The Keysight / Agilent / HP 11970K waveguide mixer is a general-purpose harmonic mixer employing a dual-diode design to achieve flat frequency response and low conversion loss. These are achieved without external dc bias or tuning stubs. Manual operation and computer-controlled hardware operation are simplified because mixer bias and tuning adjustment are not required.

The 11970K extends the frequency range of the Keysight spectrum analyzers to the K-Band (18 to 26.5 GHz). The compatible Keysight spectrum analyzers include: the E4440A/E4446A/E4448A PSA (with Option AYZ), the E4407B ESA-E (with Option AYZ), the 856xEC, the 8566B (with a preamplifier), and the 7000 modular analyzer (with the 70907A/B external mixer interface module).