ejsr_32_2_02

European Journal of Scientific Research ISSN 1450-216X Vol.32 No.2 (2009), pp.151-157 © EuroJournals Publishing, Inc. 2009 http://www.eurojournals.com/ejsr.htm

Design of New Multi Standard Patch Antenna GSM/PCS/UMTS/HIPERLAN GSM/PCS/UMTS/HIPERLAN for Mobile Cellular Phones M. Ben Ahmed Computing and Telecommunications Research Group, Abdelmalek Essaadi University Bp416, Tangier Morocco E-mail: [email protected] M. Bouhorma Computing and Telecommunications Research Group, Abdelmalek Essaadi University Bp416, Tangier Morocco E-mail: [email protected] F.Elouaai Biotechnology and pathology laboratory Abdelmalek Essaadi Ess aadi University Bp416, Tangier Morocco A.Mamouni DHS/IEMN IEMN UMR CNRS Lille France Abstract

In this paper, we present a new design of a compact, lightweight, low-cost, multistandard antenna for GSM/PCS/UMTS cellular telephone system and Hiprelan applications. Measured and simulated results of the resonant frequency, return loss, radiation patterns and SAR distribution are presented. The Simulation analysis was performed using the HFSS software. A prototype of this antenna a ntenna was fabricated; the good agreement with the simulation provides validation of the design procedure.

Keywords: Patch Antenna, Multi standard, SAR.

1. Introduction Microstrip patch antennas have been largely used in a lot of useful applications, because of their inherent characteristics of low cost, low profile, ease of fabrication, light, weight, conformability and integration with RF devices. The new cellular telephone generations integrate several communications systems at once such as GSM/DCS, Wi-Fi standards, UMTS…etc, which leads to a large need of a multi frequency microstrip patch antennas. In this paper, a new miniaturized multiband antenna which supports communication standard GSM, PCS, UMTS and HIPERLAN is proposed. A series of simulations based on the vector finite element method (Anasoft HFSS) have been carried out to optimize the physical parameters of the antenna to fit the desired resonant frequency, bandwidth and input impedance.

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Design of New Multi Standard Patch Antenna GSM/PCS/UMTS/HIPERLAN for Mobile Cellular Phones

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A multiband prototype based on calculated parameters has been fabricated and measured; a good agreement between the theoretical and the measured has been observed. The antenna design process is presented and discussed. This new design demonstrates useful features for wireless communication applications.

2. Antenna Design Several studies [1-2] have demonstrated that the use of a partial ground plane can widen the bandwidth of resonance and obtain a wideband antenna. We use a layer of fr 4epoxy as a substrate his electric permittivity εr=4.4 and thickness H = 1.6mm, as well as L2=13mm and W2=3mm that have been adjusted to conduct the input impedance to 50Ω. The length of partial ground plane is optimized to L3=3mm. The geometry of the proposed antenna is shown in Fig. 1, also the antenna parameters are given in Tab.1. Figure 1: The Antenna design.

Bottum

Face

Table 1:

The Antenna parameters. L L1 L2 L3

50mm 32mm 13mm 9mm

W W1 W2 H

35mm 18mm 3mm 1.6mm

3. Results In figure 2 we compare between the S11 curve obtained by the simulation software and that measured after prototyping.





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M. Ben Ahmed, M. Bouhorma, F.Elouaai and A.Mamouni Figure 2: Variation of S 11 in function of Frequency.

Figure 2 shows the simulated and measured results of return losses for the proposed antenna. On this curve it can be clearly seen that we have arrived and obtain a multiband patch antenna which supports the standards of GSM, PCS/UMTS and HiperLan. The simulated results are in good agreement with the measured results. The radiation patterns simulated cuts of the studied antenna are shown in Figure 3, the radiation pattern is almost omnidirectional and resembles that of a half-wave dipole. Figure 3a: The antenna radiation pattern for Fr =0.92 Ghz.





Design of New Multi Standard Patch Antenna GSM/PCS/UMTS/HIPERLAN for Mobile Cellular Phones Figure 3b: The antenna radiation pattern for Fr =2 Ghz.

Figure 3c: The antenna radiation pattern for Fr =5.1 Ghz.

