Programmable attenuators are widely used in automatic test setups to give an absolute attenuation setting for many components, sub-assemblies, and system characterizations. It is a very critical and important test equipment in the industry. The industry only has very limited offerings for waveguide programmable attenuators, especially in high millimeterwave frequency bands, such as V, E, and W bands.
Currently, SAGE Millimeter offers both general-purpose and high precision grade programmable attenuators. While the model number for general-purpose is with “-P1”, the high precision grade is with “-P8”. For example, the model numbers for the E band general purpose and high precision grade attenuators are under the model numbers of STA-60-12-P1 and STA-60-12-P8, respectively.
The following table will give “an apple to apple” comparison between two models of the E band attenuators to show the main differences.
|Descriptions||General-purpose Grade||High Precision Grade|
|Attenuation Range||Up to 60 dB||Up to 80 dB|
|Attenuation Accuracy||0.1 dB or 3% of reading up to 60 dB||0.1 dB or 2% of reading up to 60 dB|
|Attenuation Resolution||0.05 dB (0 to 20 dB) and 0.1 dB (20 to 50 dB)||0.1 dB (0 to 50 dB)|
|Attenuation Value Display||Yes||No|
|Programmable Port||IEEE-488. NI GPIB-USB-HS Adapter||PoE Ethernet Port|
|Moding||Yes, possible moding after 80 GHz and 50 dB or higher||No|
|Power Supply||AC Power Adapter||PoE Ethernet Port|
From the above table, one can see that the high precision grade programmable attenuator offers the following obvious advantages over its general-purpose grade counterpart with the same cost.
- Low VSWR improves system measurement accuracy.
- Larger attenuation dynamic range eliminates possible additional attenuation devices to save overall test set cost, especially when performing the BIT error rate and fade margin testing.
- Mode free operation provides more confidence on the test data integrity.
- Programming through the PoE Ethernet port eases the computer interface and controlling process and reduces the cost by removing the additional NI GPIB-USB-HS Adapter.
- Power over PoE Ethernet Adapter eliminates additional AC adapter saving the space and reduce the fire hazards.
- More robust mechanical configuration elongates the lifespan of the instrument.
The following plot shows the typical frequency responses of the attenuation values of an E band high precision programmable attenuator. From the plot, the high dynamic attenuation range, flat attenuation values and accurate attenuation readings cross the entire waveguide band can be observed.