IQSTAR’s Key features

  • Turnkey software solution for 50Ω circuit characterization
  • Fully customizable with flexible setup schematic
  • Complete characterization flow, including:
    • Instrument control
    • Calibration process
    • Different measurement configurations
    • Flexible DC measurements and control (up to 20 DC stages)
    • Automation and test sequencing
    • Data export to standard formats (MDIF, CSV…)
    • Data analysis
    • Reporting
  • Instrument agnostic solution
    • A large list of instrument drivers available
    • Compatible with most instrument vendors
    • A simple implementation of new drivers using a Driver Wizard.
  • No programming skills required
  • Compatible for coaxial, waveguide, fixtured, and on-wafer measurements
  • Export data files in CSV or MDIF formats for commercial circuit simulators


IQSTAR 1.2 Modules

Benefits of IQSTAR

  • Re-use of existing hardware in the lab
    • A cost-effective testing solution
    • Quicker development time and faster time to Market
    • Less downtime and reduced maintenance costs
  • Faster test times
    • Automatize your tests
    • Combine multiple measurements types
    • Single calibration, multiple measurements
  • High Accuracy
    • Proven calibration process
    • Vector and scalar calibration available
    • Embedded validation and verification procedures
  • Flexible setups
    • Great adaptability to future test requirements
    • Instrument driver wizard for new hardware
    • Multi-brand instruments setups supported.
Schematic Editor

IQSTAR is a turnkey software with a versatile and customizable schematic editor for building a test bench with available laboratory instruments. Depending on the measurements required, multiple test configurations are possible: scalar, vector, or a combination of scalar and vector. Devices and circuits can be coaxial, waveguide, fixtured or on-wafer.

Schematique Editor User Interface

Each instrument selected in the setup can be controlled using specific drivers allowing full automation of the measurements. With 15 years of device characterization software development, AMCAD masters instrument controls and provides drivers that optimize the measurement speed without sacrificing the accuracy. Each instrument can be set with different options and in different modes.


DC power supplies control

How to control DC voltage and current?

RF Power amplifier measurements can be particularly challenging when dealing with multistage circuits with several ports available for DC power supply control.

IQSTAR allows the DC power supply remote control of up to 20 accesses with associated DC or pulsed voltage and current measurements from the power supplies or using DC precision multimeters and oscilloscopes for pulsed current measurements when the RF signal is pulsed by an RF pulse modulator.
It is very easy to enter various and numerous DC power supply settings for the software GUI without any specific programming skills.

On RF Power amplifiers, different accesses can be available to supply the transistors, Gate bias, Drain bias n°1, Drain bias n°2, and so on, such as in a Doherty RF Power Amplifier for instance.

IQSTAR allows custom labelling of each instrument and its associated DC parameters to simplify the biasing procedure of multistage circuits and the proper recording of the data into the measurement file.

How to Calculate a Voltage Drop Across Resistors?

It is a must-have to measure accurate DC voltages at the Device Under Test reference plane (DUT), whatever the current consumption. Because the current can flow through a cable with a parasitic serial resistance or through a shunt resistor for differential current measurements, the voltage drop across the serial or possibly parallel resistors must be taken into account to measure the true voltage at the DUT bias access.

A resistive network can also be configured into the IQSTAR DC power supply user interface to de-embed the measurements and the voltage settings to the DUT reference plane.

In addition, customized formulas can be defined to calculate specific DC power consumption values of the RF Power Amplifier if provided with several DC ports.


How to Measure DC or Pulsed Current?

DC current can be measured simply by reading back the DC current from the DC Power supply through remote control. Nevertheless, it is preferable to use precision DC multimeters plugged in series on the DC path when high current measurement accuracy is needed. IQSTAR enables a seamless DC setup configuration when DC power supplies and DC voltage and current multimeters are used. An oscilloscope can also be used to measure both DC / Pulsed Voltage and Current. Contact us to check the oscilloscope's drivers, which are available.


How to Synchronize Pulse Measurements?

When dealing with complex setups to characterize RF power amplifiers in pulsed conditions, it is easy to face the issue of instrument synchronization, especially when using different instruments from different vendors and different generations. For example, some RF sources can generate a fixed output synchronization signal with 50nsec width, but most of the triggered instruments like Power Meters; DMMs… have a minimum trigger hold-off timing of 1usec, resulting in a bad synchronization and wrong measurements, as well as software timeouts.
In this case, it is recommended to advantageously use a Trigger Box with the RF Modulator to help build a robust bench for Pulsed Characterization of Power amplifiers.

If one of your topics of interest is not described here, please contact us.


