All vector network analyzers need to reference their measurements to well-known standard networks. These need to provide a wide dynamic range of amplitude and phase (or delay time) so that measurements between the given extremes become calibrated. PicoVNAs support SOLT calibration of transmission and reflection, whereby the short, open, and through provide known and opposing extremes of phase, high-scale amplitude, and transmit isolation. The load provides known low-scale reflect amplitude and transmit isolation. For Pico calibration standards these are all fully and traceably S-parameter characterized.
Test cables and calibration standards
A range of high-integrity 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 and perform your calibrations carefully.
A range of high-integrity RF and Microwave accessories are available from Pico Technology. Test cables and calibration standards strongly influence the overall performance of a VNA, so we recommend that you select your accessories and perform your calibrations 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. In general we recommend PC3.5 interfaces for premium or reference use and SMA interfaces for working use.
The PicoVNAs may also be used with third-party calibration kits, such as the Keysight/Agilent 85032F, that are characterized by polynomial coefficient models either in written form or as a text file.
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 8.5 GHz when a straight cable is formed as one 360° turn around a 10 cm mandrel.
PicoVNA E-Cal 8.5 GHz Automated calibration kits
Many owners and users of a vector network analyzer insist upon an automated calibration solution. Some of the benefits are obvious: automation can provide extra speed, efficiency and a simplified process. But did you know that automated VNA calibration can also improve overall calibration quality and even reduce uncertainties or errors?
The PicoVNA 108 achieves calibration automation to full published specification using either male SMA or female SMA E-Cal modules. These are USB-powered and controlled to electronically select the various Short, Open, Load and Through reference standards as they are needed within the calibration process. You simply power the module, make a single connection of the E-Cal standard between the PicoVNA test ports, and then initiate the automated procedure from within the PicoVNA 108 user interface.
Within the supplied carry and storage case, we include a fully characterized, polarized port adapter with each of the E-Cal modules; this allows both the male and female SMA devices to also calibrate insertable male-female and female-male test ports.
In addition, the PicoVNA 108 will support TRL and TRM calibration (through, reflect, line and match, respectively). These calibration mechanisms typically gain favour when needing to measure substrate mounted DUTs, for example, surface-mounted networks or components. The line, match and reflections (shorts or opens) can all be readily fabricated on substrate and at precise on-substrate measurement reference planes, for example surface mount device pins. The PicoVNA 108 will support one or two TRL bands, Open or Short reflection standards and can account for line impedance offset if required. The TRL technique can also achieve very high-precision calibration as a machined air transmission line can be fabricated more precisely than a good match can be measured, certainly at higher frequencies.
Check standards
We offer two economical check standards that can be used to validate the accuracy of a network analysis test setup and its calibration before and during or after measurements are made. Akin to the Beatty line, each check standard is a short length of mismatched line (75 mm of 25 Ω) with a predictable, smooth and stable mismatch and transmission characteristic that spans the frequency range of the PicoVNA. These devices validate system measurement accuracy in the presence of high and varying mismatch and thus present a demanding validation on which to base confidence in a setup.
A comparison utility is provided in the PicoVNA 2 or 3 software to evaluate the comparison against a combination of specified measurement uncertainties for the device, test leads and instrument. Each check standard is supplied with Touchstone measurement data on USB memory. The data is traceable via PC3.5 standards to national standards. The supplied Touchstone measurement data is compatible with and can be used to manually validate a measurement of any manufacturer’s VNA.
Two check standards are available: insertable SMA(m-f) and noninsertable SMA(f-f).
Name
Port connectors
Parameter
Minimum
Maximum
Impedance
Bandwidth
Supports S-parameters and calibration modes
CHK-INS-MF
Insertable with a male and a female port
Port 1: SMA female
Return loss
< –30 dB
> –6 dB
25 Ω
8.5 GHz
All S-parameters and insertable 12‑term calibration mode
Port 2: SMA male
Insertion loss
> –0.2 dB
< –1.9 dB
CHK-NON-F
Noninsertable with female ports
Port 1: SMA female
Return loss
< –30 dB
> –6 dB
All S-parameters and noninsertable, known and unknown thru calibration modes
Port 2: SMA female
Insertion loss
> –0.2 dB
< –1.9 dB
Test cables 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 ‘universal’ configurations.
Recommended configurations using manual SOLT calibration standards
For best overall test efficiency and uncertainty in a mix of single-port or dual-port test applications of both genders, we recommend these dual-port test lead and calibration standards configurations and the use of test port adaptors as necessary. All calibration modes are then available and where needed port adaptors can be fully included in the calibration.
Primary DUT interface
Select accessory grade
Required test leads
Required manual SOLT Cal. kits
Supported measurement and calibration modes
Port adapt for some DUTs...
