Paper Title (use style: paper title)

Size: px

Start display at page:

Download "Paper Title (use style: paper title)"

榕根呼延
5 years ago
Views:

1 Printed Multiband Antenna for Mobile and Wireless Communications Cecep Ginanjar Permana Radio Telecommunication and Microwave Laboratory School of Electrical Engineering and Informatics Institut Teknologi Bandung Bandung, Indonesia Achmad Munir Radio Telecommunication and Microwave Laboratory School of Electrical Engineering and Informatics Institut Teknologi Bandung Bandung, Indonesia Abstract In this paper, a low profile printed multiband antenna is numerically investigated and experimentally measured. The antenna is proposed to be used for GSM-850, GSM-900, UMTS- 2100, WiMAX-2.3 and WiMAX-3.3. It is developed from the existing tripleband microstrip antenna that works on frequency of 2GHz, 3.5GHz and 5.5GHz. To improve the coverage of frequency bands, the existing antenna structure is totally redesigned using FR-4 Epoxy substrate with permittivity of 4.3 and thickness of 0.8mm to produce a new antenna configuration that works at desired frequency bands. To have the proposed antenna to be as compact as possible, the meandering strip technique is applied to minimize the antenna dimension. Hence, to be possible being fed in planar, the microstrip line technique is used to feed the antenna. Prior to the fabrication, the proposed antenna is numerically designed in which some parameters of antenna including return loss, VSWR, bandwidth, gain, and radiation patternare used as design indicators. Based on the design result, the antenna with total dimension of 32mm x 32mmis then realized to be experimentally characterized. From the measured result, it is shown that the proposed antenna has working bandwidths (VSWR<2) for frequency ranges of MHz, MHz and MHz that corresponds to frequency ranges of GSM-850, GSM-900, UMTS-2100, WiMAX-2.3 and WiMAX-3.3, respectively. In addition, the measurement results of antenna parameters show good agreements with the numerical results. Keywords-antenna parameters, meandering strip, microstrip line, multiband, printed antenna. I. INTRODUCTION In mobile communications, there is some technological function, namely cellular technology that is often used, such as GSM (Global System for Mobile communication) as 2 nd generation and UMTS (Universal Mobile Telecommunications System) as 3 rd generation. GSM has different frequency bands in every country, for example GSM-850 (uplink MHz and downlink MHz) is used mostly in the America, whilst primary GSM-900 (uplink MHz and downlink MHz) and DCS-1800 (uplink MHz and downlink MHz) are mainly used in several countries in Asia, Europe, Africa and Australia. UMTS frequency commonly used at several countries including Indonesia is at 2100MHz frequency band (uplink MHz and downlink MHz)[1]. Beside the cellular technology, some technology developed in wireless communications is WiMAX (Worldwide Interoperability Mobile Access) technology. Similar to the cellular technology, WiMAX technology that provides wireless transmission of data with different modes of transmission requires different frequency bandsfor each country. In terms of transmission speed, this technology is higher than UMTS. In Indonesia, two main frequency bands have been allocated for WiMAX services based on the decision of the Minister of Communications and Informatics in 2009, there are in frequency bands of GHz and GHzfor fixed and mobile WiMAX services, respectively [2]. The different frequency bands used in mobile and wireless communications have driven the demand of antenna that can operate in multiband frequencies. Although, there is a fact that the size reduction levels remain unsatisfactory to the expectation, a microstrip-patch antenna is one of the antennas which may overcome this kind of demand due to its inherent capabilities such as low cost, low weight, low profile, and multi-band support [3]-[6]. Further, as the space in recent telecommunication devices is very limited, it is required a compacter antenna, therefore the type of microstrip-patch antenna is almost suitable for the purpose. Other kind of antenna that can accomplish the need and has similar capabilities as of microstrip-patch antenna is IFA (Inverted-F Antenna)and planar antenna [7]-[9]. However, these types of antenna have specific characteristics and can only be used for specific applications. To cover all mentioned frequency bands in a radiating device, a multiband antenna is proposed to be designed and realized. The proposed antenna structure that is printed on FR- 4 Epoxy substrate is developed from the existing structure in [9] with some enhancement in parameters to be able operate at desired frequency bands. In the design process, the structure of proposed antenna is investigated to obtain optimum design architecture. Some parameters of antenna as keys of design criteria are analyzed numerically. Hence, some techniques to minimize the antenna dimension and to feed the antenna input are discussed in order to have an antenna with the dimension as compact as possible. After the realization, the fabricated antenna is then characterized experimentally in which the results are compared with the numerical ones. This work is partially supported by the Asahi Glass Foundation Research Grant 2011, Japan /11/$ IEEE 236

