. MIIM diode with high responsivity and low resistance are reported as follows. Ni/NiO/ZnO/Cr,6 Cr/Al2O3/HfO2/Cr,7 ZrCuAlNi/Al2O3/HfO2/Al, and ZrCuAlNi/Al2O3/Ta2O5/Al. Ni–NiO–ZnO–Cr has been proposed by author Aparajita Singha et al asymmetry 16, bias 0.5 V, Cr–Cr2O3–Al2O3–Ag has been proposed by author B.J. Eliasson et al asymmetry>280, bias 0.4-0.5V, Cr–Al2O3–HfO2–Cr has been proposed by P. Maraghechi et al asymmetry 9, bias 3V.
5.0 Conclusion
In this paper, traditional and innovative power sources for unmanned applications and different combinations of energy storage have been investigated. Energy storage (battery and supercapacitors) have to be highly energetic, powerful, and able to last many cycles before replacement. Currently, state of art uses the most advanced form of Lithium Polymer battery resulting time-efficient enhancing the performance and reliability of the UAVs. Novel Air-batteries represent the future batteries. This technology promises more powerful with higher energy density than traditional batteries minimizing energy loss and inefficiencies. Energy Harvester (Solar and Plasmonic source) can be used to make a self-powered system, which never needs battery replacement. Small-unmanned aircraft system, equipped with solar cell technology has improved dramatically flight endurance and flight time (FT) but not all solar are suitable for UAVs. There are many considerations when designing a solar-powered device such as the environment indoor and/or outdoor, maximum power point tracking to maximize power while minimizing weight to optimize power-to-weight efficiency of solar cells in indoor/outdoor and so on. Solutions for indoor and outdoor environment have been presented. Although photovoltaics (PV) technologies has improved the flight time, cannot energize UAVs for whole day. A new harvester has been proposed. This technology is however in its initial stage for this application. A Plasmonic Nano Energy harvester is an attractive technology to extending the FT extracting the energy in mid-infrared radiation emitted from Earth’s surface. Rectenna can harvest MID-IR energy from the sun at night and day and convert it into DC electricity to energize any small devices all day. The most important advantage of plasmonic Rectenna is that can operate round the clock, independently of weather conditions such as humidity and cloud cover and without restriction of orientation towards the Sun. However, several challenge must be overcome. Accurate design of the antenna, and in particular rectifiers, remains a key topic. In addition to requirements which high speed and responsivity, the goal must be a rectifier that has a combination of lower resistance and lower capacitance than the existing MIM diodes. Therefore, research activities have to be fulfilled to identify the suitable materials and technology for the design and fabrication of efficient THz rectifiers.
 
Reference
[1] Chin C K, Extending the Endurance, Mission and Capabilities of Most UAVs using Advanced Flexible/Ridged Solar Cells and New High Power Density Batteries Technology, Master of science in Electrical Engineering, Monterey California, March 2011
[2] Petricca L, Ohlckers P, and Grinde C 2011 Microand Nano-Air Vehicles: State of the Art, International Journal of Aerospace Engineering, Hindawi, Volume 2011, pp.1- 17
[3] Prox Dynamics Personal Reconnaissance System PD-100 Black Hornet, 2014, pp.1-6
[4] Petricca L, Micro and Nano Technologies for Unmanned Nano Air Vehicles (NAVs), PhD Thesis, Buskerud and Vestfold University College, 2014
[5] Gupta S.G, Mangesh M,  Ghonge M.M, Jawandhiya Dr. P. M:  Review of Unmanned Aircraft System (UAS), International Journal of Advanced Research in Computer Engineering & Technology (IJARCET) Volume 2, Issue 4, April 2013, pp.1-13
[6]Papachristos C, Alexis K and Tzes A: Hybrid Model Predictive Flight Mode Conversion Control of Unmanned Quad-Tilt Rotors, 2013 European Control Conference (ECC), July 17-19, 2013, Zürich, Switzerland, pp.1-6
[7] R. Citroni, D. Passi, A. Leggieri, F. Di Paolo and A. Di Carlo, "The next generation: Miniaturized objects, self powered using nanostructures to harvest ambient energy," 18th Italian National Conference on Photonic Technologies (Fotonica 2016), Rome, 2016, pp. 1-4.
