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In maintaining the sovereignty of a country, especially in border regions was needed defense tools that had the latest technology, such as stealth technology. Stealth technology was applied to military ships or aircraft so that they could not be detected by Radio Detection and Ranging. Stealth technology in this research was realized by coating the ship's or aircraft's body using RAM (Radar Absorbing Material). RAM could be composed of dielectric materials, such as activated carbon. The activated carbon was synthesized from Dendrocalamus Asper. This research aimed to analyze the proper of composition the composite and thickness of the RAM for the X-band wave range. The methods were carbonization, activation by KOH and HCl solutions, and characterization. The characterizations were by XRD, FTIR, and SEM to identify the active carbon phase, and VNA to determine the value of reflection loss. The variations in this research were composite composition (7:3, 9:1) and thickness (1mm, 3mm). And obtained that it has been formed a composite of activated carbon of petung bamboo and latex of rubber tree, which is indicated by the formation of two broad peaks in the diffraction pattern, the presence of band groups C=C, C-C, C-H, C-O, O-H, and morphology with a porous structure. In addition, the highest reflection loss is obtained for the 9:1 composite and thickness of 3 mm, which reached -17.25 dB at a frequency of 9.32 GHz.

This study aims to develop an e-module based on Contextual Teaching and Learning (CTL) as a physics learning media and to test its feasibility. The study employed a research and development method (R & D). This research produces a digital learning media for the Physic topic of reflection of light and refraction of light, which can assist students in studying independently by following the syntax of CTL. The e-module combines video, audio, and interactive quiz features. The development process was conducted through the ADDIE model where the researcher evaluate every step in the development process. The e-module was developed according to the syntax of CTL. Validation of the e-module was conducted during the development steps. The validation results by the material expert gained a score of 85.09%, while the media expert gained a score of 82.14%. The e-module was implemented in a small group of nine students and gained a score of 84.71%. These scores mean that the e-module was considered feasible and very good.