Substrate Materials of Microfluidic-Microwave Devices: Comparison
View Latest Version
Please note this is a comparison between Version 1 by Laura Jasińska and Version 2 by Lily Guo.

The area of microfluidic devices with microwave components is constantly increasing. There are four main types of materials, that can act as a substrate for the microwave-microfluidic systems—epoxy-glass laminates, polymer materials, glass/silicon substrates, and Low-Temperature Cofired Ceramics (LTCCs). The entry describes and compares briefly all selected materials.

  • microfluidics
  • microwaves
  • sensors
  • LTCC
  • Glass-epoxy laminates
  • glass
  • silicon
  • polymers

1. Introduction

Based on the Scopus database, the number of publications related to the field of microfluidics reached nearly 6000 records in 2020. The use of microfluidic devices with integrated microwave components is notable mainly in biochemical and chemical applications, such as detecting the biological material

Based on the Scopus database, the number of publications related to the field of microfluidics reached nearly 6000 records in 2020. The use of microfluidic devices with integrated microwave components is notable mainly in biochemical and chemical applications, such as detecting the biological material

[1][2][3][4]

. Furthermore, due to the possibility of noncontact sensing and delivering the microwaves to the systems (using the antenna-based circuits), the possibilities are still increasing

[5][6][7]

. Due to the simplified geometries of the structures, the use of such systems often does not require specialized staff. Thus, these systems became common solutions in many areas, such as biotechnology, biochemistry, medical applications, etc. Moreover, the choice of the microwave methods allows different systems to be fabricated, which can be based on coaxial waveguides, as in

[9], which significantly expands on the possibilities of applications.In the literature, many materials that act as substrates for microfluidic microwave devices can be found. However, the four most common ones are glass-epoxy laminates (especially Rogers Corp., Chandler, AZ, USA), glass/silicon wafers, various polymer materials (mostly polydimethylsiloxane, PDMS), and ceramics (Low-Temperature Cofired Ceramics, LTCC). Each of them brings different advantages and technological challenges. The electrical parameters of selected materials are shown in Table 1.Table 1. The selected properties of the materials that act as substrates for microfluidic or/and microwave components in the microfluidic-microwave devices. Based on

, which significantly expands on the possibilities of applications.
In the literature, many materials that act as substrates for microfluidic microwave devices can be found. However, the four most common ones are glass-epoxy laminates (especially Rogers Corp., Chandler, AZ, USA), glass/silicon wafers, various polymer materials (mostly polydimethylsiloxane, PDMS), and ceramics (Low-Temperature Cofired Ceramics, LTCC). Each of them brings different advantages and technological challenges. The electrical parameters of selected materials are shown in Table 1.
Table 1. The selected properties of the materials that act as substrates for microfluidic or/and microwave components in the microfluidic-microwave devices. Based on

[10][11][12][13][14][15][16][17][18][19][20][21][22].

.
MaterialSiliconBorosilicate GlassPMMAPDMSRogers (RO4000 Series)LTCC
Relative permittivity (-)10–113.8–5.13.22.3–2.83.3–3.57.5–7.8
Dielectric loss tangent (-)0.001 @ 1MHz0.002–0.0040.001–0.003 @ 8.92 GHz0.02 @ 2.5 GHz0.002–0.0030.006 @ 3 GHz
Resistivity (Ω·cm)6.4 × 1044 × 10102 × 10150.6 × 1012n/n>1012
Contact angle (DI water on non-treated surface)~20–40~70~75~90–110n/n~60–70
MaterialSiliconBorosilicate GlassPMMAPDMSRogers (RO4000 Series)LTCC
Relative permittivity (-)10–113.8–5.13.22.3–2.83.3–3.57.5–7.8
Dielectric loss tangent (-)0.001 @ 1MHz0.002–0.0040.001–0.003 @ 8.92 GHz0.02 @ 2.5 GHz0.002–0.0030.006 @ 3 GHz
Resistivity (Ω·cm)6.4 × 1044 × 10102 × 10150.6 × 1012n/n>1012
Contact angle (DI water on non-treated surface)~20–40~70~75~90–110n/n~60–70

