Keysight Technologies (Agilent HP) Sensors

Keysight power sensors are divided into two main architectures: standalone USB-controlled sensors and traditional meter-dependent sensors. USB sensors contain all necessary measurement circuitry within the sensor body, drawing power directly from the USB bus and eliminating the need for a separate power meter mainframe.

• USB Power Sensors: Models such as the U2000A (10 MHz to 18 GHz) and the U2002A (50 MHz to 24 GHz) connect directly to a PC or compatible Keysight instrument. High-power requirements are addressed by the U2001H (10 MHz to 6 GHz), which extends upper limits to +30 dBm, while the U2004A is tailored for lower frequencies starting at 9 kHz.
• Meter-Based Sensors: Traditional sensors require a host power meter (such as EPM or P-series models) for control and display. They utilize multi-pin sensor cable interfaces. Examples include the 8481A thermocouple sensor and the E4412A diode sensor. These are dependent on the host meter for power and signal processing.

The choice of sensing technology determines the sensor's sensitivity, dynamic range, and measurement type:

• Thermocouple Sensors: These sensors provide true average power measurements for complex modulation formats but feature a narrower dynamic range. The 8481A and 8485A (50 MHz to 26.5 GHz) provide a 50 dB dynamic range from -30 dBm to +20 dBm. For high-power average measurements, thermocouple models like the 8481B and 8482B integrate internal attenuators to handle up to +44 dBm (25 W). For standard average measurements in lower RF bands, the thermocouple-based 8482A covers 100 kHz to 4.2 GHz, while the 8483A provides a 75 Ω nominal impedance for cable and telecommunication testing.
• Diode Sensors: These provide high sensitivity and wide dynamic ranges. The E4413A is a CW sensor delivering a 90 dB dynamic range (-70 dBm to +20 dBm). For extremely low power levels, high-sensitivity average diode sensors like the 8481D and 8485D measure down to -70 dBm.
• Thermistor Mounts: Coaxial thermistor mounts like the 478A (10 MHz to 10 GHz) offer excellent drift stability under temperature variations when paired with compatible instruments like the N432A power meter.

Pulsed signals and wideband modulations require high-bandwidth processing to measure peak power and peak-to-average ratios. P-Series wideband sensors like the N1921A and N1922A offer a 30 MHz video bandwidth, making them suitable for aerospace and communication signal analysis. They deliver rise and fall times of 13 ns or less. In the E-Series family, peak and average sensors like the E9322A and E9325A provide selectable video bandwidths up to 1.5 MHz and 300 kHz, respectively.

For millimeter-wave bands, waveguide sensors interface directly with wave transmission lines. Thermocouple options include the Ka-band N8486AR (26.5 GHz to 40.0 GHz) and the Q-band Q8486A (33 GHz to 50 GHz). Diode-based waveguide options include the R8486D (Ka-band, with a -70 to -20 dBm range), the V8486A (V-band, 50 GHz to 75 GHz), and the W8486A (W-band, 75 GHz to 110 GHz).

Keysight's sensor portfolio extends to optical power measurements. Designed for lightwave mainframe platforms, these modules feature Indium Gallium Arsenide (InGaAs) detectors:

• The 81635A is a dual-channel optical power sensor covering wavelengths from 800 nm to 1650 nm.
• The 81630B is configured for high-power optical applications, supporting measurements up to +28 dBm.
• The 81536A provides high-sensitivity optical sensing (-70 to +3 dBm) for legacy mainframe systems.

For specialized RF receiver calibration, the 11792A sensor module integrates a thermocouple sensor with a low-loss RF switch. This design enables automatic switching between high-accuracy power measurements and frequency downconversion on the HP 8902A measuring receiver.