Compact Reconfigurable Dual Frequency Microstrip Patch Antenna for 3G and 4

cases is that we added one or two more obstacles into the simu-

lation. As the number of the obstacles increases, the perform-

ance of the wideband antenna system response decreases.

Comparing Figures 7 and 9(c), we find that the distortion in

Figure 9(c) is less than that in Figure 7. Although there are

more obstacles present in the case of Figure 9(c), because plate

#1 is absent, there is a direct path from the transmit to the

receiving antenna. The signal directly radiated from the transmit

antenna is stronger than the scattered ones. Therefore, even

though there are other obstacles present in the environment, the

received current is very close to that one of Figure 4, which has

no obstacles at all.

It is interesting to observe that the distortion in Figure 9(a) is

smaller than the distortion in Figure 4 when no obstacle is

present!

4. CONCLUSION

The combination of the transmitting biconical and the receiving

TEM-horn antenna pair can transmit and receive time-domain

wideband signals with little distortion. But if there are obstacles

present in between them, especially when the antennas are oper-

ating in the near field region, the performance degrades

significantly.

However, if the obstacles are located in the far-field region,

the distortion is less than in the near field region, particularly if

a direct line of sight is present. Then with this transmit receive

pair, one can propagate wideband signals, without much distor-

tion, especially when there are no obstacles blocking the direct

transmission path. Particularly, the effect of the obstacles is

small and the performance is close to the case when there are

no obstacles present at all.

REFERENCES

1. J.R. Andrews, UWB Signal Sources, Antennas and Propagation,

Picosecond Pulse Lab, Application Note AN-14a, August, Boulder,

CO, 2003. (Also presented at the 2003 Honolulu IEEE Wireless

Conference.) Available at: http://www.picosecond.com/objects/AN-

14a.pdf

2. T.K. Sarkar, M. Salazar-Palma, and E.L. Mokole, Physics of multi-

antenna systems and broadband processing, John Wiley and Sons,

Hoboken, NJ, 2008.

3. C. Ryan, Jr., E. Weaver, and B. Cown, Plane wave spectrum scat-

tering analysis of near-field obstacle effects on directive antenna

patterns, IEEE Trans Antennas Propag 27 (1979), 772778.

4. J.E. Storer and J. Sevick, General theory of plane-wave scattering

from finite, conducting obstacles with application to the two-

antenna problems, J Appl Phys 25 (1954), 369.

5. Z. Mei, T.K. Sarkar, and M. Salazar-Palma, The design of an ultra-

wideband T-pulse with a linear phase fitting the FCC mask, IEEE

Trans Antennas Propag 59 (2011), 14321436.

VC 2013 Wiley Periodicals, Inc.

COMPACT RECONFIGURABLE DUALFREQUENCY MICROSTRIP PATCHANTENNA FOR 3G AND 4G MOBILECOMMUNICATION TECHNOLOGIES

Younes Karfa Bekali1 and Mohamed Essaaidi21 Information and Telecommunication Systems Lab, AbdelmalekEssaadi University, Tetuan, Morocco2 ENSIAS, Mohamed V Souissi University, Rabat, Morocco;Corresponding author: [email protected]

Received 25 November 2012

ABSTRACT: We propose in this article, a novel compactreconfigurable patch antenna with frequency diversity. This antenna can

be tuned by changing the switching mode of two PIN diodes from theONON state to OFFOFF state to switch it over two different mobilecommunication technologies, namely 3G and 4G. The antenna has a

simple geometry and a small structure, its dimensions are 45 38 1.5 mm3 and it is printed on an FR4 substrate with a thickness of 1.5mm. The prototype of this antenna has been fabricated and tested. The

measurement results confirmed the simulation predictions in terms offrequency diversity performances. VC 2013 Wiley Periodicals, Inc.

Microwave Opt Technol Lett 55:16221626, 2013; View this article

online at wileyonlinelibrary.com. DOI 10.1002/mop.27649

Key words: patch antenna; frequency reconfigurable; reconfigurableantenna; switching mode; dual frequency

1. INTRODUCTION

The emergence of reconfigurable antennas has been a great de-

velopment in the field of telecommunication and wireless tech-

nologies, as this generation of antennas helped to achieve good

performances with a small size and low cost. Many of the wire-

less communication technologies today require antennas that op-

erate at more than just one frequency while maintaining a small

size [1]. Reconfigurable antennas play a key role in modern tele-

communication systems [2].

