Compact microstrip antenna based on fractal metasurface with low radar cross section and wide bandwidth

Abstract

The compact antenna with wide bandwidth is important. In this paper, we have studied the microstrip slot antenna for wireless application based on the fractal structure which has covered 2.3–4 GHz (85% bandwidth). The circular slot antenna with four rectangular slots is considered and then six dual rings are added to the antenna. Finally, for improving the matching a disk is placed in the central part of the slot. The fractal model has been considered for low RCS, for improving the bandwidth, for amending the matching of the antenna by controlling the current distribution and it is modified for C-band application. The antenna gain is around 3.6 dB and around 90% efficiency with compact size 40 × 40 mm2 (0.3λ0 × 0.3λ0 at 2.5 GHz). The metasurface structure is reduced in the RCS around −15 dB at 3.3 GHz. The antenna is simulated with two various numerical methods. The antenna is designed on FR4 as a low-cost substrate. The results show that the fractal shape is used for the bandwidth enhancement and experimental results are confirmed by our simulations. As a result, we show that how the metasurface combination with the antenna can be considered for improving the bandwidth and RCS simultaneously.