SAW RFID with enhanced penetration depth
Some methods to enhance penetration depth further are proposed and demonstrated. A second harmonics SPUDT, new criterion of matching and high reflectivity reflector are utilized to reduce the losses of SAW tag. The enhancement of reading system including high signal processing gain and compensate the center frequency mismatch between reader and SAW tag are achieved. Furthermore, the effect of decreasing working frequency to penetration capability is demonstrated. Mediums such as dry sandy, dry soil and water are compared in the experiments in order to get the achievable penetration depth. In conclusion, the practical penetration depth is superior to the ground penetrating radar with the same center frequency range.
Dual-Frequency Interrogation and Hierarchical Evaluation Scheme for SAW Reflective Delay-Line Sensors
The resolution of phase difference ambiguity is critically important for simultaneously achieving wide range and high accuracy sensing with surface acoustic wave (SAW) reflective delay-line sensors. A novel scheme called dual-frequency interrogation and hierarchical evaluation (DFI-HE) is proposed to resolve integer ambiguity of phase difference and obtain precise time delay between reflectors. With DFI-HE, only two reflectors are needed as the sensing elements for SAW reflective delay-line sensors. Additionally, DFI-HE has the advantage of fast ambiguity resolution to enable both a wide range and high accuracy sensing. The basic principle of sensing with DFI-HE is elaborated, and simulations and temperature sensing experiments are carried out to verify the proposed scheme, based on a SAW reflective delay-line temperature sensor with two reflectors fabricated on 128° YX-LiNbO3 substrate. The experimental results demonstrate that the temperature measurement accuracy reaches ±2 °C in the range of 8 °C–300 °C.
Climate change, disasters and electricity generation
Abbrevia ons Foreword 1. Introduc on 8 2. The impacts of changing climate pa erns and changing disaster risks on energy 9 op ons and electricity genera on infrastructure 2.1 The rela onship between climate change and disaster risks 10 2.2 The impact of changing climate pa erns and changing disaster risks on electricity 11 genera on from fossil fuels 2.3 The impact of changing climate pa erns and changing disaster risks on electricity 14 from nuclear power 2.4 The impact of changing climate pa erns and changing disaster risks on electricity 17 genera on from renewable energy 2.4.1 Hydropower 17 2.4.2 Wind Energy 19 2.4.3 Bioenergy 22 2.4.4 Solar Energy 24 3. Climate change and changing disaster risks: implica ons for energy policy and 26 planning