Butyl rubber dispersed with low-loss Ca 0.61 Nd 0.26 TiO 3 ceramics for miniaturized flexible microwave substrate applications

Ca 0.61 Nd 0.26 TiO 3 (CNT)-filled butyl rubber (BR) composites were fabricated via Banbury mixing by changing the ceramic volume fraction from 0 to 0.5. The phase purity of the CNT filler was confirmed using X-ray diffraction, and the morphology of the composite samples was analyzed using scanning electron microscopy and atomic force microscopy. BR/CNT composites filled with 50 vol% filler possessed excellent dielectric properties with a dielectric constant of 11.12 and a very low dielectric loss of 0.0023 in the X-band (8–12 GHz) frequencies. Moreover, the material displayed an appreciable thermal conductivity of 0.883 W/mK, low water absorption of 0.0574 %, and an acceptable CTE of 37.08 ppm/ °C. Thus, the developed BR/CNT composites can be used for flexible microwave circuit applications that require miniaturization.