Bandwidth Enhancement Of Dual Band Planar Inverted F ...ijifr.com/pdfsave/12-08-201556V2-E12-003.pdf · Dual Band Planar Inverted F Antenna For Mobile ... currents in the antenna

4385

www.ijifr.com Copyright © IJIFR 2015

Research Paper

International Journal of Informative & Futuristic Research ISSN (Online): 2347-1697

Volume 2 Issue 12 August 2015

Abstract

The design of a practical mobile phone antenna is complicated and there are carrier requirements and regulatory requirements. Moreover, there are multiple antennas on each mobile phone like primary cellular antenna, diversity cellular antenna, GPS antenna, WIFI antenna and so on. A planar inverted F antenna (PIFA) works at 900 MHz and 1800MHz is designed in this paper and its band width is enhanced through different methods. A parasitic element is used in this antenna to enhance the bandwidth. This antenna has a reduced size that it does not need isolation as there is only one antenna which provides high efficiency and gain.

Bandwidth Enhancement Of Dual

Band Planar Inverted F Antenna For

Mobile Handset Applications

Paper ID IJIFR/ V2/ E12/ 003 Page No. 4385-4392 Research Area Antenna

Design

Key Words Planar Inverted Antenna, Dual Band, Ansoft HFSS, Parasitic Element,

Reflection Coefficient , Radiation Pattern

Litty Baby

M.Tech. Student, Department of Electronics and Communication St. Joseph’s College Of Engineering &Technology Palai-Kerala

Neenu Rosia Michael

Assistant Professor, Department of Electronics and Communication St. Joseph’s College Of Engineering &Technology Palai-Kerala

Sheelu Cyriac

M.Tech. Student, Department of Electronics and Communication St. Joseph’s College Of Engineering &Technology Palai-Kerala

4386

ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)

Volume - 2, Issue - 12, August 2015 24th Edition, Page No: 4385-4392

Litty Baby,Neenu Rosia Michael, Sheelu Cyriac:: Bandwidth Enhancement Of Dual Band Planar Inverted F Antenna For Mobile Handset Applications

1. Introduction Antennas are essential components of all equipment that uses radio. They are widely used in

systems such as radio broadcasting, broadcast television, two- way radio, communications

receivers, radar, cell phones, and satellite communications, as well as other devices such as garage

door openers, wireless microphones, Bluetooth-enabled devices, wireless computer networks, baby

monitors, and RFID tags on merchandise. Antennas can be designed to transmit and receive radio

waves in all horizontal directions equally (omnidirectional antennas), or preferentially in a

particular direction (directional or high gain antennas). In the latter case, an antenna may also

include additional elements or surfaces with no electrical connection to the transmitter or receiver,

such as parasitic elements, parabolic reflectors or horns, which serve to direct the radio waves into a

beam or other desired radiation pattern.

Typically an antenna consists of an arrangement of metallic conductors (elements),

electrically connected (often through a transmission line) to the receiver or transmitter. An

oscillating current of electrons forced through the antenna by a transmitter will create an oscillating

magnetic field around the antenna elements, while the charge of the electrons also creates an

oscillating electric field along the elements. These time-varying fields radiate away from the

antenna into space as a moving transverse electromagnetic field wave. Conversely, during

reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the

electrons in the antenna elements, causing them to move back and forth, creating oscillating

currents in the antenna. Here, a PIFA antenna with dual band is designed and its band width is

enhanced through different methods. This PIFA is a standard antenna and it gives an operation at

900 and 1800 MHz

2. Planar Inverted F Antenna (PIFA)

The Planar Inverted-F antenna (PIFA) is widely used in the mobile phone market. The antenna is

resonant at a quarter-wavelength (thus reducing the required space needed on the phone), and also

typically has good SAR properties. This antenna structure resembles an inverted F, which explains

the PIFA name. The Planar Inverted-F Antenna is popular because it has a low profile and an

omnidirectional pattern. Antenna designers are always looking for creative ways to improve

performance.

Figure 2.1: PIFA Antenna

4387




One method used in patch antenna design is to introduce shorting pins (from the patch to the ground

plane) at various locations. The first method is Quarter-Wavelength Patch and in this the patch is

shorted at the end, the current at the end of the patch antenna is no longer forced to be zero. As a

result, this antenna actually has same current-voltage distribution as a half-wave patch antenna.

However, we can say that the fringing fields which are responsible for radiation are shorted on the

far end, hence only the fields nearest the transmission line radiate. As a result of this, the gain is

reduced, but the patch antenna maintains the same basic properties as a half-wavelength patch, but

is reduced in size 50percent.

Figure 2.2: Quarter-wavelength patch with shorting pin at end

The next method that we can use is shorting pin at the feed to a patch antenna. In this method,

shorting pin introduces a parallel inductance to the antenna impedance. The effect of the parallel

inductance shifts the resonant frequency of the antenna. In particular, the two components in

parallel would result in their admittances (Y=1/Z) adding. Hence, the admittance of the patch has a

1/(jX) added to it. In this manner, the resonant frequency can be altered. In addition, the shorting

pin can become capacitive if instead of extending all the way to the ground plane, it is left floating a

small amount above. This introduces another design parameter to optimize performance.

