The Latest Innovations in Impedance Analyzers

Interview conducted by Mychealla RiceDec 17 2019

In this interview Dr Tim Ashworth, Applications Manager at Zurich Instruments talks to AZoM about the latest innovations in Impedance Analyzers.

Tim explains the key challenges in the world of impedance measurement and how innovative analyzers can help solve these challenges.

Please tell us about Zurich Instruments and the work you do?

We strive for innovation leadership by integrating an ever-increasing amount of functionality into our class-leading hardware, while keeping it easy to use.

As a result, our customers benefit from efficient work flows and reduced setup complexity helping them to save time and focus on their ultimate goals.

Zurich Instruments is a young dynamic company, always innovating and improving. My role is applications manager for our impedance products, and the release of the MFIA in 2016 has been both challenging and rewarding.

What are the key challenges in the world of impedance measurement?

Measuring impedance as a function of frequency is a well-known method of characterizing dielectrics, components and many other types of materials.

However, there has been little innovation to date in impedance analyzers, so many instruments are limited in their measurement speed, streaming rate, or by a lower frequency limit which misses the interesting frequency ranges.

Moreover, the impedance may change by many orders of magnitude as the frequency is swept, so you need an instrument capable of handling a wide range of impedances to get great data.

Further challenges arise when connecting the instrument to the sample; typically, you need to use a dedicated cable or fixture to make the connection. This fixture can introduce parasitics which reduce the accuracy of the impedance data. It is important to be able to counteract these parasitics.

How can innovations in impedance analyzers help solve these challenges?

The MFIA impedance analyzer from Zurich Instruments takes an innovative approach to impedance analysis. It directly measures the voltage across and current through the device under test, eliminating the need for the feedback loop common in many instruments.

This enables the MFIA to measure at frequencies right down to millihertz, and impedance measurements to the teraohm level. Importantly for sensor characterization, it allows for fast impedance measurements on a timescale of ten microseconds.

 However, the real magic lies in the software. The MFIA is controlled via LabOne, the powerful software interface which runs all Zurich Instrument products.  LabOne includes many easy-to-use software tools, such as the parametric sweeper which allows the user to sweep parameters including frequency, test signal level or bias voltage and measure impedance parameters as a function thereof. 

This means seamless data from 1 mHz to 5 MHz with no limit on the data-point density. The data is displayed in real time, and the resulting multi-trace graph can be adjusted in a matter of seconds and then exported in vector graphics ready for publication.

The addition of time-domain tools is another innovation in an impedance analyzer; the plotter tool and DAQ tool of the MFIA allow for the time evolution of impedance values to be measured fast and analyzed as a continuous data stream or as triggered shots. The scope tool gives a real-time view of the raw voltage or current data thanks to the 60 Msa/s ADC. 

What sets the MFIA apart from other impedance analyzers? How does it compare to other models on the market?

The MFIA features LabOne, an industry-leading software interface with many easy-to-use tools to speed up the process of getting data from the bench-top to the final publication.

To ensure that the data is reliable and accurate, the MFIA includes a unique “confidence -indicator” which flags up any data point which is based on unreliable fundamentals.

This delivers data that’s not just reliable, but also accurate thanks to the unbeaten basic accuracy of 0.05%.  Furthermore, our comprehensive accuracy chart shows clearly the accuracy for a given parameter set.

What are the benefits of integrating the MFIA with the MFLI lock-in amplifier?

A unique feature of the MFIA is that it also includes the full functionality of our MFLI Lock-in Amplifier, all in the same box! This gives users the power to measure small periodic voltage and current signals that would otherwise require an additional standalone instrument.

The MFLI was launched in 2015, and has already become the new standard in the world of lock-in amplifiers.

For users new to the world of impedance measurements, how can Zurich Instruments help?

In addition to the confidence-indicators, which ensure trust in measured values for both new and seasoned users, we also include a compensation-advisor. This guides the user through the process of compensating the fixtures which connect the sample to the instrument.

This reduces the uncertainty when using those all-important fixtures.

Which application areas do you see most interest from?

The fast measurement time of the MFIA makes it perfect for application fields such as sensor characterisation and transient spectroscopy.

The MFIA is a powerful tool in any application field where low to mid frequency impedance needs to be accurately or precisely measured, and also where high impedances need to be measured. For example, we see a lot of interest from researchers in dielectrics, component characterization (supercapacitors and high-Q capacitors) and bio-impedance.

What level of support can users expect with the MFIA?

Every instrument comes with Premium Customer Care and we have a team of PhD level scientists and R&D engineers with a wealth of practical lab experience to help with impedance challenges.

As an example, we regularly publish blog posts on measuring challenging impedances. Recent articles have covered fast capacitance measurements, equivalent series resistance (ESR) of a supercapacitor, and measuring the low equivalent series inductance (ESL) of DC-Link capacitors.

What does this mean for the future of impedance measurement?

The MFIA brings innovation to a key research area long neglected by instrument builders, and allows users to take accurate data with confidence.

Where can our readers go to find out more?

Check out our website, which has some excellent application notes and blogs outlining recent results on challenging samples: www.zhinst.com

Alternatively, drop me an email, or call me. I’m always happy to hear about your new impedance challenges!

About Tim Ashworth

Dr Tim Ashworth obtained his PhD degree at the University of Manchester, UK in the field of nanoscale surface science, focusing on UHV SPM. Tim subsequently worked as a post-doc at the University of Basel, using lock-in technology and PLLs to get the best possible results from their home-built SPM.

Tim built up over eight years’ experience of worldwide applications support and scientific business development, before joining Zurich Instruments in 2016.

In addition to strengthening the SPM knowledge at Zurich Instruments, Tim is an applications manager for impedance products.