A filter was designed based on elliptic function responses and fabricated using high-Q-factor monolithic ceramic materials with a relative permittivity of 37. A SMD monolithic four-cavity dielectric filter with low insertion loss was designed and manufactured by leveraging cascaded quadruplet coupling between 1 and 4 resonator, The performance indexes of the optimized filter are as follows: a center frequency of 1 268 MHz, operating bandwidth of 25 MHz, insertion loss ≤2.5 dB, return loss ≥18 dB, and out-of-band suppression ≥40 dB. On the basis of the structural parameters of the simulation model, samples were manufactured using the optimized metallization and molding process. The performance test results conform to the simulation results, demonstrating high reliability.