Access 97 Date Function

In a query, I want the criteria to limit the results to only those records with a date within the previous 30 days in this field.

I’ve tried <=Date()-30 and <=(Date()-30) and (DateDiff (d, (date()))<=30) which gave me an error message. I know I could create a field to calculate the date that is always 30 days previous to today, then have my criteria say it must be greater than the calculated field. But surely there is a compact way to do it in one field. Thanks for your help!