www.ijeee-apm.com International Journal of Electrical & Electronics Engineering 11

IJEEE, Vol. 1, Spl. Issue 1 (March 2014) e-ISSN: 1694-2310 | p-ISSN: 1694-2426

Analyzing the Different Parameters of

Dipole Antenna 1Amandeep Bath,

2Abhishek Thakur,

3Jitender Sharma ,

4Prof. Basudeo Prasad

1,2,3,4Electronics & Communication Engineering Department,

Indo Global College of Engineering, Punjab, India 1amandeep_batth@rediffmail.com,

2abhithakur25@gmail.com,

3er_jitender2007@yahoo.co.in

Abstract- Ultra wideband is a wireless technology to

realize high speed communications which is performed in wideband. In this paper the wideband dipole antenna is

designed. The simulation is done using ANSOFT HFSS

simulation software.

Index Terms- Broad band, wide beam, circular

polarization, conducting wall, micro strip antenna, Wide-

Band, Omni directional radiation pattern smart grid, Wi Max

directive antennas, UWB antennas, Biotelemetry, capsule

endoscope, dipole antenna ,planar reflector antenna.

I. INTRODUCTION

In radio and telecommunications a dipole antenna also known as doublet is the easiest and most commonly used

class of antenna. It is made up of two similar conductive

elements such as metal wires or rods which are generally

bilaterally symmetrical. The driving current from the

transmitter is given, or for receiving antennas the output

signal to the receiver is obtained and taken, between the two

halves of the antenna. Each side of the feedline to the

transmitter or receiver is joined to one of the conductors. This

is different with a monopole antenna, which is made up of a

single rod or conductor with one side of the feed line joined

to it, and the other side connected to some type of ground. The best example of a dipole is the "rabbit ears" television

antenna which is found on broadcast television sets.

The most common type of dipole is two straight rods or wires

which are connected end to end on the same axis, with the

feed line connected to the two adjacent ends. This is the

easiest type of antenna from a theoretical point of view.

Dipoles are resonating antennas, meaning that the elements

serve as resonating elements, with standing waves of radio

current which flows back and forth between their ends. So the

length of the dipole elements is calculated by the wavelength

of the radio waves used. The most common type is the one

half wave dipole, in which both of the two rod elements is approximately 1/4 wavelength long, so the complete antenna

is a half-wavelength long. Numerous different types of the

dipole are also used, such as the folded dipole, short dipole,

cage dipole, bow-tie, and batwing antenna. Dipoles may be

used as standalone antennas themselves, but they are also

used as feed antennas (driven elements) in many more

advanced antenna types, such as the Yagi antenna, parabolic

antenna, reflective array, turnstile antenna, log periodic

antenna, and phased array. The dipole was the oldest and

primitive type of antenna; it was invented by German scientist

Heinrich Hertz around 1886 in his advanced research of radio

waves

A dipole is a symmetrical antenna, as it is composed of

two symmetrical ungrounded elements. Therefore it works

best when fed by a balanced transmission line, such as a

ladder line. It happens because in that case the symmetry (one

aspect of the impedance complex, which is a complex number) matches and therefore the power transfer is external.

When a dipole with an unbalanced feed line such as coaxial

cable which is generally used for transmitting the signal, the

shield side of the cable, in addition to the antenna, radiates.

RF currents are induced into other electronic equipment very

close to the radiating feed line, producing RF interference.

Furthermore, the efficiency of the antenna is very low

because it is radiating closer to the ground and its radiation as

well as the reception pattern may be asymmetrically distorted.

At very high frequencies, where the coax diameter is

generally more than the length of the dipole, this becomes a

more prominent problem. To remove this, dipoles fed by coaxial cables have a balloon kind of structure between the

cable and the antenna, the unbalanced signal provided by the

coax is converted to a very balanced symmetrical signal for

the antenna.

Agile reconfigurable antennas for future communication

systems have attracted researchers around the globe.

