To modify the near-zero temperature coefficient of resonant frequency (τ_f) of CaWO₄-based materials and explore their structure–property relationships, Ca_1−xNd_xW_1−xNb_xO₄ (CWNNx) ceramics were prepared. Phase evolution occurred in the system from tetragonal-scheelite to monoclinic-fergusonite at x=0.7. Relative permittivity (ε_r) increased from 11.28 to 16.84, influenced by the polarizability per unit molar volume (α/V_m), whereas the negative deviations between ε_r,corr and e_r,C−M (Δε_r≈−3.39% to −12.50%) resulted from the compression effect of Ca²⁺ and Nd³⁺ coupled with Nb⁵⁺ at the B site. The quality factor (Q) rose by 52%, attributed to the decreased Raman full width at half-maximum and increased lattice energy (U). The τ_f values changed from −27.6×10⁻⁶ to 72.1×10⁻⁶ °C⁻¹, governed by the increased temperature coefficient of ionic polarizability (τ_αm), decreased coefficient of thermal expansion (α_L), and weakened A-site compression. CWNN0.3 ceramic demonstrated superior properties (ε_r=13.00, Q×f=60170 GHz, and τ_f=−1.9×10⁻⁶ °C⁻¹), suggesting potential applications in sub-6 GHz antennas.