[8]https://www.linkedin.com/pulse/how-do-drones-work-part-7-vtol-convertiplanes-tiziano-fiorenzani
[9]https://unmannedengineeriablog.wordpress.com/2015/11/23/different-types-of-aircraft-takeoff-and-landing/
[10]https://aviation.stackexchange.com/questions/16349/can-airliners-benefit-from-vertical-take-off-and-landing
[11]http://www.krossblade.com/vtol-vertical-take-off-and-landing/
[12]https://www.landviewdrones.com/firefly6sl2p
[13] Wang Z L, Zhu G, Yang Ya, Wang S, and Pan C, 2012, Progress in nanogenerators for portable electronics, Elsevier, Volume 15, Number 12, pp. 532–543
[14]https://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2004/rd73/476finalpro.htm
[15]https://irlock.com/blogs/precision-landing-blog-by-ir-lock/117527491-solar-powered-dronebox-system-w-ir-lock
[16]https://irlock.com/blogs/precision-landing-blog-by-ir-lock/117517507-drone-charging-station-swarmx-hive
[17]http://www.popsci.com/amazon-patent-puts-drones-on-streetlight-recharging-stations
[18]http://wonderfulengineering.com/amazon-plans-to-use-street-lights-and-power-poles-as-charging-stations-for-its-drones/
[19]http://www.unmannedsystemstechnology.com/2015/07/solace-power-develops-wireless-mid-flight-uav-charging/
[20]http://www.humavox.com/blog/drone-charging-stations-whats-the-best-way-to-charge-your-drone/
[21]http://www.airnest.com/blog/2016/2/18/dronebox-the-automated-connected-self-charging-drone-platform
[22]https://irlock.com/products/ir-lock-sensor-precision-landing-kit
[23]http://diydrones.com/profiles/blogs/ir-lock-sensor-for-precision-landing-etc
[24]https://www.kickstarter.com/projects/258964655/ir-lock-infrared-target-tracking-for-drones-and-di
[25]http://ardupilot.org/copter/docs/precision-landing-with-irlock.html
[26]http://diydrones.com/profiles/blogs/infrared-beacon-guidance-for-the-arducopter
[27]Tyler T: Improving Search Methodology with Unmanned System Master Thesis, Embry-Riddle Aeronautical University,  May 13, 2016
[28]D. K. Kotter, S. D. Novack, W. D. Slafer, P. J. Pinhero, Theory and Manufacturing Processes of Solar Nanoantenna Electromagnetic Collectors, Journal of Solar Energy Engineering Copyright © 2010 by ASME FEBRUARY 2010, Vol. 132 / 011014-1, pp.1-9
[29] Ahrens CD, Jackson PL, Jackson C E J, Meteorology Today, An Introduction to Weather, Climate and the Environment, First Edition Nelson Education, 2012
[30] Sardegna Ricerche, Pisano A: La radiazione solare e le relative procedure di calcolo, Cagliari, 19 settembre 2008.
[31] McKinsey & Company, The new economics of energy storage, August 2016, pp.1-6
[32]Abbas MM, Mohamed A. Tawhid MA , Saleem K, Muhammad, Z,  Saqib NA, Malik, H and Mahmood H, Solar Energy Harvesting and Management in Wireless Sensor Networks, Hindawi Publishing Corporation International Journal of Distributed Sensor Networks, Volume 2014, Article ID 436107, 8 pages
[33]Dudek M, Tomczyk P, Wygonik P, Korkosz M, Piotr Bogusz P,  Lis B,   Hybrid Fuel Cell – Battery System as a Main Power Unit for Small Unmanned Aerial Vehicles (UAV),   Int. J. Electrochem. Sci, 8 (2013) 8442 – 8463
[34] Yi J M, Kang MJ, and Noh DK, Solar Castalia: Solar Energy Harvesting Wireless Sensor Network Simulator, Hindawi Publishing Corporation International Journal of Distributed Sensor Networks Volume 2015, Article ID 415174, 10 pages
