Radio-Transparent Properties Comparison of Aramid, S-Glass, and Quartz Fiber Reinforced Radome Composites at 900 MHz Frequency

Radio-transparent composites are the functional composites that can transmit electromagnetic wave at a certain frequency and have been widely used in the fields of missiles, launch vehicles, aircrafts, microwave towers and microwave relay stations, radomes, and antenna window of communication antennas, and high-performance printed circuit boards. In this work, we examine the wave transparent properties of the synthesized S-Glass fiber-, Aramid fiber-, and Quartz fiber-composite using typical testing methods for dielectric properties (ASTM D149), density (ASTM D792), moisture content (ISO 16979), and signal transmission test to determine the most suitable composite for 900 MHz radio frequency transmission. The dielectric constant at 50 Hz is internally influenced by the polarization of the material, which depends on its molecular or atomic structure and the distribution of electrons within each fiber, and externally affected by moisture content. The highest moisture content of Composite Aramid was 2.63%, followed by S-Glass at 1.09% and Quartz at 0.71%. The results showed that the dielectric constant at 50 Hz values of composite specimens was inversely influenced by the value of the moisture content. The composite radome of Quartz and S-Glass have a tendency to amplify electromagnetic signals, while Aramid inhibits electromagnetic signal radiation. The dielectric constant was directly affecting the electromagnetic signal attenuation. Quartz gave the lowest signal attenuation which had better radio-transparent properties.