Dispersive Materials for RF/MW Applications
A dispersive material has a refractive index (the square root of permittivity) varying with the frequency. Different colours of light will be refracted, or bent, by different amounts when they pass through such a material. It is commonly used in optics, especially in lenses and prisms, to control the dispersion of light. In telecommunications, the dispersion properties of materials can also impact signal quality and data transmission rates, which is an important consideration in fibre optic communication systems. For RF/microwave antennas, dielectric materials have been used to make dielectric resonant antennas (DRAs), where non-dispersive materials (such as ceramics) are utilised to ensure stable performance over the operational frequency. However, dispersive materials have not been employed for RF/MW applications since this topic has not been properly studied before, and their suitability has been a question.
In this talk, we are going to study dispersive materials and answer whether they could be used for RF/MW applications. Especially, when the permittivity of a composite material could be configured as a special function of frequency, such as the permittivity inversely proportional to the frequency square – this means that the wavelength of an EM wave in the material becomes a constant! We can therefore make antennas (such as a half-wave antenna) to be of an ultrawide bandwidth but compact in size, which is extremely attractive. We are going to share the latest development of this work at Liverpool (the successes and problems) and hopefully, you will get some inspiration to work in this new area.
