You can try it like this:
<Where>
<And>
<Geq>
<FieldRef Name='RequestDate' /><Value IncludeTimeValue='FALSE' Type='DateTime'><Today /></Value></Geq>
<Leq>
<FieldRef Name='DecisionDate' /><Value IncludeTimeValue='FALSE' Type='DateTime'><Today /></Value></Leq>
</And>
</Where>
Please change RequestDate and DecisionDate to match your internal names, and write the CAML as one continuous string wrapped in double quotes when you use it in the function call.
Alexander