2 II. ANTENNA DESIGN A. Multiband Antenna Design Based on the existing antenna structure in [9], in order to operate at several frequency bands, the existing structure should be reconfigured by modifying each strip as well as its ground plane. The dielectric substrate for antenna deployment is also changed from RT/Duroid 5880 substrate ( r of 2.2 and thickness of 0.254mm) to FR-4 Epoxy substrate ( r of 4.3 and thickness of 0.8mm) to have a smaller antenna dimension compared to the existing one. In addition, the microstrip line feeding technique is applied for the antenna to be able feed by an SMA type connector. As the shape of each strip of antenna is in rectangular shape, to obtain its working frequency in TM mn mode it can be numerically calculated using the following equation [5]. f mn c 2 r 2 L m 2 n W where r, L, and W are the relative permittivity of used dielectric substrate, the length and the width of strip, respectively. The TM 10 mode is commonly used for determining the working frequency of rectangular strip as it is a dominant mode. Therefore, the length of strip will play an important role in determination of working frequency. To generate the frequency band of 900MHz to be used for GSM-850 and GSM-900, the most efficient technique is by adding the length of S-strip. This will shift the lowest frequency band of existing structure from 2GHz to 900MHz. Hence, to get frequency band on 2GHz for UMTS uplink, it is performed by making longer the length of T-strips. Then, the frequency bandof 2.1GHz for UMTS downlink and WIMAX- 2.3 will be produced by the V-strip, whilst the H-strip will produce the frequency band of 3.3GHz for WiMAX-3.3. The initial design of proposed antenna is illustrated in Fig. 1 where the height of S-strip (a) is 25mmand the length of V-strip (b) is 28.25mm, so the total antenna dimension including its feeding network is about 45.5mmx29mm. By adjusting the length of each strip, the desired frequency bands of GSM-850, GSM-900, UMTS-2100, WiMAX-2.3 and WiMAX-3.3 can be obtained. The simulated result of return loss is depicted in Fig. 2. It is seem that the VSWR on frequency band of 3.3GHz needs to be improved. (1) Figure 2. Simulated result of return loss for initial design of multiband antenna B. Meandering Technique and Feeding Network From Fig. 1, it can be seen that the dimension of initial design of multiband antenna is bigger than the existing antenna. Therefore, some effort to miniaturize the antenna should be conducted especially for V-strip and S-strip. Here, a meandering technique is applied to reduce the size of antenna by making the strips in a coil-like or snake-like shape. To perform the technique on V-stripas well as the S-strip, the strip width is made as small as possibleto be more easily folded. The effect of varying the width of meandered V-strip to the antenna performance is plotted in Fig.3.It seems that the width variation of meandered V-strip has no significant effect in the determination of working frequency. It should be noted that the length of meandered V-strip is more dominant to generate the working frequency around 2GHz instead of the width. This also applies for other working frequencies in connection with the length of each strip. Figure 3. Simulated result of return loss as the width variation of meandered V-strip Figure 1. Initial design of multiband antenna for GSM-850, GSM-900, UMTS-2100, WiMAX-2.3 and WiMAX-3.3 As the next step, the similar treatment to make a compacter multiband antenna is also applied to the T-strip and H-strip. Here, as the H-strip is responsible to produce the frequency band of 3.3GHz, the length of H-strip is the shortest one compared to others. Hence, to feed the proposed antenna using an SMA type connector, a microstrip line technique is applied as the feeding network using a /4 transmission line with the impedance of 50. The microstrip line is placed in planar to the antenna to be easier in the fabrication. Furthermore, in order to match with the impedance of feeding network, 2 strips connected to the microstrip line, i.e. T-strip and V-strip have to be 100 of each /11/$ IEEE 237

