proposed PIFA in practical applications, where the lossy associated electronic elements like the LCD panel, the battery and so on can have some effects on reducing the SAR effect. The HAC study is also conducted using the simulation model (SEMCAD [23]) shown in Fig. 13, where the proposed PIFA is placed at the bottom position. Note that, from the SAR analysis, since the proposed PIFA is more suitable to be placed at the bottom position of the mobile phone to achieve decreased SAR values for practical applications, the HAC study is only conducted for the bottom-position case. Table II lists the simulated near-field strengths at 859, 925, 1790, 1920, and 2045 MHz, and the simulated near-field distributions at 925 and 1795 MHz are shown in Fig. 14 for comparison. Based on the HAC stan- Fig. 13. HAC simulation model (SEMCAD [23]) for the proposed PIFA at the bottom position. dard ANSI C [17], the results are evaluated at the reference plane centered 10 mm above the center of the acoustic output in the mobile phone casing. The delivered power is 33 dbm (2 Watt continuous wave power) at 859 and 925 MHz, 30 dbm (1 Watt continuous wave power) at 1795 and 1920, and 21 dbm (0.125 Watt continuous wave power) at

8 1380 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 5, MAY 2009 proposed PIFA at the bottom position of the mobile phone, it is possible that acceptable SAR values and HAC ratings meeting the requirements for practical applications be obtained. Fig. 14. Simulated near-field distributions at 925 and 1795 MHz for the proposed PIFA at the bottom position MHz. The reference plane is divided into nine equal cells, and based on the rating methodology provided by the ANSI standard, the E-field and H-field strengths are determined by excluding three consecutive cells along the boundary of the reference plane that have the strongest field strengths [see the three crossed cells in each near-field distribution shown in Fig. 14]. From the results, a mobile phone with the studied geometry in Fig. 13 falls into the M2 category for all five operating frequencies, which is close to the M3 category to be considered hearing aid-compatible for acoustic coupling [14]. Hence, when it is tested under the practical mobile phone condition in which lossy associated electronic elements are present, the near-field emission of the mobile phone could be decreased and it is possible that the practical mobile phone with the studied geometry in Fig. 13 meets the M3 rating as a hearing aid-compatible wireless device. IV. CONCLUSION A small-size -PIFA suitable for internal mobile phone antenna application has been proposed and studied. The proposed PIFA is easily printed on the no-ground portion of the system circuit board of the mobile phone at low cost and occupies a very small area of 465 only, owing to the successful excitation of the mode as the fundamental resonant mode. The PIFA generates two wide operating bands at about 900 and 1900 MHz to cover GSM850/900 and GSM1800/1900/UMTS operations, respectively. Good impedance matching of the two wide operating bands is achieved by using the coupling feed in the proposed PIFA. The SAR and HAC analyses of the proposed PIFA have also been conducted. Results indicate that by placing the REFERENCES [1] K. L. Wong, Planar Antennas for Wireless Communications. New York: Wiley, [2] Y. X. Guo, M. Y. W. Chia, and Z. N. Chen, Miniature built-in multiband antennas for mobile handsets, IEEE Trans. Antennas Propag., vol. 52, pp , Aug [3] Y. S. Shin, B. N. Kim, W. I. Kwak, and S. O. Park, GSM/DCS/IMT triple-band built-in antenna for wireless terminals, IEEE Antennas Wireless Propag. Lett., vol. 3, pp , [4] M. Z. Azad and M. Ali, A miniaturized Hilbert PIFA for dual-band mobile wireless applications, IEEE Antennas Wireless Propag. Lett., vol. 4, pp , [5] K. L. Wong, Y. C. Lin, and T. C. Tseng, Thin internal GSM/DCS patch antenna for a portable mobile terminal, IEEE Trans. Antennas Propag., vol. 54, pp , Jan [6] K. L. Wong, Y. C. Lin, and B. Chen, Internal patch antenna with a thin air-layer substrate for GSM/DCS operation in a PDA phone, IEEE Trans. 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9 CHANG AND WONG: PRINTED 8-PIFA FOR PENTA-BAND WWAN OPERATION IN THE MOBILE PHONE 1381 Chih-Hua Chang (S 07) was born in Taipei, Taiwan, in He received the B.S. degree in electrical engineering from Feng-Chia University, Taichung, in 2004 and the M.S. degree in electrical engineering from National Sun Yat-Sen University, Kaohsiung, Taiwan, in 2006, where he is currently working toward the Ph.D. degree. His main research interests are in planar antennas for wireless communications, especially for mobile devices, WWAN, WLAN, and WiMAX applications. Mr. Chang was awarded the third place at the National (Taiwan) Mobile Handset Antenna Design Competition in 2006 and Kin-Lu Wong (M 91 SM 97 F 07) received the B.S. degree in electrical engineering from National Taiwan University, Taipei, Taiwan, and the M.S. and Ph.D. degrees in electrical engineering from Texas Tech University, Lubbock, TX, in 1981, 1984, and 1986, respectively. From 1986 to 1987, he was a Visiting Scientist with Max-Planck-Institute for Plasma Physics in Munich, Germany. Since 1987, he has been with the Department of Electrical Engineering, National Sun Yat-sen University (NSYSU), Kaohsiung, Taiwan, where he became a Professor in In 2005, he was elected to be Sun Yat-sen Chair Professor of National Sun Yat-sen University. He also served as Chairman of the Electrical Engineering Department from 1994 to 1997, Dean of the Office of Research Affairs from 2005 to 2008, and Vice President for Academic Affairs from 2007 till now at the same university. From 1998 to 1999, he was a Visiting Scholar with the ElectroScience Laboratory, The Ohio State University, Columbus. He has published more than 440 refereed journal papers and numerous conference articles and has graduated 46 Ph.D. students. He also holds over 100 patents, including U.S., Taiwan, China, Korea, European patents, and has many patents pending. He is the author of Design of Nonplanar Microstrip Antennas and Transmission Lines (New York: Wiley, 1999), Compact and Broadband Microstrip Antennas (New York: Wiley, 2002), and Planar Antennas for Wireless Communications (New York: Wiley, 2003). Dr. Wong received the Outstanding Research Award three times from National Science Council of Taiwan in 1994, 2000 and 2002, and was elevated to be a Distinguished Research Fellow of National Science Council of Taiwan in He also received the Outstanding Research Award from National Sun Yat-Sen University in 1994 and 2000, the Outstanding Textbook Award for Microstrip Antenna Experiment (in Chinese) from Ministry of Education of Taiwan in 1998, the ISI Citation Classic Award for a published paper highly cited in the field in 2001, the Outstanding Electrical Engineer Professor Award from Institute of Electrical Engineers of Taiwan in 2003, and the Outstanding Engineering Professor Award from Institute of Engineers of Taiwan in In 2008, the research achievements of Handheld Wireless Communication Devices Antenna Design of the NSYSU Antenna Lab he led was selected to be one of the top 50 scientific achievements of National Science Council of Taiwan in past 50 years ( ). He has been on the editorial board of the IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES,MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, and Chinese Journal of Radio Science (China). He is a member of the National Committee of Taiwan for URSI, Institute of Antenna Engineers of Taiwan (IAET), Microwave Society of Taiwan, Institute of Electrical Engineers of Taiwan, and Institute of Engineers of Taiwan. He is listed in Who s Who of the Republic of China (Taiwan) and Marquis Who s Who in the World.