Buying Guide
The Ultimate Engineer’s Guide to Buying a Network Analyzer
Introduction
This guide compares eight current Keysight network analyzers, spanning 900 Hz to 67 GHz. Picking between them usually looks like working through a fifty-row spec sheet. It isn't. Three questions narrow the field to one or two candidates, and this guide walks through all three. This guide covers the electrical network analyzer, meaning the radio frequency (RF) and microwave test instrument, not software "network analyzers" such as packet and protocol tools that monitor IT traffic. They share a name, but not a function. As the OEM behind the instruments, the Official Keysight Used Equipment Store can help you match a certified-used analyzer to your measurements and budget. The featured certified-used pick, in good supply now, is the Keysight E5071C ENA vector network analyzer, with the current ENA E5080B and the microwave-class PNA family also available.
TL;DR
- A network analyzer measures a device's response to a known stimulus: it drives the device under test (DUT) with its own source and reports S-parameters, gain, insertion loss, return loss, and impedance as magnitude and phase.
- The modern default is a vector network analyzer (VNA). Scalar analyzers are legacy instruments that measure magnitude only; if you need phase (and impedance matching, de-embedding, and group delay all need phase), you need a VNA.
- Seven key specifications shape most of the buying decision: frequency range, dynamic range, measurement speed, trace noise, number of ports, form factor, and test port power.
- Match frequency range to your DUT's operating band and the harmonic frequencies you need to see, with headroom for the next project.
- In good supply now, certified used: the workhorse E5071C (9 kHz to 20 GHz), the current E5080B ENA, the PNA N5225B for microwave work, and the handheld FieldFox N9952B for the field.
- Certified used from Keysight can cost 40 to 90% less than new list price, with up to 5 years warranty options, OEM calibration, and KeysightCare support.
What Is a Network Analyzer?
A network analyzer characterizes the electrical properties of devices and circuits: how much of an RF signal passes through, how much reflects back, and how the phase shifts along the way. It is a standard test instrument for characterizing RF and microwave components before they go into a system. The most common type is the vector network analyzer, which measures both the amplitude and phase response of a device under test. Keysight's application note Understanding the Fundamental Principles of Vector Network Analysis describes vector network analysis as a way to characterize components by measuring their effect on the amplitude and phase of swept-frequency test signals.
The results appear as traces of magnitude and phase plotted against frequency, so you can see where a filter's passband sits, where an antenna is matched, or where a cable assembly starts to fail. You can change the stimulus conditions, including frequency span, source power, and sweep type, to study the device's behavior across its operating envelope. For the underlying definitions, see the glossary entries on the vector network analyzer and what a network analyzer is.
A network analyzer reports S-parameters (scattering parameters): S11 and S22 describe reflection at each port, S21 and S12 describe transmission through the device. The framework goes back to Kurokawa's 1965 IEEE paper, Power Waves and the Scattering Matrix, and it still underpins every S-parameter measurement a modern VNA reports.
How Is a Network Analyzer Different from a Spectrum Analyzer?
The two instruments get confused because they share connectors and frequency coverage, but they answer different questions.
A network analyzer measures how a device changes a signal the instrument itself supplies. It has a built-in source and receivers, so it can compare what went in with what came out and report amplitude and phase at its ports. Vector error correction helps clean up systematic errors.
A spectrum analyzer measures the power of an external signal across frequency. It is a receiver with no stimulus of its own, which makes it the right tool for finding interference, checking harmonics, and measuring the spectral content of an RF signal from a transmitter. It is not the right tool for characterizing a component. A spectrum analyzer fitted with a tracking generator can make scalar transmission measurements, but it still measures magnitude only, with no phase.
Use a network analyzer to characterize or match a device. Use a spectrum analyzer to measure a signal. Some jobs need both, which is why handheld combination analyzers such as FieldFox exist. The full comparison, including when each instrument can stand in for the other, is in our guide to the network analyzer versus the spectrum analyzer.
What Do You Use a Network Analyzer For?