High power devices require measurements in pulsed mode to mitigate thermal effects. Pulsed options often add complexity to settings. Therefore, IQSTAR provides a simple user interface for full control of the pulse generators, the receivers, and the trigger signals. Different instruments in the setup can be set with appropriate timings for the pulse setting and pulse measurements.

To simplify the task for the end-user, IQSTAR embeds a Chronogram that describes, on a time axis, the pulse mode settings, and a configuration panel where all the timing specifications can be set at once. All instruments in pulsed mode are automatically showing up in the appropriate section of the chronogram: generators (RF signal Generators, DC supplies) and receivers (VNA, Multimeters, Power-Meters)

The measurement windows can be configured for each receiver, and once the chronogram is closed, all the settings are configured automatically in the appropriate instruments.



IQSTAR provides corrected data at the DUT reference plane. The correction terms are calculated during the calibration process using a step-by-step wizard. Depending on the setup configuration, different calibrations can be performed.


In the case of a scalar setup, the calibration procedure is based on power measurements using power meters and signal generators. For vector setups, the calibration of the Vector Network Analyzer (VNA) is necessary to extract the error terms. Furthermore, depending on the VNA configuration, which can be set to use three
(3) or four (4) receivers, the vector calibration and power calibration can be different.

Therefore, and to minimize the source of errors, IQSTAR provides a state-of-the-art calibration wizard that relies on the schematic setup to identify the type calibration that is possible to perform and guides the end-user through all the steps including the validation process to verify and assess the expected accuracy.


Sweep Plan

Automated measurement is an easy task with IQSTAR. Sequencing measurements with minimum human intervention is key to an optimal testing efficiency. One person can run multiple benches at the same time to speed up testing capabilities. Through drag and drop actions, it is possible to define several tasks to be performed and run the complete measurement scenario automatically.


The “Sweep Plan” takes benefit of all the GUI tools already available in the bench definition interface or from the measurement interface. This way, defining a complete measurement task is possible, without requiring any programming skills, and without any loss of flexibility.
IQSTAR automation capabilities using the “Sweep Plan” allow:

  • Single setup and multi-setup configurations
  • Measurement sequencing with loop and stop conditions
  • Nested measurements sweep
  • DUT bias control & optimization
  • Probe station control
  • Chuck temperature control
  • SCPI commands for specific instrument control during the automation
  • Possibility to save sweep plans with all parameters for future use



IQSTAR is provided with a visualization tool for each measurement module. Different displays are made available, allowing single or multiple graphs. Depending on the performed measurements, an extensive list of graph types is pre-defined, including:

  • XY Graphs
  • Smith Charts
  • Polar
  • Tables
  • Spectrum
  • CCDF traces
  • EVM constellation
  • ACPR Mask
  • And many others

Different controls allowing the display of different parameters at a specific frequency or power level make the performance evaluation of the device easier to analyze. User-defined templates can be saved and recalled. Measurement data can be exported to standard formats like CSV and MDIF.


IQSTAR is composed of different modules allowing the flexibility to choose the right configuration for the right measurement setup. Each module includes the capabilities described in the sections above:

  • Schematic Editor
  • Chronogram
  • DC supplies
  • Calibration
  • Sweep Plan
  • Visualization

IQSTAR Configuration Information


This Module allows the characterization of Power amplifiers using a scalar setup comprising an analog RF source, power meters and power supplies.


Scalar Setup


IQSTAR provides corrected data at the DUT reference plane. The correction terms are calculated during the calibration process using a step-by-step wizard.

Depending on the setup configuration, different calibrations can be performed. In the case of a scalar setup, the calibration procedure is based on power measurements using power meters and signal generators. To minimize the source of errors, IQSTAR provides a state-of-the-art calibration wizard that relies on the schematic setup to identify the type calibration that is possible to perform and guides the end-user through all the steps including the validation process to verify and assess the expected accuracy.




Different sweep settings are available to the end-user allowing appropriate characterization of different power amplifier technologies:

    • A two-dimensional (2D) sweep, with the choice of sweeping power per frequency or frequency per power
    • A fast and convenient Smart Sweep incrementing the input power with a coarse step and then with fine steps to prevent overdriving the DUT.


1Tone Power Sweep


Different operating and transducer gain compression modes are made available to characterize the power amplifier under test, including compression from linear and compression from maximum gain.
Gan-based Power amplifiers need more cautious characterization as the power sweeps need to start always from the same trapping level. For that, IQSTAR embeds a quiescent current stabilization option allowing to monitor the current settling in the quiescent state over time and assure it reaches the right level before triggering a new power sweep.
The Protection of the test bench and the measured circuits are top priorities when it comes to RF power characterization. Multiple stop conditions can be set in the software: Gain compression, Maximum output power, Efficiency compression and more.

