Technical Library

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Guide to VNA Automation in MATLAB Using the TCP Interface

August 3, 2018

Usually, Copper Mountain Technologies instruments are locally automated on the same Windows-based PC to which the instrument is connected and the VNA control software is installed. Such functionality is readily achieved on a Windows-based PC by using the Component Object Model (COM), or ActiveX interface for automation. All that is required for automation of the instrument is the applicable VNA control software and its respective Programming Manual. The last page of the VNA control software installation wizard presents the option to register a COM interface server. If this box is checked and a confirmation dialogue pops up to confirm the registration, users are ready to begin programming.

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Automation Interfaces of Copper Mountain Technologies’ Network Analyzers

August 3, 2018

Copper Mountain Technologies’ VNAs can be readily automated and there are numerous options for users who wish to do so. To help illustrate the different automation methods and interfaces available, consider the components in an automated VNA measurement system. There is hardware: the VNA itself and a computer. There is software, as well: the VNA control software loaded onto the computer. While non-automated use of these components consists of each of these components in this basic configuration, automation options alter this configuration.

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Copper Mountain Technologies’ Planar 808/1 Vector Network Analyzer Field-Tested at the Hamburg University of Applied Science

July 9, 2018

The Hamburg University of Applied Sciences is one of the larger technical universities in Germany. Over 1000 students study in the field of Electrical and Information Technology. In the Laboratory for Communication Technology, under the guidance of Prof. Ralf Wendel, training in the field of RF and Microwave Technology takes place. Students from the Electrical and Information Technology bachelor’s curriculum as well as the master’s program, Information and Communication Technology, participate in application of learned principles.

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Voltage and Current Measurements with a VNA and DMM

April 20, 2018

Vector Network Analyzers (VNAs) are used to measure the reflection and transmission coefficients, or S-parameters, of a Device Under Test (DUT). When the DUT is passive, the VNA may be the only tool necessary. But some devices are active and require an external power source for operation. In such active applications, it may be useful to perform voltage or current measurements of the DUT as the VNA generator sweeps over frequency or power.

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Pulsed Measurement Capability of CMT VNAs

April 20, 2018

Pulsed S-parameter measurements are important when testing a DUT at a higher power than it can handle without damage in the steady state, or when the normal operating mode of the DUT involves RF pulses. Examples include amplifier chips or circuits without their thermal packages and radar components or systems. This application note demonstrates how the minimum measurement window and trigger timing behavior of CMT VNAs can be experimentally verified. It was developed based on the 8 GHz Planar 804/1 VNA using v3.49 software. To ensure the measurement settings and pulse timing match the descriptions in this application note, please install v3.49 software or later.

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Spectral Analysis with a Vector Network Analyzer

April 20, 2018

Vector network analyzers (VNAs) are widely used in research, manufacturing, and service environments. These instruments contain stimulus signal sources and receivers with one or more frequency converters. Copper Mountain Technologies produces several VNA models including the Planar 304/1 VNA with a frequency range of 100 kHz to 3.2 GHz and Planar 804/1 VNA with a frequency range of 100 kHz to 8.0 GHz.

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Wireless Infrastructure Maintenance with a USB-driven VNA

April 20, 2018

Wireless infrastructure encompasses a broad range of radio technologies, antennas, towers, and frequencies. Radio networks are built from this infrastructure and from mobile radios—the radios used by municipal and commercial customers to communicate over licensed frequency bands. Typical end user applications of such systems include local and regional law enforcement, highway and local maintenance dispatch, ambulance and fi re service dispatch, and federal law enforcement communications. Wireless infrastructure is often remotely located and difficult to access—or may be completely inaccessible—due to adverse weather conditions. It is critical to perform regular maintenance like visual inspection and RF testing of exterior cabling and antennas, and testing and adjustment of radios and combining networks. Maintenance is performed on two types of links: the RF radio networks and the microwave links that provide backhaul.

