A miniaturized dual-band antenna for long-term evolution system template

and so forth, it will take long time to get samples and take the concentration test.

The LPG system has the obvious advantages, for example, real-time monitoring which can improve the efficiency of sew-age treatment process can also be implemented due to LPG’s fast response and high precision. The LPG is of great signifi-cance to the design of new sewage treatment system. The LPG system has some disadvantage too. The demodulation device used in the detection system is the optical spectrum analyzer which is expensive, bulky, and is inconvenient to be carried. In future research, demodulation device which has low cost and small size should be developed for engineering applications. 4. CONCLUSION

Dimethoate solution which belongs to the phosphorodithioate class is chosen as the representative of degradation of organo-phosphorus pesticides in wastewater. The long-period fiber gra-ting resonant wavelength has a certain good relationship with the concentration of dimethoate solution. Based on it, an on-line real-time monitoring the degradation of dimethoate solution is realized by the LPG. The degradation of dimethoate solution is achieved by the EC technology and ultrasound. The method using long-period fiber grating to measure liquid concentration or refractive index measurement has a simple structure, it can monitor and operate instantaneously. The entire system achieves all-fiber technology, it has a good prospect. The experimental results presented in this article were shown that making use of the LPG is an attractive method of permitting on-line measure-ments. The research in this article can promote the combination of the fiber-grating sensor technology and the organophosphorus pesticide sewage monitoring technology. In future, we will make some research by coating the LPG with a layer of polymer or metal film to improve on the sensitivity for our target analytes.

ACKNOWLEDGMENT

This work was supported by the key national natural science foun-dation (Nos. 61201109; 51007002; 51275239) and Anhui Province Key Project of Natural Science Foundation (Nos. KJ2010A341; KJ2011Z031).

REFERENCES

1. D. Pant, Waste glass as absorbent for thin layer chromatography (TLC), Waste Manag 29 (2009), 2040–2041.

2. M. Clariana, M. Gratac
os-Cubarsı´, M. Hort
os, J.A. Garcı´a-Reg-ueiro, and M. Castellari, Analysis of seven purines and pyrimidines in pork meat products by ultra high performance liquid chromatog-raphy–Tandem mass spectrometry, J Chromatogr A 1217 (2010), 4294–4299.

3. I. Kristiana, A. Heitz, C. Joll, and A. Sathasivan, Analysis of poly-sulfides in drinking water distribution systems using headspace solid-phase microextraction and gas chromatography–mass spec-trometry, J Chromatogr A 1217 (P2010), 5995–6001.

4. C. Silva, J.M.P. Coelho, P. Caldas, O. Fraza˜o, P.A.S. Jorge, and J.L. Santos, Optical fiber sensing system based on long-period gra-tings for remote refractive index measurement in aqueous environ-ments, Fiber Integrated Opt 29 (2010), 160–169.

5. T. Erdogan, Fiber grating spectra, J Lightwave Technol 15 (1997), 1277–1294.

6. V. Bhatia, Applications of long-period gratings to single and multi-parameter sensing, Opt Express 4 (1999), 457–466.

7. T. Erdogan, Cladding-mode resonances in short- and long-period fiber grating filters, J Opt Soc Am A 14 (1997), 1760–1773. 8. X. Shu, L. Zhang, and I. Bennion, Sensitivity characteristics of

long-period fiber gratings, J Lightwave Technol 20 (2002), 255–266. 9. M.Y.A. Mollah, R. Schennach, J.R. Parga, and D.L. Cocke,

Elec-trocoagulation (EC)—Science and applications, J Hazard Mater B 84 (2001), 29–41.

