  The atom-based traceable standard for microwave electrometry shows promising
advantages by enabling stable and uniform measurement. Here we theoretically
propose and then experimentally realize an alternative direct International
System of Units (SI)-traceable and self-calibrated method for measuring a
microwave electric field strength based on electromagnetically induced
absorption (EIA) in cold Rydberg atoms. Comparing with the method of
electromagnetically induced transparency, we show that the equivalence relation
between microwave Rabi frequency and Autler-Townes splitting is more valid and
is even more robust against the experimental parameters in the EIA's linear
region. Furthermore, a narrower linewidth of cold Rydberg EIA enables us to
realize a direct SI-traceable microwave-electric-field measurement as small as
$\sim$100 $\mu\mathrm{\!V} \mathrm{cm}^{\!-\!1}$.
