awk & shell variables containing blanks

Hi,

Currently I am experiencing a small issue with awk search patterns & korn 
shell variables.
I simplified my problem to the following example (which will explain
itself 
I suppose) :

$ x="a b"
$ awk '/'$x'/' <file>
awk: line 1: runaway regular expression /a ...

 Can anyone tell me how to get around it? Probably a small thing, but I 
can't seem to find the answer ...


Thanks!

Mark