JEPES Journal of Electrical Power and Electronics Systems
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Design and Development of UWB Microstrip Patch Antenna Structure at Frequency 5.8 GHz for UWB Indoor Application
Mohd Hezri Abdullah1,*, Abdul Rani Othman2
1Advanced Technology Training Center (ADTEC) Kulim, Lot 635, Mahang, 09700 Karangan, Kedah
2Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka (UTEM), 76100 Durian Tunggal, Melaka, Malaysia
1[email protected] Received 05 October 2018;
Accepted 05 January 2019;
Available online 12 February 2019
1. Introduction
Ultrawideband occupies a wide bandwidth exceeding at least 500MHz or a minimum of 20% of center frequency [1].
It is a new approach for short range high bandwidth wireless communication. There are many advantages pertaining to the UWB antenna systems. To begin with, UWB antennas are preferred for variety of applications such as medical imaging, wireless communications, indoor positioning as well as radar [3].
Currently, the state of the art of UWB antennas focuses in the planar monopole antennas, slot and microstrip with various types of matching techniques for improving the bandwidth ratio without losing its properties of radiation pattern [2]. A perfect antenna is supposed to be simple structure, having omni-directional patterns, as well as small size which can produce low distortion as well as having big bandwidth. An UWB antenna should have an omni-directional radiation pattern for ensuring a convenience communication between receivers and transmitters. Low directivity is preferred and the gain must be as uniform as possible for most of directions.
2. UWB Antenna Background
UWB technology has undergone many main improvements recently. However, there is still a challenge for making the technology lives up to the expectation. The design of UWB antenna is one of the specific challenges. The UWB antennas must capable for transmitting pulses as accurately and efficiently as possible. The allocated spectrum needs transmitters and receivers with wideband bandwidth antennas.
The major challenge in designing a UWB antenna is to achieve an extremely wide impedance bandwidth and in the meantime sustaining high radiation efficiency. Theoretically, an UWB antenna shall be capable to operate within the bandwidth 3.1 GHz - 10.6 GHz frequency range. As such, the UWB antenna shall achieve near to a decade of impedance bandwidth of about 7.5 GHz. High radiation efficiency of UWB antennas are needed for ensuring the transmitted power spectral density requirements can be obtained. Dielectric and conductor losses shall be minimized for maximizing radiation efficiency. An UWB antenna shall have high radiation Abstract: The project is to develop an ultrawideband (UWB) microstrip antenna at centre frequency of 5.8 GHz .The return loss is designed at S11 < -10dB for a bandwidth of 4 GHz or bigger. Based on UWB criterias, an UWB antennas shall have a large bandwidth exceeding at least 500 MHz or a minimum of 20% of center frequency . The gain of antenna should be omni- directional as well as having a gain of 5dBi or higher with Voltage Standing Wave Ratio (VSWR) of less than 2. The material used is a 0.80 mm thickness of FR4 substrate. The antenna is of microstrip line-fed as well as having 2 ground areas underneath. The antenna is well-matched with the 50-ohm impedance matching at resonant frequency. The antenna is well-matched as its return loss is greater than or equal to -10 dB at frequency between 3 GHz and 10GHz. A possible application of the antenna is for UWB indoor applications. The benefits of the antenna are its monopole simple rectangular patch design and the use of the 0.80 mm thickness FR4 substrate which shows good UWB properties at high frequency. The UWB antenna is simulated using electromagnetic CST software.
Keywords: Ultrawideband (UWB), Voltage Standing Wave Ratio, Bandwidth, microstrip and antenna
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efficiency due to its excessively low transmitted power spectral density.
To make matter worse, the losses can probably compromise the functionality of the system if the antenna produces any excessive losses. Furthermore, a nearly omnidirectional radiation pattern is preferred since it allows freedom in the location of receiver and transmitter. This can be done by minimizing gain and directivity as well as maximizing the half power beamwidth.
It is also highly recommended that the antenna is low compatibility and profile for being integrated with printed circuit board (PCB) [4]. An ideal UWB antenna should have optimal performance of overall system. For example, the antenna design shall be that the overall device (Radio Frequency (RF) antenna and front end) complies to the compulsory power emission mask outlined by the Federal Communication Committee (FCC) or other regulatory bodies.
