The radiated emission limits for unintentional radiators are specified in Section 15.109. There are both average and peak limits on radiated emissions above 1 GHz and Section 15.35 specifies the measurement detector function and bandwidth to be used when performing the required measurements.
There are a number of different types of average detectors available for performing EMI measurements on the market today. Above 1 GHz, CISPR 16-1-1 defines two modes of the average detector - linear and logarithmic. For radiated emission measurements at frequencies above 1 GHz, the appropriate average detector is the linear average detector as defined in Clause 6 of CISPR 16-1-1.
See CISPR interpretation sheet SC CIS/I/Publication CISPR 22 (2008), Sixth Edition/I-SH 01.