Antenna's characteristics such as frequency, radiation pattern

and polarization are reconfigured to attain the demands for

agile radios. A lot of researches focus on frequency

reconfiguration as future communication systems such as

cognitive radio needs an antenna that can do spectrum sensing and communication. In reconfigurable frequency antennas

development, recently a reconfigurable wide-band to agile

narrow frequencies, using a printed log periodic dipole array

antenna, was introduced. A wideband slotted multifunctional

reconfigurable frequency antenna for WLAN, WIMAX,

UWB and UMTS has been proposed in, a frequency

reconfigurable antenna, consisting of two structures; one is an

ultra-wide band (UWB) and other is a frequency

reconfigurable triangle shape antenna, is proposed for

cognitive radio communication

Ultra-wide band antennas have already been used in areas such as satellite communication, remote sensing, and

ultra-wide band radar and so on. Currently, the wireless area

network (WLAN) in the 2.4-GHz (2.4-2.485 GHz) and 5-GHz

(5.l5-5.875 GHz) bands is the most popular networks for

accessing the internet the antenna for an AP not only requires

dual-band operation but also needs to have an appropriate

International Journal of Electrical & Electronics Engineering 12 www.ijeee-apm.com

radiation profile in both bands, namely similar gain, wide

beam width, and high front-to-back ratio. Wireless

communications continues to enjoy exponential growth in

Industrial, Scientific, and Medical (ISM) band. The future

generation wireless networks require systems with broad-

band capabilities in various environments to satisfy several applications as smart grid, personal communications, home,

car, and office networking .On the other hand, many modern

wireless communication systems such as radar, navigation,

satellite, and mobile applications use the circular polarized

(CP) radiation pattern. For the best UWB performance, the

transmitter and receiver (T/R) antennas should have flat and

high directive gain, narrow beam, low side and back lobes

over the operational frequency band; to attain the largest

dynamic range, best focused illumination area, lowest T/R

coupling, reduced ringing and uniformly shaped impulse

radiation.UWB has promised to offer high data rates at short

distances with low power, primarily due to wide resolution bandwidth.

II. ANTENNA DESIGN AND CONFIGURATION

All The geometry and configuration of the proposed

antenna is shown in the figure. Initially the design properties

are selected by adjusting the local variables such as the substrate height „l=25cm' and the radius 'a=0.5mm' and the

position as well. As shown in the figure the proposed antenna

consists of a cylindrical radiating substrate which is duplicate

d around the X axis with a rectangular lumped port excitation

between them. The duplicated substrate cylindrical antenna

element around the X axis is shown in the figure.

Fig. 1: Duplicated cylindrical substrate around the axis

Fig. 2: Rectangular radiating element between substrates

The material of the substrate is kept as pec with a bulk conductivity of 1e+030 Siemens/m. The rectangular element

between the cylindrical substrates provides the lumped

excitation with a position 0,-.5,-2. The the integrating line is

drawn between the cylindrical substrates through the

rectangular element.

Fig. 3: Integrating line between the substrates

The structure is then covered by a vacuum box with the position -100,-75,-75 mm and the other dimensions as X=200,

Y=150, Z=150mm. Also the transparency is adjusted as 0.76.

Further the faces of the vacuum box are individually selected

for assigning the radiation boundary. Before the final

validation check the solution frequency is adjusted as 300

MHz for the setup. Also for the same set up the frequency

sweep is adjusted by keeping the sweep type as fast and the

start and stop frequencies as 100 and 500Mhz respectively by

keeping the count as linear. Finally the design undergoes the validation check for the errors.