The width of 50 microstrip line and 100 strips can be obtained using equations in [3]-[5] in which the used material is FR-4 Epoxy substrate with r of 4.3 and thickness of 0.8mm.

5mm, although it will affect to the performance of antenna therefore the width for 100 strips is set to be 0.5mm. In addition, to avoid the higher-order mode excited by the feeding network, the 50 microstrip line is reduced by cutting the angleon its bended-corner.

Fabricated multiband antenna for GSM-850, GSM-900, UMTS- 2100, WiMAX-2.3 and WiMAX-3.3 (a) front view, (b) back view (a) (b) Figure 4.

PARAMETERS OF PROPOSED MULTIBAND ANTENNA Parameter Dimension (mm) P 32.00 L 32.00 C 1 11.10 C 2 6.25 C 3 4.10 G 2.20 V 1 6.10 V 2 5.40 H 1 21.50 H 2 6.00 T 16.00 G r 11.10 S 1 2.60 S 2 16.50 S 3 13.

3 The width of 50 microstrip line and 100 strips can be obtained using equations in [3]-[5] in which the used material is FR-4 Epoxy substrate with r of 4.3 and thickness of 0.8mm. From the calculation, the widths are 1.5mm and 0.4mm for 50 microstrip line and 100 strips, respectively. However, due to the issue of manufacturing process that limits the strip width no less than 0.5mm, although it will affect to the performance of antenna therefore the width for 100 strips is set to be 0.5mm. In addition, to avoid the higher-order mode excited by the feeding network, the 50 microstrip line is reduced by cutting the angleon its bended-corner. As a result, the final designof multiband antenna as shown in Fig. 4 has total dimension of 32mmx32mm where its parameters are summarized in Table 1. (a) (b) Figure 5. Fabricated multiband antenna for GSM-850, GSM-900, UMTS- 2100, WiMAX-2.3 and WiMAX-3.3 (a) front view, (b) back view (a) (b) Figure 4. Final design of multiband antenna for GSM-850, GSM-900, UMTS-2100, WiMAX-2.3 and WiMAX-3.3 (a) front view, (b) back view TABLE I. III. PARAMETERS OF PROPOSED MULTIBAND ANTENNA Parameter Dimension (mm) P L C C C G 2.20 V V H H T G r S S S S S S FABRICATION AND CHARACTERIZATION From the design result, the proposed multiband antenna is then deployed on a double-side FR-4 Epoxy substrate with r of 4.3 and thickness of 0.8mm. Figure 5 shows the pictures of prototype fabricated multiband antenna to be characterized experimentally. The characterization includes the measurement of some basic parameters such as return loss, VSWR, gain and radiation pattern. Then, the results are verified and compared with the numerical design results. A. Return Loss and VSWR Figures 6 and 7 show the measured result of return loss and VSWR respectively. As comparison, the numerical design result of each is also depicted together consecutively. It is seen that from numerical design result plotted in Fig. 6, the frequency bands of GSM-850 and GSM-900 are covered by a band that has a bandwidth of 180MHz from 810MHz to 990MHz with the lowest return loss value of db at frequency 870MHz (VSWR = 1.12 shown at Fig. 7). However, from measurement result it shows that the working bandwidth only covers from 800MHz to 920MHz with the lowest VSWR of at 820MHz, Fig. 7, so that the frequency band of GSM-900 is not completely covered.this is probably evoked by the inaccuracy of manufacturing process with some capability limitation in the fabrication of minimum strip width. Hence, the frequency bands of UMTS-2100 and WiMAX- 2.3 are covered by 2 adjacent bands each other for the numerical design result. Those bands are around 1900MHz used for the UMTS-2100 uplink, whilst the UMTS-2100 downlinkis covered by another band which also includes the frequency band for WiMAX-2.3. Both these frequency bands has bandwidth of 490MHz from 1920MHz to 2410MHz with the lowest return loss value for the first band of 30.17dB at 1940MHz(VSWR = 1.06shown in Fig. 7) and for the second band of 26.86dB at 2250MHz (VSWR = 1.10 shown in Fig. 7). In the measurementresult, although the bandwidth response is only from 1900MHz to 2400MHz, Fig. 7, however it is still able to cover very well the frequency bands for UMTS-2100 and WiMAX-2.3 with VSWR value of 1.16 and 1.23 at frequencies of 1920MHz and 2240MHz, respectively. Furthermore, in the numerical design result the frequency band of WiMAX-3.3 is covered by a band with bandwidth of 190MHz ranging from 3280MHz to 3470MHzwith the lowest return loss value of 17.25dB (VSWR = 1.32 shown in Fig. 7) at center frequency of 3390MHz. Whilst in the measurement result, it is covered by a band with bandwidth of 120MHz ranging from 3300MHz to 3420MHz with the lowest return loss value of 13.32dB (VSWR = 1.55 shown in Fig. 7) at center frequency of 3360MHz. Again, the difference is probably affected by the inaccuracy of manufacturing process causes the narrower bandwidth response /11/$ IEEE 238

