Design of Planner Inverted F-Antenna for Single Band ISM Spectrum

IJSTE - International Journal of Science Technology & Engineering | Volume 2 | Issue 08 | February 2016 ISSN (online): 2349-784X

Design of Planner Inverted F-Antenna for Single Band ISM Spectrum Prof. P. D. Patil Department of Electronics Engineering Rashtrasant Tukdoji Maharaj University, Nagpur

Omkar Deshpande Department of Electronics Engineering Rashtrasant Tukdoji Maharaj University, Nagpur

Akash Dhoble Department of Electronics Engineering Rashtrasant Tukdoji Maharaj University, Nagpur

Meheresh Pophali Department of Electronics Engineering Rashtrasant Tukdoji Maharaj University, Nagpur

Aditya Dudhe Department of Electronics Engineering Rashtrasant Tukdoji Maharaj University, Nagpur

Abstract In the progress of commercial communications applications the development of small integrated antenna has played an important role. Basically PIFA are commonly used in handsets. This paper describes the performance of PIFA for single band in handsets.

It is compact, low cost and having better antenna performance in terms of return loss, radiation patterns, VSWR etc. All simulation results are performed using High frequency structural simulator (HFSS).

Keywords: PIFA, HFSS, VSWR, Return Loss ________________________________________________________________________________________________________ I.

INTRODUCTION

Now-a-days, it is a great consideration of human body interaction with antennas in cellular mobile communication. Voltage standing wave ratio (VSWR), gain and radiation patterns of the antenna of a handset are influenced by the user. Unlimited electromagnetic energy can cause a serious health hazard when tissues are exposed. In this case, specific absorption rate (SAR) has been termed by standard organizations to set exposure limits. PIFAs are conducting plates called radiating patches.

They are parallel to a ground and are connected to ground. As the integration of personal communication devices are progressing at a great speed, the necessity of the PIFAs like small integrated antennas is increasing.

There are many commercial applications, such as mobile radio and wireless communications that use planar inverted-F antennas (PIFA). The PIFA is used extensively because it is reasonably compact, has a fairly omni-directional radiation pattern, good efficiency, and is very simple. It is found that a PIFA has a good omni-directional characteristics and sufficient impedance bandwidth for most applications. Conventional planar inverted-F antenna is a L-shape monopole of quarter-wavelength and the L-shape monopole shorted the ground plane. This kind of inverted-F antenna has the advantage of low profile and better matching to 50 â„Ś, and can be mounted above a ground plane or printed on a dielectric substrate.

These antennas are generally designed to cover one or more wireless communications bands such as the Global System for Mobile Communications (GSM900 and 800), Global Positioning System (GPS 1400 and 1575), Personal Communication System (PCS 1800 and 1900), Digital Communication Systems (DCS 1800), Universal Mobile Telecommunications System (UMTS 2000), 3G IMT-2000, 4G LTE(700,1700,2300,2600), Wireless Local Area Networks (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX).

In this paper a single band PIFA antenna design is proposed by using HFSS Software by Ansoft.

II. METHODOLOGY & PARAMETERS HFSS HFSS is a specialist tool for antenna designing and 3-dimensional high frequency components .It generates the fast and accurate analysis of high frequency component.

S-Parameter S-parameters describe the input-output relationship between ports (or terminals) in an electrical system. For instance, if we have 2 ports (intelligently called Port 1 and Port 2), then S12 represents the power transferred from Port 2 to Port 1. S21 represents the power transferred from Port 1 to Port 2. In general, SNM represents the power transferred from Port M to Port N in a multi-port network.

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Design of Planner Inverted F-Antenna for Single Band ISM Spectrum (IJSTE/ Volume 2 / Issue 08 / 039)

Specific Absorption Rate (SAR) Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field; although, it can also refer to absorption of other forms of energy by tissue, including ultrasound. It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).

Where, is the sample electrical conductivity. is the RMS electric field. is the sample density. is the volume of the sample.

VSWR In telecommunications, standing wave ratio (SWR) is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide. Impedance mismatches result in standing waves along the transmission line, and SWR is defined as the ratio of the partial standing wave's amplitude at an antinode v(maximum) to the amplitude at a node (minimum) along the line.

The SWR is usually thought of in terms of the maximum and minimum AC voltages along the transmission line, thus called the voltage standing wave ratio or VSWR đ?‘‰đ?‘&#x; Γ= đ?‘‰đ?‘“

Vr: reflected wave Vf : forward wave Γ = -1 negative reflection line is short circuited. Γ=0 no reflection line perfectly matched. Γ = +1 positive reflection line open circuited.

