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Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator

Nassrin Ibrahim Mohamed Elamin
American Journal of Electrical and Electronic Engineering. 2021, 9(1), 1-6. DOI: 10.12691/ajeee-9-1-1
Received January 16, 2021; Revised February 19, 2021; Accepted March 03, 2021

Abstract

The use of transparent antennas has been gaining popularity in recent years. Today many types and designs of display apparatus can be seen along city streets and for buildings as a backup power supply. Transparent antennas can be used for cladding the modern glass buildings. Transparent antennas also can be placed directly on top of solar cells and resolve the issue of competing for limited surface real estate. Like integration with the solar panels of small satellites, where limited surface area is an issue for mounting antennas, solar cells, and space instruments. This paper discuss the methods and materials used to design a transparent antennas that can be integrated with solar cells to solve the issue of competing for limited surface real estate and backup the short of electricity in the sunny country Sudan. In this paper a proposed a 4-element meander line MIMO Multiple Inputs Multiple Outputs antenna system designed from Aluminum foil radiator over transparent glass substrate this design is transparent partially. Despite of the unfamiliar materials used for the antenna design and it is a limited size MIMO system the simulated and measured results showed XBand matched bandwidth. In this work the antenna is designed and the solar cell module has been proposed theoretically.

1. Introduction

The invention of transparent antenna innovated by the National Aeronautics and Space Agency (NASA) in the late nineties 1. The first material used for this study by NASA is the patented AgHT-8 1, the first of the two types of the AgHT performance film trademark which is a transparent electrically conductive film made of silver sandwiched between two layers of tin oxide. Since then, researchers have used semiconducting oxides of indium, zinc and cadmium and metals such as gold and titanium nitride. A figure of merit for these transparent conductive materials is the ratio of the electrical conductivity to the optical absorption factor of the film 2, The small value of the resistivity, higher the conductivity of the AgHt film must be but with a compromise on transparency. For this reasons the proposed MIMO antenna system designed from Aluminum foil over transparent glass substrate. The design gains the 100% transparency of the glass and the good conductivity of the Aluminum. Antennas developed so far have shown to have better gain by virtue of having a glass substrate or superstrate as an RF lens 2. On the other hand, for a film antenna in cellular, wearable and other non-glass applications where discreteness is warranted, a single transparent antenna with improved features such as gain and efficiency is needed. In 1958, the invention of the first important application of solar cells as a back-up power source to the Vanguard I satellite, which made it to continue sending for over a year after its chemical battery used 3. The successful of solar cells on this task was repeated in many other American and Soviet satellites, and by the late 1960s, photovoltaic (PV) technology had become their main source for power until now 4, 5, 6, 7. Electrically conductive materials used for microwave antennas are typically metals which are opaque to visible light. Fortunately, materials that are both transparent conductive have been made by cladding clear polyester sheets with very thin layers of metal oxides 8, 9 or carbon nano tubes 9, 10. Many transparent antennas have been proposed which show promising results, but gain data was not reported 11, 12 very lower gain for transparent antennas compared to their copper and other conductive materials counterparts; a transparent PIFA designed on a sheet of resistivity 20 w/sq gave approximately 10 dB lower gain at 2.4 GHz 13. And planar monopole UWB antenna on AgHT-4 gave 5 dB lower gain because of the inherent low conductivity of the transparent film 14, 15. Transparent patch antennas, as a special class of micro strip patch antennas have been studied for more than twenty years. Their typical shape consists of a top-layer conductive path, bottom-layer ground, and dielectric substrate in between. The integration of photovoltaic with antenna technology needs special ways for implementation since the necessities of photovoltaic are often in opposite to antenna requires. The researches have shown that integration is possible if all requirements are considered appropriately 16. Current government policies in the world look for improving the use of renewable energy instead of the use of grid-supplied electricity to decrease carbon dioxide emissions, and so contribute to the alleviation of climate change. With rising fossil fuel cost solar energy becomes alternative good option for powering communication systems and it is really the first choice when it comes to powering tools in space or remote areas where grid power either is too expensive or it is not available to extend to . As an energy source, solar photovoltaic systems are reliable and incur minimum maintenance 17. Antennas for communication and solar cells for energy are sharing a limited surface area which can be saved by suitably combining both technologies 18, 19. Also consumer electronics entertainment devices such as wireless headphones or mobile phones are increasingly powered with photovoltaic's (PV) 20, 21. In these systems, the communications antenna is typically displaced from the panel of photovoltaic cells. In addition, urban mobile cellular communications use an increasingly high number of limited-range building-mounted antennas operating at small power. The installation of microcell antennas on buildings often needs expensive and time-consuming retrofitting of electrical supply cables, which can guide to concern over visual amenity, vandalism and maintenance. Photovoltaic powered microcell transceivers with combined batteries offer a high inherent reliability and are insusceptible to grid-supply interruptions 22, 23. Vertical façade PV panels for building integration are shaped usually with a flat external shape 24, 25, 26, 27 which helps integration with planar antennas. Figure 1 shows general flow chart for glass building clad with transparent antenna integrated with photovoltaic film the figure extracted from the literature survey.

