<p>Mechanical antenna (MA) is a novel low frequency (LF) transmitter which has a much smaller size, costs less energy and owns higher power conversion efficiency compared to electrically small antenna (ESA) of the same frequency. The expressions of magnetic flux density induced by single rotating permanent magnetic mechanical antenna (RPMMA) are derived based on Maxwell’s equation. The radiation field patterns and directivity of single RPMMA are given subsequently. The beam width of single RPMMA is relatively wide and its directivity is not large enough to meet the demands of high-resolution detections and long-distance communications in far-field observations. A 3 × 3 planar RPMMA array is designed to narrow the beam and enhance the directivity under the inspiration of antenna array theory. The array achieved a narrow main lobe above the working plane with the function of a phased array by changing the progressive phase between adjacent elements in the array. The feasibility of the RPMMA array is verified by finite element method (FEM). The work paves the way for future research on MA arrays and other forms of MA combined with antenna theory such as the theory of reflector antennas.</p>