A Scalar Network Analyzer is an RF network analyzer used to measure amplitude properties like VSWR and Return loss of Device Under Test.
If the output of the tracking generator is connected to the input port of the spectrum analyzer and place a device (DUT) between the output of the tracking generator and the spectrum analyzer. The amplitude parameters of the signal at the spectrum analyzer will be the function of the device under test (DUT).
The network analyzers are basically classified into three types.
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To understand the Scalar Network Analyzer in a better way, we recommend understanding the following components, which are used along with the SNA for testing applications.
In this RF and Microwave Scalar Network Analyzer article, we will cover,
Scalar Network Analyzer is a type of RF and microwave network analyzer used to measure the amplitude of the DUT connected to it. Below are the prime measurements using an SNA as these measurement capabilities are part of any standard Scalar Network Analyzer.
In general, scalar network analyzers are very useful in measuring the amplitude parameter response of a variety of RF and Microwave components.
Scalar Network Analyzer and the Vector Network analyzer are two main types of network analyzers. Below is the list of prime differences between the scalar and vector network analyzers.
Scalar analyzers have been used for the basic network analyzer measurements on many types of RF and microwave components. Below listed are some of the common devices measured using scalar analyzers.
Scalar network analyzers have been used for basic parameters like return loss and/or VSWR, gain, gain flatness, gain compression, reverse isolation, and absolute power measurements on RF amplifiers.
Scalar network analyzers are commonly used to measure the conversion loss of an RF mixer, and also used for the measurement of mixer input match. Using a Scalar network analyzer, the test engineers can measure the conversion loss, return loss, absolute output power, and isolation as well as nonlinear magnitude measurements like gain compression, etc.
Scalar network analysis is used for all the basic measurements like insertion loss, return loss, and isolation of frequency-selective devices like RF and Microwave filters. In general vector network analyzer provides the most accurate and complete characterization for the frequency-selective devices.
Scalar network analyzers are used very commonly for the measurements of scalar values of transmission and reflection of the mm-wave devices in waveguide bands, by using waveguide source modules, waveguide couplers, and detectors. The advantage of scalar network analyzers is their lower cost compared to VNA in the mm-wave bands.
In general Scalar network analysis can use for the basic magnitude test requirements like insertion loss, return loss, and isolation for the Research and development (R&D) activities.
For the Manufacturing sector Test requirements, Scalar network analyzers have been ideal for the basic test due to their low capital cost, fast sweeps capability, and real-time tuning. In addition Scalar network analyzers is able to simultaneously display both the transmission and reflection response.
Most of the Scalar vector analyzers have the ability to remote their RF power detectors from the analyzer unit, it help for the remote detection and measurement of the devices located far (difficult to access) from the analyzer.
The basic architecture of a scalar network analyzer includes a signal generator, a test set, receiver, processor, and display. In 2 port SNAs have two test ports, for the measurement of amplitude parameters of the DUT.
The built-in signal generator will generate the test signal to the DUT for the measurements. High-performance scalar network analyzers will have two sources for providing the test signals to multiple ports of the DUT.
The test set of an SNA is used to route the generated signal to the different ports of the DUT and then to the receivers for further measurements and process.
The receivers in the SNA have a detector and make the amplitude measurements of the received signals from the ports. The received RF signal first will down converts using a down converter for further measurements, as it is easy to have amplitude measurements at a lower frequency.
An inbuilt processor will execute the mathematical calculations and measurements of the reflection and transmission signal and make the information available in the display in an easily understandable way as possible.
In the display of the scalar network analyzer, the processed RF signal from the receiver is displayed in a format like log formats, polar plots, Smith charts, which can be easily interpreted to the uses.
A scalar network analyzer requires periodic calibration either by any certified calibration laboratory or by the manufacturer.
The calibration process usually involves measuring the instrument against the know standards for systematic errors identification and compensation.
Mainly there are three types of calibration are followed for the scalar network analyzer SOLT (Short, Open, Load, Through) and TRL (through-reflect-line calibration). In addition, Electrical Calibration ( E-Cal) is used for quick user celebrations.
SOLT calibration is done by the known standards of Short, Open circuit, load (usually a precision 50 ohms), and a through connection. SOLT calibration is suitable for coaxial measurements in scalar network analyzers.
An electrical calibrater or E-Cal is an electronic calibration module that comes with the network analyzers to generate the required open, short, load, and through values electrically for quick calibration.
TRL of scalar network analyzer uses a transmission line of known length and impedance of know value as one standard and a high-reflection standard for the calibration. TRL calibration is ideal for noncoaxial microwave test setups such as fixtures, waveguides, or wafer probing, etc.
Scalar network analyzers are of mainly four types based on the form package it offers, like Benchtop SNA, portable SNA, handheld SNA, and USB-based SNA.
Benchtop scalar network analyzers are AC power-operated bulky instruments, for the regular lab environment test and measurement applications. Now PXI based scalar network analyzers (FPGA card-based), are available with a wide range of measurement capabilities.
Portable Scalar Network analyzer has an internal AC rechargeable battery for the field test application.
Handheld Scalar network analyzers are light-weighted and small size units with battery operation capability. These units may have only a limited accuracy and measurement capability.
USB Scalar Network Analyzer is a low-cost measurement solution that uses separate computers for the measurements, processing, control, and display purposes using the software associated with SNA. USB SNA will connect to a computer over the USB port for the test and measurement applications.
For the selection of a Scalar Network Analyzer, below are some of the key parameters test engineers need to consider for the optimization of the system cost and test features.
The frequency range defines the start and stops frequencies range of the scalar network analyzer. When selecting an SNA for the RF test application RF test engineers need to select a unit that covers the harmonics frequency range of the DUT.
A scalar network analyzer is available with different options for the number of ports like two, four, or more test ports. As cost will increase with the number of ports, the selection is dependent upon the number of RF ports in the DUT.
The dynamic range of a scalar network analyzer defines the range of power levels over which the network analyzer will support and perform the amplitude parameter measurements.
The measurement speed of the SNA indicates the time required to perform a sweep over the entire range of frequencies. In general, a scalar network analyzer is faster than a vector network analyzer. Test engineers need to check for the user calibration time, as regular user calibration will improve the measurement accuracy.
Nowadays scalar network analyzers need to communicate with the other instruments as part of the automation setup and the data transfer. In general, SNA is available with interfaces like ethernet, RS232, GPIB for easy interface.
The display of the scalar network analyzer is another factor that needs to consider as easy readability of the measured readings will help the test engineers to proceed with the test fastly.
Scalar network analyzers are one of the prime test and measurement instruments required in the RF and microwave industry for the measurement of amplitude parameters. Scalar network analyzers are available with various test features that can be offered by other test and measurement instruments like spectrum analyzers, power meters, etc.
Below are the top scalar network analyzers manufacturers. If you would like to add any specific scalar network analyzer manufacturer details, articles, etc please feel free to contact me through the contact or article submission page.
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