Product Information
PicoVNA® Vector Network Analyzers
The incredible PicoVNA: Low cost, high performance
The incredible PicoVNA: Low cost, high performance
The PicoVNA 106 and PicoVNA 108 are low-cost, small-footprint, USB-controlled Vector Network Analysers that offer up to 8.5 GHz of bandwidth with performance that punches well above their weight.
Accurate: With up to 124 dB of dynamic range and RMS trace noise of just 0.005 dB at maximum resolution bandwidth, you know that what you are recording is a true reflection of the device you are measuring.
Fast: Capable of up to 5500 dual-port S-parameter measurements per second; that is, creating a 201-point two-port .s2p file takes less than 38 ms.
Affordable: Not only is the unit itself excellent value, but calibration kits are also highly affordable and easily repairable, keeping total cost of ownership low.
Reliable: The quad-RX architecture minimises uncorrectable errors and delays.
Simple: Automated calibration with the E-Cal kit makes it easier and faster to get up and running.
PicoVNA 5 software
The new PicoVNA 5 software makes measurements easy. The intuitive controls allow you to fully customise your viewports to your needs. Add a mix of frequency and time domain measurements, group markers across traces and configure readouts exactly how you need them.
Because PicoVNA is USB-controlled, it is simple to save data to your drive — in a number of different formats, including .csv and .s2p — to use with other software or share with your team.
For those who want to control their PicoVNA remotely, or perhaps want to run automated tests, the PicoSDK is also available with PicoVNAs. Control can be via either API calls or standard SCPI commands, and you can control multiple instruments at once.
The SDK works with LabVIEW, MATLAB, Python, and C/C++/C#. As you would expect, there are many examples to get you started on the Pico GitHub.
A screenshot of PicoVNA 5 software showing the progress screen during a SOLT calibration
Simple, fast calibration
Calibrating your VNA can be a time-consuming and error-prone process, particularly for those new to microwave measurements. Using the automated Pico E-Cal can reduce errors and uncertainties, as well as increase productivity by speeding up the calibration process, even while improving the quality of the resulting calibration.
Manual SOLT calibration kits are also available, with both male and female models and either standard (SMA) or premium (3.5 mm) connectors, and the PicoVNA 5 software will guide you through the whole process to minimise errors.
All Pico cal kits and check standards, whether automated or manual, are individually characterised using the more accurate TRL (Through, Line, Reflect) calibration type. The kits are supplied with S-parameter data, allowing you to transfer the high-quality characterisation to your instrument as you calibrate it. This characterisation process reduces the manufacturing cost of the cal kits without compromising on calibration quality; in fact, the correct port match is an excellent 46 dB typical on both source and load ports.
PicoVNAs support many calibration methods, including 8- and 12-term calibration, unknown through, and also TRL and TRM (Through, Reflect, Line/Match). TRL and TRM calibrations are used when measuring a DUT mounted on a substrate, so they are perfect for your network that is already mounted to a PCB.
Great for education
PicoVNAs have been designed with the professional user in mind, but that does not mean they cannot be suitable for inexperienced hobbyists or students.
For educators, the Network Metrology Training Kit provides an ideal platform for covering all the basics of RF measurements. Included in the full kit is a PCB with a number of different circuits to test, plus a basic cal kit, N to SMA adaptors, SMA m-m and f-f adaptors, SMA test leads, a Pico wrench and a memory stick containing PicoVNA software (also available for download) and recommended software setups for use with the kit.
Also included on the memory stick are comprehensive instructions demonstrating a huge variety of possible measurements, providing a great starting point for any RF training course or for self-study.
The PCB itself has over ten different circuits. At one end of the board is a feed line-based SOLT (short, open, load, through), for a different method of calibration. There is also a 25 Ω mismatched Beatty line, low pass and bandpass Butterworth filters, an attenuator, a 6 dB power divider and space for adding your own 0603 component for testing. The final item on the board is a 6 GHz broadband amplifier (requires external +5 V DC supply, not supplied).
Paired with a PicoVNA, it provides an introduction to VNA measurements and high-frequency design. Once the basics have been grasped, it also allows demonstration of more complex topics such as P1dB and AM to PM conversion.
To take it one step further, Pico has partnered with Cadence AWR Microwave Office. The PCB files for the Network Metrology Training Kit are available to import to Microwave Office so you can compare simulations and real-world measurements. Even better, Pico’s Cadence AWR DE Interface wizard allows you to import VNA measurements to enhance your simulation.
PicoVNA features
Quad-RX architecture
Many low-cost VNAs use a two-receiver architecture. One receiver measures the reference signal, which is coupled from the source port. The other receiver measures the test signal that has passed through the DUT. To measure all four S-parameters, two sweeps are needed, and transfer switches need to change the source and receiver ports between each sweep.
PicoVNAs use a four-receiver architecture. This has a number of benefits. Measurements are faster because both sweeps can happen simultaneously. There aren’t as many transfer switches between the input and receiver, meaning previously uncorrectable errors — typically leakage and crosstalk — are significantly reduced. Another benefit appears during the calibration stage. Typical calibrations are 12-term, but the quad-RX architecture reduces some errors so much that the much simpler 8-term calibration can be used, reducing calibration time. The quad-RX architecture also allows for unknown thru calibration, meaning you need fewer calibration standards.
The quad-RX architecture also increases the reliability of the equipment. The transfer switches having to swap between receivers twice per measurement sweep will cause wear and reduce the lifetime of the instrument, but the reduction in switches and in switch operations in a quad-RX architecture reduces this wear.
Bias-Ts
Bias-Ts are used in VNA measurements to provide a DC bias or test stimulus to active devices without needing external DC blocks.
Often, VNAs won’t include any Bias-Ts and will only offer them as an extra (that you have to pay for, of course). PicoVNAs have built-in Bias-Ts, powered by the external power supply and routed to the SMB connectors on the front panel of the VNA.
Time Domain Reflectometry and Transmission measurements
Time Domain Reflectometry/Transmission are useful measurements to not only determine the quality of a match, but also the location of any problems that could be making the match worse. It is also used when there is a fault in a cable: input a pulse, and the time of flight and appearance of the reflection can tell you where the fault is and the nature of it.
To carry out TDR measurements, the PicoVNA calculates the time-domain response to a step input based on its frequency-domain measurements. First, it carries out a sweep of harmonically related frequencies. It then performs an inverse Fast Fourier Transform on the S11 (reflected) data to calculate the time-domain impulse response. Integrating the impulse response gives the step response. Based on the shape of the step response, you can calculate how far the discontinuity is from the reference plane and if it is short, open, capacitive, inductive, or some combination.
The method is the same for TDT, but the calculations are carried out on the S21 data. In this way, you can measure the pulse response and transition time of amplifiers, filters, and other networks without needing other specialist equipment.
Reference plane extensions and port de-embedding
After calibrating, the VNA assumes that the reference plane is at the end of the cable where the cal kit was connected. Often, you will want to remove additional excess path length from connectors, cables, and microstrip lines that you are assuming are ideal. With a PicoVNA, you can extend the reference plane independently for each measurement parameter (S11, S21, S12, and S22).
If you can’t assume the cables, connectors, and PCB traces are ideal, or if you want to achieve better accuracy, you can de-embed the connections on each port. Simply create or import a full Touchstone (.s2p) file for the interface network on each port.