Design and Fabrication of a C-Band Dielectric Resonator Antenna with Novel Temperature-Stable Ce(NbV)NbO ( = 0-0.4) Microwave Ceramics.

Vanadium(V)-substituted cerium niobate [Ce(NbV)O, CNV] ceramics were prepared to explore their structure-microwave (MW) property relations and application in C-band dielectric resonator antennas (DRAs). X-ray diffraction and Raman spectroscopy revealed that CNV (0.0 ≤ ≤ 0.4) ceramics exhibited a ferroelastic phase transition at a critical content of V ( = 0.3) from a monoclinic fergusonite structure to a tetragonal scheelite structure (T), which decreased in temperature as a function of according to thermal expansion analysis. Optimum microwave dielectric performance was obtained for CNV0.3 with permittivity (ε) of ∼16.81, microwave quality factor () of ∼41 300 GHz (at ∼8.7 GHz), and temperature coefficient of the resonant frequency (TCF) of ∼ -3.5 ppm/°C. ε is dominated by Ce-O phonon absorption in the microwave band; is mainly determined by the porosity, grain size, and proximity of T; and TCF is controlled by the structural distortions associated with T. Terahertz (THz) (0.20-2.00 THz, ε ∼ 12.52 ± 0.70, and tan δ ∼ 0.39 ± 0.17) and infrared measurements are consistent, demonstrating that CNV (0.0 ≤ ≤ 0.4) ceramics are effective in the sub-millimeter as well as MW regime. A cylindrical DRA prototype antenna fabricated from CNV0.3 resonated at 7.02 GHz (|| = -28.8 dB), matching simulations, with >90% radiation efficiency and 3.34-5.93 dB gain.