2. Xband Antenna Design

In this section the two design methods (simulation and fabrication) used for designing the proposed model have been shown and discussed.

2.1. Simulation

CST (Simulation): is the imitation of the operation of a real-world process or system over time 28. The act of simulating something first requires that a model be developed; this model represents the key characteristics or behaviors of the selected physical or abstract system or process. The model represents the system itself, whereas the simulation represents the operation of the system over time. Simulation is used in many contexts, such as simulation of for performance optimization, , , , , and . Often, are used to study simulation models. Simulation is also used with of natural systems or human systems to gain insight into their functioning 29.

The recommended 4-element MIMO antenna structure is designed as shown in Figure 2 (a) and (b). Four symmetrical meander line MIMO antenna elements have been used for designing the structure from aluminum foil over glass substrate. The MIMO antenna system design is not complete area transparent where the miniature meander foil line is an opaque material. The produced design is partially shaded glass, small area shaded and the remains has 100% transparency factor which is higher transparency than the AgHt-4 and AgHt-8 materials.

Making a monopole resonant frequency and matching it to the required feature impedance can be achieved by shaping the short monopole in inverted-L shape as mentioned in Paper 30. Meandered antenna represents a developing configuration or modification of the inverted L-antenna. Meandering the horizontal part of the inverted L-wire antenna in any geometric configuration tunes the monopole antenna’s capacitive reactance (or the total feeding point reactance is equal to zero) 31. The purpose of initiating the technique of Slot Meander Patch (SMP) antenna, as a new design, is to decrease the size of the current available wire antennas like log-periodic dipole arrays antennas and Yagi-Uda. The proposed SMP antenna as stated in 32 was verified by altering the design’s main variables such as the number of sections per wavelength (N) and antenna reduction ratio β (where β=l/L, l is the decreased length after meandering and L is overall length of the wire) 32.

The dielectric constant of an aluminum layer averages between 7 and 8 33. The overall length of each meander line of the 4 elements is optimized to 18 mm which is equivalent to 0.39 λ at 6.5 GHz. The antenna is designed to operate as multiband antenna at resonant frequency of 6.5 kHz by optimizing the meander line length.

The glass substrate has dimensions of 60 mm×55 mm, with thickness H=5 mm, and permittivity εr=7. A good impedance matching can be achieved by optimizing the antenna’s overall length.

MIMO technique is considered as a solution to improve the low data transmission rates and channel bandwidth (BW). Moreover, it also addresses the problems of multipath fading. The proposed design suggests more than one antenna elements in transmitter and receiver terminals to improve the channel capacity in a high multipath environment 34. Printed antennas with Co-planer Wave Guide CPW feeds have attracted a serious attention over the years. Compared with other printed radiating elements, CPW-fed antennas do not only possess a broad BW, but also a smaller mutual coupling between adjacent lines. Another advantage is the ease of integration with solid-state active devices 35, 36, 37, 38, 39. Therefore CPW-fed antennas are promising candidates as elements for MIMO applications so it is useful to separate the 4 MIMO antenna system. Furthermore, positioning MIMO antenna elements orthogonally have no effects on the antenna size. These techniques could be used in designing a compacted MIMO system that has limited size element and high isolation.

