Agilent/Keysight 423A

The Agilent/Keysight 423A is a precision RF detector that converts RF power levels into proportional DC voltage values for accurate power measurements in 50 Ω coaxial systems. Operating bias-free across 10 MHz to 12.4 GHz, this point-contact detector delivers relative power measurements up to 100 mW with exceptional sensitivity and flat frequency response. The detector outputs negative polarity DC signals (positive available via Option 003) through a BNC connector, making it ideal for signal detection, swept-source leveling, and broadband component characterization.

Technical Specifications

• Frequency Range: 10 MHz to 12.4 GHz


• Input/Output Impedance: 50 Ω nominal input; <15 kΩ output shunted by 10 pF


• Maximum Input Power: 100 mW peak or average; 100 mW typical for <1 minute short-term exposure


• Frequency Response: ±0.2 dB over any octave (10 MHz to 8 GHz); ±0.5 dB (10 MHz to 12.4 GHz)


• Sensitivity (25°C): High-level mode 0.4 mV/µW CW


• SWR: 1.20 (10 MHz–4.5 GHz); 1.35 (4.5–7.0 GHz); 1.50 (7.0–12.4 GHz)


• Temperature Coefficient: 0.015 dB/°C (0°C to 55°C)


• Operating Temperature: 0°C to +55°C


• Dimensions/Weight: 3 × 1 × 1 in; 1 lbs

Key Features

• No DC bias required for operation


• Point-contact detector element with stable, repeatable response


• Dual sensitivity modes accommodate both high-level and low-level detection


• BNC output connector compatible with standard oscilloscope inputs


• Low-pass filtering recommended below 1 GHz to attenuate RF leakage through output

Typical Applications

• CW and pulsed power detection


• Automatic level control and sweeper leveling


• Frequency response characterization of microwave networks


• Pulse envelope demodulation for oscilloscope observation


• Harmonic-frequency comparison as a mixer element

Compatibility & Integration The 423A accepts Type N or APC-7 inputs depending on frequency range. Option 001 supplies matched detector pairs with 11523A load resistor for optimized square-law performance. Option 002 provides matched load resistor alone. Standard negative output polarity integrates directly with conventional test setups; Option 003 enables positive-polarity operation when required.