James Mcspadden

Raytheon Technologies | RTN

Power beaming is the efficient point-to-point transfer of electrical energy across free space by a directive electromagnetic beam. This paper clarifies the basic principles of power beaming in simple terms, and proposes a benchmarking methodology for improving the comparative assessment of power beaming systems and technology. An in-depth historica...

This study report extends previous efforts exploring the concept of providing power to military and remote installations via solar power satellites. The goal of the study was to determine the feasibility of a coordinated development effort for this capability. Included are key findings of opportunities and challenges, as well as recommendations for a...

Power transmission by microwaves has a long history of technology development and key demonstrations. By 1975 the improvements in component conversion efficiencies (DC-to-RF and RF-DC) increased the end-to-end system efficiency from 13% to 54%. These early S-band wireless power transmission (WPT) demonstrations proved this concept as a viable form...

This paper begins with an introduction to the concept of space solar power (SSP) and summarizes selected prior studies of proposed solar power satellite (SPS) systems. The functional components of a generic SPS are delineated, and various approaches and promising concepts from prior and current development efforts are elucidated. The fundamentals o...

Power transfer between circular apertures at far-field distances is calculated using a widely applicable aperture distribution with adjustable sidelobe ratio. Power transfer efficiency is obtained by integrating the pattern out to the angle subtended by the receiving aperture. Efficiency is parameterized such that a single curve results for each si...

Future large-scale space solar power (SSP) will form a very complex integrated system of systems requiring numerous significant advances in current technology and capabilities. Ongoing technology developments have narrowed many of the gaps, but major technical, regulatory, and conceptual hurdles remain. Continuing systems concept studies and analys...

Ku-band circular patch antennas fed with a 50 Ω microstrip line have been designed and tested. A full-wave simulator is used to design the microstrip feed. Design equations are given that are accurate to 1.3% for predicting the resonant frequency from L-band to Ka-band

A one-meter diameter, 32 GHz active microstrip reflectarray capable of electronic beam steering has been studied. The 15,500 element array consists of microstrip patch antennas, microstrip phase shifters, and DC bias lines. Specifically, the study focused on the solid-state devices and DC bias layouts for scanning the beam linearly 45° from boresig...

A high-efficiency rectenna element has been designed and tested at 5.8 GHz for applications involving microwave-power transmission. The dipole antenna and filtering circuitry are printed on a thin duroid substrate. A silicon Schottky-barrier mixer diode with a low breakdown voltage is used as the rectifying device. The rectenna element is tested in...

Ku-band oscillators have been experimentally found to have a high dc-to-radio-frequency (RF) efficiency. Using a packaged pseudomorphic high electron-mobility transistor (pHEMT) device, a maximum efficiency of 60% was measured at 14.5 and 15 GHz with output powers of 16 and 23 mW, respectively. Oscillator circuits also revealed efficiencies of 48%...

A new concept for solid state wireless microwave power transmission is presented. A 2.45 GHz rectenna element that was designed for over 85% RF to DC power conversion efficiency has been used to oscillate at 3.3 GHz with an approximate 1% DC to RF conversion efficiency. The RF radiation was obtained from the same circuit by supplying the DC output...

Solar power is a reality. Today, increasing numbers of photovoltaic and other solar-powered installations are in service around the world and in space. These uses range from the primary electric power source for satellites, remote site scientific experiments and villages in developing countries to augmenting the commercial electric grid and providi...

Cavity-backed inverted circular patch antennas fed by a probe have been tested and simulated for operation in the Ka-band. Two antennas having different cavity and patch diameters operate at 34.2 and 35.9 GHz, respectively. A full-wave electromagnetic simulator accurately predicts the operating frequency and radiation patterns

A high efficiency rectenna element has been designed and tested at 5.8 GHz for applications involving microwave power transmission. The dipole antenna and filtering circuitry are printed on a thin duroid substrate. A silicon Schottky-barrier mixer diode with a low breakdown voltage is used as the rectifying device; The rectenna element is tested in...

The concept for an orbiting power satellite capable of supplying the needs of several co-orbiting manufacturing satellites is similar to the central power station and distribution network found on Earth. An experiment for testing a portion of such an “Orbital Power and Light” space power utility system-a retrodirective phased array energy transmiss...

The solar power satellite (SPS) concept is an option for providing the Earth with almost a continuous running and nondepletable power source. Solar radiation is collected in space on a large solar cell array located in geosynchronous orbit. The energy is converted into microwaves at 2.45 GHz and beamed to a receiving antenna located on Earth. The r...

On February 18, 1993, the International Space Year - Microwave Energy Transmission in Space (ISY-METS) sounding rocket was launched from the Kagoshima Space Center, Japan. The rocket experiment performed two activities: (1) it demonstrated the first microwave power transmission system in space, and (2) it studied nonlinear effects of the microwave...

Passive probe-fed inverted microstrip antennas have been designed and tested. Design formulas have been used to determine operating frequency and compared to measured results. A novel test fixture allowed the non-destructive determination of the input impedance as a function of probe position. This configuration also offers easy integration of soli...

A novel circular patch rectifying antenna (rectenna) has been developed which converts microwave energy into DC power at 2.45 GHz. Dual polarization is achieved by two orthogonal microstrip feed lines. Rectification is achieved by GaAs Schottky-barrier diodes located on each feed line. A 48% conversion efficiency from microwave power to DC power wa...

A method has been devised to experimentally characterize a packaged GaAs Schottky barrier diode by inserting it into a microstrip test mount. The nonlinear equivalent circuit parameters of the diode are determined by a small-signal test method. A large-signal measurement using the same test mount has also been configured to determine the power conv...

A method has been devised to experimentally characterize a packaged diode by insertion in a microstrip test mount. The diode was shunt-mounted to the ground plane where a network analyzer measured the scattering parameters from the two-port test fixture. The equivalent circuit parameters were extracted from the measured data. A large signal measure...

35-GHz rectennas have been developed using a patch and a microstrip dipole antenna. The power conversion efficiencies from RF to DC were measured as 29% and 39% with an input power of 120 mW. The multireflection method developed for the analysis of a mixer was used to analyze the performance of a 35-GHz rectenna using a Ka -band mixer diode. Throug...

Three experiments are proposed to demonstrate the feasibility of converting dc power into microwave or millimeter-wave beam and transmitting it to users through free space. The generator could be located on earth or on a utility power satellite. The received power would be converted back into dc or ac power. The success of the experiments could lea...

Includes bibliographical references. Vita. Thesis (M.S.)--Texas A & M University, 1993. "Major subject: Electrical Engineering."