Keysight Technologies (Agilent HP) Sensors

Keysight's sensors fall into clear classes by how they are hosted and by frequency/power focus:

• USB standalone sensors: Compact, PC‑controlled modules that do not require a separate power‑meter mainframe. Example models include U2001A (10 MHz–6 GHz), U2004A (9 kHz–6 GHz) and U2000A (10 MHz–18 GHz). Several USB sensors are bus powered.

• Meter‑attached E‑series and P‑series sensors: These plug into Keysight power meters and mainframes. E‑series examples such as E9300A/E9301A/E9304A and E9327A provide true average or peak/average functions and rely on the host for power and display. P‑series sensors (for example N1921A, N1922A) target wideband and peak/average plus high video bandwidth measurements for pulsed and complex signals.

• High‑power thermocouple/attenuator sensors: Models such as 8481B and 8482B integrate attenuators and thermocouple elements to measure up to the +44 dBm class of average power.

• Waveguide and mmWave sensors: For banded waveguide work, Keysight offers dedicated modules (for example V8486A, Q8486A, N8486AR, R8486D, W8486A) that present a waveguide flange and calibration port suited to their band.

Two sensing technologies dominate the RF/microwave lineup and each has tradeoffs:

• Diode sensors: Found in many E‑ and USB‑connected models (examples: E4412A, E4413A, 8484A, 8487D). Diode sensors reach the lowest detectable powers in the product set (−70 dBm is quoted on several diode models) and generally offer wide dynamic range. They are typically used where low‑level average or peak detection is required.

• Thermocouple/thermistor sensors: Used where high continuous power or integrated attenuation is required. Examples include 8481B and 8482B which are positioned for measurement of milliwatt to multiwatt average power levels (0 to +44 dBm quoted on those models). Thermocouple sensors tolerate higher input and often have integrated attenuators for high‑power applications.

Waveguide and banded thermocouple/diode sensors (V8486A, N8486AR, Q8486A, R8486D, W8486A) trade connector format and band‑specific SWR for banded waveguide coupling and calibration features appropriate to millimeter‑wave work. Optical sensor modules (for lightwave mainframes, e.g. 81630B) use InGaAs detectors and are specified by wavelength and optical power range rather than RF power.

If you need peak or time‑gated measurements, examine video bandwidth and rise/fall times or explicit peak modes:

• P‑series examples N1921A and N1922A specify wide video bandwidth (N1921A: video bandwidth ≤ 30 MHz; N1922A: 30 MHz VBW) and fast rise/fall times (N1921A rise/fall ≤ 13 ns) to support peak and short‑pulse analysis.

• USB and E‑series peak sensors are also available. The U2021XA (USB peak/average) lists a 30 MHz video bandwidth and ≤13 ns rise/fall, while meter‑attached peak/average sensors like E9327A expose time‑gated peak/average capability when used with compatible meters (E9327A: video bandwidth up to 5 MHz for gated measurements).

Check the sensor's maximum peak and continuous average ratings before applying pulses: sensors list both maximum continuous average power and maximum allowed pulse/peak power or damage levels.

Choose a sensor class by how you plan to integrate it:

• USB standalone sensors (U2001A, U2004A, U2000A, U2002A, U2001H, U8487A, U8488A) connect directly to a PC or compatible Keysight host via USB 2.0 (USBTMC/USBTMC‑USB488 in many models) and in numerous models are bus powered. They are convenient for bench and automated PC‑based test where a separate power‑meter mainframe is not required.

• E‑series and P‑series sensors rely on a host power meter (EPM, EPM‑P, P‑series and compatible mainframes listed in each sensor's notes) for power, control and display. They are suited to lab test racks and where multiple sensor types are used under a single meter.

• Calibration and stability: many Keysight sensors specify a recommended calibration interval of 1 year; some sensors include onboard EEPROM to store calibration factors (for example E4412A/E4413A/E4412‑class sensors and others note EEPROM storage).

Practical checklist: match required frequency band and connector type, verify the power range and damage limits for your signals, confirm peak/video bandwidth when pulse timing matters, and select the host interface (USB vs meter) that fits your automation and display needs.