VC_{2013 Wiley Periodicals, Inc.}

A MINIATURIZED DUAL-BAND ANTENNA

FOR LONG-TERM EVOLUTION SYSTEM

TEMPLATE

Chih Peng Lin, T. Y. Lin, Jie-Huang Huang, and Christina F. Jou

School of Communication Engineering Department, National Chiao Tung University, Taiwan; Corresponding author:

jadanz.cm96g@gmail.com

Received 26 September 2012

ABSTRACT: Long-term evolution (LTE) (fourth generation mobile networks) has utilized multiple-input–multiple output (MIMO)

technology to achieve very high data rates in both uplink and downlink. MIMO is based on the multiple antenna systems within the small size mobile terminal. One of the challenges is to miniaturize the mobile terminal. In this article, a compact antenna with the dual-band characteristics, which meet the specification of the LTE frequency band (680–900 MHz and 2.28–2.82 GHz) is proposed. The bandwidths of both the lower and the higher frequency bands are 320 and 540 MHz, respectively. The total size of the antenna is 54 26.6 mm2

. A fairly good agreement has been shown between the simulation and experimental results. The study on the effect of the various antenna parameters has also been discussed.VC _{2013 Wiley Periodicals, Inc.} Microwave Opt Technol Lett 55:1379–1382, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27566

Key words: LTE; MIMO; multiband

1. INTRODUCTION

In recent years, long-term evolution (LTE) [1, 2] has become a pop-ular mobile network technology after GSM (the second generation mobile networks) and Universal Mobile Telecommunications Sys-tem (UMTS; the third generation mobile networks). LTE is a pro-ject of the third Generation Partnership Propro-ject and a set of enhancements to the UMTS. LTE is internet protocol based tech-nology with broader bandwidth, high transmission rate, and less wireless network delay. It will have theoretical peak data rates for downlink of at least 100 Mbps, an uplink of at least 50 Mbps and supporting scalable carrier bandwidths, from 1.4 to 20 MHz.

Generally, there are two operating modes of the LTE system. One is based on time division duplexing (TDD), and the other is based on frequency division duplexing (FDD). FDD using the paired spectrum is anticipated to form the migration path for the current 3G services. TDD using unpaired spectrum is providing the evolution or upgrade path for TD-SCDMA.

For the LTE antenna, designing the lower frequency band will pose some design challenges in the mobile terminal due to size limitations. In this article, the design of the proposed antenna in the lower frequency band is being taken into consideration first, and then the additional technique such as stub and slot are TABLE 2 The Organic Phosphorus Concentration of

Dimethoate Solution Change with the Degradation Time

Degradation Time (min) 10 20 30 40 50 60

Organic phosphorus concentration (mg/L)

37.13 30.05 23.85 20.33 15.91 15.87

applied to improve the bandwidth and gain in the higher fre-quency band. The measured results have shown good agreement with the simulated results.

2. ANTENNA DESIGN

The geometry of the proposed antenna is shown in Figure 1. The fed-in is composed of a 50 X CPW. The substrate is FR4 with a dielectric constant of 4.4 and the thickness of 0.8 mm. Figure 1 Geometry of the proposed antenna with associated parameters

Figure 2 The reflection coefficient variation with differentLh

Figure 3 The reflection coefficient variation with differentLsandWs

Figure 4 The reflection coefficient variation with differentLg

Figure 5 Peak gain value with differentLg

Figure 6 The top view of the fabricated antenna. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

The first step is to consider the design of the lower frequency band (698–894 MHz). The current distribution of the longest resonant path is about 113.2 mm, which is longer than the quar-ter wavelength at 800 MHz. The technique has been proposed in Refs. 3 and 4. It can support the operating frequency from 700 to 900 MHz. Second, to achieve the desired LTE frequency band (2.3–2.7 GHz), an additional path Lhis added to create the

frequency band at 2.8 GHz. Moreover, a slot is added on the CPW ground plane to increase the bandwidth.

To extend the bandwidth to 2.4 GHz, the stubLhis added to

create the current path from the ground plane to its end about 33 mm, which can resonate around 2.4 GHz. As shown in Fig-ure 2, the simulatedS11shifts toward the lower frequency in the

higher frequency band as Lh increases. However, the peak gain

will decrease as Lh increases. Therefore, the optimized Lh is

selected to be 16 mm.

For the slot design [5], varying different sizes of (Ls Ws) will

affect the reflection coefficient as shown in Figure 3. When the size

of (Ls Ws) increases, the bandwidth also increases, but the gain

will decrease. AsLs¼ 4 mm and Ws¼ 4 mm, the proposed antenna

will reach a compromise between the bandwidth and the gain for the higher frequency band (2.3–2.69 GHz) application.