Figure 2.3: Shorting Pin at the feed to a patch antenna

4388




3. Proposed Antenna

The proposed antenna is a dual band antenna which has a parasitic element. This parasitic element

resonates at a frequency and it is responsible for the bandwidth enhancement. The length and width

of parasitic element has different effect on antenna performance. The dimension of slot of the

proposed antenna plays a vital role in the antenna efficiency and bandwidth.

Figure 3.1: Structure of the proposed antenna.

4. Design of the Antenna

Figure 4.1: Dimension of feed position

4389




Figure 4.2: Geometry of the proposed antenna.

The wavelength corresponding to upper frequency is three times the first slot length and the

wavelength corresponding to lower frequency is the total length of parasitic width, spacing and

element length. This antenna has linear polarization and it is used in 3G and GSM. This antenna

provides 3.5 dB gain which is appropriate for a mobile antenna. The frequency of operation is

dependent on slot length and the parasitic element. The design and simulation were done in HFSS.

5. Results

The design and simulation of the antenna were done in Ansoft HFSS and graphs were plotted. The

plots of reflection coefficient and radiation pattern are shown below. It is clear from the output that

designed antenna has a good relfection coefficient over the required frequency range.

Figure 5.1: Simulated S11 plot of the antenna.

4390




Figure 5.2: Radiation pattern of the antenna.

6. Analysis

The frequency ratio can be increased by increasing the first section of the slot. The bandwidth can

be increased by increasing the element length. The effect of changing antenna height and slot

length on bandwidth is studied and results are shown below. The upper frequency is lowered when

height of the antenna is increased and it is shown in figure 5.1.

Figure.6.1. Bandwidth of the antenna when height of the antenna is increased .

4391




Figure 6.2. Bandwidth of the designed antenna when height is decreased.

Figure.6.3. Bandwidth of the designed antenna when slot length is increased.

Figure.6.4. Bandwidth of the designed antenna when slot length is decreased.

4392




7. Conclusion and Future Scope

From this work, it can be concluded that this antenna provides enough bandwidth and gain for

mobile phone applications. The parasitic element included in the design provides bandwidth

enhancement which is the most important parameter for a mobile phone antenna. This is a standard

antenna and it can be used in practical applications. Furthermore, the antenna has many advantages

which include simple structure, easiness of fabrication, size reduction and low cost. This

antenna can be modified by changing the slot length and parasitic width. Each modification results

in different bandwidth and gain which can be used for various applications.

References

[1] R.Warty, M. R. To_ghi, U. Kawoos, and A. Rosen, “A four antenna system with high isolation for

mobile phones”, IEEE antennas and wireless propagation letters, Vol .12, Oct. 2013

[2] J.-B. Yan, C.-Y. Chiu, and R. D. Murch, “Handset 4-port MIMO antenna using slit separated PIFA

and quarterwave-slot antenna pair,” in Proc. IEEE Antennas Propag. Soc. Int. Symp., 2008, pp. 1–4.

[3] Y. Ding, Z. Du, K. Gong, and Z. Feng, “A novel dual-band printed diversity antenna for mobile

terminals,” IEEE Trans. Antennas Propag.,vol. 55, no. 7, pp. 2088–2096, Jul. 2007.

[4] H. Chung, Y. Jang, and J. Choi, “Design of a multiband internal antenna for mobile application,” in

Proc. IEEE Antennas Propag. Soc.Int. Symp., 2009, pp. 1–4.

[5] S. Blanch, J. Romeu, and I. Corbella, “Exact representation of antenna system diversity performance

from input parameter description,” Electron. Lett., vol. 39, pp. 705–707, 2003.

[6] Constantine A. Balanis, Antenna Theory Analysis and Design (2nd

edition),John Wiley & sons Inc.,

Newyork(1997)

[7] K.C.Gupta & Peter S.Hall, Analysis And Design of Integrated Circuit Antenna Modules, Wiley

publications.

[8] David M.Pozar, Microwave Engineering (4th

edition),Wiley Publications.

Biographies

1st. Litty Baby is an M.Tech Advanced Communication and Information Systems student in St.Joseph’s

College Of Engineering And Technology, Pala. She received B.Tech degree in Electronics And

Communication from Mahatma Gandhi University .

2nd. Neenu Rosia Michael is currently working as an Assistant Professor in department of Electronics

And Communication at St.Joseph’s College Of Engineering And Technology, Pala. She pursued the

B.Tech degree in Electronics And Communication in Mahatma Gandhi University and the M.Tech

degree in Communication engineering in Cochin University.

3rd. Sheelu Cyriac is currently doing M.Tech in Advanced Communication and Information Systems at

St.Joseph’s College Of Engineering And Technology, Pala. She pursed the B.Tech degree in

Electronics And Communication from Mahatma Gandhi University.

Documents

Bandwidth Enhancement Of Dual Band Planar Inverted F ...ijifr.com/pdfsave/12-08-201556V2-E12-003.pdf · Dual Band Planar Inverted F Antenna For Mobile ... currents in the antenna