1-Tone measurements with a scalar setup allow the characterization of Power Amplifiers by measuring the following parameters:

  • Power & frequency sweeps
  • Gain Compression
  • PAE
  • Power Gain (3 power meters are needed)
  • Transducer Gain (2 Power meters are needed)

During the measurements, the user can consult the results on the live visualization tool. Besides the history measurements (up to fifty iterations) available for display, it is also possible to set some specifications limits that the circuit under test needs to reach. A color-coded display allows a fast evaluation of the DUT and indicates if it passes or fails.


IQSTAR 1 tone



This Module is an add-on to the IQS100B10. It unlocks vector measurements capabilities to all the functionalities of the Scalar Bench control module.



  • Schematic editor: Vector instruments are unlocked in this module allowing setups with Vector Network analyzers (VNA) and Spectrum analyzers. It is possible to have a hybrid setup combining scalar and vector measurements with this option.
  • Chronogram: see IQS100B-10
  • DC Supplies: See IQS100-B10
  • Calibration: For vector setups, the calibration of the Vector Network Analyzer (VNA) is necessary to extract the error terms. Furthermore, depending on the VNA configuration, which can be set to use three (3) or four (4) receivers, the vector calibration and power calibration can be different.
  • S-Parameters Measurements: Perform a frequency sweep on the VNA and display the corrected S-parameters at the DUT reference plane using the live visualization tool. Device tuning becomes easier with trace history as up to fifty (50) iterations, and measurements can be displayed on the same graph. Import S2P simulation files and compare them with measurements in different display formats.



With Probe station control, measure multiple devices with one click. IQSTAR supports major automatic probe station vendors and remotely controls the wafer movement. Adding the bias conditions to the sweep plan, one can generate a large amount of data with minimum interaction with the instruments.



  • 1-Tone measurements: Adding to the capabilities of the scalar setup, the vector bench control takes advantage of the dynamic range of the VNA receivers as well as it measurement speed to enhance the characterization experience. Additional parameters are added to the measurement list like:
    • AM-PM
    • Return Loss
    • Harmonic power (Requires Frequency Offset option on the VNA)



IQSTAR allows multiple configurations to measure intermodulation distortion (IMD) with a 2-Tone signal.

Either using two combined analog RF sources or one vector signal generators, a spectrum analyzer, or a vector network analyzer, IQSTAR guides you through a simplified calibration procedure and provides high measurement accuracy.

Using the VNA, IQSTAR takes advantage of the dynamic range of the receivers and measures the a- and b-waves to extract the intermodulation product signals along with the two carrier tones to calculate the IMD up to the ninth level. The “Frequency Offset” option is required in the VNA for these measurements. As for the generators, IQSTAR handles sources from the VNA, independent sources, or a combination of both and optimizes the tones balance levels for an accurate IMD characterization. The use of a spectrum analyzer or signal analyzer is also possible by setting the right instruments in the setup schematic.

A 3D nested sweep, including the carrier frequency, the power, and the spacing of the tones, can be performed to extract a complete IMD characterization of the Power Amplifier in one step.

VBW measurements represent a challenging measurement task. IQSTAR handles this measurement efficiently, setting the amplitude of the tones according to the target third-order intermodulation distortion (IMD3) value set by the user. The software sweeps the spacing between the tones and adjusts the balance between them before recording the intermodulation—up to the ninth order. Taking advantage of the speed of VNA sweeps, this measurement takes just a few minutes.




The growing complexity of wireless systems imposes a thorough and detailed characterization of RF power amplifiers using wideband signals. IQSTAR enables the measurements of high-speed signal quality to evaluate the performances of the DUT in terms of (EVM, ACPR, CCDF, PAPR…)

Based on hardware built-in capabilities, it is possible to set the modulation scheme manually with adequate settings and have IQSTAR recall the required state on the instrument. Otherwise, it is possible to generate an IQ waveform using third party software and use it directly in IQSTAR by loading a text file containing the two columns “I” and “Q”. Finally, IQSTAR embeds a waveform generator that can create different PSK and QAM signals and inject them directly into the signal generator.

The Vector Signal Generator and Analyzer with appropriate options associated with power meters are used to measure different parameters like:

  • Adjacent Channel Power Ratio (ACPR)
  • Error Vector Magnitude (EVM)
  • Complementary-Cumulative-Distribution-Function (CCDF)
  • Peak-to-Average Power Ratio (PAPR)
  • Spectrum

IQSTAR Modulation measurements support multiple combinations of vector signal generators and signal analyzers from different vendors, allowing the test engineers to switch between instruments without having to know how to set the parameters on different interfaces.