2. Glass-Epoxy Laminates

From the perspective of the microwave technique, the most characterized substrates are glass-epoxy laminates. This is related to many features, such as ease of fabricating the geometries of conductive paths and the possibility of easy integration of various active and passive electronic components

1. Glass-Epoxy Laminates

From the perspective of the microwave technique, the most characterized substrates are glass-epoxy laminates. This is related to many features, such as ease of fabricating the geometries of conductive paths and the possibility of easy integration of various active and passive electronic components

[23][24][25]

. Moreover, these materials are characterized by small dielectric losses and stable relative permittivity over a wide frequency range. The most common substrates dedicated to microwave purposes are those made by Rogers Corporation. However, with their adequate electrical parameters, laminates are usually less resistant to harsh environmental conditions, such as increased humidity, temperature, and various chemical agents. Moreover, the presence of the mentioned conditions is typical for microfluidic systems. Due to this, the majority of microfluidic components are made with the use of other materials and they are attached to the PCB system

[24][25][26][27][28][29][30][31][32]. Due to the possibilities offered by microfluidic-microwave systems, despite some technological challenges, numerous examples of such devices can be observed in the literature.The fabrication process of the microwave devices integrated with the microfluidic components consists of several steps. After designing the dimensions of the whole structure, the first step is typically the manufacturing of the microstrip lines (or coplanar waveguides, CPWs) and specific pattern (if necessary) of the ground plane. Most of the glass-epoxy laminates dedicated to microwave applications are covered by thin copper layers, which makes the fabrication of the conductive lines a simple process. However, the accurate integration of the microfluidic components with the circuit made on the glass-epoxy laminate is more complicated. Usually, this requires the choice of some polymer material, such as Polytetrafluoroethylene (PTFE) or PDMS, and then the integration in the designed part of the microwave microstrip circuit. Frequently, the use of some positioning components, made, e.g., by 3D printing as in

. Due to the possibilities offered by microfluidic-microwave systems, despite some technological challenges, numerous examples of such devices can be observed in the literature.
The fabrication process of the microwave devices integrated with the microfluidic components consists of several steps. After designing the dimensions of the whole structure, the first step is typically the manufacturing of the microstrip lines (or coplanar waveguides, CPWs) and specific pattern (if necessary) of the ground plane. Most of the glass-epoxy laminates dedicated to microwave applications are covered by thin copper layers, which makes the fabrication of the conductive lines a simple process. However, the accurate integration of the microfluidic components with the circuit made on the glass-epoxy laminate is more complicated. Usually, this requires the choice of some polymer material, such as Polytetrafluoroethylene (PTFE) or PDMS, and then the integration in the designed part of the microwave microstrip circuit. Frequently, the use of some positioning components, made, e.g., by 3D printing as in

[25]

or some steel frame, is necessary, as shown in

[33][34].

3. Glass/Silicon Substrates

One of the first microfluidic device manufactured on a silicon substrate was developed in the 1980s

.

2. Glass/Silicon Substrates

One of the first microfluidic device manufactured on a silicon substrate was developed in the 1980s

[35]

. There are many examples of devices that are based on silicon or glass substrates operating in the microwave frequency range. This technology mostly appears in LOC microsystems, which can be made on, among other things, quartz

[1][36][37][38]

, silicon

[39]

, or glass

[40][41]

substrates. Due to fact that the material, which acts as a microwave circuits’ substrate, should be characterized by high resistivity, the silicon ones are mostly the high-resistive ones

[42][43][44]

