IJEEE, Vol. 1, Spl. Issue 1 (March 2014)
e-ISSN: 1694-2310 | p-ISSN: 1694-2426
Analyzing the Different Parameters of Dipole Antenna 1
Amandeep Bath, 2Abhishek Thakur, 3Jitender Sharma , 4Prof. Basudeo Prasad 1,2,3,4
Electronics & Communication Engineering Department, Indo Global College of Engineering, Punjab, India
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amandeep_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, WideBand, 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 www.ijeee-apm.com
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
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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 broadband 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.
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 Fig. 1: Duplicated cylindrical substrate around the axis
III. DIPOLE CHARACTERISTICS A. Frequency versus length
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 International Journal of Electrical & Electronics Engineering
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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 halfwave dipole is cut to length l for frequency f in hertz according to the formula
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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.
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
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: 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
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
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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 Omnidirectional 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
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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. 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. 6: XY Rectangular Plot
Fig. 10: Electric fields (blue) and magnetic fields (red) radiated by a dipole antenna
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. International Journal of Electrical & Electronics Engineering
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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 位/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
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. 30053017, 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. www.ijeee-apm.com
[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. 502503, 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 International Journal of Electrical & Electronics Engineering
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