This paper presents a flexible saw-shaped bow-tie antenna with a slotted ground plane for Ku and K-band applications. Three unequal rectangular slots having a 1.5 mm gap from each other are cut on the ground plane of the antenna that provides ultra-wide impedance bandwidth. The 50 by 25 mm2 antenna is fabricated on a 0.1 mm Rogers Ultralam 3850 substrate. The very low thickness and the bending property of the substrate make this antenna flexible. Utilizing Computers Simulation Technology (CST) Electromagnetic Studio, the antenna's radiation patterns and return losses are simulated. The calculated impedance bandwidth, or 254.14%, is approximately 17.745 GHz from 11.512 GHz to 29.257 GHz, with a return loss smaller than -10 dB. The comparison between measurement and simulation results has an excellent agreement. In addition, there is very little effect on the performance due to the bending of the antenna that makes it compatible for incorporating with the portable devices.