Theoretical study of new microwave resonators utilizing dispersive materials

This paper studies innovative microwave resonators, utilizing special dispersive materials whose relative permittivity is inversely proportional to the frequency square. The “dispersive material” refers not only to natural or synthesized materials but also to equivalent materials achieved through advanced dispersion management techniques. The new resonator theory and analysis of the electromagnetic properties and eigenmode frequency of these new resonators are presented comprehensively and validated through a combination of analytical and numerical simulations using commercially available electromagnetic simulation software (CST Studio Suite). Detailed deduction and demonstration of wideband resonance characteristic, unloaded quality factor (Q), and new formulas are given. Several new types of resonators are introduced including rectangular waveguide cavity resonators and dielectric resonators. This inverse-square property of the special dispersive material provides the new resonators with wideband resonance characteristics. Besides, other dispersive materials whose relative permittivity is inversely proportional to the frequency by the power of n are also demonstrated to be useful for bandwidth enhancement. Moreover, the theory behind these dispersive materials and their equivalent approaches for achieving similar material characteristics through various techniques of dispersion management are also discussed in detail. Compared with the traditional resonator, the new resonator breaks the bandwidth limitation and offers the potential to a variety of new microwave devices and antennas such as bandwidth enhancement, stable radiation patterns, and other merits. This could make it useful for a variety of applications including 6G communication, broadband radar systems, and ultrahigh-speed data transfer.