Impedance Measurements Using Network Analyzer

Hi,
My name is Bryan and I am a Mechanical Engineer undergraduate working as a research assistant. My field of research is using mems (microelectromechanical systems) devices to perform EIS or electro-impedance spectroscopy. I am using a Keysight LCR meter as well as a Keysight Network Analyzer to perform measurements and am getting some slightly conflicting results. The data from the LCR meter produces a nice Bode Plot (impedance vs. frequency). The impedance decay's until only the physical resistance of the sensor is prevalent. The Network Analyzer shows a Bode Plot where the impedance spikes to a maximum before it decays. Once the impedance begins to decay, the data from each machine begins to match. What I want to know is, why would the impedance rise before it decays and why is it only one machine that detects that behavior. I am a mechanical engineer undergrad, so I may be using either machine incorrectly or there may be something else going on. Any advice would be greatly appreciated. Thank you.

TeriSerugi said:

The Network Analyzer shows a Bode Plot where the impedance spikes to a maximum
before it decays.
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What I want to know is,
why would the impedance rise before it decays

Click to expand...

It seems to be self-resonance.

TeriSerugi said:

and why is it only one machine that detects that behavior.

Click to expand...

Most probably, it is due to difference of calibration between LCR meter and VNA.

Resonance peaking might be parasitic resonance of environment not DUT.

Show me followings.

(1) Product Number of LCR meter and VNA
(2) Measurement Frequency Range. Fstart, Fstop, Number_of_Points
(3) What is your DUT ?
(4) How do you connect LCR and VNA to DUT ?
(5) Where is a reference plane for VNA ?