Skip to main content

Advertisement

SpringerLink
Log in

Design analysis and simulation of a digital RF MEMS varactor with high capacitive ratio

  • Technical Paper
  • Published:
Microsystem Technologies Aims and scope Submit manuscript

Abstract

This work presents a variable RF MEMS capacitor based on five cantilever shunt switches for the first time. Conceptually, the proposed varactor design comprises five identical cantilever shunt switches, which allow the creation of 32 discrete capacitance values ranging from 0.091 to 6.04 pF. The latter translates to a tuning range of around 67. The overall varactor’s size is 400 μm × 850 μm. As verified by finite element simulations, the proposed beam configuration reduces sensitivity to in-plane residual stresses, which alleviates the pull-in voltage effect. The pull-in voltage and switching time were 24.18 V and 2.39 μs, respectively. It was found that the pull-in voltage of 24.18 V is less affected by the residual stresses. The high capacitance ratio of the varactor is achieved by the new design of a fixed and different capacitor with asymmetric design as the base structure of the varactor. The minimum capacitance (Cmin) is minimized by selecting the minimum overlap capacitor area. Moreover, the selection of fixed plate capacitors minimized the stresses. A thin layer of 0.5 μm was deposited on specified regions to avoid contact between the drive electrodes and the beam structure, thus improving the device's reliability. Furthermore, investigated and verified in-plane residual stress (induced by the fabrication process) and stress gradient's effects on spring constant and the beam's displacement profile. It was verified that the beam's behavior is minimally affected by the in-plane residual stresses, attributed to 3.2 GPa. The proposed RF-MEMS varactor provides a good solution for wireless multi-standard communication systems, such as phase shifters and reconfigurable filters as RF MEMS switching and varactors can be fabricated in a small package with low cost, low insertion loss, high linearity, high isolation, and low power consumption.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

Similar content being viewed by others

References

  • Al Farisi MS, Hirano H, Tanaka S (2020) Zero-balance method for evaluation of sealed cavity pressure down to single digit pa using thin silicon diaphragm. J Microelectromech Syst 29(3):418–426

    Article  Google Scholar 

  • Chaudhary R, Mudimela PR (2020) 3D modeling graphene oxide-based nanoelectromechanical capacitive switch. Microsyst Technol 26:2931–2937

    Article  Google Scholar 

  • Dussopt L, Rebeiz GM (2003) An X- to Ku-band 3-bit digital MEMS varactor. IEEE Microw Wirel Compon Lett 13(9):361–363. https://doi.org/10.1109/LMWC.2003.817118

    Article  Google Scholar 

  • Fedder GK (1994) "Simulation of microelectromechanical systems. PhD diss., University of California, Berkeley

  • Goldsmith CL, Malczewski A, Yao ZJ, Chen S, Ehmke J, Hinzel DH (1999) RF MEMs variable capacitors for tunable filters. Int J RF Microw Comput Aided Eng 9(4):362–374. https://doi.org/10.1002/(SICI)1099-047X(199907)9:4%3c362:AID-MMCE7%3e3.0.CO;2-H

    Article  Google Scholar 

  • Gupta P, Singh P, Srivastava P (2013) Design and analysis of RF MEMS varactor for extended tuning range. In: 2013 International Conference on control, computing, communication, and materials (ICCCCM). IEEE, New York, pp 4–7. 10.1109/ ICCCCM.2013.6648915.

  • Hamid R, Saeed Kh (2019) Design and simulation of a novel RF MEMS shunt capacitive switch with a unique spring for Ka-band applications. Microsyst Technol 25:531–540

    Article  Google Scholar 

  • Jason Yao J (2000) Topical review: RF MEMS from a device perspective. J Micromech Microeng 10:R9–R38

    Article  Google Scholar 

  • Jmint B et al (2018) Modeling, designing, and simulation a radio frequency microelectromechanical system capacitive shunt switch. Int J Numer Model 31:e2266

    Article  Google Scholar 

  • Lucibello A, Proietti E, Giacomozzi F, Marcelli R, Bartolucci G, De Angelis G (2013) RF MEMS switches fabrication by using SU-8 technology. Microsyst Technol 19(6):929–936. https://doi.org/10.1007/s00542-013-1753-8

