Using Diamond Quantum Magnetometer to Characterize Near-Field Distribution of Patch Antenna

In this paper, a noninvasive quantum imaging method of the near-field (NF) distribution of patch antenna was proposed by using a diamond containing nitrogen-vacancy (NV) centers. We applied AM/FM pulse modulation technique combined with optical detection magnetic resonance to measure the microwave magnetic field of a patch antenna. A full reconstruction formulation of the magnetic field vector, including the amplitude and phase, is proposed by measuring both the left and right circular polarizations along the four NV axes. Furthermore, we proposed a novelty method to reconstruct the surface current distribution imaging of patch antenna by using an integral equation based on magnetic field. The proposed quantum imaging method can directly measure the NF distribution of real antenna. Compared with HFSS simulation, the microwave imaging experiment is sensitive to actual manufacturing details such as the metal cross section due to etching and dielectric layers such as solder masks and shows the microwave field distribution of the real antenna. A nanoscale diamond probe enables nanoscale high-resolution imaging. The proposed method is expected to have applications in diagnosis on monolithic microwave integrated-circuits chip, antenna characterization, and the field mode imaging of nanoscale semiconductor radio frequency devices.