2.1. Fabrication

The proposed MIMO antenna structure is fabricated manually as shown in Figure 3. Four symmetrical miniature meander MIMO antenna elements have been used for designing the structure. The antenna is designed to operate at a resonant frequency of 6.5 GHz by optimizing the meander section to 0.39λ. The MIMO antenna system designed from Aluminum foil over transparent glass substrate. This design makes its transparent partially as it is a radiated element. The glass substrate has dimensions of 60 mm × 55 mm, with thickness H=5 mm, and the Aluminum foil permittivity is εr=7 40.

3. Results and Discussion

The proposed design covers the X-band as verified by the simulated and measured results below. The main motivation and benefits of this prototype is building the unit can be used in cladding the glass building.

3.1. Simulation Results

The CST simulator was used for measuring the simulated antenna’s S-parameters and the radiated power as shown in Figure 4 and Figure 5. Figure 4 shows that the antenna covered the XBand (frequency range to 6.4 GHz to 12 GHz), and Figure 5 shows that the antenna radiating high power about 71 dB.

3.2. Measured Results

The model is miniature size this makes the manual fabrication so difficult and no way to make the slots over the meander shape as result the measured BW a little bit narrower than the simulated (Figure 6) results as mentioned in 32.

The R&S® PR100 used in measuring the matched BW is a portable receiver for radio monitoring in the wide frequency range from 9 kHz to 7.5 GHz. Whether used for monitoring emissions, detecting interference, or locating miniature transmitters, the receiver offers features unrivaled in its class. Together with the R&S® HE300 portable directional antenna, it forms a compact receiving system. The R&S® PR100 is notable for its wide frequency range, excellent receive characteristics, real time bandwidth of 10 MHz, and large 6” color display.

4. Conclusion

In this paper 4-element MIMO antenna system was simulated, fabricated, and measured. The results shows accepted characteristics despite the new materials (glass and foil) used. The measured BW is a little bit narrower than the simulated this because no way to make manually the slots over the miniature meander shape.

Acknowledgments

Great thank for the ministry of technique and Telecommunications for doing the measurement by their R&S® PR100 is a portable receiver for radio monitoring.

References

[1]  R.N. Simons and R.Q. Lee, Feasibility Study of Optically Transparent Micro strip Patch Antenna, International Symposium and Radio Science Meeting cosponsored by IEEE, AP-S, and U.R.S.I., Montreal, Canada, July 13-18, 1997.
In article      
 
[2]  R. G. Gordon, “Criteria for Choosing Transparent Conductors,” MRS Bulletin, vol. 25, pp. 52-57, August 2000.
In article      View Article
 
[3]  R. L. Easton and M. Votaw, Vanguard I IGY satellite (1958 beta), Review of Scientific Instruments, vol. 30, pp. 70-75, 1959.
In article      View Article
 
[4]  Y. Hamakawa, Thin-Film Solar Cells: Next Generation Photovoltaics And Its Applications. Springer-Verlag, Berlin-Heildelberg, Germany, 2004.
In article      View Article
 
[5]  S. Mehta. (2010, Mar.) Thin film 2010: Market outlook to 2015. [Online]. Available: http://www.gtmresearch.com/.
In article      
 
[6]  A. Luque and S. Hegedus, Handbook of Photovoltaic Science and Engineering. John Wiley & Sons Ltd., Sussex, UK, 2003.
In article      View Article
 
[7]  A. Goetzberger, C. Hebling, and H. W. Schock, Photovoltaic materials,history, status and outlook, Materials, Science & Engineering : R :Reports, vol. 40, no. 1, pp. 1-46, 2003.
In article      View Article
 
[8]  F. G. Gillery, Transparent, colorless, electrically conductive coating, US Patent 4194022, 1980.
In article      
 
[9]  R. G. Gordon, Criteria for choosing transparent conductors, MRS Bulletin, vol. 25, no. 8, pp. 52-57, Aug. 2000.
In article      View Article
 
[10]  J. S. Moon, J. H. Park, T. Y. Lee, Y.W. Kim, J. B. Yoo, C. Y. Park, J. Kim, and K. W. Jin, Transparent conductive film based on carbon nano tubes and PEDOT composites, Diamond & Related Materials, vol. 14, no. 11-12, pp. 1882-1887, Nov. 2005.
In article      View Article
 