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Optimizing VNA Measurement Speed

April 19, 2018

Users of Vector Network Analyzers (VNAs) often need to estimate and strive to optimize their instrument’s measurement speed. Many RF Engineers are interested in the tradeoffs between speed, accuracy and resolution in VNA measurements, especially those striving to achieve optimal automation of the instrument integrated in a larger measurement system or production environment. This application note details the determining factors for measurement cycle time in Copper Mountain Technologies VNAs. Generally speaking, the measurement cycle for any VNA consists of three major components: the per-point tuning and settling time of the generator, the per point measurement time, and a per-sweep time needed to process and transfer results, switch the generator between output ports, and return the generator to the start frequency. An additional, user-programmable delay between points is available in CMT instruments, which may be useful for integration with external equipment or DUTs with settling times of their own. As will be seen, some of the delay components are effectively fixed, while others depend upon the measurement parameters and thus may be optimized by the user.

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Wi-Fi, Bluetooth & PCB Tuning and Antenna Testing

April 19, 2018

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RF Mixer Characterization

April 19, 2018

Mixers are 3-port devices that incorporate nonlinear elements, typically diodes or transistors, to produce the sum or difference of two input frequencies. For example, in transceivers mixers are used to translate radio frequencies (RF) to intermediate frequencies (IF) to allow easier, cheaper, and more accurate processing as well as to translate intermediate frequencies to RF for communication, especially over antennas which are more efficient and smaller at higher frequencies. Engineers developing mixers or integrating mixers in systems often need to measure mixer performance, including conversion loss, phase and group delay, the 1 dB compression point, isolation between ports, and port VSWR. Measurements characterizing these parameters are easily performed on Vector Network Analyzers (VNAs) with advanced calibration techniques, including Scalar Mixer Calibration (SMC) and Vector Mixer Calibration (VMC). Both of these calibration methods are described in detail in the operating manuals of Copper Mountain Technologies’ S2 family of VNAs, available for download at www.coppermountaintech.com. This application note will give a brief overview of mixer fundamentals, describe important mixer characteristics, and detail various measurement processes.

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Design & Test a 3D Printed Horn Antenna

April 19, 2018

The horn antenna is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves into a beam. 3D printing is a fast-growing technology for rapid prototyping of mechanical structures at a relatively low cost. This enables quick production and demonstrations of experimental models and measurement results for innovative ideas. In this application note, we describe our experiences fabricating a pyramidal horn antenna using 3D printing technology.

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Multiport Testing with CMT VNAs & Off-the-shelf RF Switches

April 19, 2018

Copper Mountain Technologies offers VNA with one port, two ports or four ports. But sometimes, more ports are required, for example for testing multi-port devices. There are many options to achieve multi-port measurements, such as manually connecting and disconnecting each port, or using an OEM switch matrix system. Manual re-connection can be time-consuming to the point of being impractical, depending on the test requirements; on the other hand, test equipment vendors’ switch systems are relatively expensive especially considering these are often repackaged versions of commercially available switches.

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Measurements in 75 Ohm Coaxial Transmission Lines Using a 50 Ohm VNA

April 19, 2018

One application of a vector network analyzer (VNA) is the measurement of 75 Ω coaxial transmission lines. In this article, we will discuss making these measurements using the most common type of VNAs, which have 50 Ω test ports, in conjunction with 50Ω‐to‐75Ω Minimum Loss Pads (MLP), i.e. impedance‐matching attenuators with insertion loss of 5.7 dB. As 50Ω VNAs we suggest using the VNAs manufactured by Copper Mountain Technologies: PLANAR TR1300/1, PLANAR 304/1, and PLANAR 804/1 (as of 2012). The use of an MLP affects accuracy of measurements by changing the calibration error and, depending on the location of the attenuator in the measurement circuit, impacts stability of measurements related to test cable bending.