[35]Chin CK: Extending the Endurance, Missions and Capabilities of Most UAVs using Advanced Flexible/Rigid Solar Cells and New High Power Density Batteries Technology, Master of Science in Electrical Engineering, Nanyang Technological University, 2001
[36]Linden D, Reddy T B, Handbook of Batteries, Third Edition McGraw-Hill, 2002
[37] Durmus Y E, Modeling of Silicon- Air Batteries,  Master Thesis, Ulm University, December 2013
[38]Rahman A, Wang X and Wen C, High Energy Density Metal-Air Batteries: A Review, Journal of The Electrochemical Society, 160 (10) A1759-A1771 (2013)
[39]Iglesias L, Vega V, García J, Hernando B and Prida V M,  Development of electrostatic supercapacitors by atomic layer deposition on nanoporous anodic aluminum oxides for energy harvesting applications, Frontiers in Physics, March2015, Volume3,  pp.1-10
[40]Banerjeea P,  Pereza I, Henn-Lecordiera,L, Leec, S.B, Rubloff G.W, ALD based Metal-insulator-metal (MIM) Nanocapacitors for Energy Storage, ECS Transactions, 25 (4) 345-353 (2009)
[41]Li L. J, Zhu B, Ding S.J, Lu H.L, Sun Q.Q, Jiang A, Zhang D.W and Zhu C, Three-dimensional AlZnO/Al2O3/AlZnO nanocapacitor arrays on Si substrate for energy storage, Nanoscale Research Letters 2012, 7:544
[42]Abdin Z, Alim M.A, Saidur R. Islam M.R, Rashmi W, Mekhilef S. Wadi A, Solar energy harvesting with the application of nanotechnology, Elsevier, 26(2013)837–852
[43]Mazhar Abbas M,  Tawhid M.A, Saleem K,  Muhammad Z, Saqib, NA, Malik H, and Mahmood H, Solar Energy Harvesting and Management in Wireless Sensor Networks, Hindawi Publishing Corporation International Journal of Distributed Sensor Networks Volume 2014, Article ID 436107, 8 pages
[44]AltaDevices Company, Harnessing the Sun: Extend Your UAV’s Endurance with GaAs Solar Power, April 29th, 2015
[45]AltaDevices Company:  Solar Power Energy Harvesting Electrical Integration, pp.1-10
[46]http://www.explainthatstuff.com/solarcells.html
[47]http://fortune.com/2016/09/23/solar-drones-alta-devices/
[48]http://www.unmannedsystemstechnology.com/company/alta-devices/
[49]http://www.wpafb.af.mil/News/Article-Display/Article/399512/afrl-incorporates-solar-cell-technology-into-small-unmanned-aircraft-systems/
 [50]Minnaert B and Veelaert P: A Proposal for Typical Artificial Light Sources for the Characterization of Indoor Photovoltaic Applications, Energies 2014, 7, 1500-1516
[51] Green, M.A.; Emery, K.; Hishikawa, Y.; Warta, W.; Dunlop, E.D. Solar cell efficiency tables (version 40). Prog. Photovolt. 2012, 20, 606–614.
[52] Zhao, J.H.; Wang, A.H.; Green, M.A.; Ferrazza, F. 19.8% efficient “honeycomb” textured multicrystalline and 24.4% monocrystalline silicon solar cells. Appl. Phys. Lett. 1998, 73, 1991–1993.
[53] Petermann, J.H.; Zielke, D.; Schmidt, J.; Haase, F.; Rojas, E.G.; Brendel, R. 19%-efficient and 43 μm-thick crystalline Si solar cell from layer transfer using porous silicon. Prog. Photovolt. 2012, 20, 1–5.
[54] Bhattacharya, R.N.; Contreras, M.A.; Egaas, B.; Noufi, R.N.; Kanevce, A.; Sites, J.R. High efficiency thin-film CuIn1-xGaxSe2 photovoltaic cells using a Cd1−xZnxS buffer layer. Appl. Phys. Lett. 2006, 89, doi:10.1063/1.2410230.
[55] Wu, X.Z. High-efficiency polycrystalline CdTe thin-film solar cells. Sol. Energy 2004, 77, 803–814.
[56] Meier, J.; Spitznagel, J.; Kroll, U.; Bucher, C.; Fay, S.; Moriarty, T.; Shah, A. Potential of amorphous and microcrystalline silicon solar cells. Thin Solid Films 2004, 451, 518–524.