[11]  R. N. Simons and R. Lee, Feasibility study of optically transparent microstrip patch antenna, in International Symposium and Radio Science Meeting, Montreal, Canada, Jul. 13-18 1997.
In article      
 
[12]  C.-F. Huang and L. Chen, Realisation of printed-on-display antenna for mobile terminals, Electronic Letters, vol. 38, no. 20, pp. 1162-1163, Sep. 2002.
In article      View Article
 
[13]  N. Guan, H. Furuya, D. Delaune, and K. Ito, Antennas made of transparent conductive films, PIERS online, vol. 4, no. 1, pp. 116-120, 2008.
In article      
 
[14]  A. Katsounaros, Y. Hao, N.Collings, and W. Crossland, Optically transparent ultra-wideband antenna, Electronics Letters, vol. 45, no. 14, pp. 722-723, 2009
In article      View Article
 
[15]  Tursunjan Yasin, TRANSPARENT ANTENNAS FOR SOLAR CELL INTEGRATION, UTAH STATE UNIVERSITY, Logan, Utah, 2013.
In article      
 
[16]  C. Bendel, J. Kirchhof and N. Henze. Institute for Solar Energy Supply Technology (ISET), Koenigstor 59, D-32119 Kassel, Germany. Application of photovoltaic solar cells in planar antenna structures. 3rd World Conference on Photovoltaic Energy, Osaka, Japan, May 11-18, 2003.
In article      
 
[17]  B. Pattan, “Satellite-based cellular communications”, McGraw-Hill, New York, USA, 1997.
In article      
 
[18]  J. D. Hagerty, Radio telemetry buoy for long-range communication, US Patent 5452262, Sep. 1995.
In article      
 
[19]  S. Baglio, S. Gagliano, D. Neri, N. Savalli, and G. Tina, Optimal design of photovoltaic systems for wireless sensor networks, in IEEE International Symposium on Industrial Electronics 2008 (ISIE 2008), Cambridge, UK, Nov. 2008, pp. 2108-2113.
In article      View Article
 
[20]  D. Honore, Wireless solar entertainment system, US Patent 5551065, Aug. 1996.
In article      
 
[21]  M. Shaff, Solar-powered mobile telephone, US Patent 7072696, Jul.2006.
In article      
 
[22]  B. Lindemark and G. Öberg, Solar power for radio base station (RBS) sites applications including system dimensioning, cell planning and operation, in 23rd International Telecommunications Energy Conference (INTELEC 2001), Edinburgh, UK, Oct. 2001, pp. 587-590.
In article      View Article
 
[23]  W. Yu and X. Qian, Design of 3kW wind and solar hybrid independent power supply system for 3G base station, in Proc. of the 2009 2nd International Symposium on Knowledge Acquisition and Modeling, vol. 3, Wuhan, China, Dec. 2009, pp. 289-292.
In article      View Article
 
[24]  A. Zacharopoulos, P. Eames, D. McLarnon, and B. Norton, Linear dielectric non-imaging concentrating coveres for PV integrated building façades, Solar Energy, vol. 68, no. 5, pp. 439-452, 2000.
In article      View Article
 
[25]  J. D. Mondol, Y. G. Yohanis, M. Smyth, and B. Norton, Long-term validated simulation of a building integrated photovoltaic system, Solar Energy, vol. 78, no. 2, pp. 163-176, 2005.
In article      View Article
 
[26]  V.L. Soethe, E.L. Nohara, L.C. Fontana and M.C. Rezende, Radar absorbing materials based on titanium thin film obtained by sputtering technique, Journal of Aerospace and Technology Management, vol. 3, issue 3, pp. 279-286, 2011.
In article      View Article
 
[27]  T. Peter, Y.Y. Sun, T.I. Yuk, H.F. AbuTarboush, R. Nilavalan and S.W. Cheung, “Miniature transparent UWB antenna with tunable notch for green wireless applications”, International Workshop on Antenna Technology (iWAT), 2011, pp.259-262, 7-9 March 2011.
In article      View Article
 
[28]  J. Banks, J. Carson, B. Nelson, D. Nicol, “Discrete-Event System Simulation”, Prentice Hall. p. 3, 2001.
In article      
 
[29]  In the words of the Simulation article in Encyclopedia of Computer Science, “designing a model of a real or imagined system and conducting experiments with that model”.
In article      
 