Fig. 4: Air box over the dipole

III. DIPOLE CHARACTERISTICS

A. Frequency versus length

Dipoles that are very small even smaller than the wavelength of the signal are called Hertz an, short, or

infinitesimal dipoles. These have a very low radiation

resistance and a high capacitive reactance, so they are not

very much efficient; though inefficient, they can be practical

antennas for long wavelengths. Dipoles whose length is half

the wavelength of the signal are called half-wave dipoles, and

are more efficient. In general radio engineering, the term

dipole usually means a half-wave dipole (center-fed).A half-

wave dipole is cut to length l for frequency f in hertz according to the formula

www.ijeee-apm.com International Journal of Electrical & Electronics Engineering 13

Where λd is the wavelength on the dipole elements, λ0 is

the free-space wavelength, c is the speed of light in free space

(299,792,458 meters per second (983,571,060 ft/s)), and k is

called adjustment factor. The adjustment factor completely

compensates for propagation speed being somewhat less than

the speed of light. The dipole elements will have distributed

inductance and capacitance. The value of k is around 0.95.

For thin wires with the dimensions (radius = 0.000001

wavelengths), k is approximately 0.981; for thick wires (radius = 0.01 wavelengths), k drops to about 0.915.The

above formula which is given is often shortened to the length

in meters = 143/MHz or the length in feet = 468/MHz; MHz is

the frequency in megahertz.

A. Elementary doublet

From a theoretical point of view, the dipole antenna is the

simplest antenna. An elementary doublet or Hertzian dipole as

shown in the figure is a small length of conductor δℓ (small

compared to the wavelength λ) carrying an alternating current whose equation is:

Fig. 5: Elementary doublet.

Here ω = 2πf is the angular frequency (and f the

frequency), and i = √−1 is the imaginary unit, so that I is a

phasor. It is used in, for example, analytical calculation on

more complex antenna geometries. Note that physical construction of the dipole is difficult because the current

needs somewhere to come from and somewhere to go to.

Actually, this small length of conductor will be just one of the

multiple segments into which we must divide a real antenna,

in order to calculate its properties. In the case of the

elementary doublet which is shown in the figure it is possible

to find exact, closed-form expressions for its electric field, E,

and its magnetic field, H. In spherical coordinates, they are

where r is the distance from the doublet to the point where the fields are evaluated, k = 2π/λ is the wave number,

and Z = √μ/ε = 1/εc = μc is the wave impedance of the

surrounding medium (usually air or vacuum) and the

concerned equations are also shown .The energy associated

with the term of the near field flows alternately out of and

back into the antenna. The exponent of e accounts for the

phase dependence of the electric field on time and the

distance from the dipole. Often one is interested in the

antenna's radiation pattern only in the far field, when

r ≫ λ/2π. In this regime, only the 1/r term contributes, and hence. The concerned equations are

The far electric field, Eθ, of the electromagnetic wave is

co-planar with the conductor and perpendicular with the line joining the dipole to the point where the field is calculated. If

the dipole were placed in the center of a sphere with the axis

south-north, the electric field would be parallel to geographic

meridians and the magnetic field of the electromagnetic wave

would be parallel to geographic parallels

B. Dipole antenna techniques

Implementation of wideband antenna for smart grid applications with a frequency bandwidth of 40% and gain of 3

to 4dbThe antenna design and simulation was carried out

using ANSYS‟ HFSS software which is the industry-standard

simulation tool for 3-D full-wave electromagnetic field

simulation. The total size of the antenna is 20mm x 10mm x 2mm. This new design offers a wide fractional frequency

bandwidth of about 40% with a gain from 3dB-4.3dB over the

frequency band (5GHz – 7.5GHz)

Using ultra wideband dipole antenna operating at 1.75 to 40

GHz .It is shown that the proposed antenna works well in

1.7GHz-40GHz frequency range and the main direction of the

radiation pattern keeps stable during the whole frequency

range. The H plane demonstrates an excellent Omni-

directional pattern.