[57] Chiba, Y.; Islam, A.; Watanabe, Y.; Komiya, R.; Koide, N.; Han, L.Y. Dye-sensitized solar cells with conversion efficiency of 11.1%. Jpn. J. Appl. Phys. 2006, 45, L638–L640.
[58] Chiu, S.W.; Lin, L.Y.; Lin, H.W.; Chen, Y.H.; Huang, Z.Y.; Lin, Y.T.; Lin, F.; Liu, Y.H.; Wong, K.T. A donor-acceptor-acceptor molecule for vacuum-processed organic solar cells with a power conversion efficiency of 6.4%. Chem. Commun. 2012, 48, 1857–1859.
[59]Qinling Z, Jian H and  Feifei W,  Energy Balance Design and Analysis of Long-flight-time Solar Powered UAV, Proceedings of the 2nd International Conference on Computer Science and Electronics Engineering (ICCSEE 2013), Published by Atlantis Press, Paris, France.  pp. 1-3
[60] Betancourth N.J.P, Parra Villamarin J.E, Vaca Rios J.J, Bravo-Mosquera P.D, Cerón-Muñoz H.D: Design and Manufacture of a Solar-Powered Unmanned Aerial Vehicle for Civilian Surveillance Missions, J. Aerosp. Technol. Manag., São José dos Campos, Vol.8, No 4, pp.385-396, Oct.-Dec., 2016
[61]Gonzalez Vidales H.M, Design, Construction and Test of the Propulsion System of a Solar UAV, March 2013, pp.1-10
[62]Sanchez V.M,  Barbosa, R, Cruz, J.C, Chan, F and Hernandez, J: Optimal Sizing of a Photovoltaic-Hydrogen Power System for HALE Aircraft by means of Particle Swarm Optimization, Hindawi Publishing Corporation Mathematical Problems in Engineering, Volume 2015, Article ID 183701, 8 pages
[63] http://www.phy6.org/stargaze/Isun1lite.htm
[64]http://www.ces.fau.edu/nasa/module-2/energybudget.php
[65]http://www.photonics.com/Article.aspx?AID=45403
[66] Mescia L and Massaro A, 2014, New Trends in Energy Harvesting from Earth Long-Wave Infrared Emission, Hindawi, Volume 2014, pp-1-11
[67] Gadalla MN 2013 Nano Antenna Integrated Diode (Rectenna) For Infrared Energy Harvesting, Master of Science, King Abdullah University of Saudi Arabia
[68] C. Di Garbo, P. Livreri and G. Vitale, 2016, Review of Infrared Nanoantennas for Energy Harvesting, Proc. Int. Conf. on Modern Electrical Power Engineering (las Palmas de Gran Canaria 6 ‐ 8 of July), pp.1-7
[69] Moddel G and Grover S 2013 Rectenna Solar Cells, Springer
[70] Yesilkoy F 2012 IR Detection and Energy Harvesting Using Antenna Coupled MIM Tunnel Diodes, PhD Dissertation, University of Maryland
[71]  Ameziane M, Solar Nanoantenna Electromagnetic Collectors For Energy Production, Master of Science, Tampere University, May 2015,
[72]Naser Sedghi, J. W. Zhang, J. F. Ralph, Y. Huang, I. Z. Mitrovic, and S. Hall: Towards Rectennas for Solar Energy Harvesting, Proc. Int. Conf. on 43rd European Solid-State Device, 16-20 September 2013, Bucharest, Romania
[73]Saber H. Zainud-Deen, Nermeen A. Eltresy, Hend A. Malhat, and Kamal H. Awadalla, Single/Dual-Polarized Infrared Rectenna for Solar Energy Harvesting, Advanced Electromagnetics, Vol. 5, NO. 1, May 2016, pp.1-9
[74] Hend A. Malhat, Nermeen A. Eltresy, Saber H. Zainud-Deen, and Kamal H. Awadalla,  Nano-Dielectric Resonator Antenna Reflectarray/Transmittarray for Terahertz Applications, Advanced Electromagnetics, Vol.4, NO.1 , June 2015, pp.1-9
[75]Franzen S, Surface Plasmon Polaritons and Screened Plasma Absorption in Indium Tin Oxide Compared to Silver and Gold, J. Phys. Chem. C 2008, 112, 6027-6032
[76]Cai W, Shalaev V, Optical Metamaterials Fundamentals and Applications, Springer, 2010
[77]http://www.wikiwand.com/en/Permittivity#/Vacuum_permittivity