III. DESIGN AND SIMULATIONS In this paper we have designed a single band PIFA at a resonant frequency ranging from 2.4-2.48GHz. Figure shows the geometry of proposed antenna. The antenna is fabricated on FR4 substrate with a dielectric constant ɛᾣ= 4.4.

Air is used as dielectric between FR4 substrate and top radiating patch. The proposed antenna structure includes a radiation patch, a ground plate, a coaxial feed, and a shorting plate.

Fig.1: Basic Structure Representation

Fig. 2: Simulated Single Band Antenna

IV. RESULTS Return Loss: It is a parameter which indicates the amount of power that is “lost� to the load and does not return as a reflection. Hence the RL is a parameter to indicate how well the matching between the transmitter and antenna has taken place. A graph of s11 of an antenna vs frequency is called its return loss curve.

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Design of Planner Inverted F-Antenna for Single Band ISM Spectrum (IJSTE/ Volume 2 / Issue 08 / 039)

For better transmission the return loss it must be below -10dB the simulated results of our antenna is shown in fig.from the graph we can see at the resonant frequency at 2.23Ghz we have got return loss of -31dB resp.

Fig. 3: Return Loss Input Impedance: The input impedance of an antenna is defined as “the impedance presented by an antenna at its terminals or the ratio of the voltage to the current at the pair of terminals or the ratio of the appropriate components of the electric to magnetic fields at a point�. Hence the impedance of the antenna can be written as given below.

Zin = Rin + JXin Where, Zin is the antenna impedance at the terminals Rin is the antenna resistance at the terminals Xin is the antenna reactance at the terminals.

Fig. 4: input impedance

3D&2D Gain:Gain is a measure of the ability of the antenna to direct the input power into radiation in a particular direction and is measured at the peak radiation intensity.

The gain and efficiency are the two important parameters of the antenna. The overall gain of the antenna obtained after simulating the PIFA structure is shown in Fig. below A peak gain of 2.34dB has been achieved.

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Design of Planner Inverted F-Antenna for Single Band ISM Spectrum (IJSTE/ Volume 2 / Issue 08 / 039)

Fig. 5: 3D GAIN

Fig. 6: 2D Gain VSWR: Voltage Standing Wave Ratio (VSWR) is a ratio of peak voltage on the minimum amplitude of voltage of standing wave . The VSWR is always a real and positive number for antennas. The smaller the VSWR is, the better the antenna is matched to the transmission line and the more power is delivered to the antenna. In Fig. below that at 2.34 GHz VSWR is 1.0 dB. Also it is observed from the results that at these resonant frequencies the Voltage Standing Wave Ratio is below 2 dB which is desirable for most of the wireless applications.

Fig. 7: VSWR

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Design of Planner Inverted F-Antenna for Single Band ISM Spectrum (IJSTE/ Volume 2 / Issue 08 / 039)

Fig. 8: 3D VSWR Directivity: Directivity is a fundamental antenna parameter. It is a measure of how 'directional' an antenna's radiation pattern is. An antenna that radiates equally in all directions would have effectively zero directionality, and the directivity of this type of antenna would be 1.

Fig. 9: Directivity

REFERENCES [1] [2] [3] [4] [5] [6] [7]

Dual-Band Planar Inverted-F Antenna for Application in ISM, HIPERLAN, and UNII by Hua-Xian Liu1,Yih-Chien Chen1, Chung-Yen Wu 2 and PinTang Chiu2.

P.W. Chan, H. Wong and E.K.N. Yung, “Wideband planar inverted-F antenna with meandering shorting strip,” Electron. Lett., vol. 44, no. 6, pp. 395-396, 2008.

Yu-Shin Wang, Ming-Chou Lee, and Shyh-Jong Chung, “Two PIFA-Related Miniaturized Dual-Band Antennas,” IEEE Trans. Antennas Propag., vol. 55, no. 3, pp. 805-811, 2007.

S.H. Yeh, K.L. Wong, T.W. Chiou, and S.T. Fang, “Dual-band planar inverted-F antenna for GSM/DCS mobile phones,” IEEE Trans Antennas Propag 2003 51, 1124–1126.

C.R. Rowell and R.D. Murch, “A compact PIFA suitable for dualfrequency 900/1800-MHz operation,” IEEE Trans Antennas Propag 1998, 46, 596–598.

F. Wang, Z. Du, Q. wang, and K. Gong, “Enhanced-bandwidth PIFA with T-shaped ground plane,” Electronicsletters 2004 40(23) 1504~1505.

Xu Jing, Zhengwei Du, Ke Gong, “Bandwidth enhancement design of pifa with slotted T-shaped ground plane,” Microwave and Optical Technology Letters, 2006, 48(10): 2106~2108.

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