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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 $1400\times 700\,\,\mu \text{m}^{2}$ , the microwave near-field distribution radiated by invisible microstrip defects was reconstructed with a resolution of $1.63~\mu \text{m}$ /pixel, and the microwave magnetic field detection sensitivity reached 0.7 nT/Hz $^{\mathrm {1/2}}$ . 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.

This article proposed a microwave (MW) detection method by utilizing the effect of the dual MW on nitrogen-vacancy (NV) centers in diamond. We established a theoretical model of dual MW superposition and experimentally discovered the unusual peak in the optically detected magnetic resonance (ODMR) spectrum. The peak frequency and the full-width at half-maximum of the unusual peak, as well as fluorescence intensity in the nonresonant frequency range of the ODMR spectrum, were systematically analyzed to obtain the frequency and amplitude of the measured MW signals. The broadband MW detection was realized in a wide range of 2240–4512 MHz by utilizing the linear relation between the magnetic field and the resonant frequency in the Zeeman splitting. The experiments showed that the minimum detection power was up to $1~\mu \text{W}$ . The proposed approach can greatly improve the practicability of detecting MW fields on chip surfaces by quantum engineering techniques.