Keysight Technologies (Agilent HP) 8491B vs Keysight Technologies (Agilent HP) 8493C
This comparison evaluates the Keysight Technologies (Agilent HP) 8491B and the Keysight Technologies (Agilent HP) 8493C coaxial fixed attenuators. Designed for RF and microwave test systems, these precision components reduce signal levels with flat frequency response and low standing wave ratios (SWR). While they share similar power handling capabilities, they differ significantly in connector interfaces, frequency coverage, SWR performance, and available attenuation values. This guide helps technical buyers and RF engineers select the correct attenuator for their frequency requirements and system interfaces.
- 8491B Frequency Range
- DC to 18 GHz
- 8493C Frequency Range
- DC to 26.5 GHz
- 8491B Connector Type
- Type-N
- 8493C Connector Type
- 3.5 mm (APC-3.5)
- Power Handling (Average/Peak)
- 2 W / 100 W (Both)
Specifications
| Specification | Keysight Technologies (Agilent HP)8491B | Keysight Technologies (Agilent HP)8493C |
|---|---|---|
| Electrical Specifications | ||
| Frequency Range | DC to 18 GHz | DC to 26.5 GHz |
| Impedance | 50 Ω | 50 Ω |
| Nominal Attenuation Values | 3 dB, 6 dB, 10 dB, 20 dB, 30 dB, 40 dB, 50 dB, 60 dB | — |
| Maximum SWR (DC to 8 GHz) | 1.2 | 1.1 |
| Maximum SWR (8 to 12.4 GHz) | 1.3 | 1.15 |
| Maximum SWR (12.4 to 18 GHz) | 1.5 | — |
| Nominal Attenuation | — | 3, 6, 10, 20, 30, 40 dB options |
| Maximum SWR (12.4 to 26.5 GHz) | — | 1.25 |
| Maximum Average Power | — | 2 W |
| Maximum Peak Power | — | 100 W |
| Power Handling | ||
| Maximum Average Power | 2 W | — |
| Maximum Peak Power | 100 W | — |
| Mechanical and Physical Specifications | ||
| Connector Type | Type-N | — |
| Connector Gender | Male to Female | — |
| Ordering and Configurations | ||
| Attenuation Value Options | 3 dB, 6 dB, and 10 dB increments from 10 dB to 60 dB | — |
| Mechanical Specifications | ||
| Connector Type | — | 3.5 mm (APC-3.5) |
| Connector Configuration | — | Male to Female |
Frequency Range and Connector Interfaces
The primary differences between these two models are their operating frequency limits and connector types. The Keysight 8491B operates from DC to 18 GHz and uses Type-N connectors with a Male to Female gender configuration. The Keysight 8493C extends this range up to 26.5 GHz and utilizes 3.5 mm (APC-3.5) connectors with a Male to Female configuration. The choice between them is often dictated by the system's prevailing interface and the required upper frequency limit.
SWR and Impedance Comparison
Both attenuators are matched to a 50 Ή nominal impedance, but the 8493C offers lower maximum SWR across comparable bands. From DC to 8 GHz, the 8493C maintains a maximum SWR of 1.1 compared to 1.2 for the 8491B. From 8 to 12.4 GHz, the 8493C SWR is a maximum of 1.15, whereas the 8491B is 1.3. In their upper frequency bands, the 8491B has a maximum SWR of 1.5 from 12.4 to 18 GHz, while the 8493C maintains a maximum SWR of 1.25 up to its limit of 26.5 GHz.
Power Handling and Attenuation Values
Both models share the same power constraints, supporting up to 2 W of average power and 100 W of peak power. However, their available nominal attenuation configurations differ. The 8491B provides broader attenuation options, including 3 dB, 6 dB, 10 dB, 20 dB, 30 dB, 40 dB, 50 dB, and 60 dB, with options for 3 dB, 6 dB, and 10 dB increments from 10 dB to 60 dB. The 8493C is available in nominal attenuation values of 3, 6, 10, 20, 30, and 40 dB.
Frequently asked questions
- What is the connector difference between the 8491B and 8493C?
- The Keysight 8491B utilizes Type-N connectors, whereas the Keysight 8493C uses 3.5 mm (APC-3.5) connectors.
- Can the 8491B be used for testing applications up to 26.5 GHz?
- No. The Keysight 8491B is specified for use from DC to 18 GHz. For applications up to 26.5 GHz, the Keysight 8493C must be selected.
- Which model offers a higher maximum attenuation option?
- The Keysight 8491B offers higher attenuation options, supporting up to 50 dB and 60 dB configurations. The Keysight 8493C offers a maximum attenuation option of 40 dB.