Design of SubstrateIntegrated Waveguide Loading Multiple Complementary Open Resonant Rings (CSRRs) for Dielectric Constant Measurement In order to solve the lowsensitivity problem of the dielectric constant with the resonant cavity method, a sensor based on a substrateintegrated waveguide structure loaded with a multicomplementary open resonant ring is proposed. With the enhanced resonance characteristics of the sensor, this design realized the measurement of complex dielectric constants in a wide range. The frequency selectivity of the sensor is improved by the highquality factor of the substrateintegrated waveguide. By loading three complementary resonant rings with different opening directions in the ground plane, a deeper notch and better outofband suppression are achieved. The effect of the complex dielectric constant on both resonant frequency and quality factor is discussed by calculating the material under test with a known dielectric constant. Simulation and experimental results show that a resonance frequency offset of 102 MHz for the per unit dielectric constant is achieved. A wide frequency offset is the prerequisite for accurate measurement. The measurement results of four plates match well with the standard values, with a relative error of the real part of the dielectric constant of less than 2% and an error of less than 0.0099 for the imaginary part.

MultiParameter Sensing in a Multimode SelfInterference MicroRing Resonator by Machine Learning A universal multiparameter sensing scheme based on a selfinterference microring resonator (SIMRR) is proposed. Benefit from the special intensity sensing mechanism, the SIMRR allows multimode sensing in a wide range of wavelengths but immune from frequency noise. To process the multiple mode spectra that are dependent on multiple parameters, we adopt the machine learning algorithm instead of massive asymptotic solutions of resonators. Employing the proposed multimode sensing approach, a twoparameter SIMRR sensor is designed. Assuming that two gases have different wavelength dependence of refractive indices, the feasibility and effectiveness of the twoparameter sensing strategy are verified numerically. Moreover, the dependence of parameter estimation accuracy on the laser intensity noises is also investigated. The numerical results indicate that our scheme of multiparameter sensing in a multimode SIMRR holds great potential for practical highsensitive sensing platforms compared with the singlemode sensing based on whispering gallery mode (WGM) resonators.