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Using a VNA as a Signal Generator

April 19, 2018

A common question from users of Copper Mountain Technologies’ USB-based Vector Network Analyzers is whether the analyzer can be used as a signal source. Users’ motivations for doing so vary, but most commonly the question arises when an additional source is needed in a test setup but is not available. For example, a source might be needed as the LO to a mixer, to check functionality of another test equipment like a power meter or spectrum analyzer, or to produce a reference clock for use elsewhere in a test system. Fortunately, any CMT VNA can readily be used as a signal source. This application note describes the process of configuring a CMT VNA as a signal source, and the expected performance of an analyzer so-configured. This application note is based on the S2 family of instruments’ software; other instruments will follow similar menu structures and procedures.

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Using Compact USB VNAs with an Off-the-shelf Battery

April 19, 2018

Copper Mountain Technologies provides Vector Network Analyzers without a built-in computer, which enables the VNAs to be highly compact, lightweight and very low power. Those characteristics allow for easily taking CMT’s well-known lab-grade measurement results into the field. There are three main categories of VNA form factor available from Copper Mountain Technologies: small, pocket size devices (R series Reflectometers); compact instruments (including S- and TR-series devices); and rackable (Planar and Cobalt series 2- and 4-port instruments). Using the reflectometers and compact VNAs when A/C mains are not available is very simple, though the latter requires using an external battery pack instead of the ordinary +12V supply. This application note describes both configurations, presents some recommendations, and shows photos taken in the field.

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Using a Pair of Copper Mountain Technologies Vector Reflectometers

April 19, 2018

Reflectometers are used to measure the reflection, or S11 parameter, of a Device Under Test (DUT). This measurement only provides characterization of a single-ended device. For analysis of a twoport device, a traditional Vector Network Analyzer (VNA) is typically used. Using Copper Mountain Technologies’ R series reflectometers however, it is possible to configure two of these devices to measure all four S-parameters’ magnitudes for full characterization of a two-port device’s attenuation behavior.

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Testing & Matching PCB Antennas

April 19, 2018

Connecting to an Antenna Under Test (AUT) integral to a Device (DUT) may involve some tradeoffs between measurement accuracy, electrical considerations, and mechanical ruggedness. In this paper, we describe some aspects of this connection with practical advice for such test and measurement scenarios.

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Power Integrity Measurements with CMT VNAs and Picotest Accessories

April 19, 2018

Power integrity measurements are essential in all modern electronics, including RF and Microwave circuits. Poor power integrity results in spurs and degraded phase noise. As is the case with RF and high speed signals the goal is a flat, frequency independent impedance. Unlike RF and high speed signals, the magnitude of the impedance is not defined, and must be determined based on the circuit noise tolerance. The power distribution network (PDN) measurement includes the voltage regulator, printed circuit board planes and decoupling capacitors. Measuring capacitors, ferrite beads and the PDN impedance can be a challenge, including very low impedance magnitudes large dynamic range and a wide frequency range. For example, the impedance of a 10 nF capacitor at 20 kHz is approximately 800 Ω while at its series resonant frequency it is on the order of 10 mΩ. Similarly, a ferrite bead might be 10 mΩ at 20 kHz and more than 500 Ω at resonance occurring as high as 100 MHz or more.

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Calibration Types and Considerations

April 19, 2018

One of the most frequently asked questions we receive at Copper Mountain Technologies’ sales and support departments goes something like this: “What about calibration?” It’s an unfortunate reality that in the English language, Calibration has two completely distinct definitions. The first relates to checking out the instrument periodically to make sure it is operating within its specifications. “Performance test” is the procedure by which the analyzer performance is verified, typically annually. The second meaning is to do with Measurement or User calibration, a collection of techniques by which measurement accuracy is maximized and made to exclude elements of the system from those measurements (such as cables, adapters and the like). In this application note, we discuss both meanings of calibration as related to Copper Mountain Technologies’ Vector Network Analyzers (VNAs). First, we describe Annual Calibration and then later we discuss measurement calibration.