An UWB antenna also shall have good time domain characteristics. In UWB system, a minimum pulse distortion in the received waveform is of paramount important since signal is the carrier of useful information. In the case of narrow band antenna, ideally the antenna shall have the same performance within the whole bandwidth. In addition, the main parameters, such as return loss as well as gain shall have fewer or less variation within the operational band.
Nowadays, latest design of UWB antennas concentrates using microstrip with slots and planar monopole antennas with variety types of matching techniques for improving the ratio of bandwidth and in the mean time doesn’t loss its radiation pattern properties [5]. The designed antennas shall be omni directional patterns, small size and simple structure which can accommodate large bandwidth as well as low distortion [6].
This paper only concentrates for creating a very simple antenna having a bandwidth satisfying the UWB requirements using planar FR4 printed circuit board (PCB) and being analysed using CST Microwave Studio version 2010 antenna simulation software as well as developing a hardware prototype .
3. List of Existing UWB antennas
The research papers that have been already published by other researchers have been studied and summarized in Table 1.0.
Based on the journals presented in Table 1.0, all of the design had achieved and surpassed the minimum UWB requirement of 500MHz. The widest bandwidth was obtained by [2].
Unfortunately, their designs were quite complicated with very tight in dimension tolerances. Furthermore, some of the antenna dimensions were not small enough to be fitted for UWB indoor application appliances. In general, the UWB antennas in Table 1.0 may be well-suited for other applications but is not suitable for UWB indoor application as required in this project.
Table 1.0: List of the existing UWB antennas
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Published by FAZ Publishing http://www.fazpublishing.com/jepes 4. Design of UWB Patch antenna
The UWB antenna shall have a return loss of S11 < - 10dB between from 3.1GHz to 10.6GHz for UWB applications. However in this project, the expected bandwidth is 4 GHz or bigger based on its dimensions and structure. The antenna will produce a gain of 5 dbi or higher as well as Voltage Standing Wave Ratio (VSWR) of less 2.
The operating frequency shall be chosen to be in the bandwidth of UWB as well as any resonance frequency shall appear within the required UWB bandwidth. In this project, the operating frequency and resonance frequency shall be at 5.8 GHz. This structure can be implemented for UWB indoor application.
Figure. 1 shows the actual antenna that has been designed and tested. Figure 2 shows the top, bottom and side views of the proposed antenna.
Figure 1: Actual UWB that had been produced
(a) Top view
Figure 2: Configuration of the proposed antenna
5. Result and Discussions
As shown in Figure 2, the patch is printed on top of the substrate FR4 having thickness 1.6 mm and relative permittivity (εr) 4.2. The return losses were measured by using Agilent 8722 ES network analyzer. The measured of both prototypes and simulated return loss curves are plotted in Figure 3-11. The predicted return loss obtained by using CST software is reasonably close to the measured values.
Figure 3: Measured and simulated return loss (S11) of UWB antenna
Figure 4: Measured VSWR of antenna
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Figure 5: Simulated VSWR of UWB the UWB antenna
Figure 6 : Measured radiation pattern of E-plane at 5.8GHz
Figure 7 : Simulated E-plane radiation pattern at 6 GHz
Figure 8 : Simulated E-plane radiation pattern at 6.5 GHz
Figure 9 : Simulated impedance value at 6.5 GHz
Figure 10: Simulated impedance value from 3.5GHz until 13GHz
Figure 11 : Measured impedance value from 3.5GHz until 13 GHz
The Smith Chart plot shows how the impedance of the antenna varies with frequency. The impedance value should be close to 50 ohms in order to perfectly match the port with the antenna.
6. Conclusion
The Ultra-wideband (UWB) technology is projected to be the mainstream solution for the future WPAN systems. This probably can happen due to the large frequency spectrum occupied by UWB as well as its ability to achieve very high
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data rate .In addition, the UWB system as well produces extremely low power emission level. As a result, this wills constraint UWB systems from triggering severe interference with existing wireless systems.
Designing an UWB antenna as the only non-digital part of a UWB system is basically a challenging topic. The scenario happens due to there are various stringent requirements for a UWB antenna in comparison to that of narrowband. A conventional structure rectangular planar monopole antenna has been successfully simulated and designed due to its low profile, simple structure, easy to fabricate as well as UWB properties with close to omni- directional radiation patterns.
