Advantages and Disadvantages of Scalar Network Analyzer (SNA), Vector Network Analyzer (VNA)

This page explores the advantages and disadvantages of different types of network analyzers, specifically focusing on Scalar Network Analyzers (SNA) and Vector Network Analyzers (VNA).

What is a Network Analyzer?

Network analyzers are essential instruments for making both transmission and reflection measurements. Transmission measurements involve parameters like transmission coefficient, insertion loss, and gain. Reflection measurements, on the other hand, cover reflection coefficient, return loss, and impedance.

Figure 1: Shows an SNA model (8757D) and a VNA model (E5072A).

What is a Scaler Vector Analyzer (SNA)?

A Scalar Network Analyzer is used to measure only the amplitude properties of a device. It does not measure both amplitude and phase, but can be used for parameters like VSWR and Return loss. This requires only the measurement of the magnitude of a signal at a particular frequency or frequency range, and not requiring measurement the phase.

Advantages of SNA

• Simpler Hardware: The hardware required for down conversion and power detection is relatively simple in an SNA.
• Cost-Effective: Due to their simpler design, SNAs are generally more affordable than VNAs.
• Faster Sweeps: SNAs can perform measurement sweeps more quickly compared to VNAs.

Disadvantages of SNA

• No Phase Measurements: SNAs cannot measure the phase of signals, limiting their use in applications where phase information is crucial.

What is a Vector Vector Analyzer (SNA)?

A Vector Network Analyzer (VNA) is a test instrument used to measure the electrical performance of high-frequency components. It operates by sending a known stimulus signal into a device and measuring both the amplitude and phase of the resulting transmitted and reflected wave

Advantages of VNA

• Magnitude and Phase Measurements: VNAs can measure both the magnitude and phase of signals, offering comprehensive characterization capabilities.

Disadvantages of VNA

• Slower Sweeps: VNAs tend to perform measurement sweeps more slowly than SNAs.
• Complex Design: VNAs are considerably more complex than SNAs due to the use of a full heterodyne architecture in their receiver section. This complexity is necessary for measuring both magnitude and phase.
• Higher Cost: Due to their complex design, VNAs are more expensive than SNAs.