Network analyzers characterize, match, and debug RF components and microwave assemblies. Common jobs include:
- Filter characterization. Passband insertion loss, stopband rejection, and ripple, read from S21. A network analyzer shows a filter's frequency response and whether it meets its rejection spec.
- Antenna work. Reflection measurements from S11 give return loss and voltage standing wave ratio (VSWR), which tell you how well an antenna is matched. A two-antenna S21 setup measures gain. Our guide on how to measure antenna gain using a network analyzer walks through the method.
- Cable and connector test. Insertion loss, return loss, and time-domain distance-to-fault along a cable assembly, on the bench or in the field.
- Amplifier characterization. Gain, gain flatness, input and output match, and compression behavior of amplifiers and other active components.
- Impedance measurement and matching. Complex impedance on a Smith chart, which is what you need to design a matching network. Impedance matching depends on phase, which is why this is vector-analyzer territory.
One boundary worth stating: sound-and-vibration measurement is not a network analyzer job. Low-frequency acoustic and vibration analysis belongs with dynamic signal analyzers, a different instrument class. If a page or catalog blurs that line, it is describing a different tool.
What Are the Types of Network Analyzers?
Three type names appear in catalogs, but the modern buying decision has one default:
- Vector network analyzers (VNAs) measure magnitude and phase and support vector error correction. Current Keysight network analyzer families, including ENA, PNA, PNA-X, Streamline USB, and FieldFox handheld models with VNA mode, are vector instruments. For RF network characterization today, a VNA is the instrument to buy.
- Scalar network analyzers (SNAs) measure magnitude only: return loss, VSWR, and gain, with no phase. They were the affordable option before VNA prices came down. Today they are a legacy category.
- Large-signal network analyzers (LSNAs) are specialist instruments for characterizing nonlinear behavior, such as amplifiers driven into compression. Nonlinear characterization needs are now commonly covered by a PNA-X-class VNA with the appropriate software options rather than a separate LSNA.
| Type | Measures | Error correction | Status today |
|---|---|---|---|
| Vector network analyzer (VNA) | Magnitude and phase (full S-parameters) | Vector error correction (12-term model) | The current default for component test |
| Scalar network analyzer (SNA) | Magnitude only (return loss, VSWR, gain) | Normalization only | Legacy; superseded by VNAs |
| Large-signal network analyzer (LSNA) | Nonlinear (large-signal) behavior | Specialized calibration | Specialist; largely covered by PNA-X-class VNAs with nonlinear options |
The practical rule is simple: if you need to measure phase, you need a vector instrument. Impedance matching, de-embedding, and group delay all need phase. The rest of this guide assumes you are buying a VNA.
What Specifications Should You Look For in a Network Analyzer?
Once you know the measurements you need, seven VNA specifications help separate the models. Work through them in order.
- Frequency Range
- Dynamic Range
- Measurement Speed
- Trace Noise
- Number of Test Ports
- Size and Form Factor
- Test Port Power
Frequency Range
Frequency range is the first specification to settle, and usually the biggest cost driver. Every step to higher frequency adds hardware. Match the analyzer's range to your DUT's operating frequency and the harmonics you need to measure, with headroom for the next project. A 2.4 GHz Wi-Fi front end can be characterized on an 8.5 GHz analyzer with room for the third harmonic. A 28 GHz beamforming module cannot.
Three practical bands cover most buying decisions:
- Basic RF testing up to 8.5 or 9 GHz: general component test for sub-6 GHz wireless, Internet of Things (IoT) devices, and cable assemblies. Entry ENA configurations cover this.
- RF and microwave to 18 or 20 GHz: radar bands, satellite links, and other high-frequency component tests. This is the E5063A and E5071C class.
- Advanced RF and millimeter-wave above 20 GHz: 5G FR2, automotive radar, and aerospace programs. This is PNA and PNA-X territory, with banded millimeter-wave extensions beyond that.
