**Shyh-Kuang Ueng**

Department of Computer Science & Engineering, National Taiwan Ocean University, Keelung 202, Taiwan; skueng@mail.ntou.edu.tw

Received: 26 June 2020; Accepted: 25 September 2020; Published: 29 September 2020

**Abstract:** Wind turbine towers produce significant scatterings when illuminated by radars. Their reflectivity a ffects air tra ffic control, military surveillance, vessel tracking, and weather data sensing processes. Reducing the radar cross-section (RCS) of wind turbines is an essential task when building wind farms. It has been proved that round and bumpy structures can scatter radar waves and reduce the RCS of a reflector. Other research showed that taper towers generate smaller radar returns than cylindrical towers. In this research, we combine both strategies to devise a more e ffective method for designing wind turbine towers in the hope that their RCS can be further reduced. The test results reveal that the proposed method out-performs current reshaping methods. Wind turbine towers possessing taper shapes and periodic surface bumps deflect incident electromagnetic waves to insignificant directions. Thus, radar returns in the back-scattering directions decrease. Other experiments also verify that the proposed method maintains its e ffectiveness for radar waves with varying frequencies and polarization.

**Keywords:** RCS reduction; wind turbines; reshaping methods
