Configuring a S11 2 Couplers System

  • Refer to the hardware requirements listed in S11 2 Couplers System Hardware Requirements.
  • Ensure all components are installed in the chassis before completing the following steps.
  • If using the PXIe-5842, ensure the modules are properly interconnected, as described in Interconnecting the PXIe-5842.
Complete the following steps to configure your hardware for S-parameter measurements using S11 two couplers per DUT port.
Note The PXIe-5831 does not have dedicated RF IN/OUT ports. Use the IF IN/OUT 1 port as RF IN and the IF IN/OUT 0 port as RF OUT if using a PXIe-5831.
Figure 1. S11 2 Couplers System Connections


  1. Connect the RF OUT or IF IN/OUT 0 port of the IN port of a coupler using SMA cables.
  2. Connect the output ports of the two couplers with an adapter.
  3. Connect the coupled port of each coupler to the channels of the RF IN switch or switch bank using SMA cables.
  4. Connect the COM port of the RF IN switch or switch bank to the RF IN or IF IN/OUT 1 port of the VST using an SMA cable.
  5. Connect the unconnected input port of the coupler pair to the DUT for measurement or the calibration kit for calibration using SMA cables.
  6. If using the PXIe-5841, share the local oscillator (LO) signal by connecting the TX LO OUT port to the RX LO IN port of the VST using a MMPX-to-MMPX cable. If using the PXIe-5831 or PXIe-5842, no additional connection needs to be made as the LO is shared internally.

S11 2 Couplers System Hardware Requirements

In this hardware configuration, use two couplers to measure the reflection wave of the DUT.

The following tables list the NI and third-party accessories required to perform an S-parameter measurement with an S11 two couplers system.
Table 9. Required NI Hardware
HardwareModelMinimum RequirementsQuantity
PXI Vector Signal TransceiverPXIe-5831, PXIe-5841, or PXIe-5842—1
PXI ChassisPXIe-1095—1
PXI Controller—16 GB/s bandwidth and 16 GB RAM1
PXI RF Multiplexer SwitchPXIe-2543—

0, if using a PXIe-5831 or PXIe-5842

1, if using a PXIe-5841

PXI-2597—

0, if using a PXIe-5841

1, if using a PXIe-5831 or PXIe-5842

MMPX-to-MMPX Cables122 mm Flexible Cables—

0, if using a PXIe-5831 or PXIe-5842

1, if using a PXIe-5841

Table 10. Required Third-Party Accessories
HardwareModelQuantity
Directional CouplerRD Microwave C1-C31-C202
SMA CablesVelocity Microwave Conexus 3.5 mm Cables5
SMA Male-to-Male AdapterMini Circuit SM-SM50+1
3.5 mm VNA Calibration KitMaury Microwave 8050CK51 Characterized Device (CD) Fixed Load SOLT Kit with Adapters 1