  We study unextendible maximally entangled bases (UMEBs) in \(\mathbb
{C}^{d}\otimes \mathbb {C}^{d^{\prime}}\) ($d<d'$). An operational method to
construct UMEBs containing $d(d^{\prime}-1)$ maximally entangled vectors is
established, and two UMEBs in \(\mathbb {C}^{5}\otimes \mathbb {C}^{6}\) and
\(\mathbb {C}^{5}\otimes \mathbb {C}^{12}\) are given as examples. Furthermore,
a systematic way of constructing UMEBs containing $d(d^{\prime}-r)$ maximally
entangled vectors in \(\mathbb {C}^{d}\otimes \mathbb {C}^{d^{\prime}}\) is
presented for $r=1,2,\cdots, d-1$. Correspondingly, two UMEBs in \(\mathbb
{C}^{3}\otimes \mathbb {C}^{10}\) are obtained.