Figure 6. Simulated and measured results of return loss Figure 9.

Simulated and measured results of VSWR B.

Figure 8 shows the measured gain for each frequency band, whilst Fig.

From the numerical design result,it shows the maximum gain value for each frequency

58dB for WiMAX-2.3 and -0.02dB for WiMAX-3.3. While from measurementresult, the maximum gain is -3.

4 Figure 6. Simulated and measured results of return loss Figure 9. Simulated gain of multiband antenna for each frequency band Figure 7. Simulated and measured results of VSWR B. Gain and Radiation Patterns The next step of experimental characterization is gain measurement for each frequency band. To obtain the optimum result, the gain measurement is taken at the maximum value. Figure 8 shows the measured gain for each frequency band, whilst Fig. 9 plots the gain of numerical design result as comparison. From the numerical design result,it shows the maximum gain value for each frequency band is dB for GSM-850, dB for GSM-900, -2.37dB for UMTS-2100, dB for WiMAX-2.3 and -0.02dB for WiMAX-3.3. While from measurementresult, the maximum gain is -3.10dB for GSM-850 and GSM-900, 1.18dB for UMTS-2100, 0.14dB for WiMAX-2.3 and -2.69dB for WiMAX-3.3. From the results, it is indicating that the gain of proposed antenna is quite low almost for all frequency bands. This occurs as the dimension of antenna aperture is too small whilst the gain is proportional to the antenna aperture. Figure 8. Measured gain of multiband antenna for each frequency band (a) (b) Figure 10. Simulated and measured results of radiation patterns foreach frequency band (a) E-plane and (b) H-plane /11/$ IEEE 239

