Research On The Co-Design Of Patch Antenna And Solar Cells

With the development of the times,wireless communication systems have evolved from a dipole antenna to antennas with more complex structures and more diversified functions,such as synthetic aperture antennas,reconfigurable antennas,and metamaterial antennas.At present,antennas have been able to achieve wide bandwidth,even ultra-bandwidth,high gain,high radiation efficiency,and other good radiation performance.Due to the wide range of application scenarios,solar cells have developed rapidly.The development of solar cells has accelerated its integration with other disciplines,including wireless communication systems.Integrating wireless microwave devices with solar cells can realize the system be miniaturized,dual-function,low-cost,and green communication.Based on the above prospects,in this paper,the solar cell is integrated with the antenna as the radiator of the antenna,and a special integration methods are adopted to enable the solar cell antenna to achieve port isolation without any filter,and achieve good radiation performance and power generation efficiency.This dissertation designs three types of patch antennas integrated with solar cells,which are aperture-coupled patch antennas integrated with solar cells,low-profile patch antennas integrated with solar cells and suspended panel antennas with solar cells.The main contents are as follows:1.Firstly,the integration of aperture-coupling patch antenna and the solar cell is proposed.Among them,solar cells are capable of powering low-power wireless sensors,while antennas can achieve good radiation performance.Meanwhile,the solar cells as part of radiators are located at the top of the structure,which avoids the shielding of the solar cell during integration.The solar cell direct-current（DC）output microstrip line and the antenna radio-frequency（RF）input microstrip line presents a vertical state in space,further improving the isolation so that the isolation between the two ports can be achieved without any additional filters.To achieve broadband performance,the antenna adopts a multi-point feed structure.The aperture-coupled multipoint-fed solar cell antenna was fabricated and measured to verify the radiation performance and improve the light energy collection capability of the proposed solar cell antenna.The simulation and measurement results agree well with each other,thus demonstrating that its total size of only 1.31λ₀×1.31λ₀×0.06λ₀（λ₀is the free-space wavelength at the center frequency）and the antenna has achieved a stable gain varied from 9.47 to 10.85 d Bi over the operating band of 4.8-5 GHz for 5G communication.2.To further reduce the profile and cost of solar cell antennas,a study on the integration of low-profile patch antennas and solar cells has been proposed.The solar cells are integrated with low-profile dual-compression high-order modes antennas for green communication.First,to enhance the gain of the antenna and the ability of optical energy harvesting,the antenna resonates at the higher order compression mode.Secondly,the solar cell works through the direct-current loop,and the antenna works through the radio-frequency loop,separately.A differentially coupling fed structure and two rows of vias are employed to enhance the bandwidth of the antenna and prevent the two loops from interfering with each other.Intrinsic isolation is achieved without any extra circuits.Based on the above integration method,a single-polarization solar cell antenna is designed.The measurement results show that the single-polarization solar cell antenna has a gain of 9.27-10.16 d Bi in the bandwidth of 4.37-5.06 GHz.Based on the online polarized solar cell antenna,the antenna is rotated by 90°to realize the dual-polarized solar cell antenna to achieve functions such as expanding the channel capacity.The dual-polarized solar cell antenna has the gain higher than 8.6 d Bi in the target frequency band of 4.8-5 GHz.The optical energy harvesting capability was verified through optical experiments.The proposed single-polarization and dual-polarization solar cell antennas have maximum output powers of 0.11 W,0.23 W,0.46 W and 0.098 W,0.212 W,0.454 W under light intensity of 250 W/m²,500 W/m²,and 1000 W/m²,respectively.3.Finally,a wideband suspended plate antenna（SPA）is integrated with solar cells.The dielectric substrate of the antenna is air,which can reduce the dielectric loss of the antenna and reduce the cost.A hollow cylindrical structure is introduced into the air dielectric layer of the antenna to support the suspended plate patch,and more importantly,the gain is improved by suppressing the higher-order mode.The antenna uses a differential fed and L-shape coaxial probe to increase the bandwidth to feed the SPA.Two solar cells are stacked with the anode and the cathode connected in a tile type and are located directly above the patch.By comparing the test results of the copper SPA and the solar cell SPA,the influence of the solar cell on the radiation performance is obtained.Moreover,based on copper SPA,the proposed solar cell SPA is fabricated and measured to verify the stability of radiation performance and energy harvesting performance.The measurement shows that the bandwidth of the proposed solar cell SPA is 3.2-5.1 GHz for wideband application and the gain is higher than9.51 d Bi in the operating band.Under natural light,the maximum output power of solar cells is 85.71 m W（2.67 V×32.1 m A）.