. The process of manufacturing microwave devices with microfluidic components usually consists of fabricating thin-layer microwave planar waveguides on a glass or silicon substrate and adding a part constituting a microfluidic channel. Typically, the technological process consists of two stages. The first stage includes the fabricating of the conductive microwave circuit, by photolithography and/or electroplating. The second one is the manufacturing of the microfluidic components in the volume of polymer—typically PDMS—using soft lithography. Then, bonding to a glass/Si substrate containing a microwave microstrip circuit using oxygen plasma is carried out

[43]

. However, the possibility of omitting the plasma-bonding in the fabrication process has recently been reported, which is described well in

[45].The exemplary technological process of a device made on a glass substrate is presented in

.
The exemplary technological process of a device made on a glass substrate is presented in

[46]

, where the microwave circuit was made on the glass substrate using a combination of electroplating and electro lithography. In this case, the thin layer of SiO

2

was coated (using the magnetron sputtering) due to avoid the risk of contamination as a result of direct contact between gold microstrip lines and liquid. The fabrication of the PDMS microfluidic components was preceded by fabrication SU-8 masters on silicon wafers using soft lithography. In the last fabrication stage, the microwave glass substrate and PDMS component were treated with oxygen plasma. However, the process of manufacturing the microfluidic components is also hard to carry out, as in

[47]

. Due to this, the monolithic microwave-microfluidic systems are also encountered—e.g., as in works

[43][48].

4. Polymers

Polymer materials are relatively standard substrates for microfluidic systems and a sufficient description of the technological processes is included in the

.

3. Polymers

Polymer materials are relatively standard substrates for microfluidic systems and a sufficient description of the technological processes is included in the

[49]

. Such materials have many advantages, such as relative ease of three-dimensional structuration and higher resistance to humidity and chemical agents in comparison to the glass-epoxy laminates. However, polymeric materials are sensitive to temperature changes and their dielectric losses significantly depend on frequency

[50]

. Moreover, the integration of electronic components with a single polymer substrate is more difficult in comparison to the laminates, which significantly prolongs the fabrication process. In the case described in

[51], the first step of the technological process was cutting the Cyclic Olefin Copolymer (COC) substrate into a designed shape and forming the microchannel’s geometry using a CNC milling machine. Then, the slit in the microchannel was fabricated using photolithography. In the next step, the copper self-adhesive tape was placed on the top and bottom surfaces of the COC substrate and the transmission line and ground plane were patterned.The state of art shows a leading trend, which is the application of transparent polymers in microfluidic-microwave devices, such as PDMS, Polymethylmethacrylate, polymethyl methacrylate (PMMA)

, the first step of the technological process was cutting the Cyclic Olefin Copolymer (COC) substrate into a designed shape and forming the microchannel’s geometry using a CNC milling machine. Then, the slit in the microchannel was fabricated using photolithography. In the next step, the copper self-adhesive tape was placed on the top and bottom surfaces of the COC substrate and the transmission line and ground plane were patterned.
The state of art shows a leading trend, which is the application of transparent polymers in microfluidic-microwave devices, such as PDMS, Polymethylmethacrylate, polymethyl methacrylate (PMMA)

[52][53]

or COC

[51][54]

. Typically, the polymer acts as the substrate containing the microfluidic structures made by soft photolithography. The microwave circuits are usually made of self-adhesive copper foil

[27]

or using an ink-jet printing process

[28]. Due to this, in comparison to the other mentioned technologies, there are only several publications that describe the microfluidic-microwave devices based only on the polymer material. The fabrication of microwave circuits is usually the last stage of fabricating the microfluidic-microwave devices based mainly on polymers.

5. Low-Temperature Cofired Ceramics

For years, LTCC (low-temperature cofired ceramics) have acted as the substrates for microwave circuits thanks to the development of substrate materials with various dielectric parameters, which are stable over a wide frequency range. Recently, LTCC has also been used successfully as a base for microfluidic modules due to the chemical resistance of LTCC, the possibility of fabrication of three-dimensional structures inside and outside the module, and humidity resistance. Due to the specificity of LTCC materials, both microwave systems (mainly antennas, but also other circuits)

. Due to this, in comparison to the other mentioned technologies, there are only several publications that describe the microfluidic-microwave devices based only on the polymer material. The fabrication of microwave circuits is usually the last stage of fabricating the microfluidic-microwave devices based mainly on polymers.