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M. Ben Ahmed, M. Bouhorma, F.Elouaai and A.Mamouni

The cell phone models were positioned beside the head according to the intended use position specified by CENELEC [4], [5]. The phantom represents a human head filled with The spherical model had a uniform content at its core (representing the human brain) and the core was surround by two spherical shells representing the skull (bone), the muscle and the skin(skin) with their respective electromagnetic properties. The properties of the materials used in the simulations are presented in table 2 [6]. Table 2:

The phantom tissues dielectric characteristics in 915 MHz. Relative permittivity 41.4 16.62 45.8

DRY SKIN BONE BRAIN

Conductivity (S/m) 0.867 0.242 0.766

The simulation approach consists on measuring and computing the level of SAR absorbed by the phantom in the case of a phone composed by the new multiband patch antenna when a mobile phone emits at maximum power. In mobile certification, the SAR is defined as the power absorbed by the unit of mass of tissue (W/kg) and is deduced from electric field values using the following equation: 2

σ. E d dW SAR = ( )= dt dm 2ρ Where E is the total electric field in V/m, σ is the conductivity in mhos/m, and ρ the density of the tissue in kg/m3. SAR is calculated as a function of position from the estimates of local fields and tissues properties. Numerical studies have ha ve shown that the tissues of the ear region are most exposed, e xposed, and a large part of the absorbed power is concentrated in the tissues in the vicinity of the antenna. The electric field values decrease rapidly as the probe moves toward the centre of the head. The region near the skin–mobile phone interface is therefore primary to characterize Figure 5 shows the SAR quantity caused by the cell phone equipped with our patch antenna in function of distance that separates the cell phone from the Phantom. Figure 4: The SAR distribution in the head caused by patch antenna.





Design of New Multi Standard Patch Antenna GSM/PCS/UMTS/HIPERLAN for Mobile Cellular Phones

156

Figure 5: The SAR quantity in function of distance caused by patch antenna.

SKIN

BRAIN

BONE

It is clearly shown that the peak average SAR in the head induced by a multiband patch antenna is about a 1.5W/Kg, the presented antenna respects the SAR limit recommended by the ICNIRP, which is 2W/kg averaged over 10g of tissue.

5. Conclusion A new miniaturized multiband antenna suitable for mobile phone applications and WLAN applications has been presented and studied. Both simulated and measured results have been presented. The studied antenna respects the SAR limits and it has three bands of operation: the GSM/PCS, UMTS and HiperLan band. A good agreement, between the HFSS simulated results and measurements, was obtained.

Acknowledgement This work has been achieved in the setting of the franco-morrocan cooperation in scientific research and it is done in the IEMN laboratories at USTL Lille.







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References [1] [2] [3]

[4]

[5]

[6]

Design of a Tuning Fork type UWB Patch Antenna A. H. M. Zahirul Alam, Rafiqul Islam, and Sheroz Khan PROCEEDINGS OF WORLD ACADEMY OF SCIENCE, ENGINEERING AND TECHNOLOGY VOLUME 26 DECEMBER 2007 ISSN 2070-3740 Study of EM Interaction between Human Head and Mobile Cellular Phone M. Bouhorma, A. Benahmed, F. Elouaai, A. Astito and A. Mamouni. Information and Communication Technologies International Symposium. Tetuan, Morocco 3-4-5-6 June 2005. Evaluation of the SAR distribution in the human head for cellular phones. M. Bouhorma, M. Benahmed, F. Elouaai,H. Drissi A. Mamouni. IWWCUCA June, 6th and 7th 2005 in Val-d'Or Quebec, Canada. D. Manteuffel, A. Bahr, D. Heberling, and I. Wolff, “Design considerationsfor integrated mobile phone antennas,” in Proc. 11th Int. Conf. Antennas Propagat., Apr. 17–20, 2001, pp. 252–256. S. Khalatbari, D. Sardari, A. A.Mirzaee and H. A. Sadafi,, ”Calculating SAR in Two Models of the Human Head Exposed to Mobile Phones Radiations at 900 and 1800 MHz”, Progress In Electromagnetic Research Symposium 2006, Cambridge, USA, 2, (1), March 26-29,pp.104109.

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