帮我按照科研论文摘要重新组织表达下面这句话让它更加符合逻辑：Fano resonance is considered to be a promising approach for nanoparticle sensing However achieving Fano resonance on ultra-compact chips and applying for nanoparticles de

Fano resonance has been recognized as a promising method for nanoparticle sensing; however, achieving Fano resonance on ultra-compact chips and applying it to nanoparticle detection remains challenging, with some theories and mechanisms still unclear. In this study, we propose a theoretical model based on the transfer matrix method (TMM) to quantitatively explain the impact of a micro-reflective unit (MRU) etched on the straight waveguide of a microring resonator (MRR). When the MRU is etched in the coupling region, the clock-wise (CW) and counter-clock-wise (CCW) modes in the cavity will couple due to a single nanoparticle or the rough cavity walls, resulting in a shift and split in the Fano lineshape. Compared to single particle sensing of MRR, the CCW mode in the cavity can be caused not only by particles and rough cavity walls, but also by the MRU, leading to a sharp change in the resonance lineshape. The proposed model's effectiveness is confirmed through application to single nanoparticle sensing and its agreement with FDTD simulation. The results demonstrate the practicality of the model and its ability to provide a new theoretical basis for regulating microcavity Fano resonance lineshape, thereby offering new insights for highly sensitive integrated sensing of silicon photonic devices