4. Low-Temperature Cofired Ceramics

For years, LTCC (low-temperature cofired ceramics) have acted as the substrates for microwave circuits thanks to the development of substrate materials with various dielectric parameters, which are stable over a wide frequency range. Recently, LTCC has also been used successfully as a base for microfluidic modules due to the chemical resistance of LTCC, the possibility of fabrication of three-dimensional structures inside and outside the module, and humidity resistance. Due to the specificity of LTCC materials, both microwave systems (mainly antennas, but also other circuits)

[55][56][57][58][59]

and microfluidic modules

[60][61][62][63]

are fabricated as monolithic systems. The LTCC modules are the multilayer ones. Due to this, the fabrication process consists of several steps: forming the layers and the three-dimensional structures (such as microchannels and microchambers), screen printing, stacking and laminating and then, cofiring. Due to this, the LTCC technology allows the manufacturing of both the conductive paths and microchannels in one technological process. Moreover, a new trend of fabricating ceramic microsystems has recently appeared—additive manufacturing, which in the near future will significantly increase the variety of fabricated ceramic microsystems

[64]

. Hence, LTCC seems to be suited for solutions combining microfluidic components with microwave technology, a trend that can be observed in the literature

[5][65][66][67].

.
 

References

  1. Zhang, L.Y.; Du Puch, C.B.M.; Dalmay, C.; Lacroix, A.; Landoulsi, A.; Leroy, J.; Melin, C.; Lalloue, F.; Battu, S.; Lautrette, C.; et al. Discrimination of colorectal cancer cell lines using microwave biosensors. Sens. Actuators A Phys. 2014, 216, 405–416.
  2. Crupi, G.; Bao, X.; Babarinde, O.J.; Schreurs, D.M.M.-P.; Nauwelaers, B. Biosensor Using a One-Port Interdigital Capacitor: A Resonance-Based Investigation of the Permittivity Sensitivity for Microfluidic Broadband Bioelectronics Applications. Electronics 2020, 9, 340.
  3. Liu, T.-M.; Chen, H.-P.; Wang, L.-T.; Wang, J.-R.; Luo, T.-N.; Chen, Y.-J.; Liu, S.-I.; Sun, C.-K. Microwave resonant absorption of viruses through dipolar coupling with confined acoustic vibrations. Appl. Phys. Lett. 2009, 94, 043902.
  4. Muñoz-Enano, J.; Vélez, P.; Gil, M.; Jose-Cunilleras, E.; Bassols, A.; Martín, F. Characterization of electrolyte content in urine samples through a differential microfluidic sensor based on dumbbell-shaped defected ground structures. Int. J. Microw. Wirel. Technol. 2020, 12, 817–824.
  5. Liang, Y.; Ma, M.; Zhang, F.; Liu, F.; Liu, Z.; Wang, D.; Li, Y. An LC Wireless Microfluidic Sensor Based on Low Temperature Co-Fired Ceramic (LTCC) Technology. Sensors 2019, 19, 1189.
  6. Hamzah, H.; Abduljabar, A.; Lees, J.; Porch, A. A Compact Microwave Microfluidic Sensor Using a Re-Entrant Cavity. Sensors 2018, 18, 910.
  7. Chow, H.; Chen, B.; Chen, H.; Feng, W. Integrated Systems for Biomedical Applications: Silicon-Based RF\/Microwave Dielectric Spectroscopy and Sensing. IEEE Microw. Mag. 2017, 18, 57–72.