7. Future works
Future work can be carried out in the following areas based on the limitations of the work presented as well as the drawn conclusions:
Firstly, it is observed that the asymmetry slots UWB antennas operate within UWB bandwidth. A more comprehensive understanding of the mechanism for current distribution as well as the variations of impedance due to the asymmetry slot could lead to improved design of UWB antennas.
Secondly, the use of different type of feeding such as coplanar waveguide (CPW) can be further studied for being used with the proposed UWB antenna.
Lastly, antenna might be embedded inside a laptop or other devices in the future UWB systems. As a result, the antenna performances are needed to be investigated due to devices' effects. The impact from human body should also be considered whenever the antenna is built on a portable device.
References
[1] Federal Communications Commission, Washington, DC, “FCC report and order on ultra wideband technology”, 2002.
[2] Peyrot Solis M.A, Galvan Tejada and Jardon A.H.
“State of the Art in Ultra-Wideband Antennas” . 2nd International Conference on Electrical and Electronics Engineering (ICEEE) and XI Conference on Electrical Engineering (CIE 2005). Mexico City, Mexico.
September 7-9, 2005. 101 –105
[3] Rafi G.Z and Shafai L, “Wideband V-Slotted Diamond- Shaped Microstrip Patch Antenna,”
Electronics Letters, Vol. 40, No. 19, 2004, pp. 1166 – 1167
[4] Chen Z. N. et. al. (2004). Considerations for Source Pulses and Antennas in UWB Radio Systems. IEEE Transactions on Antennas and Propagation,Vol. 52(7).
[5] Mohamed A.H and Shafai L. (2011). “Performance Study on Modern Ultra Wideband Monopole Antennas, Ultra Wideband Communications “: Novel Trends - Antennas and Propagation, Dr. Mohammad Matin (Ed.), ISBN: 978-953-307-452-8,
[6] Garg R., Bhartia P., I. Bahl L., Itipiboon A. (2000).
Microstrip antenna design handbook, Artech House, Boston –London.
[7] Eng G L, Zhao W., Chi U L, Yuanzhe W., Man K.L, (2010)“ Ultra Wideband Antennas – Past and Present ” IAENG International Journal of Computer Science, 37:3, IJCS_37_3_12
[8] Zian K.D, Meriah S M , (2012). “New Diamond Antenna for Ultra Wideband Applications” , IJCSI
International Journal of Computer Science Issues, Vol.
9, Issue 4, No 1 ,ISSN (Online): 1694-0814
[9] Sadat S. , Fardis M, Geran F. and Dadashzadeh G.
(2007) . A compact microstrip square-ring slot antenna for UWB applications. Progress In Electromagnetics Research, Vol. 67, 173-179.
[10] Z. Yashar, G. Changiz and N Javad,(2006) “ Antenna Design for Ultra Wideband Application Using a New Multilayer Structure” , PIERS ONLINE, VOL. 2, NO.
6.
[11] Baskaran K. , Lee C. P., Chandan K. C.(2011), “A Compact Microstrip Antenna for Ultra Wideband Applications”, European Journal of Scientific Research ,ISSN 1450-216X Vol.67 No.1 , pp. 45-51 ,©
EuroJournals Publishing, Inc.
[12] Khodaei G.F., J. Nourinia J., and C. Ghobadi C (2008).,
“A Practical Miniaturized U-Slot Patch Antenna With Enhanced Bandwidth”, Progress In Electromagnetics Research B, Vol. 3, 47–62.
[13] Dong J., Li Q. and Deng L., (2017) “ Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications”.Sensors 2017 , 17, 349;
doi:10.3390/s17020349.
[14] Kulkarni S.P, Kasabegoudar V.G. (2017)“ Bandwidth Enhancement of Compact Circular Slot Antenna for UWB Applications ” , Global Journal of Researches in Engineering: F: Electrical and Electronics Engineering Volume 17 Issue 1 Version 1.0 Year 2017
Type: Double Blind Peer Reviewed International Research Journal
Publisher: Global Journals Inc. (USA)
Online ISSN: 2249-4596 & Print ISSN: 0975-5861
