The Keysight (formerly Agilent / HP) 8481D is a high-accuracy diode RF and microwave power sensor. Operating across a frequency range of 10 MHz to 18 GHz, it is designed for measuring low power levels from -70 dBm to -20 dBm. To facilitate calibration with standard 1 mW (0 dBm) 50 MHz power meter reference outputs, the sensor is supplied with a precision 30 dB reference attenuator (Model 11708A). It provides exceptional SWR for minimized mismatch uncertainty and is compatible with a wide range of Keysight EPM, EPM-P, P-series, and legacy power meters.
Specifications
General
| Parameter | Value |
|---|---|
| Interfaces | Proprietary multi-pin connector for power meter sensor cables |
| Display | None (uses connected power meter display) |
Physical
| Parameter | Value |
|---|---|
| Power Supply | Supplied by connected power meter via sensor cable |
| Operating Temperature | 0 to 55 °C |
Measurement & Performance
| Parameter | Value |
|---|---|
| Frequency Range | 10 MHz to 18 GHz |
| Power Measurement Range | -70 to -20 dBm (100 pW to 10 µW) |
| Sensor Technology Type | Diode power sensing element |
| Sensor Dynamic Range | 50 dB |
| Zero Set | ±20 pW |
| Zero Drift | ±4 pW |
| Measurement Noise (Zero Noise) | 45 pW |
Maximum Input Ratings
| Parameter | Value |
|---|---|
| Maximum Continuous Average Power | 100 mW (+20 dBm) |
| Maximum Peak Power | 100 mW (+20 dBm) |
RF & Impedance Characteristics
| Parameter | Value |
|---|---|
| RF Input Impedance | 50 Ω nominal |
Calibration & Traceability
| Parameter | Value |
|---|---|
| Reference Calibration Factor | Traceable to US National Institute of Standards and Technology (NIST) |
Compatibility & Interface
| Parameter | Value |
|---|---|
| RF Input Connector Type | Type-N (male) |
| Compatible Power Meter Models | EPM (E4418A/B, E4419A/B), EPM-P (E4416A, E4417A), P-series (N1911A, N1912A), E1416A VXI, and discontinued 435B, 436A, 437B, 438A, 70100A |
| Compatible Interface Cables | Keysight 11730 Series (11730A, 11730B, 11730C, 11730D, 11730E, 11730F) |
Accessories & Configuration Options
| Parameter | Value |
|---|---|
| Included Reference Attenuator Model | Agilent 11708A 30 dB Attenuator |
Environmental & Reliability
| Parameter | Value |
|---|---|
| Storage Temperature Range | -40 °C to +75 °C |
Environmental
| Parameter | Value |
|---|---|
| Operating Humidity | Up to 95% relative humidity at 40 °C (non-condensing) |
| Operating Altitude | 4572 m (15000 ft) |
| Non-Operating Altitude | 15240 m (50000 ft) |
Power Limits with Attenuator
| Parameter | Value |
|---|---|
| Maximum Peak Power (with Attenuator) | 250 mW (+24 dBm) peak, pulse width <= 10 µs |
Reference Attenuator
| Parameter | Value |
|---|---|
| Reference Attenuator Attenuation Accuracy (50 MHz) | ±0.05 dB |
| Reference Attenuator SWR (DC to 12.4 GHz) | 1.20 |
| Reference Attenuator SWR (12.4 to 18 GHz) | 1.25 |
Technology
Diode
Applications
RF and microwave power measurement