How do you replace a cut vw antenna cord?

when i went to replace my radio in my 2001 vw jetta i found out that my antenna had been cut and taped back together with electrical tape. I cant get the tape to keep the antenna together any longer and get a good signal. I was wondering what the piece is that i would need to fix this problem.How do you replace a cut vw antenna cord?you might need to if you dont really want so much hassle to buy a new antenna , or if they sell just the cord then buy just the cord