01-10-2014, 12:29 PM
Optimal Matched Rectifying Surface for Space Solar Power satellite APPLICATIONS
Optimal Matched.pptx (Size: 886.44 KB / Downloads: 9)
ABSTRACT
Microwave energy reception approach for space solar power satellite applications .
Concept of artificial perfectly matched layer.
Embedding rectifying diodes into well-designed metamaterial cells.
Obtained rectifying surface simultaneously exhibits a nearly perfect impedance matching to the air and the rectifying circuits, and a strong impedance mismatching to the air at harmonic frequencies
Simple structure that can be implemented using commercial multi-layer printed circuit board technology.
Rectifying surface has free-space wavelength
Power absorption rate of 99.92% under normal incident power, density of 0.1 mW/cm, and a 56.16-dB
INTRODUCTION
Convert direct solar radiation into electrical power and transmit it wirelessly to the earth. In all SSPS schemes.
Transmit gigawatt power to the earth, and huge rectenna arrays
Occupying areas up to tens of square kilometers are used to receive and rectify microwave energy into dc power .
Rectennas have been considered as mature and well-functional
They are non ideal options for SSPS applications.
Combining conventional antennas (or array antennas) and rectifying circuits.
Rectennas have the same limitations of traditional antennas.
PRINCIPLE
Fig. 1(a) shows the block diagram of a conventional rectenna [23]–[27]. In Fig. 1(a), a conventional antenna is used to receive microwave power from the air. The RF LPF plays two roles: matching the resistive impedance of the antenna with the complex impedance of the rectifier, and preventing secondary emission of the harmonics generated during rectifying. The rectifier and the dc pass filter (normally a high-quality capacitance) convert microwave energy into dc power, and transfer it to a load. As indicated, the conventional rectenna technology is not ideally suitable for SSPS applications because it suffers from unavoidable back scattering, non ideal aperture efficiency, incidence angle dependence, difficulty in complex impedance matching, and additional insertion loss due to the RF filter.
To overcome the aforementioned disadvantages, we propose a new rectifying scheme that can nearly perfectly receive microwave energy based on the concept of the artificial PML. One unit of such an artificial surface is shown in Fig. 1(b). The conventional antenna is replaced with a sub-wavelength MM pattern embedded with a microwave rectifying diode, and only the dc pass filter remains to transfer the rectified power to the unit can be periodically arranged in a plane, creating a rectifying surface. Using the approach proposed in [28] and [29], we expect this effective artificial surface to exhibit PML-like energy reception and impedance matching for normal and small-angle incidences
FABRICATION AND MEASUREMENT
IT shows the fabricated rectifying surface placed in the measurement environment. The inset shows the realistic MM unit with the soldered HSMS-2828. The 480-mm -sized experimental sample consists of 256 units, soldered with 256 HSMS2828 bridge diodes and 256 10-pF SMT ceramic capacitors. A 12- resistor is soldered on the bottom layer of the sample, in parallel with all the 10-pF capacitors. The 12- resistance equals to the resistance of 256 3-k parallel resistors
CONCLUSION
In conclusion, based on the concept of an artificial PML surface, we propose a new microwave energy reception scheme for SSPS applications. By embedding rectifying diodes into MM cells, the obtained rectifying surface can exhibit a unity surface refractive index that perfectly matches with the air, and the complex conjugate impedance that perfectly matches with the diodes. Due to inherent dispersion, the MM surface can be designed to simultaneously exhibit strongly mismatched impedances at the harmonic frequencies, eliminating the need for RF filters in traditional rectennas and yielding a simple structure that can be implemented with standard multi-layer PCB technology.