    Article  Google Scholar 

  • McFeetors G, Okoniewski M (2007) Performance and operation of stressed dual-gap RF MEMS varactors. In: Proceedings of the 36th European Microwave Conference, EuMC 2006, 10 Sept. IEEE, New York, pp 1064–1067. 10.1109/ EUMC.2006.281117

  • Mehrdad Kh, Akbar B, Habib BG (2021) Design and simulation of a novel RF MEMS tunable narrowband LCfilter in the UHF band. Microsyst Technol 27:325–334

    Article  Google Scholar 

  • Patel CD, Rebeiz GM (2012) High-Q 3 b/4 b RF MEMS digitally tunable capacitors for 08–3 GHz applications. IEEE Microw Wirel Compon Lett 22(8):394–396. https://doi.org/10.1109/LMWC.2012.2205301

    Article  Google Scholar 

  • Pertin O, Kurmendra, (2018) Pull-in-voltage and RF analysis of MEMS-based high-performance capacitive shunt switch. Microelectron J 77:5–15

    Article  Google Scholar 

  • Ramli NA, Arslan T, Haridas N, Zhou W (2016a) design and modeling a digital MEMS varactor for wireless applications. In: 7th International Conference on thermal, mechanical, and multi-physics simulation and experiments in microelectronics and microsystems (EuroSimE). IEEE, New York, pp 3–7. https://doi.org/10.1109/EuroSimE.2016.7463383

  • Ramli NA, Arslan T, Haridas N, Zhou W (2016b) Design and simulation of a high tuning range MEMS digital varactor using SU-8. In: Symposium on design, test, integration, and packaging of MEMS/MOEMS, DTIP 2016, pp 1–6. https://doi.org/10.1109/DTIP.2016.7514842

  • Ramli NA et al (2018) Design, simulation, and analysis of a digital RF MEMS varactor using thick SU-8 polymer. Microsyst Technol 24:473–482

    Article  Google Scholar 

  • Rebeiz GM (2003) RF mems-theory, design and technology, vol 53. Wiley, New York. https://doi.org/10.1017/CBO9781107415324.004

    Book  Google Scholar 

  • Reines I, Pillans B, Rebeiz GM (2009) A stress-tolerant temperature- stable RF MEMS switched capacitor. In: Proceedings of the IEEE international conference on micro-electro-mechanical systems (MEMS). IEEE, New York, pp 880–883. https://doi.org/10.1109/MEMSYS.2009.4805524

  • Reinke JR (2011) CMOS-MEMS variable capacitors for reconfigurable RF circuits. Ph.D. Dissertations, Carnegie Mellon University

  • Saeid A, Nooshin N (2019) A new MEMS-based variable capacitor using an electrostatic vertical comb-drive actuator and auxiliary cantilever beams. Microsyst Technol 25:3317–3327

    Article  Google Scholar 

  • Sasaki T, Hane K (2011) Initial deflection of silicon-on-insulator thin membrane micro-mirror and fabrication of varifocal mirror. Sens Actuators A 172(2):516–522

    Article  Google Scholar 

  • Yang HH, Zareie H, Rebeiz GM (2014) A high power stress-gradient resilient RF MEMS capacitive switch. J Microelectromech Syst 24(3):599–607

    Article  Google Scholar 

  • Yongqing Xu et al (2018) a Noval RF MEMS switch on frequency reconfigurable antenna application. Microsyst Technol 24:3833–3841

    Article  Google Scholar 

Download references

Acknowledgements

This work was partially funded by American University in Cairo, Faculty Support Grant# RSG1-20.

Author information

Authors and Affiliations

  1. Radiation Engineering Department, NCRRT, Egyptian Atomic Energy Authority, Cairo, Egypt

    A. Sharaf & A. Nasr

  2. KAPSARC, Riyadh, Saudi Arabia

    A. M. Elshurafa

  3. Department of Mechanical Engineering, American University in Cairo, New Cairo, Egypt

    M. Serry

Authors
  1. A. Sharaf
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. A. Nasr
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. A. M. Elshurafa
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. M. Serry
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to A. Sharaf.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Sharaf, A., Nasr, A., Elshurafa, A.M. et al. Design analysis and simulation of a digital RF MEMS varactor with high capacitive ratio. Microsyst Technol 28, 1831–1844 (2022). https://doi.org/10.1007/s00542-022-05318-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00542-022-05318-4

Search

Navigation