Since your knife is stainless steel, it is a bit more difficult as you can't use the "usual" methods of adding patina on a carbon steel blade (mustard, vinegar, etc.).
You would need to etch the blade with ferric chloride to discolor it, then bead blast the stripe pattern. Alternatively, you could try brushing the ferric chloride on in stripes, but chances are it will look blotchy and the edges of the stripes won't have the subtle fading that you get with media blasting.