(electrical nano-antennas - telecommunications) electric-optical nano-antennas and Rectenna 

Researcher  and author: Dr.   (   Afshin Rashid)



Note: When the solar electromagnetic wave hits the surface of the nano-antenna, a time-varying current is created on the surface of the nano-antenna, and as a result, a voltage is produced at the place of its feeding gap. 

An antenna is a device that can receive the electromagnetic wave in space. In order to receive the solar electromagnetic wave by the antenna, the dimensions of the antenna must be in the order of the wavelength of the input to its surface. They include visible and ultraviolet, an antenna with dimensions of nanometers is needed. Since the use of optical nano-antennas to collect solar energy provides a practical solution with high efficiency compared to other common photovoltaic technologies such as solar panels, it has led to rapid development in the nano and optical materials industry.



Therefore, by placing a  suitable rectifier in the slot of the nano antenna, the desired DC power is produced. In the Solar Rectenna system, millions of nanoantennas are  placed next to each other with a suitable rectifier, and each one produces electric energy using sunlight. The conversion of the solar light energy absorbed by the antenna is done by  a suitable rectifier. Suitable diodes for this frequency range  are 12MIMs. This diode should be able to work at frequencies of more than 30 terahertz. Schottky diode , which is a semiconductor diode with low voltage drop and relatively fast response speed  , has the ability to rectify and detect signals with a frequency of up to 5 terahertz. MIM diode due to femtosecond tunneling time and gainRemarkable speed of response, it can be used as a replacement for Schottky diode in infrared and visible frequency range. Since nanoantennas have the ability to absorb a wide angle, even in the case of oblique solar radiation to the surface of the solar panel, their efficiency is maintained to a significant extent. This system can also absorb the energy radiated from the earth, that is, the terrestrial radiation that is caused by the daily radiation of the sun to the earth's surface and occurs in wavelengths of 10 micrometers , i.e. frequencies of about 90 terahertz, for this reason By collecting these radiations during the night or in bad weather conditions,  the nanoantennas of the solar system can produce electrical energy. Currently, diode and antenna structures are used in solar rectifiers They are made using the electronic sketching method. Although this  construction method is expensive and time-consuming for production in laboratory and research scales  , but if these structures are produced in a large volume and with an appropriate method , they reduce the cost and speed of the construction process.



(Nano Rectenna) how to make and uses 


The combination of optical antennas along with the appropriate rectifier system, which is  called Rectenna for short, has been introduced in recent years to convert the  solar energy into electrical energy and is rapidly being developed and  researched. While the efficiency of common solar cells in the market is around 30% at best, the efficiency of two to three times this amount  can be achieved for Recten. It should be noted that Rectenna has been studied in recent years, especially in the issue of power transmission in  the microwave band. For example, in theory  , for a single frequency of 9.2 GHz, more than 10% efficiency is predicted  . Of course, this is the fact that the practical efficiency of making these materials may  be slightly different and should be determined in practice. Dipole antenna with Linear polarization and 2/λ length, which has a relative bandwidth of 11%, will be able to  collect about 75.2 pW. For this reason, if  using an antenna with double polarization, a power of 5.5 pW will be obtained. Due  to the low receiving power of each independent antenna,  it is customary to use antenna arrays in this cell, which has its own rules and methods  .

An antenna is a device that can receive the electromagnetic wave in the space. In order to receive the solar electromagnetic wave by the antenna , the dimensions of the antenna must be in the same order as the wavelength of the input to its surface  . include infrared, visible and ultraviolet, an antenna with nanometer dimensions is needed. Since  the use of optical nanoantennas to collect solar energy provides a practical solution with high efficiency compared to other  common photovoltaic technologies such as solar panels has led to rapid development in nano and optical materials industry.



Conclusion : 

When the solar electromagnetic wave hits the surface of the nano-antenna, a time-varying current is created on the surface of the nano-antenna, and as a result, a voltage is produced at the place of its feeding gap.

Researcher  and author: Dr.   (   Afshin Rashid)

Specialized doctorate in nano-microelectronics