Enhancing the bandwidth of antennas using polymer composites with high dielectric relaxation

Abstract

We propose a concept using a frequency-dependent property (dielectric relaxation) of dielectric materials to enhance the bandwidth of the antenna widely used in wireless communications. The bandwidth enhancement can be achieved when a loading dielectric material with a relative permittivity that is inversely proportional to the frequency by the power of n. The bandwidth for a selected antenna example could be increased by 135% when the power n = 2. A solid material, composed of plasticized PVDF containing nano-sized silica particles, exhibiting dielectric relaxation of n = 0.52, is developed in order to prove the theoretical concept and used to test the performance of an example mobile phone antenna. The influence of hydrogen bonding on tuning the frequency-dependent power n in the developed composite material is verified. The bandwidth of the antenna was increased by 18% over the operating frequency band using a newly developed dielectrically relaxing material, n = 0.52 compared to the conventional non-relaxing material, n = 0.