Abstract: The rapid growth of low-altitude economy is likely to increase low-altitude flight activities， placing higher demands on continuous and reliable coverage by low-altitude communication networks and on precise traffic management of aerial vehicles. Therefore， an urgent need exists for wireless systems to provide integrated communication-and-sensing services in three-dimensional space with high reliability， low latency， and wide coverage. Traditional multiple-input multiple-output （MIMO） systems are constrained by fixed antenna architectures， resulting in insufficient spatial degrees of freedom （DoFs）， which coupled with limits on hardware scaling， make it difficult to break the current performance ceilings. This article proposes an innovative wireless communication system architecture based on a rotatable antenna （RA）. The flexible antenna boresight rotation is leveraged to unlock new spatial DoFs in antenna arrays， demonstrating significant potential for enhancing wireless network performance. Specifically， RA-enabled dynamic adjustment of antenna orientations/boresights through mechanical or electronic control mechanisms improves channel conditions and enhances energy/spectral efficiency in wireless systems. First， a comprehensive overview of RA technology， including its potential applications， hardware architectures， and radiation pattern characteristics is provided. The performance enhancements of RA over fixed antennas in interference suppression， spatial multiplexing， and flexible beamforming are elaborated on. Key challenges in RA system design， such as rotational scanning scheduling， channel estimation， boresight/orientation optimization， and antenna configuration， are further addressed. In experimental results， the RA system offered a 7 dB signal-to-noise ratio （SNR） gain over its fixed-antenna counterpart when the user was located at the sector edge. In addition， simulation results demonstrated a 3.2 dB improvement in signal-to-interference-plus-noise ratio （SINR） for multiuser communication scenarios. In integrated sensing and communication systems， RA enabled a ten-fold increase in target detection power while maintaining the same communication data rate constraint. With its capability for agile antenna/array reconfiguration， RA is poised to become a key enabler for building intelligent， reliable， and flexible wireless networks in the next generation wireless network.