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Conducting Calibration with the SOLR (Unknown Thru) Method

April 19, 2018

This article describes advantages of vector network analyzer (VNA) calibration by Unknown Thru (SOLR) method, compared to traditional SOLT calibration for measurement of 2-port noninsertable devices. Errors, which surface during SOLT calibration, are demonstrated. Recommendations are given for assessing the quality of the conducted SOLR calibration.

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Automated Antenna Testing

April 19, 2018

As the number of devices featuring wireless connectivity grows, ensuring their performance specifications while staying within regulatory requirements becomes even more important. Antenna pattern measurement is a critical step in the design process of antennas and wireless devices. Compact antenna measurement systems combined with a high performance VNA are necessary to characterize parameters such as pattern, gain, VSWR, and efficiency. These results are used to validate simulated designs and identify possible performance issues before final testing. By using an in-house measurement system, multiple design revisions can be tested and pre-certified without the high cost of using an accredited or certified measurement facility for each test. Other considerations like portability and low cost are important to engineers in various environments like defense or education, respectively.

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Using a Databased SOLT Calibration Kit

April 19, 2018

Copper Mountain Technologies produces lab-grade VNAs with outstanding measurement accuracy. As with every VNA, performing a good calibration is necessary for maximizing the accuracy of VNA measurement results, for de-embedding the effects of imperfect cables and components in the fixture, and for moving the reference plane to the DUT interfaces. There are several approaches for determination and application of VNA measurement corrections, including port extension (a relatively crude, approximate method), fixture de-embedding (with accuracy depending on correctness of the model), and calibrating with a calibration kit (a high accuracy approach). Generally, there are two broad categories of calibration kit types: traditional mechanical kits and automatic/electronic calibration modules. Within mechanical kits, there are two types of kits: those with standard “polynomial” coefficients and those with full S-parameter characterization data, also known as databased kits. This application note introduces databased calibration kits, explains why their use is growing in popularity, and describes how they can be used with Copper Mountain Technologies VNAs.

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Waveguide Calibration of Copper Mountain Technologies’ VNAs

April 19, 2018

Waveguide components possess certain advantages over their counterpart devices with co-axial connectors: they can handle larger power and exhibit lower loss. Therefore, it is very common to employ waveguide interfaces in the high power devices, such as microwave transmitters. The performance of waveguide components at microwave frequencies are typically measured with a Vector Network Analyzer (VNA). However, when measuring the performance of waveguide components with a VNA, non-idealities of any uncalibrated VNA introduce uncertainty in the measurement results. This application note describes how to perform an SSL calibration with a Copper Mountain Technology VNA. It also covers the procedures and the calculations to define a waveguide calibration kit in the CMT VNA. Finally, it provides an example of the 1-port return loss measurement of a waveguide band-pass filter.

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Passive RF System Measurements in a Strong RF Environment: Using an Amplifier with a 2-Port VNA

April 19, 2018

It is sometimes necessary to evaluate passive RF systems in environments where there is significant ingress from other sources. The most common cases are antenna system measurements at community transmitter sites. If there is sufficient RF present in the near field, the antenna being tested doesn’t even need to be particularly broadband for problems to arise. Vector network analyzers are sensitive instruments, typically operated at very low signal levels. Ingress from local sources can skew measurements, and if the ingress is strong enough the analyzer can be damaged. Coordinating multiple station sign-offs can be difficult, if not impossible. When working with broadband antennas in a large market, the interferer doesn’t even need to be collocated to impact the measurements. With another repacking of broadcast spectrum looming, the congestion will only get worse.

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Design & Fabrication of a TRL Calibration Kit

April 19, 2018

Copper Mountain Technologies provides metrologically sound, lab grade USB VNAs which support advanced calibration techniques, including TRL calibration. True TRL calibration requires a VNA with 2 dedicated measurement receivers per test port; except for the TR series and Planar 304/1, all 2+ ports CMT instruments have all the necessary receivers and internal architecture required for true TRL calibration. This application note introduces TRL calibration and describes how to configure TRL kit and perform a TRL calibration in the CMT software.

