BULLETIN OF THE KOREAN MATHEMATICAL SOCIETY, vol.61, no.6, pp.1447-1457, 2024 (SCI-Expanded)
. In this paper, we study the structure of cyclic, quasi-cyclic and constacyclic codes over the finite ring R = Z4+wZ4 of order 16, where w2 = 2. Additionally, self-dual codes and their properties are discussed. Two Gray maps are defined to obtain linear codes over Z4. Gray images of cyclic, quasi-cyclic and constacyclic codes over R are examined under these maps. We present new linear codes over Z4 obtained from codes over R via each Gray map.