[30]  N. I. Mohamed, T. A. Rahman, and C. Y. Leow, “Issues and challenges of LTE antenna designs for USB-dongle device,” in Antennas and Propagation in Wireless Communications (APWC), 2012 IEEE-APS Topical Conference on, 2012, pp. 43-46.
In article      View Article  PubMed
 
[31]  N. Mohamed, T. Rahman, and A. Abdulrahman, “Developing Alternatives of Small Monopole Antenna Design for Achieving 4G-LTE Requirements in a Limited Antenna Size,” 2013.
In article      
 
[32]  N. I. M. Elamin, T. A. Rahman, and A. Y. Abdulrahman, “New Adjustable Slot Meander Patch Antenna for 4G Handheld Devices,” Antennas and Wireless Propagation Letters, IEEE, vol. 12, pp. 1077-1080, 2013 (IF 1.695).
In article      View Article
 
[33]  Morokuma, Aluminum electrolytic capacitor 2000.
In article      
 
[34]  CRC materials science and engineering handbook Shackelford, James F. Alexander, William, 2000
In article      
 
[35]  B.-K. Ang and B.-K. Chung, “Wide-band E-shaped patch antennas for wireless communications,” IEEE Transactions on Antennas and Propagation, vol. 49, pp. 1094-1100, 2001.
In article      View Article
 
[36]  N. I. Mohamed, T. Abd Rahman, and M. I. Sabran, “Multiband Printed Slot Meander Patch Antenna for MIMO Implementation in 4G Handheld Devices,” Jurnal Teknologi, vol. 64, 2013.
In article      View Article
 
[37]  R. Karimian, M. Soleimani, and S. Hashemi, “Tri-band four elements MIMO antenna system for WLAN and WiMAX application,” Journal of Electromagnetic Waves and Applications, vol. 26, pp. 2348-2357, 2012.
In article      View Article
 
[38]  E. Antonino-Daviu, M. Cabedo-Fabres, B. Bernardo-Clemente, and M. Ferrando-Bataller, “Printed multimode antenna for MIMO systems,” Journal of Electromagnetic Waves and Applications, vol. 25, pp. 2022-2032, 2011.
In article      
 
[39]  L. Jaejin, Y.-K. Hong, B. Seok, G. S. Abo, W.-M. Seong, and K. Gi-Ho, “Miniature Long-Term Evolution (LTE) MIMO Ferrite Antenna,” IEEE Antennas and Wireless Propagation Letters, vol. 10, pp. 603-606, 2011.
In article      View Article
 
[40]  Rohde & Schwarz GmbH & Co. KG.
In article      
 

Published with license by Science and Education Publishing, Copyright © 2021 Nassrin Ibrahim Mohamed Elamin

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

Cite this article:

Normal Style
Nassrin Ibrahim Mohamed Elamin. Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator. American Journal of Electrical and Electronic Engineering. Vol. 9, No. 1, 2021, pp 1-6. http://pubs.sciepub.com/ajeee/9/1/1
MLA Style
Elamin, Nassrin Ibrahim Mohamed. "Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator." American Journal of Electrical and Electronic Engineering 9.1 (2021): 1-6.
APA Style
Elamin, N. I. M. (2021). Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator. American Journal of Electrical and Electronic Engineering, 9(1), 1-6.
Chicago Style
Elamin, Nassrin Ibrahim Mohamed. "Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator." American Journal of Electrical and Electronic Engineering 9, no. 1 (2021): 1-6.
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  • Figure 2. (a) Photo of prototype of simulated 4-element MIMO antenna system, (b) photo of one of the four symmetric antenna elements
[1]  R.N. Simons and R.Q. Lee, Feasibility Study of Optically Transparent Micro strip Patch Antenna, International Symposium and Radio Science Meeting cosponsored by IEEE, AP-S, and U.R.S.I., Montreal, Canada, July 13-18, 1997.
In article      
 
[2]  R. G. Gordon, “Criteria for Choosing Transparent Conductors,” MRS Bulletin, vol. 25, pp. 52-57, August 2000.
In article      View Article
 
[3]  R. L. Easton and M. Votaw, Vanguard I IGY satellite (1958 beta), Review of Scientific Instruments, vol. 30, pp. 70-75, 1959.
In article      View Article
 
