If you need a 100W stepped attenuator for RF applications covering 0-3 GHz with SMA connectors, here’s what you should look for:

Specifications:

1. Power Rating: 100W
2. Attenuation Range: Stepped attenuator with increments, often in dB steps like 1 dB, 2 dB, 5 dB, 10 dB, etc.
3. Frequency Range: 0-3 GHz
4. Connector Type: SMA (SubMiniature version A)
5. Attenuation Accuracy: High precision in the attenuation steps for accurate signal control.
6. Insertion Loss: Minimal loss when the attenuator is not in use.
7. VSWR: Low Voltage Standing Wave Ratio, typically less than 1.2:1 for minimal signal reflection.

Features to Consider:

1. Stepped vs. Continuously Variable: Stepped attenuators provide discrete attenuation values, while continuously variable ones offer smooth adjustment. Confirm that a stepped attenuator meets your specific needs.
2. Build Quality: Ensure it has a durable construction to handle the power rating and maintain performance over time.
3. Thermal Management: Adequate heat dissipation to handle the power without degrading performance.

Recommended Manufacturers and Suppliers:

1. Mini-Circuits: Known for a wide range of RF components including attenuators.
2. Keysight Technologies: Offers high-quality RF components and test equipment.
3. Wavestream Corporation: Specializes in high-power RF components.
4. RFMW: Distributes various RF components, including attenuators.