5 Figure 10 shows the radiation patterns of multiband antenna for E-plane and H-plane for each frequency bands at maximum gain. Both in the numerical design and measurement result, it shows that for each frequency band taken at the maximum gain has different angles both of and. This means that for each frequency band is dominated by its respective strip. From the measurementresult, it is seen that the radiation patterns shows a different shape and not as smoothas to the numerical design result because of the manufacturing issue, however it is still acceptable for some far-field distance and can resemble the simulation results qualitatively. IV. CONCLUSIONS A printed multiband antenna for mobile and wireless communications has been numerically designed and experimentally characterized. The antenna that has a compact dimension of 32mmx32mm including its /4 transmission line as a feeding network was deployed on FR-4 Epoxy substrate with r of 4.3 and thickness of 0.8mm. It consists of 4 meandering stripsin which each of strips has designated for each frequencyband. One of the strips was located at the groundplane side to produce the frequency band of GSM-850 and GSM-900, while other three stripswere printed oppositely to the ground plane side to obtain the frequency bands of UMTS-2100, WiMAX-2.3 and WiMAX-3.3. From the results of numerical design and experimental characterization, although there was a slight different in the shape of radiation patterns and the overall gain was quite low, however it has been shown that the characteristics of proposed antenna had good agreements each other in terms of return loss, bandwidth, VSWR, and gain. It has also been demonstrated that the meandering technique could make the dimensions of proposed antenna to be smallerand compacter, whilst the microstrip line technique has made the proposed antenna ease for the fabrication. In addition, the gain improvement and size reduction of fabricated multiband antenna are still being investigated for the current research where the result will be reported in the near future. REFERENCES [1] T. S. Rappaport, Wireless Communication Principles and Practice, New Jersey: Prentice Hall, 1996, pp [2] Decision No 4, 5, 7, 8 and 9/KEP/M.KOMINFO/01/2009, accessed 17 May [3] J. R. James and P. S. Hall, Handbook of Microstrip Antennas, London: Peter Peregrines, [4] D. M. Pozar and D. H. Schaubert, Microstrip Antennas: The Analysis and Design of Microstrip Antennas and Arrays, New York: IEEE Press, [5] P. Bhartia, I. Bahl, R. Garg, and A. Ittipiboon, Microstrip Antenna Design Handbook, Norwood: Artech House, [6] G. Kumar and K. P. Ray, Broadband Microstrip Antenna, London: Artech House, [7] C. Soras, M. Karaboikis, G. Tsachtiris and V. Makos, Analysis and design of an inverted-f antenna printed on a PCMCIA card for the 2.4 GHz ISM band, IEEE Antenna s and Propagation Magazine, vol. 44, no. 1, Feb [8] M. Napitupulu and A. Munir, Compact dual band inverted-f antenna for 2.3GHz and 3.3GHz WiMAX application, 4 th Indonesia Japan Joint Scientific Symposium (IJJSS) 2010 Proc., Bali, Indonesia, Sep [9] R. L. Li, B. Pan, T. Wu, J. Laskar, and M. M. Tentzeris, A triple-band low-profile planar antenna for wireless applications, Antennas and Propagation Society (AP-S) International Symposium 2008 Proc., San Diego, USA, Jul /11/$ IEEE 240

易迪拓培训专注于微波射频天线设计人才的培养网址 :http://www.edatop.com 射频和天线设计培训课程推荐易迪拓培训 (www.edatop.com) 由数名来自于研发第一线的资深工程师发起成立, 致力并专注于微波射频天线设计研发人才的培养 ; 我们于 2006 年整合合并微波 EDA 网 (www.mweda.

永业科技全一电子等多家台湾地区企业易迪拓培训课程列表 :http://www.edatop.com/peixun/rfe/129.

