Impedance measurement front-end based on signal four-phase detection


  • G. I. Barylo Lviv Polytechnic National University, Ukraine
  • R. L. Holyaka Lviv Polytechnic National University, Ukraine
  • I. N. Prudyus Lviv Polytechnic National University, Ukraine
  • S. E. Fabirovskyy Lviv Polytechnic National University, Ukraine



impedance spectroscopy, signal front-end, Internet of Things, SPICE simulation


Internet of Things (IoT), a new direction in information and communication systems, has a significant impact on the development of novel electronics devices. Further progress in the field of IoT devices is conditioned by the development of sensor devices, and in particular, analog front-ends and signal converters for IoT sensors. High sensitivity and wide range applications of IoT sensors can be achieved by methods of impedance spectroscopy. Compared with other methods of physical research, impedance spectroscopy and based on it IoT sensor devices provide ease of implementation, high energy efficiency, good resolution and selectivity. In this paper, we present results of the development and model study of the impedance measuring transducer using the four-phase signal integration method.
The implementation of impedance spectroscopy assumes a transition from frequency plots to plots on the complex plane, called as Nyquist plots. The data obtained in this paper are based on the SPICE (Simulation Program with Integrated Circuit Emphasis) model studding methodology, which compares small signal Alternative Current Analysis with large signal Transient Analysis. During the Alternative Current Analysis, Nyquist impedance plot are obtained in the idealized case, and during the Transient Analysis the active ReZ value and reactive ImZ impedance components are calculated for the actual parameters of the measuring transducers and the form of the activating signals.
We have proposed a new solution of the impedance measuring transducer based on the four-phase signal commutation and integration method. This method consists in the formation of four informative signals, namely, the voltages $V_{Q1}$, $V_{Q2}$, $V_{Q3}$ та $V_{Q4}$, each of which corresponds to the integration results in the corresponding four phases of the activation signal. In these phases, or time t, the sign functions $A_{Q1}(t)$, $A_{Q2}(t)$, $A_{Q3}(t)$, $A_{Q4}(t)$ of synchronous detections are used: $A_{Q1}(t)=1$ at $t=[0...\pi/2]$; $A_{Q2}(t)=1$ at $t=[\pi/2...\pi]$; $A_{Q3}(t)=1$ at $t=[\pi...3\pi/2]$; $A_{Q4}(t)=1$ at $t=[3\pi/2...2\pi]$. In other time these sign functions are equal 0. Output signals of the impedance measuring transducer, namely, voltages of active $V_{RE}$ and the reactive $V_{IM}$ components are formed by adding and subtracting the numerical values of the above four voltages: $V_{RE}=V_{Q1}+V_{Q2}-V_{Q3}-V_{Q4}$; $V_{IM}=V_{Q1}-V_{Q2}-V_{Q3}+V_{Q4}$. The main units of the impedance measuring analog front-end are a synchronous quadrature detector and an integrator or filter.
In comparison to traditional two-phase detection, four-phase detection we have proposed allows avoiding intermediate signal transducing, which provides a significant simplification of impedance measuring transducing. This simplification is achieved by directly integrating the instantaneous value of the $I_{Z}(t)$ current. Important dependences of the measuring transducer output voltages with four-phase integration on the operational amplifiers bandwidth are obtained.
Results presented in the article are important for developing a new generation of microelectronic IoT sensor devices based on impedance spectroscopy methods. Main areas of application of such sensor devices are materials science, biochemistry, instrumentation, avionics, ecology, etc.

Author Biographies

G. I. Barylo, Lviv Polytechnic National University

Barylo G. I., Cand. of Sci (Tech)

R. L. Holyaka, Lviv Polytechnic National University

Holyaka R. L., Doc. of Sci (Tech), Prof.

I. N. Prudyus, Lviv Polytechnic National University

Prudyus I. N., Doc. of Sci (Tech), Prof.

S. E. Fabirovskyy, Lviv Polytechnic National University

Fabirovskyy S. E., Cand. of Sci (Tech)


Vermesan O. and Friess P. (2013) Internet of Things: Converging Technologies for Smart Environments and Integrated Ecosystems, River Publishers, 363 p.

Yoshimatsu T., Tsuda N. and Yamada J. (2016) Signal processing for distance measurement using laser voltage fluctuation due to self-coupling effect. 2016 10th International Conference on Sensing Technology (ICST). DOI: 10.1109/icsenst.2016.7796306

Holyaka R. and Kostiv N. (2011) Energy-efficient signal converter of thermocouple, temperature sensors. Informatyka, Automatyka, Pomiary, no. 4, pp. 26-28.

Hajimorad M., Alhloul S., Mustafa H., So M. and Oswal H. (2016) Application of polypyrrole-based selective electrodes in electrochemical impedance spectroscopy to determine nitrate concentration. 2016 IEEE SENSORS. DOI: 10.1109/icsens.2016.7808592

Gajasinghe R. W RL, Tigli O., Jones M. and Ince T. (2016) Label-free tumor cell detection and differentiation based on electrical impedance spectroscopy. 2016 IEEE SENSORS. DOI: 10.1109/icsens.2016.7808466

Hong B., Sun A., Pang L., Venkatesh A., Hall D. and FAINMAN Y. (2016) Integrated biosensor for simultaneous detection by surface plasmon resonance and Faradaic electrochemical impedance spectroscopy. Conference on Lasers and Electro-Optics. DOI: 10.1364/cleo_at.2016.jw2a.113

Jun-Rui Z., Nanolab I.A. and Mazza M. (2016) Low-energy biomarker detection through charge-based impedance measurements. 2016 IEEE SENSORS. DOI: 10.1109/icsens.2016.7808744

Kamat D.K. and Patil P.M. (2016) Multi-frequency and multi-segment bio-impedance measurement using tetra-polar electrode setup. 2016 2nd International Conference on Control Science and Systems Engineering (ICCSSE). DOI: 10.1109/ccsse.2016.7784380

Mankovskyy S. and Mankovska E. (2016) Symbolic model of the quadrature detector. 2016 13th International Conference on Modern Problems of Radio Engineering, Telecommunications and Computer Science (TCSET). DOI: 10.1109/tcset.2016.7451978

Culurciello E., Montanaro H. and Kim D. (2009) Ultralow Current Measurements With Silicon-on-Sapphire Integrator Circuits. IEEE Electron Device Letters, Vol. 30, Iss. 3, pp. 258-260. DOI: 10.1109/led.2008.2010564

Sandler Steven and Hymowitz Charles. (2006) SPICE Circuit Handbook. The McGraw Hill. - 362 p. DOI: 10.1036/0071468579

MICRO-CAP (2014) Electronic Circuit Analysis Program. Spectrum Software., 8 p.

Barylo G. I., Holyaka R. L., Prudyus I. N. and Fabirovskyy S. E. (2017) Technique of increasing the impedance measuring transducers accuracy at inharmoniousness signals. Visn. NTUU KPI, Ser. Radioteh. radioaparatobuduv., no. 70, pp. 30-36. (in Ukrainian)





Theory and Practice of Radio Measurements