Pico VNA 106 6 GHz Vector Network Analyzer

Vector network analysis for the many

Once the domain of an elite few, microwave measurement has encroached into the lives of scientists, educators, surveyors, inspectors, engineers and technicians alike. Today’s microwave measurements need to be straightforward, portable, accurate, cost-effective and easy to learn.

The Pico VNA 106 is an all new, UK-designed, professional USB-controlled, laboratory grade vector network instrument of unprecedented performance, portability and value for money. Despite its simple outline, small footprint and low cost, the instrument boasts a four-receiver architecture to minimize the uncorrectable errors, delays and unreliability of internal transfer switches.

Despite its small size, the Pico VNA 106 delivers an exceptional dynamic range of 118 dB at 10 Hz and only 0.005 dB RMS trace noise at its maximum operating bandwidth of 140 kHz. It can also gather all four S-parameters at every frequency point in just 190 µs; in other words, a 500 point 2-port .s2p Touchstone file in less than a tenth of a second. Its low price means that the Pico VNA 106 would be cost-effective as a deep dynamic range scalar network analyzer or a single-port vector reflectometer. However, despite its size and price, the Pico VNA 106 really is a full-function dual-port, dual-path vector network analyzer. It’s affordable in the classroom, in small businesses and even in amateur workshops, yet capable of meeting the needs of all users up to the microwave laboratory technician and expert.

Vector network analysis everywhere

The Pico VNA’s small size, weight and cost, and high performance suit it to field service, installation test, embedded and classroom applications. With its remote automation capability, it’s also attractive in applications such as:

• Test automation
• Manufacturers needing to integrate a reflectometry or transmission measurement core
• Inspection, test, characterization and calibration in the manufacture, distribution and service center industries
  • Electronics component, assembly and system, and interface/interconnect ATE (cable, PCB and wireless)
  • Material, geological, life science and food sciences; tissue imaging; penetrating scan and radar
• Broadband cable and harness test at manufacture, installation and fault-over-life monitoring
• Antenna matching and tuning

PicoVNA 2 software

PicoVNA 2 presents standard VNA measurement and calibration simply, intuitively and with efficient usage at its heart. The software offers a comprehensive range of measurements and plot formats in its one, two or four user-configurable measurement channels. All the standard vector network analyzer functions can be seen at a glance.

Quad RX four-receiver architecture

In a VNA a swept sine-wave signal source is used to sequentially stimulate the ports of the interconnect or device under test. The amplitude and phase of the resultant transmitted and reflected signals appearing at both VNA ports are then received and measured. To wholly characterize a 2-port device under test (DUT), six pairs of measurements need to be made: the amplitude and phase of the signal that was emitted from both ports, and the amplitude and phase of the signal that was received at both ports for each source. In practice this can be achieved with a reasonable degree of accuracy with a single source, a transfer switch and two receivers; the latter inputs being switched through a further pair of transfer switches. Alternatively three receivers can be used with an additional input transfer switch or, as in the PicoVNA, four receivers can be used. Using four receivers eliminates the receiver input transfer switch errors (chiefly leakage and crosstalk) that cannot be corrected. These residual errors are always present in two and three-receiver architectures and lead to lower accuracy than that of the Quad RX design.

Support for 8 and 12-term calibration and the unknown thru

Almost all vector network analyzers are calibrated for twelve error sources (six for each signal direction). This is the so-called 12-term calibration, which experienced VNA users are used to performing fairly regularly. In a four-receiver design some error sources are so reduced that 8-term calibration becomes possible, along with an important and efficient calibration technique known as the unknown thru. This gives the ability to use any thru interconnect (including the DUT) during the calibration process, vastly simplifying the procedure and reducing the number of costly calibration standards that need to be maintained.

Bias-Ts

Bias-Ts are often not provided, or available as costly extras, on other VNAs. Use the Pico VNA 106’s built-in bias-Ts to provide a DC bias or test stimulus to active devices without the complexity and cost of external DC-blocks. The bias is supplied from external power supplies or test sources routed to the SMB connectors adjacent to each VNA port.

Other I/O

Power (12 to 15 V DC @ 22 W) and USB 2.0 control are located on the rear panel. Trigger I/O for sweep synchronization and 10 MHz I/O for reference clock synchronization are available on four BNC sockets.

Test cables and calibration standards

A range of RF and Microwave accessories are available from Pico Technology. Test cables and calibration standards have particular significance to the overall performance of a VNA, so we recommend that you select your accessories carefully. Cables and standards are often the weakest links in a VNA measurement, generally contributing significantly to measurement uncertainty despite their high cost. At the lowest levels of uncertainty, costs can be significant and measurements can be compromised by seemingly quite minor damage or wear. For these reasons, many customers hold both premium-grade items for calibration, reference or measurement standards, and standard-grade items as working or transfer standards and cables. Pico Technology can now offer cost-effective solutions in both grades.

Phase- and amplitude-stable test leads

Two test cable types and grades are recommended and provided by Pico Technology. Both of high quality, with robust and flexible construction and stainless steel connectors, the main difference between them is the stability of their propagation velocity and loss characteristic when flexed; that is, the degree to which a measurement could change when the cables are moved or formed to a new position. Cables are specified in terms of flatness and phase variation at up to 6 GHz when a straight cable is formed as one 360° turn around a 10 cm mandrel.

Test leads and calibration standards selection guide

Calibration kits can be purchased as a pair or as a single kit depending on the primary (best uncertainty) measurement application and its DUT interface, and sometimes to meet a secondary purpose with other DUT interfaces. Budget may also be a consideration. Pico Technology provides for all purchase options. You can order any combination of accessories, but to get you started we recommend that you choose one of the following standard configurations.

Configuration 1: universal

For best overall test efficiency and uncertainty in a mix of single- or dual-port test application of both genders, we recommend this dual-port, insertable test lead and calibration standards configuration and the use of additional test port adaptors as necessary. All calibration modes are then available using the test lead ports or adapted test ports.

Configurations 2 to 5: gender-specific and port-number-specific

The following configurations are recommended where there is a focus upon a particular DUT port or measurement arrangement.