6 易迪拓培训专注于微波射频天线设计人才的培养网址 : 射频和天线设计培训课程推荐易迪拓培训 ( 由数名来自于研发第一线的资深工程师发起成立, 致力并专注于微波射频天线设计研发人才的培养 ; 我们于 2006 年整合合并微波 EDA 网 ( 现已发展成为国内最大的微波射频和天线设计人才培养基地, 成功推出多套微波射频以及天线设计经典培训课程和 ADS HFSS 等专业软件使用培训课程, 广受客户好评 ; 并先后与人民邮电出版社电子工业出版社合作出版了多本专业图书, 帮助数万名工程师提升了专业技术能力客户遍布中兴通讯研通高频埃威航电国人通信等多家国内知名公司, 以及台湾工业技术研究院永业科技全一电子等多家台湾地区企业易迪拓培训课程列表 : 射频工程师养成培训课程套装该套装精选了射频专业基础培训课程射频仿真设计培训课程和射频电路测量培训课程三个类别共 30 门视频培训课程和 3 本图书教材 ; 旨在引领学员全面学习一个射频工程师需要熟悉理解和掌握的专业知识和研发设计能力通过套装的学习, 能够让学员完全达到和胜任一个合格的射频工程师的要求课程网址 : ADS 学习培训课程套装该套装是迄今国内最全面最权威的 ADS 培训教程, 共包含 10 门 ADS 学习培训课程课程是由具有多年 ADS 使用经验的微波射频与通信系统设计领域资深专家讲解, 并多结合设计实例, 由浅入深详细而又全面地讲解了 ADS 在微波射频电路设计通信系统设计和电磁仿真设计方面的内容能让您在最短的时间内学会使用 ADS, 迅速提升个人技术能力, 把 ADS 真正应用到实际研发工作中去, 成为 ADS 设计专家... 课程网址 : HFSS 学习培训课程套装该套课程套装包含了本站全部 HFSS 培训课程, 是迄今国内最全面最专业的 HFSS 培训教程套装, 可以帮助您从零开始, 全面深入学习 HFSS 的各项功能和在多个方面的工程应用购买套装, 更可超值赠送 3 个月免费学习答疑, 随时解答您学习过程中遇到的棘手问题, 让您的 HFSS 学习更加轻松顺畅课程网址 : `

易迪拓培训专注于微波射频天线设计人才的培养网址 :http://www.edatop.

7 易迪拓培训专注于微波射频天线设计人才的培养网址 : CST 学习培训课程套装该培训套装由易迪拓培训联合微波 EDA 网共同推出, 是最全面系统专业的 CST 微波工作室培训课程套装, 所有课程都由经验丰富的专家授课, 视频教学, 可以帮助您从零开始, 全面系统地学习 CST 微波工作的各项功能及其在微波射频天线设计等领域的设计应用且购买该套装, 还可超值赠送 3 个月免费学习答疑课程网址 : HFSS 天线设计培训课程套装套装包含 6 门视频课程和 1 本图书, 课程从基础讲起, 内容由浅入深, 理论介绍和实际操作讲解相结合, 全面系统的讲解了 HFSS 天线设计的全过程是国内最全面最专业的 HFSS 天线设计课程, 可以帮助您快速学习掌握如何使用 HFSS 设计天线, 让天线设计不再难课程网址 : MHz NFC/RFID 线圈天线设计培训课程套装套装包含 4 门视频培训课程, 培训将 13.56MHz 线圈天线设计原理和仿真设计实践相结合, 全面系统地讲解了 13.56MHz 线圈天线的工作原理设计方法设计考量以及使用 HFSS 和 CST 仿真分析线圈天线的具体操作, 同时还介绍了 13.56MHz 线圈天线匹配电路的设计和调试通过该套课程的学习, 可以帮助您快速学习掌握 13.56MHz 线圈天线及其匹配电路的原理设计和调试详情浏览 : 我们的课程优势 : 成立于 2004 年,10 多年丰富的行业经验, 一直致力并专注于微波射频和天线设计工程师的培养, 更了解该行业对人才的要求经验丰富的一线资深工程师讲授, 结合实际工程案例, 直观实用易学联系我们 : 易迪拓培训官网 : 微波 EDA 网 : 官方淘宝店 : 专注于微波射频天线设计人才的培养易迪拓培训官方网址 : 淘宝网店 :

ANSYS 在航空航天器电磁兼容、电磁干扰分析中的应

ANSYS 在航空航天器电磁兼容、电磁干扰分析中的应易迪拓培训专注于微波射频天线设计人才的培养网址 :http://www.edatop.com 射频和天线设计培训课程推荐易迪拓培训 (www.edatop.com) 由数名来自于研发第一线的资深工程师发起成立, 致力并专注于微波射频天线设计研发人才的培养 ; 我们于 2006 年整合合并微波 EDA 网 (www.mweda.com), 现已发展成为国内最大的微波射频和天线设计人才培养基地,