Design and Analysis of RF MEMS Shunt Capacitive Switch for Low Actuation Voltage and High Capacitance Ratio

Author(s):  
Johnson Taye ◽  
Koushik Guha ◽  
Srimanta Baishya
Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Kun Deng ◽  
Fuxing Yang ◽  
Yucheng Wang ◽  
Chengqi Lai ◽  
Ke Han

In this paper a high capacitance ratio and low actuation voltage RF MEMS switch is designed and fabricated for Ka band RF front-ends application. The metal-insulator-metal (MIM) capacitors is employed on a signal line to improve the capacitance ratio, which will not degrade the switch reliability. To reduce the actuation voltage, a low spring constant bending folding beam and bilateral drop-down electrodes are designed in the MEMS switch. The paper analyzes the switch pull-in model and deduces the elastic coefficient calculation equation, which is consistent with the simulation results. The measured results indicated that, for the proposed MEMS switch with a gap of 2 μm, the insertion loss is better than −0.5 dB and the isolation is more than −20 dB from 25 to 35 GHz with an actuation voltage of 15.8 V. From the fitted results, the up-state capacitance is 6.5 fF, down-state capacitance is 4.3 pF, and capacitance ratios is 162. Compared with traditional MEMS capacitive switches with dielectric material Si3N4, the proposed MEMS switch exhibits high on/off capacitance ratios of 162 and low actuation voltage.


2018 ◽  
Vol 7 (2.31) ◽  
pp. 4 ◽  
Author(s):  
K Jayavardhani ◽  
S K. Noureen Fathima ◽  
K Bhima Sankar ◽  
K Kavya Sri ◽  
S Sunithamani

This paper presents the design and simulation of RF MEMS shunt capacitive switch with low actuation voltage, low insertion loss and high isolation. Actuation voltage depends on the parameters like air gap, spring constant and actuation area. In this design, we have proposed a serpentine meander structure to reduce the spring constant of the beam thus reducing actuation voltage. The rectangular perforation is used to reduce the squeeze film damping by decreasing the mass of the switch. The proposed switch has attained a low actuation voltage of 4.5V for a displacement of 0.84μm. The air gap between the beam and the dielectric is 1μm. This radio frequency (RF) MEMS shunt switch is designed and simulated using COMSOL Multiphysics 5.2. The RF performance of the shunt switch is analyzed in Ansoft HFSS 13 and the results show that the return loss was about -13.50 dB at 20GHz in the OFF state and -8.5 dB at 18 GHz in the ON state. A high isolation of -36.00 dB was achieved in the OFF state at a frequency of 5GHz and a low insertion loss is obtained. The results show that the switch is suitable for wireless applications operating in the frequency range from 5 to 20GHz. 


Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 390 ◽  
Author(s):  
Ke Han ◽  
Xubing Guo ◽  
Stewart Smith ◽  
Zhongliang Deng ◽  
Wuyu Li

This paper proposes a novel high-capacitance-ratio radio frequency micro-electromechanical systems (RF MEMS) switch. The proposed RF MEMS mainly consists of serpentine flexure MEMS metallic beam, comprised of coplanar waveguide (CPW) transmission line, dielectric and metal-insulator-metal (MIM) floating metallic membrane. Comparing the proposed high-capacitance-ratio MEMS switch with the ones in available literature, an acceptable insertion loss insulation, acceptable response time and high capacitance ratio (383.8) are achieved.


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