Recognizing Microwave Field Contrast of Invisible Microstrip Defects With High Accuracy by Quantum Wide-Field Microscope

Invisible microstrip defect detection is of great significance for ensuring the reliability of integrated circuits and improving the performance of communication system. In this article, the microwave fields radiated by six typically invisible microstrip defects were experimentally characterized with high accuracy based on quantum wide-field microscope, and the origin of microwave field contrast was theoretically analyzed. In a view of <inline-formula> <tex-math notation="LaTeX">$1400\times 700\,\,\mu \text{m}^{2}$ </tex-math></inline-formula>, the microwave near-field distribution radiated by invisible microstrip defects was reconstructed with a resolution of <inline-formula> <tex-math notation="LaTeX">$1.63~\mu \text{m}$ </tex-math></inline-formula>/pixel, and the microwave magnetic field detection sensitivity reached 0.7 nT/Hz<inline-formula> <tex-math notation="LaTeX">$^{\mathrm {1/2}}$ </tex-math></inline-formula>. Meanwhile, the causes of microwave field discrepancies were analyzed specifically on the basis of microstrip transmission line theory. It was attributed to the transmission loss and the uneven distribution of induced current arising from variations in geometrical structures. The phenomenon validated the feasibility of detecting invisible microstrip defects utilizing the microwave field intensity distribution. The proposed approach is expected to have applications in microchip design and radio frequency (RF) equipment maintenance, thereby notably improving the practicability of quantum measurement technology.