This paper describes the analysis of Kapton material in antenna design for telecommunication systems. Kapton is usually used in the design of radio and microwave frequency antenna. It is a flexible material and with different dielectric() value. The antenna is made of a Kapton substrate, a patch and copper (FR4). The dielectric characteristics of Kapton substrate changes according to temperature. The simulation result shows that the bandwidth of the antenna increased up to 10 MHz with a second layer of Kapton substrate. While the antenna gain decreased 1.19 dB when the dielectric value is increased. Computer Simulation Technology (CST) software was used to analyse the antenna's performance.