Flexible ultra-wideband rectangle monopole antenna with O-slot insertion design

Slot insertion design has proven to be an effective method to increase the bandwidth in the design of microstrip antenna. In this paper, the slot insertion design is applied to the flexible ultra-wideband (UWB) antenna. A flexible rectangular UWB monopole antenna is proposed and fabricated with O-slot design using the transfer printing method. By simulating the influence of O-slot design parameters on electromagnetic performance of the antenna, an optimized antenna design is obtained to keep the reflection coefficient under -10 dB with the frequencies ranging from 3.5 to 17.8 GHz when the antenna is bent with curvature radius as small as 11 mm. The effect of bending on the reflection coefficient is analyzed. Mechanical simulations indicate that the existence of O-slot can reduce the strain concentration on the metal layer of antenna, which enhances the flexibility of the antenna.