Network Analyzers Target Production Testing

July 8, 2015
Network analyzers are reaching new performance levels, enabling greater throughput for high-volume manufacturing. Options are also available to equip network analyzers with increased test capability.
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High-volume manufacturing requirements are driving the latest generation of  vector network analyzers (VNAs).  Mobile devices, network equipment, and data centers are being designed for commercial trends such as higher-speed mobile data. These devices need to be produced in very high volumes at low costs. Therefore, production throughput is an extremely important parameter for these applications. Recognizing today’s production requirements, VNA suppliers are making an effort to deliver  RF/microwave VNAs capable of increased throughput in high-volume manufacturing environments.

1. The MS46522B and MS46524B VNAs feature multiple simultaneous test-signal sources to speed swept measurements to 8.5 GHz. (Photo courtesy of Anritsu)

Anritsu’s new Performance ShockLine MS46500B Series of VNAs lowers the cost of test and speeds time to market in numerous testing applications to 8.5 GHz. These applications include mobile network equipment design and manufacturing, mobile devices, automotive cables, high-speed data interconnects, and system integration components.

The MS46500B Series is made up of the two-port MS46522B and the four-port MS46524B models, expanding the ShockLine family to a broader range of test applications (Fig. 1). This series utilizes a modern architecture: the MS46522B has two independent sources and four receivers, while the MS46524B has four independent sources and eight receivers. All sources can sweep at the same time, allowing  the measurement of forward and reverse S-parameters in a single sweep.

Due to this unique simultaneous sweeping feature, the MS46522B is capable of making a full two-port measurement in half the time it would take to make the same measurement with a traditional single-source sweep, while the MS46524B can make a full four-port measurement in one-quarter the time of a conventional VNA. With shorter test times, the MS46500B Series significantly improves throughput in manufacturing environments.

Improvements in Dynamic Range and Measurement Speed

Filters used in base transceiver stations (BTSs) in today’s high-speed mobile networks have extremely steep skirts, rejecting out-of-band signals by as much as 110 dB. To accurately measure these components, a VNA with a wide dynamic range is needed. When using previous-generation VNAs, test times can be quite long when measuring devices with a wide dynamic range.Recognizing the need for VNAs to provide wide dynamic range at faster measurement speeds, suppliers have released VNAs with improved performance intended for these applications.

Keysight’s new E5080A VNA provides improved performance compared to previous-generation models (Fig. 2). In comparison with the previous-generation E5071C VNA, the E5080A has 10 dB more dynamic range, with  increased measurement accuracy. In addition, the likelihood of errors during manual filter tuning is reduced by the improved VNA performance. When comparing measurement speeds at the same dynamic range, the E5080A is about 10 times faster than the E5071C, enabling greater throughput to be achieved during production testing. The E5080A is available with frequency ranges of 9 kHz to 4.5 GHz, 9 kHz to 6.5 GHz, and 9 kHz to 9 GHz.

2. The model E5080A VNA offers a wide dynamic range and high accuracy in combination with fast measurement speed, to increase production testing throughput. (Photo courtesy of Keysight Technologies)

Copper Mountain Technologies recently released its Cobalt Series of VNAs, featuring models C1209 and C1220 (Fig. 3). The C1209 model is capable of analyzing a frequency range from 100 kHz to 9 GHz, while the C1220 model has a frequency range from 100 kHz to 20 GHz. This new series achieves fast measurement speeds by incorporating a hybrid dual-core DSP/FPGA signal processing engine along with new frequency synthesizer technologies.

Dynamic range of more than 145 dB at a 1-Hz intermediate-frequency-bandwidth (IFBW) is achieved, allowing the Cobalt VNAs to maintain a wide measurement range at fast measurement speeds. This combination of wide dynamic range and fast measurement speed makes the Cobalt Series VNAs ideal for testing and tuning high-performance filters. When using 801 measurement points along with a 30-kHz IFBW, a complete S-parameter measurement of a BTS filter requires  only 0.08 seconds, while maintaining more than 100 dB of measurement dynamic range.

