Pattern in illustrator

Hi everyone,

Ive tried to figure this one out quite a while ago, but still havent found the perfect solution. The attached pattern is what I`m trying to recreate in Illustrtor. I drew a line and defined a pattern. but when filling a recangle with the pattern, it looks like the attached. Does anyone know how I would get this effect with straight and continous lines?

Thanks in advance,
m.