Buying more range than your test plan needs is a common way to overspend. Buying too little is a common reason an analyzer gets replaced early. State your highest harmonic of interest, then add margin.
Dynamic Range
VNA dynamic range is the span between the largest signal the receiver can measure accurately and its noise floor, stated in decibels. Keysight's application note Network Analyzer Dynamic Range defines it as bounded by the maximum receiver input before compression errors at the top and the receiver noise floor at the bottom.
Dynamic range matters most for high-rejection measurements. To measure a filter's 100 dB stopband rejection with confidence, the analyzer needs more than 100 dB of dynamic range at the chosen settings. Many benchtop VNAs offer roughly 120 dB or more; the current ENA E5080B specifies up to 140 dB.
Two settings commonly trade dynamic range against speed: reducing the IF bandwidth and enabling averaging both lower the noise floor, and both make the sweep slower. Cutting the IF bandwidth to a quarter improves the noise floor by about 6 dB, at roughly four times the sweep time. That trade-off is normal operation, not a defect, and it is why quoted dynamic-range figures always carry an IF bandwidth condition.
Measurement Speed
Measurement speed is the time the analyzer needs to complete a sweep at a given number of points and IF bandwidth. On an R&D bench, the difference between a 10-millisecond and a 100-millisecond sweep may not matter; in manufacturing and production environments running thousands of units, sweep time adds up to real test time and cost.
Speed is related to accuracy. Narrow IF bandwidth and heavy averaging lower the noise floor but lengthen every sweep, so a production line may run wider IF bandwidth at a dynamic range it can still tolerate. When you compare models, compare sweep times at the same number of points and the same IF bandwidth. Also check the analyzer's data-transfer speed if automated test systems will read traces over the network or bus: a fast sweep loses its value when the automation waits on data transfer.
Trace Noise
VNA trace noise is the small, random variation the analyzer itself adds to a measured trace, typically specified in thousandths of a decibel (0.001 dB). It sets a floor on how small a ripple you can reliably resolve: measuring a filter's 0.1 dB passband ripple through 0.05 dB of trace noise leaves little margin.
Trace noise improves with narrower IF bandwidth and averaging, at the usual cost in sweep time. Good cable discipline also helps the whole measurement: use phase-stable test cables and torque connectors properly, and keep the setup away from strong interference sources. A vector analyzer's ratioed measurements also make it less sensitive to source power drift than a scalar setup.
Number of Test Ports
The number of ports determines which devices you can characterize in one connection. A 2-port VNA measures the four S-parameters of a two-port device, such as a filter, cable, or amplifier, and handles one-port devices such as antennas. A 4-port instrument characterizes differential pairs, couplers, and duplexers without re-cabling. Multiport test sets extend a bench analyzer further by routing high-count devices through internal switch paths (the E5071C, for example, supports multiport expansion to 22 ports with the E5092A test set).
More ports cost more, so buy the port count your DUTs need rather than the maximum. Two related checks matter on any analyzer, new or used:
- Connector type and grade. Precision coaxial connectors are standardized by IEEE Std 287.1-2021, and the front-panel connector must match your frequency range and cable ecosystem, including the connector gender on your test cables.
- Connector condition. Connector damage is a common and costly repair on RF instruments. On a certified-used unit from the OEM, port connectors are part of the inspection. On a unit of unknown provenance, connector condition may be uncertain. Always use a torque wrench.
Size and Form Factor
Network analyzers come in three practical forms, and the right one follows from where the measurement happens:
- Benchtop (ENA, PNA, PNA-X): the high-performance choice for lab benches and production applications.
- USB and modular (Streamline P-Series): a compact, PC-driven analyzer, useful where rack space is tight or the analyzer travels between stations. The Streamline P5008A provides 100 kHz to 53 GHz coverage in a compact PC-driven module.
- Handheld (FieldFox): battery-powered combination analyzers with a full 2-port VNA mode plus spectrum analysis and cable-and-antenna test, built for tower, field, installation and maintenance, and site compliance testing.