IQSTAR uses IQ values sent to the Vector Signal Generator (VSG) and fetches the IQ values from the Vector Signal Analyzer (VSA). The IQ data is resized, realigned, and demodulated in IQSTAR to extract user-selected parameters (ACPR, EVM, CCDF, PAPR, Dynamic AM-AM…). With this option, the VSA does not need to have any software options.

The Available Measurements are:

  • IQ Data
  • EVM on symbol
  • ACPR
  • CCDF with Trace
  • Dynamic AM/AM and AM/PM
  • Instrument-based DPD evaluation

If the signal is generated by the Waveform Generator (now supports only PSK and QAM), then IQ Option can also extract the EVM Constellation and EVM Data.

With the IQ Module, no software options are required in the instruments to analyze the signal, which makes it a flexible solution with minimum hardware updates needed. The setup is only limited by the instantaneous bandwidth of the signal generator and the signal analyzer. DPD measurements are only available if the hardware is equipped with prebuilt DPD capabilities.




Power Amplifiers are the most critical components in a communication system and are inherently nonlinear. The nonlinearity generates spectral regrowth, which leads to adjacent channel interference and violations of the out-of-band emission requirements. To enhance the Efficiency without compromising the linearity, power amplifiers must be linearized using different techniques. IQSTAR 1.2 introduces several DPD techniques and algorithms to verify that the Power amplifier under test can be linearized with more or less complexity:

  • Sample-based, iterative measurement base technique that allows achieving quasi-ideal linearization results for reference purposes.
  • Memoryless (M),  a basic methodology for PA with memoryless nonlinearities
  • Memory Polynomial (MP), commonly used for wideband PA exhibiting memory effects. 
  • Generalized Memory Polynomial (GMP), an advanced version of the MP method taking into account cross-term order
  • Nanosemi Algorithm (DLL to be acquired by the customer). This option controls the Nanosemi algorithm through a DLL and applies it externally to the measurements using instruments from different vendors. 
  • Matlab-based customer-developed DPD algorithm. This option is a gateway to run a Matlab-based DPD algorithm developed by the user. An Open-source MP algorithm adjustable and optimizable by the user is also provided with this option.


IQSTAR Scripting

SCRPT is an add-on module to IQS100-B10/B11/B20/B30/B40 which enables advanced measurement sequencing using a dedicated scripting language.

Scripting is available internally to IQSTAR through a dedicated editor. Starting Rev 1.3, Scripting will also be available via an external script server and be controlled in slave mode by a third-party application or software.

Multiple functions are included in the script editor and divided intodifferent categories:

  • Measurements System: these functions allow full automation of the measurement process including the setup creation, the measurements configurations, the device biasing, the biasing optimization, the wafer mapping and many more.
  • User Interface: Multiple functions related to the creation of 2D and 3D graphs as well as dialogue boxes and different utilities.
  • Math functions: an extensive mathematical library is made available to compute necessary parameters. These functions include arrays manipulations like SVD and LU operations, polynomial modelling and curve fittings and many more functions.
  • Native: This category of functions is very useful when dealing with external DLL that needs to be controlled during the measurements.
  • Net Visa: Dedicated Visa-based instruments control is allowed directly from the script to integrate additional instruments to the bench like thermal chambers for example.


Scripting User Interface


This Whiteboard module allows the user to create and customize as many graphics as necessary and position them into a user-defined template to visualize measurement results. It is possible to incorporate texts and images to create an interactive measurement report. An interactive display, including tables and graphics, can be generated using different filters or sliders.



IQSTAR & WHITEBOARD Editor Bundle allows the visualization of as much data as possible without compromising flexibility. Circuit or system designers generally wish to import measurement or simulation data into a suitable environment to verify their design and/or verify the agreement between simulated results, measured performances, and reference data. If they don't have dedicated tools, they use homemade ones, which are generally costly in development time, workforce, and maintenance.

The data can be analyzed in a raw format or be processed via an equation editor, allowing to customize the analysis. By customizing his analysis environment, with a few clicks, the user can reload new measurement or simulation data in a predefined analysis environment.

This tool is essential for the in-depth analysis of RF systems simulations results. The simulated quantities, the variables used, and the size of the data can be parameterized at any time.



IQSTAR 1.1 Release 2020
IQSTAR Wideband DPD at NI-Week 2019
IQSTAR AMCAD Live Demo with Copper Moutain VNA at IMS 2019
IQSTAR AMCAD Live Demo at IMS 2018