  8. Scopus Database Home Page. Available online: (accessed on 30 December 2020).
  9. Rowe, D.J.; Porch, A.; Barrow, D.A.; Allender, C.J. Microfluidic device for compositional analysis of solvent systems at microwave frequencies. Sens. Actuators B Chem. 2012, 169, 213–221.
  10. Krupka, J.; Breeze, J.; Alford, N.M.; Centeno, A.E.; Jensen, L.; Claussen, T. Measurements of Permittivity and Dielectric Loss Tangent of High Resistivity Float Zone Silicon at Microwave Frequencies. In Proceedings of the 2006 International Conference on Microwaves, Radar & Wireless Communications, Krakow, Poland, 22–24 May 2006; pp. 1097–1100.
  11. Aras, G.; Orhan, E.; Selçuk, A.; Ocak, S.B.; Ertuğrul, M. Dielectric Properties of Al/Poly (methyl methacrylate) (PMMA)/p-Si Structures at Temperatures Below 300 K. Proc. Soc. Behav. Sci. 2015, 195, 1740–1745.
  12. Tanwar, A.; Gupta, K.K.; Singh, P.J.; Vijay, Y.K. Dielectric parameters and a.c. conductivity of pure and doped poly (methyl methacrylate) films at microwave frequencies. Bull. Mater. Sci. 2006, 29, 397–401.
  13. Rogers Corporation. Rogers Corporation Datasheet RO4000 Series; Chandler: San Francisco, CA, USA, 2018.
  14. Continential Trade. Borosilicate Glass 3.3—DIN 7080 Information Sheet. Available online: (accessed on 30 December 2020).
  15. Simorangkir, R.B.V.B.; Yang, Y.; Hashmi, R.M.; Bjorninen, T.; Esselle, K.P.; Ukkonen, L. Polydimethylsiloxane-Embedded Conductive Fabric: Characterization and Application for Realization of Robust Passive and Active Flexible Wearable Antennas. IEEE Access 2018, 6, 48102–48112.
  16. Malecha, K.; Remiszewska, E.; Pijanowska, D.G. Surface modification of low and high temperature co-fired ceramics for enzymatic microreactor fabrication. Sens. Actuators B Chem. 2014, 190, 873–880.
  17. Nawrot, W.; Malecha, K. Biomaterial Embedding Process for Ceramic–Polymer Microfluidic Sensors. Sensors 2020, 20, 1745.
  18. Malecha, K.; Gancarz, I.; Golonka, L.J. A PDMS/LTCC bonding technique for microfluidic application. J. Micromech. Microeng. 2009, 19.
  19. DeRosa, R.L.; Schader, P.A.; Shelby, J.E. Hydrophilic nature of silicate glass surfaces as a function of exposure condition. J. Non Cryst. Solids 2003, 331, 32–40.
  20. Bryk, P.; Korczeniewski, E.; Szymański, G.S.; Kowalczyk, P.; Terpiłowski, K.; Terzyk, A.P. What Is the Value of Water Contact Angle on Silicon? Materials 2020, 13, 1554.
  21. Zdziennicka, A.; Szymczyk, K.; Krawczyk, J.; Jańczuk, B. Some remarks on the solid surface tension determination from contact angle measurements. Appl. Surf. Sci. 2017, 405, 88–101.
  22. Gao, X.; Huang, Y.; Liu, Y.; Kormakov, S.; Zheng, X.; Wu, D.; Wu, D. Improved electrical conductivity of PDMS/SCF composite sheets with bolting cloth prepared by a spatial confining forced network assembly method. RSC Adv. 2017, 7, 14761–14768.
  23. Abduljabar, A.A.; Choi, H.; Barrow, D.A.; Porch, A. Adaptive Coupling of Resonators for Efficient Microwave Heating of Microfluidic Systems. IEEE Trans. Microw. Theory Tech. 2015, 63, 3681–3690.
