Structural health monitoring technology is a science used to evaluate the severity of structural damage and locate the position of the damage. The 13th Five-Year Plan clearly states the need to establish a large number of transportation hub projects and control hub projects. With the implementation of these national strategic engineering projects, structural health monitoring is bound to become a focal point in the field of civil engineering. Existing monitoring technologies face issues such as huge workload for sensor deployment, data redundancy, and lack of an effective fatigue accumulation damage assessment mechanism (50%-90% of failures in large structures are caused by fatigue damage). The project 'Key Technologies of Passive Wireless Strain Detection and Their Applications in Structural Strain Monitoring' applies cutting-edge technologies from the field of microwave engineering to civil engineering, with results applied to areas including civil, architectural, road, bridge, pipeline, vehicle, and ship. Structures such as dams have achieved goals including 'precise strain sensing, rapid data transmission, low cost, and risk prediction'. The main innovation points of the project are: 1. Strain sensor multi-physical field coupling and multi-dimensional information fusion technology: A multi-physical coupling model has been established for RFID sensors' mechanical models, electromagnetic models, and mechanical deformation models. Scientific research has been conducted on information fusion and processing methods, clarifying the physical layer information required for structural health monitoring. At the same time, optimization design has been carried out for indicators such as strain sensitivity, effective monitoring range, and sensor miniaturization. The results provide a reliable theoretical basis for structural health monitoring, high-efficiency information processing and monitoring technology solutions, and support the core technologies of this project. 2. Microscopic mechanism damage pattern recognition technology: A microscopic mechanism damage model based on cavity growth has been introduced. The model is applicable to the monitoring of ductile damage in steel materials. By simulating damage under quasi-static conditions and using pattern recognition paradigms to describe structural health monitoring issues, it clarifies the degree of fatigue damage and the evolution laws of damage in inspected structures. It solves the long-standing problem in the field of structural health that there has been a lack of an effective mechanism for evaluating fatigue damage. 3. Damping Residual Strain Topology Optimization Detection Technology: Through topology optimization of random excitation structures containing additional dampers, a scheme is proposed that simultaneously obtains the optimal topology of the random excitation structure and the optimal distribution of discrete dampers, achieving the measurement of residual strains in the structure; by arranging multiple point RFID strain sensors on the inspection structure, performance indicators based on maximum historical strain and residual strain at multiple points are used to assess damage, providing an efficient information utilization scheme. The project has solved the optimization layout problem of sensors and data redundancy in practical engineering applications. 4. Road and bridge structure monitoring technology: Using RFID patch antennas as strain sensors and transmission terminals for wireless data transmission, eliminating the need for complex wiring; completed numerical simulation and experiments to prove that the resonant frequency drift of rectangular patch antennas is linearly related to the strain in the antenna's length direction, with a normalized sensitivity of -0.9972 in the UHF band, which is an improvement of 20%-60% compared to similar studies. Currently, based on project achievements, 22 authorized invention patents and 39 utility model patents have been obtained, and 124 high-level academic papers have been published. The results have received positive evaluations from academicians of the American Academy of Engineering, Samii, and Chinese Academy of Sciences, Mao Junfa, as well as active promotion by Xue Songtao, an expatriate academician of the Japanese Academy of Engineering. The project's technology is generally at the international advanced level, with key technologies reaching the international leading level. The project's achievements were exhibited at an international industrial expo; it participated in a national key research and development program of Shanghai Construction Engineering Group; through the cooperative transformation of technical services, the project's technology has been industrialized and applied, with current cooperative transformation income reaching 452.43 million yuan.