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The zero resonant frequency temperature coefficient (zf) of microwave dielectric ceramics (MWDCs) at high and low temperature have attracted great attention in the development of microwave communication equipment. In this work, the Mg2TiO4-MgTiO3-CaTiO3 (MMC) ceramics with meeting the application requirements of 5G communication were prepared by traditional solid-phase sintering after investigating the relationship among phase compositions of xMg2TiO4-(0.931-x)MgTiO3-0.069CaTiO3 and 0.34Mg2TiO4-0.591MgTiO3-yCaTiO3, sin-tering process, and dielectric properties in detail. The results show that the dielectric properties of MMC ceramics are strongly affected by the phase relative contents of MgTiO3, Mg2TiO4 and CaTiO3. For instance, MMC ceramics with approximate zf = 0 is contributed by mutual compensation of Mg2TiO4 and MgTiO3, in which the Mg2TiO4 phase plays an important role in decreasing the zf value; and the increase of CaTiO3 will greatly increase the epsilon r value for MMC ceramics, while has a negative effect in the Q x f value. After three-phase regulation, the 0.32Mg2TiO4-0.611MgTiO3-0.069CaTiO3 microwave dielectric ceramic has a better dielectric temperature sta-bility, associated with dielectric properties of er = 19.7, Q x f = 55,400 GHz (at 8.43 GHz), zf-= 4.5 ppm/degrees C (-40 degrees C-25 degrees C), and zf+ =-5.1 ppm/degrees C (25 degrees C-90 degrees C).