**4. Conclusions**

The viability of the CMOS embedded microfluidic device for dielectrophoretic immobilization of particles was investigated by finite element modeling (FEM) simulations. This study proposed a sensing platform to enable the immobilization of particles with micron and submicron sizes constrained by technological advances, such as silicon-based microfluidics and millimeter wave readout circuit. IDE's geometrical parameters were characterized and optimized based on essential external parameters, such as voltage, frequency, and velocity of the fluid through the microfluidic channel. By increasing the applied voltage trapping of smaller particles on electrodes is enhanced. The change of frequency does not influence the DEP force for improving the immobilization of particles but rather influences the crossover frequency between negative and positive DEP. Reducing the fluid flow velocity forces the immobilization of submicron particles. By keeping the voltage constant at CMOS compatible range, the impact of IDE's geometrical parameters on the tracing and immobilization of the particles was investigated. The ratio between the electrodes' spacing and the width impacts the IDE's performance. According to simulations, the width of the IDE's finger has to be increased, whereas the spacing has to be reduced. The simulation and design of planar IDEs were evaluated to maximize the immobilization probability of submicron sized particles. The IDE design for the immobilization of micron and submicron size particles with optimum geometrical parameters of IDE and the fluid flow rate was demonstrated. Furthermore, a study on the impact of temperature (also due to chip self-heating) in IDE parameters was investigated though electromagnetic momentum simulations. It was observed that the change in impedance of IDE is only up to 3.07 Ȕ from room temperature up to 50 ◦C which is less likely to a ffect the short term measurements. Lastly, the presented optimized IDEs can be combined with various readout architectures. The 60 GHz high-frequency reflectometer based architecture was chosen to enable higher miniaturization of a sophisticated sensing platform, and its homodyne architecture will enable a dc-in and dc-out based impedance spectroscopy.

**Author Contributions:** Methodology, H.M.E. and S.G.; Validation, H.M.E., R.K.Y. and S.G.; Software, H.M.E. and R.K.Y.; Formal analysis, H.M.E., R.K.Y. and C.W.; Data curation, H.M.E., R.K.Y. and S.G.; Writing—original draft preparation, H.M.E.; Writing—review & editing, H.M.E., R.K.Y. and C.W.; Supervision, C.W.; Funding acquisition, C.W.

**Funding:** This research was funded by the Brandenburg Ministry of Science, Research, and Cultural A ffairs for funding the project within the StaF program in Germany.

**Acknowledgments:** The authors would like to thank the technology department of IHP for the fabrication of the sensor chip.

**Conflicts of Interest:** The authors declare no conflict of interest.