[78]https://www.physicsforums.com/threads/understanding-complex-permittivity.705719/
[79]https://www.matematicamente.it/forum/densita-di-corrente-campo-elettrico-conduttori-ideali-t51962.html
[80]Gai H, Wang J, and Tian Q, Modified Debye model parameters of metals applicable for broadband calculations, 2007,  Optical Society of America, pp.1-5
[81]Mehnaj Mahbuba M, Chisty N.A, Study of the Relative Permittivity Response of Metal Nanoantenna at Optical Frequency, International Journal of Engineering Research, Volume No.3, Issue No.10, pp : 584-587
[82]Sagor R,H, Saber Md G, Al-Amin Md T and Al Noor A, An optimization method for parameter extraction of metals using modified Debye model, Springer Plus 2013, 2:426, pp.1-5
[83]http://acoustics.org/pressroom/httpdocs/147th/pedersen.htm
[84]http://www.ntmdt-si.com/spm-basics/view/metal-energy-band-structure
[85]Citroni R, Leggieri A, Passi D, Di Paolo F, Di Carlo A: Nano Energy Harvesting with Plasmonic Nano-Antennas: A review of MID-IR Rectenna and Application, Advanced Electromagnetics, Vol.6, No.2,  March 2017, pp.1-13
[86]Gadalla, M. N., Abdel-Rahman, M. & Shamim, A. Design, optimization and fabrication of a 28.3 thz nanorectenna for infrared detection and rectification. Scientific Reports 4, 4270 (2014).
[87]Donchev E 2015 Thin-Film Diode Structures for Advanced Energy Applications, PhD thesis, Imperial College London
[88] G Moddel, Z Zhu and S Grover, 2011, Solar power conversion using diodes coupled to antennas, Spie, pp.1-3
[89] Berland, B. Photovoltaic technologies beyond the horizon: Optical rectenna solar cell. Subcontractor Report, National Renewable Energy Laboratory (2002). URL http:// www.nrel.gov/docs/fy03osti/33263.pdf.
[90] Jennings, D., Petersen, F. R. & Evenson, K. Extension of absolute frequency measurements to 148 thz: Frequencies of the 2.0 and 3.5μ m xe laser. Applied Physics Letters 26, 510-511 (1975).
[91]http://ecetutorials.com/analog-electronics/schottky-barrier-diode/
[92] Bhatt K, Shriwastava S, Kumar S, Tripathi S and Tripathi C, Terahertz Detectors (THzDs): Bridging the Gap for Energy Harvesting, in Jamal Uddin (Ed): Terahertz Spectroscopy - A Cutting Edge Technology, Intech, March 13, 2017
[93]Song H.J, Nagatsuma T: Handbook of Terahertz Technologies, Devices and Applications, CRC Press, 2015
[94]G Moddel, Z Zhu, and S Grover, 2011, Solar power conversion using diodes coupled to antennas, Spie, pp.1- 3
[95]Zhu Z J: Graphene Geometric Diodes for Optical Rectennas, M.S., Electrical Engineering, University of Colorado Boulder, 2011
[96] Stellingwerff S A: Solar energy harvesting using graphene rectennas: a proof-of-concept study, Master Thesis, University of Twenty, April 10, 2015
[97]C. Di Garbo, P. Livreri and G. Vitale, 2016, Review of Infrared Nanoantennas for Energy Harvesting, Proc. Int. Conf. on Modern Electrical Power Engineering (las Palmas de Gran Canaria 6 8 of July), pp.1-7
[98] Rawal Y, Ganguly S, and Baghini MS 2012 Fabrication and Characterization of New Ti-TiO2-Al and Ti-TiO2-Pt Tunnel Diodes, Hindawi, Vol. 2012, pp.1-6
[99] Abdel-Rahman, M. R., Gonzalez, F. J. & Boreman, G. Antenna-coupled metal-oxide-metal diodes for dualband detection at 92.5 ghz and 28 thz. Electronics Letters 40, 116-118 (2004).
[100]Fumeaux, C., Herrmann, W., Kneubuhl, F. K. & Rothuizen, H. Nanometer thin-film diodes for detection and mixing of 30 (THz) radiation. Infrared Physics & Technology 39, 123-183 (1998).
