  This study is to use the non-interleaved sextupole scheme to design PETRA IV
storage ring, which is an upgrade from PETRA III, toward diffraction-limit
synchrotron light source. The lattice is constructed by mixing different types
of cells. Double minus identity cell is responsible for the chromaticity
correction with non-interleaved sextupoles, while the combined function FODO
cells provide straights with small beta functions for undulators. These are the
basic building bricks. In addition, two hybrid sections with 10-m long super ID
are custom-made to adapt to the configuration of DESY's current cite plan. The
beam dynamic behaviors are simulated and discussed.