As mentioned earlier, the additional path and the slot on the ground plane are utilized to improve the reflect coefficient in the desire band of the lower frequency band from 680 to 900 MHz and the higher frequency band from 2.28 to 2.82 GHz, respectively. However, the peak gain at the higher frequency band is only 0.3 dB, which is too small for 2.6 GHz application. Therefore, a stub (Lg) is added to increase the gain. The variations on the gain and

the S11 according to Lg have been shown in Figures 4 and 5,

respectively. The peak gain saturates as Lg ¼ 6 mm, and

mean-while theS11is only slightly affected.

According to the above discussions, the optimized parametri-cal values can be decided as follows: L ¼ 54 mm, W ¼ 26.6 mm,Lg¼ 6 mm, Lh¼ 16 mm, Ws¼ 3 mm, and Ls¼ 3 mm.

3. EXPERIMENTAL VERIFICATION

The fabricated antenna is shown in Figure 6, and the total size of the proposed antenna is 54  26.6 mm2_{, which is a fairly}

compact for the applications below 1 GHz.

The simulated and measuredS11 is shown in Figure 7. The

measured result has shown fairly good agreement with the simu-lated result. The slight disagreement should be caused by manu-facturing errors. The frequency shift in the lower frequency band is only 20 MHz. In the higher frequency band, the band-width decreases about 20 MHz, but theS11is improved.

The simulated and the measured radiation patterns at 775 MHz are shown in Figures 8. The conventional monopole pattern and the omnidirectional pattern in thex–z plane have been shown. The radiation patterns at 2570 MHz are shown in Figure 9. Due to the asymmetric structure of the proposed antenna, the main radiation is inx direction.

The simulated peak gain values at 775 and 2570 MHz are
7.7 and 1.5 dB, respectively. The measured gains at each fre-quency are
10 and 1.2 dB, respectively. Notice that in the LTE system, the minimum acceptable gain is
10 dB, which is the same value as our measured result.

Figure 7 The reflection coefficient of the simulated and the measured result

Figure 8 The radiation pattern at 775 MHz in (a)x–z plane; (b) y–z plane; and (c)x–y plane

Figure 9 The radiation pattern at 2570 MHz in (a)x–z plane; (b) y–z plane; and (c)x–y plane

4. CONCLUSION

In this article, a CPW feed, compact size, dual-band antenna for LTE application is presented. The effect on the reflection coeffi-cient according to different design parameters has been shown and discussed. The lower frequency band of the proposed antenna can cover UMTS-800 (830–885 MHz) and GSM850 (824–894 MHz). The higher frequency band can cover IMT-2000 (2300–2400 MHz), bluetooth (2400–2500 MHz), WLAN (2400–2500 MHz), and WiMax (2500–2600 MHz). The total size of the proposed antenna is 54  26.6 mm2

, which is rela-tively small for the application below 1 GHz.

REFERENCES

1. D. Astely, et al., LTE: The evolution of mobile broadband, IEEE Commun Mag 47 (2009), 44–51.

2. A. Ghosh, et al., LTE-advanced: Next-generation wireless broad-band technology, IEEE Wireless Commun 17 (2010), 10–22. 3. W.H. Hsu, et al., Design of a sinuous route monopole antenna for

handset, In: IEEE Asia Pacific Microwave Conference, Singapore, 2009, pp. 2791–2793.

4. C.H. Chang and K.L. Wong, Penta-band one-eighth wavelength PIFA for internal mobile phone antenna, In: IEEE Antennas and Propagation Society International Symposium, Charleston, SC, 2009, pp. 1–4.

5. M.A. Antoniades and G.V. Eleftheriades, A compact multiband monopole antenna with a defected ground plane, IEEE Antennas Wireless Propag Lett 7 (2008), 652–655.