[101] Abdel-Rahman, M. R., Gonzalez, F. J. & Boreman, G. Antenna-coupled metal-oxide-metal diodes for dualband detection at 92.5 ghz and 28 thz. Electronics Letters 40, 116-118 (2004).
[102] Fumeaux, C., Herrmann, W., Kneubuhl, F. K. & Rothuizen, H. Nanometer thin-film diodes for detection and mixing of 30 THz radiation. Infrared Physics & Technology 39, 123-183 (1998).
[103] Hobbs, P. C. D., Laibowitz, R. B. & Libsch, F. R. Ni-NIO-NI tunnel junctions for terahertz and infrared detection. Appl. Opt. 44, 6813-6822 (2005).
[104] Hoofring, A. B., Kapoor, V. J. & Krawczonek, W. Submicron nickel-oxide-gold tunnel diode detectors for rectennas. Journal of Applied Physics 66, 430-437 (1989).
[105] Krishnan, S., La Rosa, H., Stefanakos, E., Bhansal, S. & Buckle, K. Design and development of batch fabric able metal insulator metal diode and microstrip slot antenna as rectenna elements. Sensors and Actuators A: Physical 142, 40-47 (2008).
[106] Krishnan, S., Stefanakos, E. & Bhansali, S. Effects of dielectric thickness and contact area on current voltage characteristics of thin film metal insulator metal diodes. Thin Solid Films 516, 2244-2250 (2008).
[107] Esfandiari, P. et al. Tunable antenna-coupled metal oxide-metal (mom) uncooled IR detector (invited paper). vol. 5783, 470-482.
[108] Gustafson, T. K., Schmidt, R. V. & Perucca, J. R. Optical detection in thin- film metal-oxide- metal diodes. Applied Physics Letters 24, 620-622 (1974).
[109] Dickinson, R. M. & Brown, W. C. Radiated microwave power transmission system efficiency measurements. Tech. Rep. Tech. Memo 33-727, Ames R.C. Rsch. Review, NASA, California Inst. Technol. Pasadena, CA, USA (1975).
[110] Periasamy, P. et al. Fabrication and characterization of mim diodes based on nb/nb2o5 via a rapid screening technique. Advanced Materials 23, 3080-3085 (2011).
[111] Periasamy, P. et al. Metal insulator metal diodes: Role of the insulator layer on the rectification performance. Advanced Materials 25, 1301-1308 (2013).
[112] Periasamy, P. et al. A novel way to characterize metal-insulator-metal devices via nanoindentation. In Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE, 001754-001757 (2011).
[113] Cowell, E. W. et al. Advancing mim electronics: Amorphous metal electrodes. Advanced Materials 23, 74-78 (2011).
[114] Grossman, E. N., Harvey, T. E. & Reintsema, C. D. Controlled barrier modification in nb/nbox/ag metal insulator metal tunnel diodes. Journal of Applied Physics 91, 10134-10139 (2002).
[115] Hagerty, J., Helmbrecht, F., McCalpin, W., Zane, R. & Popovic, Z. Recycling ambient microwave energy with broadband rectenna arrays. Microwave Theory and Techniques, IEEE Transactions on 52, 1014-1024 (2004).
[116] Bailey, R. L. A proposed new concept for a solar energy converter. Journal of Engineering for Power 94, 73-77 (1972).
[117] Hegyi, B., Csurgay, A. & Porod, W. Investigation of the nonlinearity properties of the dc i-v characteristics of metal-insulator-metal (mim) tunnel diodes with double-layer insulators. Journal of Computational Electronics 6, 159-162 (2007).
[118] Maraghechi, P., Foroughi-Abari, A., Cadien, K. & Elezzabi, A. Y. Enhanced rectifying response from metal-insulator-insulator-metal junctions. Applied Physics Letters 99, 253503 (2011).
[119] Grover, S. & Moddel, G. Engineering the current voltage characteristics of metal insulator metal diodes using double-insulator tunnel barriers. Solid-State Electronics 67, 94-99 (2012).
[120] G Moddel, Z Zhu, and S Grover, 2011, Solar power conversion using diodes coupled to antennas, Spie, pp.1-3