In this article, we present a new design of a reconfigurable circu-

lar patch antenna with switchable slot using two PIN diode switches.

This antenna can operate easily at two frequencies depending on the

bias state of these two switches. The desired antenna performances

are obtained through a parametric study which optimized the fre-

quency response of the antenna in different switch states.

The proposed reconfigurable antenna is desirable for several

mobile and wireless communication technologies and standards

such as 3G and 4G. As far as the reconfigurable behavior is con-

cerned, there are many techniques that have been proposed and

implemented successfully to achieve frequency diversity [2].

Most of these techniques are based on different switching tech-

niques including PIN diodes, GaAs field-effect transistor, and

RF micro-electronic mechanical system (MEMS) switches [3].

The PIN diode play behaves like a switch that can go from the

ON state to OFF state depending on its bias state, which is con-

trolled by DC bias currents fed through vias. When the switch is

in the ON state, it is modeled as a very thin metal tape while

the OFF mode it is an open circuit [1]. MEMS switches have

been simulated by transmission lines for the closed state and

for the open state the switches are simply removed [3]. But

in reality, the electrical behavior of PIN diodes slightly influen-

ces the development patterns of current in the patch. We can

also use MEMS like a switch for this antenna. The proposed

antenna design and performances are optimized using CST

Microwave Studio [4]. A first validation of the simulation

results, prior to the prototype production and measurement tests,

TABLE 1

Example Output Current Distortion Variable E

Example 1 Figure 3 0.1427




Example 5(a) Figure 9(a) 0.4200

Example 5(b) Figure 9(b) 0.4261

Example 5(c) Figure 9(c) 0.1815

1622 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 55, No. 7, July 2013 DOI 10.1002/mop

is carried out using another of the shelf commercial EM simula-

tor, namely, Ansoft High Frequency Structure Simulator (HFSS)

[5].

2. ANTENNA DESIGN PROCEDURE

2.1. Geometry of the AntennaThe geometry of the proposed switchable printed circular patch

antenna is shown in Figure 1. It consists of a printed circular

patch antenna on an FR4 epoxy substrate with a thickness of 1.5

mm and a relative permittivity of er 4.4. The substrate has alength of 45 mm and a width of 38 mm. The dimensions of the

truncated ground plane are 38 10.6 mm2 and the radius of cir-cular patch is 8 mm.

The excitation is launched through a 50-X microstrip feedline having a width of 2.8 mm. In order to achieve frequency di-

versity for this antenna, a slot has been introduced in it and two

switches are inserted close to the edges of this slot (Fig. 1). The

switches are being used to change the geometry of the disc

antenna producing a reconfigurable antenna structure that offers

Figure 1 Geometry of the novel reconfigurable patch antenna (a) with and (b) without switches

Figure 2 Geometry of the slot

Figure 3 PIN diode DC bias circuit

TABLE 1 Dimensions of the Proposed ReconfigurableAntenna

FR4 Substrate (X, Y, Z) 38 45 1.5 mm3

Disc Radius R 8 mmPosition of Center of the Disc (X, Y, Z) (19,28,1.5) mm3

Width of Microstrip Feed Line w 2.8 mm

Ground Plane (X, Y) 38 10.5 mm2Feed Line Length h 24 mm

TABLE 2 Dimensions of the Slot

Distance Length (mm)

d1 1.0

d2 2.5d3 12.0

d4 13.0d5 0.5

Figure 4 Simulated return loss for the proposed reconfigurableantenna for ONON state. [Color figure can be viewed in the online

issue, which is available at wileyonlinelibrary.com]

DOI 10.1002/mop MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 55, No. 7, July 2013 1623

more frequency agility. The dimensions of all parts of this

antenna are presented in Table 1. The geometry and dimensions

of the slot are presented in Figure 2 and Table 2.

2.2. Switching TechniqueIn order to achieve reconfigurable antenna behavior with fre-

quency diversity, PIN diodes or RF MEMS can be used [610].

In this proposed reconfigurable antenna design, the PIN BAR63

model [11] is used due to its weak capacity in blocked mode.