A smaller instrument is easier to deploy and share. A benchtop test instrument generally offers a higher performance ceiling. Choose by measurement location first, performance second.
Test Port Power
Test port power is the output signal level the analyzer drives into your device, set in dBm. Two numbers on the datasheet matter:
- Source power range. Enough output power to overcome fixture and cable losses in lossy setups, plus low-power capability for measuring active devices near their small-signal region without compressing them. Power sweeps used to characterize an amplifier's compression point need a calibrated source range.
- Maximum input (damage) level. Every receiver port has a maximum input level, stated in dBm on the datasheet, above which you risk damaging the front end. If you test amplifiers, plan attenuation so the amplified signal stays below that limit.
This is different from the instrument's mains power draw, and it is separate from the impedance of your DUT: a VNA's ports present a 50-ohm reference impedance, and vector error correction handles the mismatch mathematics from there.
What About Calibration?
A VNA measurement is only as trustworthy as the calibration behind it, so calibration belongs on the spec sheet even though it is not a hardware number. A VNA's accuracy and precision depend on vector error correction: the analyzer measures known calibration standards, such as short, open, load, thru, or an electronic calibration module, and mathematically removes systematic errors from the test setup. Keysight Application Note 1287-3, Applying Error Correction to Network Analyzer Measurements, covers how a full 2-port calibration corrects twelve systematic error terms. Datasheet numbers state VNA performance at specific settings. Calibration is what delivers that performance at your reference plane.
For a buying decision, that means three checks: which calibration methods the analyzer supports, whether a calibration kit or ECal module is included, and whether the instrument carries a current, traceable factory calibration. NIST defines metrological traceability as a measurement result linked to national standards through a documented, unbroken chain of calibrations. That chain, not the instrument's age, is what makes a measurement defensible.
Which Keysight Network Analyzer Should You Buy?
Match the instrument to the job, frequency range, and RF characteristics you need to measure. The table below maps common needs to current Keysight models, with frequency ranges from their official product pages.
| Job | Keysight model | Family | Frequency range | Ports |
|---|---|---|---|---|
| Workhorse S-parameters, certified used | E5071C | ENA | 9 kHz to 20 GHz | 2 or 4 |
| Value passive-device test | E5063A | ENA | 100 kHz to 18 GHz | 2 |
| Current benchtop ENA, up to 140 dB dynamic range | E5080B | ENA | Specialist; largely covered by PNA-X-class VNAs with nonlinear options | 2 or 4 |
| Microwave, high performance | N5225B | PNA | Options from 9 kHz up to 53 GHz maximum | 2 or 4 |
| Active-device and nonlinear characterization | N5247B | PNA-X | 900 Hz to 50 GHz | 2 or 4 |
| Compact USB, PC-driven | P5008A | Streamline | 900 Hz to 67 GHz | 2 |
| Field, handheld, VNA plus spectrum | N9952B | FieldFox | 100 kHz to 53 GHz | 2-port VNA mode |
| Field, handheld, mid-band | N9917B | FieldFox | 300 kHz to 50 GHz | 2-port VNA mode |
Buy a Network Analyzer Trusted by 70% of Engineers Worldwide
Purchasing a network analyzer is an investment. Like any investment, you want to ensure you are getting your money's worth and a product that fits the task. With so many different analyzers on the market, making that decision can be difficult.
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(* Two weeks shipping time offer available for US customers only. Dependent on item availability and location.)
Closing Thoughts From Keysight
In this buying guide, we have covered the key features and uses of network analyzers. A better understanding of this information is the key to purchasing an excellent network analyzer.
Ask yourself, what are the tasks I need this analyzer to perform? What analyzer functions will most effectively and efficiently help me achieve these? The answers to these questions will help you find the perfect network analyzer.
Keysight is a leading manufacturer of the best quality network analyzers, offering a wide range of models to meet your specific needs.
See Keysights Used Equipment for the widest selection of discounted, high-quality, and premium refurbished network analyzers.
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