The Keysight U281A is a waveguide-to-coaxial adapter engineered for precision transitions between EIA WR-19 waveguide transmission lines and 1.85 mm coaxial connectors. Operating across the 40 GHz to 60 GHz U-Band, this adapter maintains signal integrity in microwave and millimeter-wave measurement systems while supporting bidirectional power transmission.
Technical Specifications
• Frequency Range: 40 GHz to 60 GHz (U-Band)
• Waveguide Interface: EIA WR-19 with UG-383 (mod)/U flange
• Coaxial Interface: 1.85 mm female connector
• Impedance: 50 ohms
• Maximum SWR: 1.17 typical; ≤ 1.3 maximum
• Insertion Loss: ≤ 0.5 dB typical
• Return Loss: ≥ 22 dB typical
• Repeatability: ≥ -50 dB typical
• Operating Temperature: 0 to 55°C
– Key Features
• Bidirectional transmission capability supports both source and measurement configurations
• Superior RF performance with SWR of 1.17 typical ensures minimal reflections and signal degradation
• Low insertion loss ≤ 0.5 dB preserves measurement accuracy across the full U-Band
• Excellent repeatability at -50 dB typical enables consistent device characterization
• Return loss ≥ 22 dB typical reduces impedance mismatch effects
– Typical Applications
• Characterization of waveguide components at millimeter-wave frequencies
• Connection of coaxial test instruments to waveguide transmission systems
• Transition between network analyzer ports and waveguide devices in 40–60 GHz measurements.
• Integration of 50-ohm coaxial sources and loads with waveguide-based RF systems
– Compatibility & Integration
The 1.85 mm female coaxial connector mates directly with 2.4 mm connectors, providing flexibility in test system configuration. The UG-383 (mod)/U waveguide flange ensures reliable connection to standard EIA WR-19 transmission lines.
