With the HP 11722A Sensor Module, you get all the performance from your HP 8901B or HP 8902A, plus superb power measurement accuracy, at one single connector. You can characterize a signal without switching back and forth between the power sensor and the analyzer’s RF input.
HP / Agilent 11722A Sensor Module for 8902A, 8901B
The Agilent 11722A is an accessory for the 8901B and 8902A which lets the user make all measurements including RF power from a single connection. It contains a silcon monolithic thermocouple as a power sensing element.