This ensures a good isolation on a relatively broad band. The

PIN diodes are biased using a DC bias circuit that controls the

way they operate as shown in Figure 3. In the remaining part of

this article, we will simulate the diodes behavior according to

two different ways. The first simulation method of the diode

consists of substituting it by its electrical characteristics. The

PIN diodes, in ON state and OFF state, are easily modeled by

Figure 6 Prototype of compact dual frequency reconfigurable microstrip patch antenna: (a) slot (b) antenna photos. [Color figure can be viewed in theonline issue, which is available at wileyonlinelibrary.com]

Figure 7 Return loss characteristics of dual frequency microstrip patch antenna (a) OFFOFF state (b) ONON state. [Color figure can be viewed inthe online issue, which is available at wileyonlinelibrary.com]

Figure 8 E- and H-plane radiation patterns for the proposed reconfig-urable antenna at 2.1 GHz for ONON state. [Color figure can be

viewed in the online issue, which is available at wileyonlinelibrary.com]

Figure 5 Simulated return loss for the proposed reconfigurableantenna for OFFOFF state. [Color figure can be viewed in the online

issue, which is available at wileyonlinelibrary.com]


series RLC circuits. The BAR63 PIN diode considered in this

design can be modeled in the ON state by a resistor of 0.5 X inseries with an inductor of 0.5 nH. In OFF mode, it is repre-

sented by a capacitor of 0.15 pF [11].

According to a second method, the switch is removed from

the simulation and the patch should be simulated with a com-

plete slot in the OFF mode. When the switch is ON, the PIN

diode is replaced by a very thin metal tape with a width of 0.1

mm in the simulations.

3. RESULTS AND DISCUSSION

Figure 4 shows the return loss for ONON state for both CST

and HFSS simulations. We can see that the antenna operates at

frequency bands ranging from 2 to 2.26 GHz (HFSS) and 1.8

2.47 GHz (CST). These frequency bands include the frequency

band around 2.1 GHz corresponding to third generation mobile

communications, namely, 3G.

The results obtained for the OFFOFF state are presented in

Figure 5, which shows a good agreement between HFSS and

CST simulations. It is easily seen that HFSS results give a band-

width from 2.33 to 3.02 GHz while those obtained from CST

simulations give a bandwidth ranging from 2.2 to 3 GHz. So,

both of them cover the frequency band around 2.6 GHz corre-

sponding to 4G mobile communication technologies.

These simulations were used as a basis for the optimization

and validation of the proposed reconfigurable antenna for 3G

and 4G mobile communications. As a consequence of them, a

prototype of this antenna was fabricated (Fig. 6) and measured.

The measured return loss of this antenna confirms the simu-

lations of two frequency bands related with the ONON mode

[Fig. 7(a)] and the OFFOFF mode [Fig. 7(b)] corresponding,

respectively, to 2.1 and 2.6 GHz frequency bands standardized

for 3G and 4G mobile communication technologies.

The E- and H-plane radiation patterns of the proposed recon-

figurable antenna for 2.1 and 2.6 GHz are depicted in Figures 8

and 9, respectively. These radiation patterns have a dipole-like

behavior.

The gain of the antenna is illustrated in Figure 10 for 2.1

GHz corresponding to ONON state and Figure 11 for 2.6 GHz

frequency band related with OFFOFF state. It is found that the

maximum gain is obtained for the ONON state which is 7.9

dB, while the maximum gain for the OFFOFF state is about

5.88 dB at 2.6 GHz.

4. CONCLUSION

A novel compact single feed microstrip antenna with reconfigur-

able frequency capability for frequency diversity applications

has been designed, constructed, and measured in this article.

Figure 10 Gain (dB) for / 0 and / 90 at 2.1 GHz for ONON state. [Color figure can be viewed in the online issue, which is available atwileyonlinelibrary.com]

Figure 9 E- and H-plane radiation patterns for the proposed reconfig-urable antenna at 2.6 GHz for the OFFOFF state. [Color figure can be

viewed in the online issue, which is available at wileyonlinelibrary.com]

DOI 10.1002/mop MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 55, No. 7, July 2013 1625

The agreement between simulation and measured results is very

good. PIN diode switches are used to tune the proposed recon-

figurable antenna between the two operating frequency bands

corresponding to 3G and 4G mobile communication technolo-

gies. The radiation pattern and the gain of the antenna have

been also investigated and make it, together with its small size,

a very good candidate for mobile 3G and 4G smart phones and

tablets handsets.