  24. Schwerthoeffer, U.; Weigel, R.; Kissinger, D. A highly sensitive glucose biosensor based on a microstrip ring resonator. In Proceedings of the 2013 IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO), Singapore, 9–11 December 2013; pp. 1–3.
  25. Ebrahimi, A.; Withayachumnankul, W.; Al-Sarawi, S.F.; Abbott, D. Microwave microfluidic sensor for determination of glucose concentration in water. In Proceedings of the 2015 IEEE 15th Mediterranean Microwave Symposium (MMS), Lecce, Italy, 30 November–2 December 2015; pp. 1–3.
  26. Abdolrazzaghi, M.; Daneshmand, M.; Iyer, A.K. Strongly Enhanced Sensitivity in Planar Microwave Sensors Based on Metamaterial Coupling. IEEE Trans. Microw. Theory Tech. 2018, 66, 1843–1855.
  27. Wessel, J.; Schmalz, K.; Scheytt, J.C.; Cahill, B.P.; Gastrock, G. Microwave biosensor for characterization of compartments in teflon capillaries. In Proceedings of the 42nd European Microwave Conference, Amsterdam, The Netherlands, 29 October–1 November 2012; pp. 534–537.
  28. Abduljabar, A.A.; Rowe, D.J.; Porch, A.; Barrow, D.A. Novel Microwave Microfluidic Sensor Using a Microstrip Split-Ring Resonator. IEEE Trans. Microw. Theory Tech. 2014, 62, 679–688.
  29. Ebrahimi, A.; Withayachumnankul, W.; Al-Sarawi, S.; Abbott, D. High-Sensitivity Metamaterial-Inspired Sensor for Microfluidic Dielectric Characterization. IEEE Sens. J. 2014, 14, 1345–1351.
  30. Velez, P.; Su, L.; Grenier, K.; Mata-Contreras, J.; Dubuc, D.; Martin, F. Microwave Microfluidic Sensor Based on a Microstrip Splitter/Combiner Configuration and Split Ring Resonators (SRRs) for Dielectric Characterization of Liquids. IEEE Sens. J. 2017, 17, 6589–6598.
  31. Salim, A.; Kim, S.-H.; Park, J.Y.; Lim, S. Microfluidic Biosensor Based on Microwave Substrate-Integrated Waveguide Cavity Resonator. J. Sens. 2018, 2018, 1–13.
  32. Ebrahimi, A.; Scott, J.; Ghorbani, K. Microwave reflective biosensor for glucose level detection in aqueous solutions. Sens. Actuators A Phys. 2020, 301, 111662.
  33. Ebrahimi, A.; Scott, J.; Ghorbani, K. Ultrahigh-Sensitivity Microwave Sensor for Microfluidic Complex Permittivity Measurement. IEEE Trans. Microw. Theory Tech. 2019, 67, 4269–4277.
  34. Ye, D.; Wang, P. A Dual-Mode Microwave Resonator for Liquid Chromatography Applications. IEEE Sens. J. 2021, 21, 1222–1228.
  35. Abgrall, P.; Gue, A.M. Lab-on-chip technologies: Making a microfluidic network and coupling it into a complete microsystem—A review. J. Micromech. Microeng. 2007, 17, R15.
  36. Bao, X.; Ocket, I.; Crupi, G.; Schreurs, D.; Bao, J.; Kil, D.; Puers, B.; Nauwelaers, B. A Planar One-Port Microwave Microfluidic Sensor for Microliter Liquids Characterization. IEEE J. Electromagn. RF Microwaves Med. Biol. 2018, 2, 10–17.
  37. Markovic, T.; Bao, J.; Ocket, I.; Kil, D.; Brancato, L.; Puers, R.; Nauwelaers, B. Uniplanar microwave heater for digital microfluidics. In Proceedings of the 2017 First IEEE MTT-S International Microwave Bio Conference (IMBIOC), Gothenburg, Sweden, 15–17 May 2017; pp. 1–4.