VC_{2013 Wiley Periodicals, Inc.}

MULTIPLE MODE RESONANCE BPF

DESIGN USING SUSPENDED STRIPLINE

WITH SOURCE-LOAD COUPLING

STRUCTURE

Min-Hua Ho,1_{Wanchu Hong,}1_{Hong-Yin Lin,}2 and Po-Fan Chen3

1_{Graduate Institute of Communications Engineering, National} Changhua University of Education, #2, Shih-Da Road, Changhua City, Taiwan 50074, Republic of China; Corresponding author: ho@cc.ncue.edu.tw

2_{Institute of Computer and Communication Engineering, National} Cheng Kung University, #1, University Road, Taiwan 70101, Republic of China

3

King Yuan Electronics Co., Ltd, #81, Section 2, Gongdaowu 5th Road, Hsin-Chu, Taiwan 30070, Republic of China

Received 26 September 2012

ABSTRACT: A multiple-mode resonance bandpass filter of suspended stripline structure is proposed in this article with a source-load coupling feed design. Equivalent quasilumped elements circuit model is developed to represent the proposed filter’s discontinuities and to emulate its frequency responses. The odd- and even-mode equivalent half circuits extracted from the derived LC circuit model are also examined for analyzing the circuit’s mode resonances. Multiple resonances, which relate to two odd modes and two even modes, are observed. The circuit’s physical layout of the proposed filter is guided by the LC circuits, and then the circuit’s dimensions are optimized by sonnet simulation. Experiment is conducted to verify the filter’s performance and agreements between the simulations and the measurements are observed.VC _{2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett} 55:1382–1385, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27565

Key words: quasilumped element; multiple mode resonance; even/odd mode; suspended stripline; source-load coupling

1. INTRODUCTION

The suspended stripline (SSL) was first proposed by Rooney and Underkoefler [1] in 1978. It’s wide range of realizable char-acteristic impedances and high-reachable quality factor made itself a very good candidate in building filter of various func-tions, including low-pass, high-pass, bandstop, and multiplexing. In an SSL configuration, the substrate enclosed by a rectangular metal channel is suspended in air. Hence, most of the SSL’s electromagnetic field is distributed in air, benefits the SSL with low loss, high- quality factor, and sharper band edge. In addi-tion, the SSL structure is more flexible in layout because, with the metal housing serves as the ground, the circuit patterns can be deployed on both sides of the substrate. Furthermore, the metal housing provides isolation between the interior circuit and the exterior space, preventing the former from radiating electro-magnetic fields into the latter and preventing the electroelectro-magnetic noises in the latter from interfering with the former. In building a filter, the housing may be fitted with a variety of RF connec-tors or be equipped with 50-ohm feed-throughs for direct con-nection to MICs.

In the past, filters of SSL structure were proposed by Mobbs and Rhodes[2, 3], who built filters and diplexers in various forms. Recently, Menzel and coworkers [4–7] designed SSL fil-ters and diplexers using quasilumped approach. In their quasi-lumped approach, a few quasi-lumped inductive and capacitive ele-ments accounting for the effects of discontinuities in an SSL component and for the electric or magnetic coupling effects between two adjacent SSL components were used to establish an equivalent LC circuit. Those lumped-element circuit models characterized the resonance frequencies of coupled SSL resona-tors. However, in calculating the entire scope of frequency response, full-wave simulations were unavoidably required in the entire design process.

In fact, full-wave simulations can be engaged in the last stage during the circuit design, whereas the quasilumped approach is extensively used. For given filter specifications, a circuit-layout configuration is proposed first, and subsequently a corresponding meaningful LC circuit model representing the complete filter structure can be established. The element values of the equivalent LC circuit can then be optimized using a cir-cuit-level simulator (e.g., ADS). Once these LC element values are obtained, the structural dimensions of the circuit layout can be adjusted accordingly because there is a meaningful corre-spondence between each lumped circuit element and some spe-cific part of the circuit layout. It is only in this stage that a full-wave simulator is required.

In this article, an multiple-mode resonance (MMR) bandpass filter (BPF) of SSL structure is presented to achieve a wide-band response. To demonstrate the flexibility of the design, a source-load coupling for enhancing signal selectivity of the pass-band is incorporated in the BPF design. For that purpose, the SSL resonator is printed on the side opposite to the feed lines extended from the signal lines of the SMA connectors, thus allowing the two feed lines to be brought closer to establish the source-load coupling without increasing the circuit size. For the proposed BPF, a circuit layout is proposed first and is followed by the establishment of the corresponding quasilumped circuit. Experiments are conducted to verify the BPF design and agree-ments are observed between the measured and simulated data.

2. MULTIPLE MODE RESONANCE BPF DESIGN

The proposed BPF is shown in Figure 1 with the circuit configu-ration originated from Ref. 8, which attaches two narrow strips