"Universal" capability. Dual-port devices or any single-port device with male or female or male and female ports
Standard SMA
1x TA336 SMA male port
1x TA337 SMA female port
1x TA344 SMA male ports
1x TA345 SMA female port
All single and dual‑port calibration modes and S‑parameters.
To address dual-port single-gender non‑insertable devices, use and include within calibration 1x TA342 SMA(m-m) or TA343 SMA(f‑f) test port adapter.
Premium PC3.5
1x TA338 PC3.5 male port
1x TA339 PC3.5 female port
1x TA346 PC3.5 male ports
1x TA347 PC3.5 female ports
To address dual-port single gender non‑insertable devices, use and include within calibration 1x TA340 PC3.5(m-m) or TA341 PC3.5(f‑f) test port adapter.
The following configurations use just one SOLT calibration standard and are recommended where there is a focus on a particular port gender.
Primary DUT interface
Select accessory grade
Required test leads
Required manual SOLT Cal. kits
Supported measurement and calibration modes
Port adapt for some DUTs...
Single port or dual-port noninsertable with female port(s).
Standard SMA
2x TA336 SMA male port*
1x TA345 SMA female ports
All S-parameters and all single and dual-port calibration modes except insertable.
Note that mixed gender dual-port insertable devices can be addressed by adding and de-embedding 1x TA341 PC3.5(f‑f) or TA343 SMA(f‑f) test port adaptor**.
Premium PC3.5
2 x TA338 PC3.5 male port*
1x TA347 PC3.5 female ports
Single port or dual-port noninsertable with male port(s).
Standard SMA
2x TA337 SMA female port*
1x TA344 SMA male ports
Note that mixed gender dual-port insertable devices can be addressed by adding and de-embedding 1x TA340 PC3.5(m-m) or TA343 SMA(m-m) test port adaptor**.
Premium PC3.5
2x TA339 PC3.5 female port*
1x TA346 PC3.5 male ports
* Can reduce to a single test lead in single-port measurement applications.
** With only one calibration kit it is not possible to calibrate after port gender adaptation. Purchase a second calibration kit of opposing gender for full calibration of a port adaptor. Alternatively, once a noninsertable calibration has been performed, it is possible to measure the port adaptor(s) and de-embed their error. A third option is to use reference plane shift and/or normalization for a lesser correction of adaptor errors.
Recommended configurations using automated E-Cal SOLT calibration standards
Primary DUT interface
Select accessory grade
Required test leads
Required manual Cal. kits
Supported measurement and calibration modes
Also suited to DUTs...
“Universal” capability. Dual-port devices or any single-port device with male or female or male and female ports
Standard SMA test leads
2x TA336 SMA male port
2x TA343 SMA(f‑f) adaptor
1x TA518 SOLT-AUTO-M
and
1x TA519 SOLT-AUTO-F*
All dual-port calibration modes and S‑parameters.
Use and include within calibration:
1) A test port adaptor to address insertable dual-port devices**.
2) Both port adaptors to address dual male port non‑insertable devices.
Premium PC3.5 test leads
2x TA338 PC3.5 male port
2x TA341 PC3.5(f‑f) port adaptor
Alternatively using 1x automated E-Cal calibration standard …
Primary DUT interface
Select accessory grade
Required test leads
Required manual Cal. kits
Supported measurement and calibration modes
Also suited to DUTs...
Dual-port non‑insertable devices or any single female port device
Standard SMA test leads
2x TA336 SMA male port
1x or 2x TA343 SMA(f‑f) adaptor
1x TA519 SOLT-AUTO-F
All dual-port calibration modes and S-parameters
Use and include within calibration a test port adaptor to address insertable dual-port devices or single-port device of opposing gender**.
Note that opposing gender dual-port non‑insertable devices can be addressed by adding and de-embedding a further port adaptor.***.
Premium PC3.5 test leads
2x TA338 PC3.5 male port
1x or 2x TA341 PC3.5(f‑f) adaptor
Dual-port non‑insertable devices or any single male port device
Standard SMA test leads
2x TA337 SMA female port
1x or 2x TA342 SMA(m-m) adaptor
1x TA518 SOLT-AUTO-M
Premium PC3.5 test leads
2x TA339 PC3.5 female port
1x or 2x TA342 SMA(m-m) adaptor
* This automated dual E-Cal SOLT configuration is available with discount. Please see TA520.
** To calibrate use the characterized and polarized through adaptor supplied with your E-Cal standard. The PicoVNA E-Cal calibration wizard guides this setup.
*** With only one calibration kit it is not possible to calibrate after two-port gender adaptations. Purchase a second E-Cal calibration kit of opposing gender for full calibration after two-port adaptions. Alternatively, once a non‑insertable calibration has been performed, it is possible to measure the second port adaptor and de-embed its error. A third option is to use reference plane shift and/or normalization for a lesser correction of adaptor errors.