A Dual-band Wide-beam width WLAN Access Point

Antenna with similar gain and wide beam width in both the 2.4- and 5-GHz WLAN bands. This paper describes a dual

band printed dipole antenna that has nearly identical radiation

patterns with similar gain and wide beam width in both the

2.4- and 5-GHz WLAN bands. The proposed design employs

two techniques to improve the radiation pattern. These

techniques are the use of an angle dipole and vertical copper

International Journal of Electrical & Electronics Engineering 14 www.ijeee-apm.com

plates arranged on the ground plane for improvement in the

radiation pattern of lower and upper bands, respectively .Ultra

band dipole antenna and circularly polarized antenna provides

the best Omni directional radiation pattern. Also the

techniques such as angled dipole and vertical copper plates on

ground plane are used for the further improvement of the radiation pattern of the antenna.

IV. RESULTS AND DISCUSSION

In this section the lambda /2 dipole antenna is

constructed and the numerical and experimental results

regarding the radiation characteristics are presented and

discussed. The simulated results are obtained by using the An soft simulation software high frequency structure simulator.

The measured and simulated characteristics of the antenna are

shown and from the far field report the rectangular plot, the

3D polar plot and are drawn and the radiation characteristics

are also plotted.

Fig. 6: XY Rectangular Plot

Fig. 7: 3D Polar Plot

Unlike other antennas reported in the literature to date, the proposed antenna displays a good omnidirectional radiation

pattern even at higher frequencies. The designed antenna has

a small size and good return loss and radiation pattern

characteristics are obtained in the frequency band of interest.

The simulated and experimental results show that the

proposed antenna could be a good candidate for UWB

applications. The radiation pattern is shown in the figure for

the dipole antenna.

Fig. 8: Radiation Pattern

Next the radiation pattern for a half wave dipole antenna is

shown along with the stacked XY plot

Fig. 9: XY stacked plot

Fig. 10: Electric fields (blue) and magnetic fields (red) radiated by a

dipole antenna

A. Radiation Pattern and Gain

Dipoles have a radiation pattern, shaped like a toroids (doughnut) symmetrical about the axis of the dipole. The

radiation is maximum at right angles to the dipole, dropping

off to zero on the antenna's axis. The theoretical maximum

gain of a Hertzian dipole is 10 log 1.5 or 1.76 dBi. The

maximum theoretical gain of a λ/2-dipole is 10 log 1.64 or

2.15 dBi.

V. CONCLUSION AND FUTURE WORK

With the rapid progress of wireless technology in recent years, various wireless systems such as GSM,

WCDMA/UMTS, Bluetooth, WLANs, and GPS have been

www.ijeee-apm.com International Journal of Electrical & Electronics Engineering 15

highly integrated into the mobile devices, and in order to

fulfill the RF system requirements using the different

frequency band, antenna technology is required to wideband

characteristics .On the other hand, many modern wireless

communication systems such as radar, navigation, satellite,

and mobile applications use the circular polarized (CP) radiation pattern. The attractive advantages of the CP antenna

are existed as follows. Firstly, since the CP antennas send and

receive in all planes, it is strong for the reflection and

absorption of the radio signal. In the multi-path fading

channel environment, the CP antenna overcomes out of phase

problem which can cause dead-spots, decreased throughput,

reduced overall system performance. Additionally. Also

further improvements could be done by using antenna

substrates with higher dielectric constants in order to reduce

the size a broad band wide beam circular polarization micro

strip antenna. The configuration of the antenna is simple and

easy to fabricate compared with conventional micro strip antenna, the radiation beam is broadened obviously. Further

research on circularly polarized wideband micro strip

antenna is required as it gives the best performance and

overall improvement of antenna parameters.

REFERENCES

[1] Gaboardi P., Rosa L., Cucinotta A., and Selleri S., “Patch Array Antenna for UWB Radar Applications”, in 3rdEuropean RadarConference, 2006, p.281-284.

[2] Yoann Letestu and Ala Sharaiha, “Size reduced multi-band printed quadrifilar helical antenna,” IEEE Trans. Antennas Propag., vol. 59, pp. 3138-3143, 2011.

[3] A. Siligaris et al., “A 65-nm CMOS fully integrated transceiver module for 60-GHz Wireless HD applications,” IEEE Journal of Solid-State Circuits, vol. 46, no. 12, pp. 3005-3017, Dec. 2011.