[4]  Y. Hamakawa, Thin-Film Solar Cells: Next Generation Photovoltaics And Its Applications. Springer-Verlag, Berlin-Heildelberg, Germany, 2004.
In article      View Article
 
[5]  S. Mehta. (2010, Mar.) Thin film 2010: Market outlook to 2015. [Online]. Available: http://www.gtmresearch.com/.
In article      
 
[6]  A. Luque and S. Hegedus, Handbook of Photovoltaic Science and Engineering. John Wiley & Sons Ltd., Sussex, UK, 2003.
In article      View Article
 
[7]  A. Goetzberger, C. Hebling, and H. W. Schock, Photovoltaic materials,history, status and outlook, Materials, Science & Engineering : R :Reports, vol. 40, no. 1, pp. 1-46, 2003.
In article      View Article
 
[8]  F. G. Gillery, Transparent, colorless, electrically conductive coating, US Patent 4194022, 1980.
In article      
 
[9]  R. G. Gordon, Criteria for choosing transparent conductors, MRS Bulletin, vol. 25, no. 8, pp. 52-57, Aug. 2000.
In article      View Article
 
[10]  J. S. Moon, J. H. Park, T. Y. Lee, Y.W. Kim, J. B. Yoo, C. Y. Park, J. Kim, and K. W. Jin, Transparent conductive film based on carbon nano tubes and PEDOT composites, Diamond & Related Materials, vol. 14, no. 11-12, pp. 1882-1887, Nov. 2005.
In article      View Article
 
[11]  R. N. Simons and R. Lee, Feasibility study of optically transparent microstrip patch antenna, in International Symposium and Radio Science Meeting, Montreal, Canada, Jul. 13-18 1997.
In article      
 
[12]  C.-F. Huang and L. Chen, Realisation of printed-on-display antenna for mobile terminals, Electronic Letters, vol. 38, no. 20, pp. 1162-1163, Sep. 2002.
In article      View Article
 
[13]  N. Guan, H. Furuya, D. Delaune, and K. Ito, Antennas made of transparent conductive films, PIERS online, vol. 4, no. 1, pp. 116-120, 2008.
In article      
 
[14]  A. Katsounaros, Y. Hao, N.Collings, and W. Crossland, Optically transparent ultra-wideband antenna, Electronics Letters, vol. 45, no. 14, pp. 722-723, 2009
In article      View Article
 
[15]  Tursunjan Yasin, TRANSPARENT ANTENNAS FOR SOLAR CELL INTEGRATION, UTAH STATE UNIVERSITY, Logan, Utah, 2013.
In article      
 
[16]  C. Bendel, J. Kirchhof and N. Henze. Institute for Solar Energy Supply Technology (ISET), Koenigstor 59, D-32119 Kassel, Germany. Application of photovoltaic solar cells in planar antenna structures. 3rd World Conference on Photovoltaic Energy, Osaka, Japan, May 11-18, 2003.
In article      
 
[17]  B. Pattan, “Satellite-based cellular communications”, McGraw-Hill, New York, USA, 1997.
In article      
 
[18]  J. D. Hagerty, Radio telemetry buoy for long-range communication, US Patent 5452262, Sep. 1995.
In article      
 
[19]  S. Baglio, S. Gagliano, D. Neri, N. Savalli, and G. Tina, Optimal design of photovoltaic systems for wireless sensor networks, in IEEE International Symposium on Industrial Electronics 2008 (ISIE 2008), Cambridge, UK, Nov. 2008, pp. 2108-2113.
In article      View Article
 
[20]  D. Honore, Wireless solar entertainment system, US Patent 5551065, Aug. 1996.
In article      
 
[21]  M. Shaff, Solar-powered mobile telephone, US Patent 7072696, Jul.2006.
In article      
 
[22]  B. Lindemark and G. Öberg, Solar power for radio base station (RBS) sites applications including system dimensioning, cell planning and operation, in 23rd International Telecommunications Energy Conference (INTELEC 2001), Edinburgh, UK, Oct. 2001, pp. 587-590.
In article      View Article
 
