Antenna Arrangement Verification for Low Sidelobe Levels

Space-to-earth Wireless Power Transfer (WPT) in large scale will not be allowed unless the side lobe levels (SLL) can be reduced many orders of magnitude lower than the current technology allows. In particular, high SLL could potentially interfere with aircraft communications around the beam, while the area inside the beam would necessarily be a no-fly zone, similar as over nuclear power plants. To overcome this, the transmitting antenna must be cleverly designed and controlled. In this work, independent validation of the layout, spacing, and envelope arrangement of a design first proposed in 2016 is performed and presented. This design involves a hexagonal design with a triangular antenna element arrangement and a spacing of 0.8 wavelengths using the Dolph-Chebychev beam profile. While this has been shown to produce -240 dB SLL in the AWR Design Environment already, it will now be analyzed using the MATLAB Phased Array System Toolbox. The design will also be investigated on a smaller scale, with the potential for use in other applications, including the powering of low orbit weather balloons or unmanned aerial vehicles (UAVs). The possibility of very low SLL would be transformational in these and other WPT applications, including space solar power, and could greatly benefit humanity and the environment

Spacetenna Flatness and Error Correction

Wireless Power Transfer (WPT) from space-to-earth at a large scale will not be possible until the Side Lobe Levels (SLL) are reduced many orders of magnitude from the current technology available today. To accomplish this, careful design of the transmitting antenna (spacetenna) is imperative. Any module failures or errors in connectivity, including askew angles between adjacent sandwich modules, reduce the effectiveness of the antenna design and thereby increase SLL. This work examines two interrelated issues; error detection and repair, and spacetenna flatness correction. Multiple different designs of sandwich module mechanical connections, wiring, and control are examined. The results of the analysis and best options are presented in order to facilitate for ultra-low SLL for use in Space Solar Power for the benefit of humanity and the environment

Performance Estimates for a Fuel-Free Stationary Platform in the Stratosphere

High-altitude pseudo-satellites (HAPS) may be kept aloft indefinitely with station-keeping provided by plasma air thrusters (PAT) using wireless power transfer (WPT) from a terrestrial phased array antenna (PAA). One example is the patented “Sitallite” superpressure balloon with a rectifying antenna (rectenna) covering its underside, with thrusters around the periphery. Such a stationary platform can provide continuous observation and communications capabilities covering vast areas for a fraction of the cost required for an orbiting satellite. This work builds upon the design and safety study published elsewhere to provide performance estimates for a long-duration, persistent HAPS powered by electronically-steerable microwave beams. Newly-derived efficiency equations are used to provide accurate estimates of free-space WPT transfer efficiency based on the dimensions of the ground-based PAA and the rectenna. Calculations of air drag for a spheroidal bouyant shape are used to derive PAT power requirements, and these, together with power conversion circuitry, are used to size the overall system. Accurate estimates of cost are derived. These performance estimates can be used to help make economic and logistic decisions, as a fuel-free HAPS with PAT and powered by WPT can be lofted in less time, and with lower risk, than an orbital satellite of comparable capabilities

Wireless Power Transfer to Sitallite Stratospheric Platform

The following topics are dealt with: artificial satellites; ionospheric electromagnetic wave propagation; Global Positioning System; satellite navigation; ionospheric techniques; radiowave propagation; space vehicle electronics; ionospheric disturbances; total electron content (atmosphere); and magnetic storms