[4] S. Manafi, S. Nikmehr, and M. Bemani, "Planar reconfigurable

multifunctional antennaforWLAN/wimax/UWB/pcsdcs/UMTS applications," Progress In Electromagnetics Research C, Vol.26, 123- 137, 2012.

[5] C. R. Medeiros, E. B. Lima, 1. R. Costa, and C. A.Fernandes, "Wideband slot antenna for WLAN accesspoint, " IEEE

Antenna Wireless Propagate. Lett., vol. 9,pp. 79-82,2010. [6] F. Ghanem, P. S. Hall and J. R. Kelly, “Two port frequency

reconfigurable antenna for cognitive radios”, Electronics Letters,vol.45, 2009,pp.534-536.

[7] E. Ebrahimi, J. R. Kelly and P. S. Hall, “A reconfigurable Narrowband antenna integrated with wideband monopole for cognitive radio applications”, IEEE Antennas and Propagation Society International Symposium( APSURSI), 2009.

[8] J. W. Baik, S. Pyo, T.H. Lee, and Y.S. Kim, “Switchable printed Yagi- Uda antenna with pattern reconfiguration”, ETRI Journal, vol.31 2009,pp.318-320

[9] M. Sanad, "A Small Size Micro strip Antenna Circuit", IEEE International Conference on Antenna and Propagation, vol. 1, pp. 465-471, April1995.

[10] P. Suraj and V. R. Gupta, “Analysis of a Rectangular Monopole Patch Antenna” „International Journal of Recent

Trends in Engineering,Vol. 2, No. 5, pp. 106-109, November 2009.

[11] M. N. Srifi, M. Meloui and M. Essaaidi, “Rectangular Slotted Patch Antenna for 5-6GHz Applications”, International Journal of Microwave and Optical Technology, Vol.5 No. 2, pp., 52-57 March 2010.

[12] Ansoft Corporations, HFSS V.12- Software based on the finite

element method [13] G. Augustin, S. V. Shynu, C. K. Aanandan, and K. Vasudevan, "Compact dual-band antenna for wireless access point, " Electron. Lett., vol. 42, no. 9, pp. 502-503, Apr. 2006.

AUTHORS

First Author – Amandeep Batth:

M. Tech. in Electronics and Communication Engineering from

Punjab Technical University, MBA

in Human Resource Management

from Punjab Technical University ,

Bachelor in Technology (B-Tech.)

from Punjab Technical University .

Six years of work experience in

teaching. Area of interest: Antenna

Design and Wireless Communication. International

Publication: 1, National Conferences and Publication: 4.

Working with Indo Global College of Engineering Abhipur,

Mohali, P.B. since 2008. Email: amandeep_batth@rediffmail.com

Second Author– Abhishek Thakur:

M. Tech. in Electronics and

Communication Engineering from

Punjab Technical University, MBA

in Information Technology from

Symbiosis Pune, M.H. Bachelor in

Engineering (B.E.- Electronics)

from Shivaji University Kolhapur,

M.H. Five years of work experience in teaching and one year of work

experience in industry. Area of interest: Digital Image and

Speech Processing, Antenna Design and Wireless

Communication. International Publication: 7, National

Conferences and Publication: 6, Book Published: 4

(Microprocessor and Assembly Language Programming,

Microprocessor and Microcontroller, Digital Communication

and Wireless Communication). Working with Indo Global

College of Engineering Abhipur, Mohali, P.B. since 2011.

Email: abhithakur25@gmail.com

Third Author – Jitender Sharma: M. Tech. in Electronics and Communication Engineering from Mullana University,

Ambala, Bachelor in Technology (B-Tech.)from Punjab

Technical University . Five years of work experience in

teaching. Area of interest:, Antenna Design and Wireless

Communication. International Publication: 1 National

Conferences and Publication:6 and Wireless

Communication). Working with Indo Global college since

2008.

E-mail:er_jitender2007@yahoo.in