In an effort to achieve high throughput at an attractive price, Rohde & Schwarz recently introduced a new VNA to its product line. The ZND model, which is a two-port VNA, enables users to easily measure S-parameters of components such as filters, connectors, and antennas. This VNA is intended for production environments, providing the required functionality at a low cost. The ZND offers a specified dynamic range to 120 dB, making it ideal to measure high-performance passive components.

The ZND base model provides unidirectional measurements, with the option to upgrade to bidirectional measurement capability. The base model operates from 100 kHz to 4.5 GHz. The option to extend the frequency range to 8.5 GHz is also available.

The previously mentioned MS46500B Series from Anritsu also offers excellent dynamic range, low trace noise, and a fast sweep speed. This series addresses the S-parameter requirements of a complete range of passive components, including BTS filters, duplexers, and antennas.

Four-Port VNA

Anritsu also recently introduced its module-based VectorStar ME7838A4 four-port broadband VNA, which features differential broadband sweep from 70 kHz to 110/125 GHz. This VNA is capable of performing extremely stable and fast measurements when characterizing differential devices, providing new performance levels to on-wafer and signal-integrity engineers when conducting differential measurements.

Utilizing an exclusive Anritsu design that incorporates nonlinear-transmission-line technology (NLTL), the compact modules lend themselves to easy mounting on wafer probe station platens where space is limited. Modules are available that can extend the ME7838A4 to a four-port 145 GHz system.

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PC-Based VNAs

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VNAs controlled by an external PC transfer all processing functions from the VNA’s measurement module to an external PC, separating the measurement module from the processing module. The measurement results are brought to the external PC using software. These PC-driven VNAs offer several distinct advantages compared to VNAs with integral computers, making them ideal for many RF and microwave applications. By providing their own external PC, users can take advantage of the latest processors, better display capabilities, and the more reliable performance of an external PC, while simplifying maintenance of the VNA.

3. The Cobalt series of VNAs rely on advanced signal processing to achieve wide dynamic range as fast measurement speeds to 20 GHz. (Photo courtesy of Copper Mountain Technologies)

In addition, the external PC can be replaced or upgraded at the user’s discretion. Conventional VNAs, in contrast, already have a built-in computer, which can quickly become outdated. Thus, PC-driven VNAs offer greater flexibility by allowing users to have control of the processing module by supplying their own PC.

PC-driven VNAs also cost less than half the price of a conventional VNA, while still delivering equal or better performance. In addition, there are far fewer potential points of failure. The typical point of failure on a conventional VNA is the built-in processing module and its peripheral devices, such as the display, control knobs, and buttons. This problem is completely eliminated when using an external PC, which can be easily and inexpensively replaced by users according to their needs.

Another advantage of a PC-driven VNA is external data storage. Since data is stored on the external PC rather than inside the VNA itself, the analyzer can easily be moved to different locations. A PC-driven VNA is also well suited for classified applications because test data is processed and stored on an external PC, which means there is no need for hard-drive purging in order to move the PC-driven VNA from a secure area. Maintenance time is reduced, and security improvements in classified or controlled installations are achieved.

Copper Mountain Technologies’ PC-driven VNAs enable engineers to downsize their equipment, while capitalizing on the performance of PCs. A wide range of VNAs is offered, with varying features for different applications. These VNAs have the same performance as traditional VNAs, while offering flexibility as they can be easily adapted to multiple users. This series is well suited for lab, production, field, and secure testing environments.

Anritsu’s ShockLine VNA family also consists of the MS46121A and MS46122A USB Series. These series of VNAs eliminate the need to buy expensive instruments for simple S-parameter measurements. Multiple architectures are employed that reduce manufacturing costs, enhance calibration stability, and minimize measurement uncertainty. The one-port MS46121A is a series of two VNAs packaged in a compact housing, while the two-port MS46122A is a series of three VNAs packaged in a compact 1U chassis.

