Network Analyzers

A “VNA analyzer” is a common misnomer for a vector network analyzer, or VNA. So, the term “VNA analyzer” actually means, “vector network analyzer analyzer”, which is redundant.

Vector network analyzers are also correctly referred to as “network analyzers.” However, VNAs should not be confused with networking testers, which are a different kind of test instrument used to measure Internet or mobile network speeds.

For more information about network analyzers, check out:What is a Network Analyzer?

A network analyzer conducts component characterization tests. Network analyzers provide calibrated stimulus signals to the RF network or device under test (DUT) and measure the vector response over the frequency with phase and amplitude information. A VNA captures transmission (transmission coefficient, insertion loss, gain), reflection (reflection coefficient, VSWR, return loss), and impedance measurements, as well as the S-parameters S11, S12, S21, S22.

A VNA measures a variety of devices and networks with numerous measurements for many different use cases like spectrum analysis, pulse measurements, and active device tests. The following guide describes how to set up network analyzer measurements, calibrate your measurement setup, and interpret results: Making Measurements with a Vector Network Analyzer.

Network analyzers include both signal sources and receivers. The receivers detect changes to the output signal from a device (or network) and compare that to the source signal input. A VNA measures both the amplitude and phase responses to assess the device's effect on current and voltage. The resulting transmission and reflection measurements, impedance, and S-parameters enable test engineers to characterize their DUT. 

There are three categories of network analyzers:

• Vector network analyzers (VNA)
• Scalar network analyzers (SNA)
• Large-signal / nonlinear network analyzers (NVNA)

VNAs, the most common network analyzer on the market today, offer several benefits to test engineers, including simultaneously measuring all four S-parameters and supporting a wide range of frequencies.

A scalar network analyzer only measures the amplitude properties of the circuit, so no phase information gets captured.

Nonlinear network analyzers are less common than VNAs and SNAs, but they offer the advantage of measuring nonlinear circuits. While NVNAs are extremely accurate, they also pose significant operation complexity, often requiring specialized training to use.

Network analyzers come in handheld, benchtop, and modular form factors, including 2-port, 4-port, and 8-port options. Keysight offers five different types of vector network analyzer families ranging from high-end to compact: 

• Our high-end PNA family provides unrivaled excellence in measurement integrity and repeatability. PNA-X maximizes measurement flexibility, replacing an entire rack of equipment.
• Our midrange and economy ENA family reduces test cost while providing ​reliable measurements, an intuitive UI, and upgradable instruments. ENAs balance speed, performance, and budget. 
• The handheld analyzer ​delivers benchtop precision in a rugged, highly integrated handheld unit. ​ 
• Modular PXI VNAs drive down the lab space needed for multi-port testing. Customize the network analyzer's capabilities to only what you need and get fast, accurate multiport measurements.​ 
• The Streamline USB VNA enables a compact​ form factor with zero compromises. Streamline USB VNAs offer all the performance of a benchtop instrument, but at a fraction of the size.

Selection criteria for a VNA varies based on the application or use case of interest. Typical selection criteria include frequency range, number of required ports from 2 up to 24 (multiport) or even 48 in a switch matrix, output power, and instrument class from economy to handheld to high-end.

We recommend you consider these seven main network analyzer aspects before purchasing:

• Frequency Range
• Dynamic Range
• Measurement speed
• Trace noise
• Number of test ports
• Size
• Input power

For more information, check out: Key Vector Network Analyzer Specifications

A vector network analyzer measures a variety of devices and networks with numerous measurements for many different use-cases like spectrum analysis, pulse measurements, power amplifier (PA) characterization, and active device tests. The following guide describes how to set up network analyzer measurements, calibrate your measurement setup, and interpret results: Making Measurements with a Vector Network Analyzer.