A classic cape, knitted from bottom to top, finished with rib. If you are capable of cable knitting, then the new concept of 360-degree cabling is easy for you,

Directions are given only to the right side, wrong side knit as stitches appear.
Knit all yarn overs, knit front and back for yarn over twice.
No buttonhole needed, as the cable edge has natural holes

Knit
Purl
Yarn over
Yarn over twice
Slip Slip Knit
Knit 2 together
Knit front & back (Increase 2 sts. from Yarn over twice)
Cable tie 12 sts
Cable Front
Cable Back