We characterize the dielectric properties of aqueous sugar solutions using an open-ended coaxial probe combined with full-wave electromagnetic simulations to enable X-band (8–12 GHz) liquid sensing. Reflection coefficient (s11) measurements acquired with a vector network analyzer are used to extract the complex permittivity, and the resulting values are validated using Computer Simulation Technology (CST) Studio Suite models that replicate the experimental geometry. The revised analysis resolves previously noted inconsistencies by unifying the measurement frequency range to 8–12 GHz and by clarifying the role of εr in the workflow—εr is first estimated from experimental data and then used to cross-validate the simulation. Because the open-ended coaxial probe acts as a microwave sensor, this study demonstrates how the measured and simulated dielectric responses can serve as calibration data for developing and validating liquid sensor technologies. The measured and simulated trends exhibit close agreement across sugar concentrations, and the results of targeted sensitivity analyses confirm that small changes in permittivity (Δεr ≤ 0.1) are detectable. The main contribution of this work is a rigorously benchmarked experiment-plus-simulation methodology that provides reference data and guidance for calibrating broadband dielectric liquid sensors. Owing to its nondestructive, real-time operation and compatibility with automated measurements, the approach is directly applicable to sensor design for environmental monitoring, biomedical fluids, and industrial quality control.