SUMMARYThis paper presents a front propagation method using the Eikonal equation, ∇ · ∇ = 1, in which, represents the smallest Euclidean distance field to the front to be propagated. The offset capturing approach consists in first calculating the field over a uniform Cartesian grid fully covering the front to be propagated, and then constructing the iso-curves or surfaces as the propagated result. The calculation of uses a 3D numerical scheme, the Fast Sweeping Scheme. Validation for accuracy of the method is presented using academic test cases. A real 3D industry application, draft tube with two piers, is successfully propagated and demonstrated using special boundary conditions to cope with inlet and outlet planes during front propagtion. This application involves the propagation of a front that exhibits both concave and convex shape regions, sharp corners, and local tangent plane surface discontinuities as well as a multi-connected domain.

Several rectifier topologies dedicated for radio frequency (RF) energy harvesting have been proposed, but only a few have been reported to be able to harvest RF energy at low input power (LIP) levels. In this paper, we are focusing on fully gate cross-coupled (FGCC) rectifier structure, which gives good performance at LIP levels. In order to get an enough high output DC voltage, a 3-stage FGCC rectifier using low-threshold-voltage (LTV) transistors is designed. According to simulation results, with 850MHz input AC signal, the designed rectifier has power conversion efficiency (PCE) of 70% at 20μW (-17.0dBm) input power with 100kOhms load. Also, a multi-band RF energy harvesting topology is proposed. Simulation results show that PCE of the tri-channel rectifier achieves 66.3% at 4.8μW (-23.2dBm) input power per channel and 1V DC output voltage is generated at 5.1μW (-22.9dBm) input power per channel with only 100kOhms load, showing both high-efficiency and sensitivity.