  38. Dubuc, D.; Mazouffre, O.; Llorens, C.; Taris, T.; Poupot, M.; Fournié, J.-J.; Bégueret, J.-B.; Grenier, K. Microwave-based biosensor for on-chip biological cell analysis. Analog. Integr. Circuits Signal Process. 2013, 77, 135–142.
  39. Koziej, D.; Floryan, C.; Sperling, R.A.; Ehrlicher, A.J.; Issadore, D.; Westervelt, R.; Weitz, D.A. Microwave dielectric heating of non-aqueous droplets in a microfluidic device for nanoparticle synthesis. Nanoscale 2013, 5, 5468–5475.
  40. Song, C.; Wang, P. A radio frequency device for measurement of minute dielectric property changes in microfluidic channels. Appl. Phys. Lett. 2009, 94, 23901.
  41. Camli, B.; Altinagac, E.; Kizil, H.; Torun, H.; Dundar, G.; Yalcinkaya, A.D. Gold-on-glass microwave split-ring resonators with PDMS microchannels for differential measurement in microfluidic sensing. Biomicrofluidics 2020, 14, 054102.
  42. Markovic, T.; Ocket, I.; Baric, A.; Nauwelaers, B. Design and Comparison of Resonant and Non-Resonant Single-Layer Microwave Heaters for Continuous Flow Microfluidics in Silicon-Glass Technology. Energies 2020, 13, 2635.
  43. Markovic, T.; Ocket, I.; Jones, B.; Nauwelaers, B. Characterization of a novel microwave heater for continuous flow microfluidics fabricated on high-resistivity silicon. In Proceedings of the 2016 IEEE MTT-S International Microwave Symposium (IMS), San Francisco, CA, USA, 22–27 May 2016; pp. 1–4.
  44. Markovic, T.; Jones, B.; Barmuta, P.; Ocket, I.; Nauwelaers, B. A Transmission Line Based Microwave Heater at 25 GHz for Continuous Flow Microfluidics Fabricated on Silicon. In Proceedings of the 2019 49th European Microwave Conference (EuMC), Paris, France, 1–3 October 2019; pp. 654–657.
  45. Bao, J.; Markovic, T.; Brancato, L.; Kil, D.; Ocket, I.; Puers, R.; Nauwelaers, B. Novel Fabrication Process for Integration of Microwave Sensors in Microfluidic Channels. Micromachines 2020, 11, 320.
  46. Yesiloz, G.; Boybay, M.S.; Ren, C.L. Effective Thermo-Capillary Mixing in Droplet Microfluidics Integrated with a Microwave Heater. Anal. Chem. 2017, 89, 1978–1984.
  47. Iliescu, C.; Taylor, H.; Avram, M.; Miao, J.; Franssila, S. A practical guide for the fabrication of microfluidic devices using glass and silicon. Biomicrofluidics 2012, 6, 016505–1650516.
  48. Govind, G.; Akhtar, M.J. Design of an ELC resonator-based reusable RF microfluidic sensor for blood glucose estimation. Sci. Rep. 2020, 10, 1–10.
  49. Becker, H. Polymer microfluidic devices. Talanta 2002, 56, 267–287.
  50. Kachroudi, A.; Basrour, S.; Rufer, L.; Sylvestre, A.; Jomni, F. Dielectric properties modelling of cellular structures with PDMS for micro-sensor applications. Smart Mater. Struct. 2015, 24, 125013.
  51. Shah, J.J.; Geist, J.; Gaitan, M. Microwave-induced adjustable nonlinear temperature gradients in microfluidic devices. J. Micromech. Microeng. 2010, 20.