An external PC controls these VNAs via USB connection, which runs the same graphical user interface (GUI) software as the rest of the ShockLine family of VNAs. The combination of small size and good performance makes the MS46121A and MS46122A VNAs ideal for passive device test applications where performance and small form factor are desired.

PXI Form Factor

VNAs can be delivered in the modular PXI form factor, reducing the size of test setups by delivering VNA functionality to the flexible PXI platform. PXI VNAs are capable of performing fast, accurate measurements, while reducing the cost of test.

The Keysight M937XA PXI VNA Series is a full two-port VNA that fits into just one slot. This VNA is ideal for those who simply wish to make basic S-parameter measurements. Each module is a completely independent two-port network analyzer, and as many as 16 modules can be added to a chassis, enabling multiport measurements as well as simultaneous measurements of different devices.

New Enhancements

Suppliers are expanding the measurement capabilities offered by VNAs by introducing new options to their existing VNA products. These options serve as enhancements, enabling measurements to be performed beyond the VNA’s traditional test capabilities.

Keysight recently announced a new capability, which adds high-performance spectrum analysis to its PNA and PNA-X Series VNAs. This option adds a fast spurious-signal search capability to these VNA series, replacing a standalone spectrum or signal analyzer. By replacing a standalone spectrum or signal analyzer, the size of test systems can be reduced.

This spectrum analyzer option is implemented through firmware, which means no additional RF hardware is required to add spectrum analysis capability to the VNA. The incorporation of this functionality into a VNA simplifies system connections and saves time, improving test throughput by a factor ranging to 500 in comparison with existing approaches.

Measurement results are comparable to those obtained with today’s most sophisticated standalone spectrum or signal analyzers. This option also enables the VNA to perform simultaneous spectrum measurements on all test ports, providing unparalleledinsight into the performance of a device with just a single set of connections.

Anritsu recently introduced intermodulation distortion (IMD) measurement options for its VectorStar platform, which expand the measurement capability to meet the need to conduct highly accurate and efficient IMD measurements. These options consist of a dual source, an internal RF combiner/switch, and the IMDView software. The dual source and the internal RF combiner/switch enable the VNA to automatically switch from an S-parameter measurement to an IMD measurement, providing the capability to perform both S-parameter measurements and IMD measurements in one connection.

The IMDView software option provides graphical interface and guidance for configuring IMD measurements, simplifying the setup of traces for IMD parameters. IMDView also offers the unique capability to modify tone parameters while viewing the results in real-time, enabling engineers to quickly determine optimum performance capabilities.

User Interface Advancements

Suppliers are increasing efforts to provide more intuitive user interfaces. Touchscreen features, such as touch-driven trace displays and windows as well asdrag-and-drop functionality, provide a simplified user experience.

Keysight designed the E8050A’s intuitive and flexible user interface to streamline flow. A variety of dialog menus assists users to easily setup measurements, while essential features can be directly accessed through the toolbar. The layout of traces and windows can be flexibly allocated with intuitive drag-and-drop operations, enabling users to overlay traces with different channel settings on the same window.

Rohde & Schwarz’s ZND user interface is based on the interface of the ZNC and ZNB models. Designed to make VNA measurements easy to perform for users of all levels, the interface enables users to access all functions of the VNA in a maximum of three operating steps. In addition, the large touchscreen is fully integrated with the VNA’s software. Drag-and-drop operation is incorporated, which allows users to quickly configure the VNA. Traces and channels can be arranged in any desired combination, enabling results to be displayed in a clear and straightforward manner.

Anritsu’s ShockLine software provides a powerful GUI for test and engineering use. When attached to a touchscreen monitor supplied by the user, the GUI provides a full set of comprehensive capabilities. These capabilities include network extraction, embedding/de-embedding networks, and time-domain with time-gating. The GUI is a common feature among the entire ShockLine family of VNAs.

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