REFERENCES

1. T. Al-Maznaee and H.E. Abd-El-Raouf, Design of reconfigurable

patch antenna with a switchable V-Slot, Prog Electromagn Res C 6

(2009), 145158.

2. G. Monti, L. Corchia, and L. Tarricone, Patch antenna with recon-

figurable polarisation, Prog Electromagn Res C 9 (2009), 1323.

3. J.A. DeSignor and J. Venkataraman, Reconfigurable dual frequency

microstrip patch antenna using RF MEMS switches, Department of

Electrical Engineering Rochester Institute of Technology, Roches-

ter, NY (report).

4. Computer Simulation Technology, Available at: http://

www.cst.com.

5. Ansoft High Frequency Structure Simulator Corporation, V 9.2,

2004, Available at: http://www.ansoft.com/hfss.

6. M.T. Ali, M.R. Kamarudin, and T.A. Rahman, Design of reconfig-

urable multiple elements microstrip rectangular linear array

antenna, Prog Electromagn Res C 6 (2009), 2135.

7. H. Torpi and Y. Damgaci, Design of dual-band reconfigurable

smart antenna, Progress in Electromagnetics Research Symposium,

Prague, Czech Republic, 2007, August 2730.

8. S. Nikolaou, R. Bairavasubramanian, C. Lugo, I. Carrasquillo, D.C.

Thompson, George, E. Ponchak, J. Papapolymerou, and M.M.

Tentzeris, Pattern and frequency reconfigurable annular slot

antenna using PIN diodes, IEEE Trans Antennas Propag 54 (2006).

9. R. Saranya and K. Ramprakash, Design of reconfigurable antenna

array for WLAN and WIMAX application, In: Proceedings of the

international conference on manmachine systems (ICoMMS), 11

13 October 2009, Batu Ferringhi, Penang, Malaysia.

10. H. Kim, D. Chung, D.E. Anagnostou, Y.J. Yoon, and J. Papapoly-

mero, Hardwired Design of Ultra-Wideband Reconfigurable

MEMS Antenna, In: 18th annual IEEE international symposium on

personal, indoor and mobile radio communications (PIMRC007).

11. Infineon, Silicon PIN BAR63 Diode, Datasheet. Available at:

http://www.infineon.com.

VC 2013 Wiley Periodicals, Inc.

CARD-TYPE SLOT ANTENNA FOR UHFRFID TAG CLOSE TO THE CHEST OF AHUMAN BODY

Chien-Wen Chiu, Chen-An Ou, Hwang-Cheng Wang,and Yu-Chou ChuangDepartment of Electronic Engineering, National Ilan University, Ilan260, Taiwan; Corresponding author: [email protected]

Received 22 October 2012

ABSTRACT: This article presents a UHF radio frequency identificationtag antenna used in proximity to the chest of a human body for student

ID card identification. The proposed tag antenna is a rectangular slot-type patch structure printed on a PVC card. For near-body applications,

stratified square plates with physical parameters are used as a humanmodel. The radiation properties of the slotted tag antenna placed nearthe model and the absorption effects due to human body are

investigated. The research used the HFSS simulator to optimally designthe antenna and employed the FEKO simulator to verify the simulated

results. The designed tag was constructed for testing the reading range.The measured reading range achieved is around 4.2 m as the tag is putclose to the chest. VC 2013 Wiley Periodicals, Inc. Microwave Opt

Technol Lett 55:16261631, 2013; View this article online at

wileyonlinelibrary.com. DOI 10.1002/mop.27610

Key words: UHF radio frequency identification tag; slot antenna; tag

antenna; human body effect; read range

1. INTRODUCTION

Radio frequency identification (RFID) is a rapidly developing

technology which uses RF signals for the automatic identifica-

tion of objects. Nowadays, RFID finds many applications in

Figure 11 Gain (dB) at / 0 and / 90 at 2.6 GHz for OFFOFF state. [Color figure can be viewed in the online issue, which is available atwileyonlinelibrary.com]


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Compact Reconfigurable Dual Frequency Microstrip Patch Antenna for 3G and 4

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