  52. Marchiarullo, D.J.; Sklavounos, A.H.; Oh, K.; Poe, B.L.; Barker, N.S.; Landers, J.P. Low-power microwave-mediated heating for microchip-based PCR. Lab Chip 2013, 13, 3417–3425.
  53. McKerricher, G.; Conchouso, D.; Cook, B.S.; Foulds, I.; Shamim, A. Crude oil water-cut sensing with disposable laser ablated and inkjet printed RF microfluidics. In Proceedings of the 2014 IEEE MTT-S International Microwave Symposium (IMS2014), Tampa, FL, USA, 1–6 June 2014; pp. 1–3.
  54. Duffy, D.C.; McDonald, J.C.; Schueller, O.J.; Whitesides, G.M. Rapid Prototyping of Microfluidic Systems in Poly(dimethylsiloxane). Anal. Chem. 1998, 70, 4974–4984.
  55. Jantunen, H.; Kangasvieri, T.; Vähäkangas, J.; Leppävuori, S. Design aspects of microwave components with LTCC technique. J. Eur. Ceram. Soc. 2003, 23, 2541–2548.
  56. Chen, X.-P.; Wu, K. Substrate Integrated Waveguide Filters: Design Techniques and Structure Innovations. IEEE Microw. Mag. 2014, 15, 121–133.
  57. Wolff, I. Integrated beam steerable antennas in LTCC-technology. In Proceedings of the 2010 International Workshop on Antenna Technology (iWAT), Lisbon, Portugal, 1–3 March 2010; pp. 1–4.
  58. Nafe, A.; Ghaffar, F.A.; Farooqui, M.F.; Shamim, A. A Ferrite LTCC-Based Monolithic SIW Phased Antenna Array. IEEE Trans. Antennas Propag. 2016, 65, 196–205.
  59. Feng, W.; Gao, X.; Che, W.; Yang, W.; Xue, Q. LTCC Wideband Bandpass Filters with High Performance Using Coupled Lines with Open/Shorted Stubs. IEEE Trans. Compon. Packag. Manuf. Technol. 2017, 7, 602–609.
  60. Atalay, Y.T.; Vermeir, S.; Witters, D.; Vergauwe, N.; Verbruggen, B.; Verboven, P.; Nicolaï, B.M.; Lammertyn, J. Microfluidic analytical systems for food analysis. Trends Food Sci. Technol. 2011, 22, 386–404.
  61. Malecha, K.; Golonka, L.J.; Bałdyga, J.; Jasińska, M.; Sobieszuk, P. Serpentine microfluidic mixer made in LTCC. Sens. Actuators B Chem. 2009, 143, 400–413.
  62. Gongora-Rubio, M.R.; Fontes, M.B.; Da Rocha, Z.M.; Richter, E.M.; Angnes, L. LTCC manifold for heavy metal detection system in biomedical and environmental fluids. Sens. Actuators B Chem. 2004, 103, 468–473.
  63. Achmann, S.; Hämmerle, M.; Kita, J.; Moos, R. Miniaturized low temperature co-fired ceramics (LTCC) biosensor for amperometric gas sensing. Sens. Actuators B Chem. 2008, 135, 89–95.
  64. Nawrot, W.; Malecha, K. Additive manufacturing revolution in ceramic microsystems. Microelectron. Int. 2020, 37, 79–85.
  65. Malecha, K.; Macioszczyk, J.; Slobodzian, P.; Sobkow, J. Application of microwave heating in ceramic-based microfluidic module. Microelectron. Int. 2018, 35, 126–132.
  66. Gomez, H.C.; Cardoso, R.M.; Schianti, J.D.N.; De Oliveira, A.M.; Gongora-Rubio, M.R. Fab on a Package: LTCC Microfluidic Devices Applied to Chemical Process Miniaturization. Micromachines 2018, 9, 285.
  67. Jasińska, L.; Szostak, K.; Kiliszkiewicz, M.; Słobodzian, P.; Malecha, K. Ink-jet printed ring resonator with integrated Microfluidic components. Circuit World 2020, 46, 301–306.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
ScholarVision Creations
Feedback