[23]  W. Yu and X. Qian, Design of 3kW wind and solar hybrid independent power supply system for 3G base station, in Proc. of the 2009 2nd International Symposium on Knowledge Acquisition and Modeling, vol. 3, Wuhan, China, Dec. 2009, pp. 289-292.
In article      View Article
 
[24]  A. Zacharopoulos, P. Eames, D. McLarnon, and B. Norton, Linear dielectric non-imaging concentrating coveres for PV integrated building façades, Solar Energy, vol. 68, no. 5, pp. 439-452, 2000.
In article      View Article
 
[25]  J. D. Mondol, Y. G. Yohanis, M. Smyth, and B. Norton, Long-term validated simulation of a building integrated photovoltaic system, Solar Energy, vol. 78, no. 2, pp. 163-176, 2005.
In article      View Article
 
[26]  V.L. Soethe, E.L. Nohara, L.C. Fontana and M.C. Rezende, Radar absorbing materials based on titanium thin film obtained by sputtering technique, Journal of Aerospace and Technology Management, vol. 3, issue 3, pp. 279-286, 2011.
In article      View Article
 
[27]  T. Peter, Y.Y. Sun, T.I. Yuk, H.F. AbuTarboush, R. Nilavalan and S.W. Cheung, “Miniature transparent UWB antenna with tunable notch for green wireless applications”, International Workshop on Antenna Technology (iWAT), 2011, pp.259-262, 7-9 March 2011.
In article      View Article
 
[28]  J. Banks, J. Carson, B. Nelson, D. Nicol, “Discrete-Event System Simulation”, Prentice Hall. p. 3, 2001.
In article      
 
[29]  In the words of the Simulation article in Encyclopedia of Computer Science, “designing a model of a real or imagined system and conducting experiments with that model”.
In article      
 
[30]  N. I. Mohamed, T. A. Rahman, and C. Y. Leow, “Issues and challenges of LTE antenna designs for USB-dongle device,” in Antennas and Propagation in Wireless Communications (APWC), 2012 IEEE-APS Topical Conference on, 2012, pp. 43-46.
In article      View Article  PubMed
 
[31]  N. Mohamed, T. Rahman, and A. Abdulrahman, “Developing Alternatives of Small Monopole Antenna Design for Achieving 4G-LTE Requirements in a Limited Antenna Size,” 2013.
In article      
 
[32]  N. I. M. Elamin, T. A. Rahman, and A. Y. Abdulrahman, “New Adjustable Slot Meander Patch Antenna for 4G Handheld Devices,” Antennas and Wireless Propagation Letters, IEEE, vol. 12, pp. 1077-1080, 2013 (IF 1.695).
In article      View Article
 
[33]  Morokuma, Aluminum electrolytic capacitor 2000.
In article      
 
[34]  CRC materials science and engineering handbook Shackelford, James F. Alexander, William, 2000
In article      
 
[35]  B.-K. Ang and B.-K. Chung, “Wide-band E-shaped patch antennas for wireless communications,” IEEE Transactions on Antennas and Propagation, vol. 49, pp. 1094-1100, 2001.
In article      View Article
 
[36]  N. I. Mohamed, T. Abd Rahman, and M. I. Sabran, “Multiband Printed Slot Meander Patch Antenna for MIMO Implementation in 4G Handheld Devices,” Jurnal Teknologi, vol. 64, 2013.
In article      View Article
 
[37]  R. Karimian, M. Soleimani, and S. Hashemi, “Tri-band four elements MIMO antenna system for WLAN and WiMAX application,” Journal of Electromagnetic Waves and Applications, vol. 26, pp. 2348-2357, 2012.
In article      View Article
 
[38]  E. Antonino-Daviu, M. Cabedo-Fabres, B. Bernardo-Clemente, and M. Ferrando-Bataller, “Printed multimode antenna for MIMO systems,” Journal of Electromagnetic Waves and Applications, vol. 25, pp. 2022-2032, 2011.
In article      
 
[39]  L. Jaejin, Y.-K. Hong, B. Seok, G. S. Abo, W.-M. Seong, and K. Gi-Ho, “Miniature Long-Term Evolution (LTE) MIMO Ferrite Antenna,” IEEE Antennas and Wireless Propagation Letters, vol. 10, pp. 603-606, 2011.
In article      View Article
 
[40]  Rohde & Schwarz GmbH & Co. KG.
In article