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DCOM Configuration Guide

April 18, 2018

Usually, automation of Copper Mountain Technologies instruments is achieved on the same computer which is running the VNA applications. Such functionality can be readily achieved using COM, or ActiveX automation. Nothing is required for automation of the instrument other than the PlanarR54.exe application and its Programming Manual. When you install the application, on the last page of the wizard there's an option to register the COM server. If this box is checked and you see a confirmation dialogue pop up, you are ready to begin programming.

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Automation via Wireless (or Ethernet) USB Sharing Hubs

April 18, 2018

There are several ways to control Copper Mountain Technologies’ VNAs. In the simplest and most typical configuration, users directly control the VNA or write automation programs that execute on the same PC which is running the CMT VNA software application. The PC must be located within a USB cable’s reach of the VNA, or within several cables’ reach if daisy chained together. There are several other approaches to control CMT VNAs remotely; pros and cons of these are found in the table at the end of this note.

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Antenna Statistics of Handheld Wireless Devices with a 1-Port R54

April 17, 2018

A cell phone’s GSM antenna is typically located on the lower back side of the phone so as to keep the radiating elements as far from the user’s hand and body as practical. With the small size of today’s phones, that is not necessarily very far, but it at least minimizes the Specific Absorption Rate (SAR) of transmit power and maximizes the receive sensitivity if the carrier has a Total Isotropic Sensitivity (TIS) requirement. Clever industrial design can encourage the user to hold the phone so that the hand doesn’t cover the antenna, but the user presents a challenge anyway in how the phone is actually held during conversation.

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VNA Power Calibration with any VISA Power Meter

April 17, 2018

The Copper Mountain Technologies S2 family of instruments, including all 2-port 2-path (so-called “full reversing”) VNAs supports power calibration with certain specific R&S power meters including the NRP-Z51 USB power sensor.

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Getting Started with the CMT VNA: Top 10 Tips and Tricks

February 14, 2018

The examples created in this document are based on the S5048, but apply to most of the Copper Mountain Technologies VNAs in a similar way. These tips will help you use your VNA with ease and help you get more intuitive results.

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Why USB VNAs?

February 14, 2018

USB VNAs separate the measurement module from the processing module, bringing the measurement results to any external PC using the VNA software. The user can take advantage of the latest OS processing power, bigger display, and more reliable performance of an external PC while simplifying maintenance of the analyzer. USB VNAs are flexible. They can be easily adapted to multiple users and are well-suited for lab, production, field, and secure testing environments.

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What Makes a Good VNA?

February 14, 2018

Everyone knows that a good VNA should have both excellent hardware performance and an easy to use software interface with useful post-processing capabilities. There are numerous VNAs in the market with different performance levels; some of them are economy grade, and others are truly laboratory test grade. What separates the two?

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Product Leader for USB VNAs

February 14, 2018

Frost & Sullivan awarded the 2017 Global Product Leadership Award for USB VNAs to CMT, because we are at the forefront of this trend for affordable and portable high-quality VNAs.

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Measurement of High Power Devices

February 14, 2018

High input power requirements of some Devices Under Test (DUTs) introduce challenges to the measurement therefore. Various measurement techniques such as load-pull analysis and noise figure measurement may also require a higher input power to the DUT than the maximum output power of the VNA.

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A Guide to CMT Software Families and VNA Series

February 14, 2018

Copper Mountain Technologies (CMT) provides a variety of Vector Network Analyzers (VNA) to accommodate a wide range of test and measurement needs. The CMT VNA family covers a wide span of frequencies starting from 20 kHz, and extending to 20 GHz, with 1-port, 2-port or 4-port configurations. 2-port VNAs are further divided into two groups: one capable of measuring 2-port 1-path measurements, and the other capable of full 2-port 2-path measurements.

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