Analyzers Network
6 subcategories
Network analyzers are essential test instruments used to characterize high-frequency electrical networks and components. By injecting a known stimulus signal and measuring the transmitted and reflected responses, these instruments evaluate the performance of RF and microwave devices such as filters, amplifiers, and cables. This guide is designed for RF design engineers, system integrators, and technical buyers seeking to select the right analyzer for their specific measurement tasks. It explains the operational distinction between vector and scalar systems, reviews key architectural specifications such as port counts and frequency ranges, and highlights critical evaluation parameters like dynamic range and trace noise. Understanding these metrics helps ensure the selection of an instrument with the proper speed and accuracy for both laboratory research and high-volume production testing.
- Dynamic Range Max
- 135 dB (Keysight E5080A)
- Frequency Span Min
- 5 Hz (Keysight E5061B)
- Frequency Span Max
- 110 GHz (Anritsu 560 system)
- VNA Port Configuration
- 2 or 4 ports
Subcategories
Vector vs. Scalar Architecture
Network analyzers are divided into two primary types based on what they measure: vector network analyzers (VNAs) and scalar network analyzers (SNAs).
VNAs, such as the Keysight E5071C or the Rohde & Schwarz ZVA24, measure both the amplitude and phase of the transmitted and reflected signals. This allows them to output complete complex S-parameters (such as S11, S21, S12, and S22) and display formats like the Smith chart, group delay, and polar plots.
Conversely, scalar network analyzers like the Anritsu 560 mainframe measure amplitude only. When configured with compatible external bridges and detectors, scalar analyzers are used to evaluate insertion loss, gain, return loss, and SWR across wide bands (spanning up to 110 GHz in waveguide configurations). The Keysight 8757D is another high-performance scalar analyzer capable of AC and DC detection modes.
Additionally, combination instruments exist. The Keysight 4395A and Keysight 4396B integrate vector network, spectrum, and optional impedance measurements into a single chassis.
Defining Specifications and Performance Limits
Selecting an analyzer requires matching several fundamental electrical performance parameters to the test requirements:
- Frequency Range: Systems cover low frequencies up to microwave bands. For instance, the Keysight E5061B can cover a range from 5 Hz to 3 GHz (with Option 3L5), while higher-end microwave instruments like the Keysight E8364C or Keysight N5245B extend measurements up to 50 GHz.
- Dynamic Range: This specification determines the system's ability to resolve very weak signals or deep rejection bands. The next-generation Keysight E5080A (designed as the successor to the Keysight E5071C) delivers a system dynamic range of up to 135 dB, and the Keysight N5232A provides up to 133 dB.
- Trace Noise and Speed: Lower trace noise increases measurement precision. For example, the Keysight E5071C features trace noise of 0.004 dB rms, while the older Keysight E5071B reaches 0.001 dB rms. Measurement speed, such as the 9.6 µs per point rate of the Keysight E5071B or less than 26 µs per point on the Keysight E8364C, is crucial for high-throughput production lines.
Port Configuration and Test Integration
Instruments vary in the number of integrated test ports and source configurations. While a basic Transmission/Reflection (T/R) architecture like the Keysight 8714ET or Keysight E5061A provides simplified S11 and S21 routing, full S-parameter test sets support complete forward and reverse measurements.
Two-port systems are standard for basic components, but multiport analyzers like the 4-port configurations of the Keysight N5222A or Keysight N5224A allow the characterization of multi-port devices without manual cable changes.
Furthermore, high-end analyzers like the PNA-X series (including the Keysight N5242A and Keysight N5244A) can feature multiple built-in sources. The Rohde & Schwarz ZVA24 employs a unique architecture with one measurement receiver and one reference receiver per port to enable true differential measurements. For field applications, portable units like the Keysight N9923A FieldFox provide rugged, battery-powered operation with full S-parameter capabilities in a compact form factor.
Frequently asked questions
- What is the purpose of an electronic calibration (ECal) module like the Keysight N4694A?
- Electronic calibration modules replace mechanical calibration standards (such as shorts, opens, loads, and thrus) with a single, automated USB-controlled device. The **Keysight N4694A** operates from 10 MHz to 67 GHz, providing rapid, highly repeatable calibrations that minimize human error during the setup process.
- What is the difference between Transmission/Reflection (T/R) and full S-parameter test sets?
- A T/R test set, such as the standard configuration on the **Keysight E5061A** or **Keysight 8714ET**, only measures the forward path (S11 and S21). It requires physically reversing the device under test to measure reverse parameters (S22 and S12). A full S-parameter test set, featured on models like the **Keysight E5071C**, automates this routing with internal solid-state switches, allowing complete two-port or four-port measurements in a single setup.
- How does a combination analyzer differ from a standalone vector network analyzer?
- Combination analyzers like the **Keysight 4395A** and **Keysight 4396B** house separate measurement modes (network, spectrum, and impedance analysis) in one instrument. While they offer extreme versatility, standalone VNAs like the **Keysight N5230C** focus exclusively on high-performance network analysis, typically offering higher frequency limits (up to 50 GHz) and options like time-domain analysis or frequency-offset modes for mixer testing.