Characterization of down-state capacitance degradation in capacitive RF MEMS switch with rough dielectric layer

Functional operation of RF MEMS resistive switches depends on dynamic characteristics of the cantilever contacts. Characteristics of these contacts, in turn, depend on parameters defining their shape and dimensions, material properties, boundary conditions, and actuation voltages. In this paper, a simple analytical model is presented and used to develop an understanding of the switch behavior. In addition, uncertainties corresponding to this model are also determined to quantitatively show the influence that various parameters defining the cantilever contact have on its dynamics which, in turn, influences performance of the RF MEMS switch. This performance can be optimized with the objective of achieving resonance frequency within, e.g., 1% of the desired value while constraining the nominal dimensions and finding the optimum set of uncertainties in these dimensions. Analytical results correlate well with the preliminary experimental characterization of the contacts.

Download Full-text

Design and Analysis of a Non-Uniform Meander RF MEMS Switch

INFORMATION TECHNOLOGY IN INDUSTRY ◽

10.17762/itii.v9i2.409 ◽

2021 ◽

Vol 9 (2) ◽

pp. 756-767

Author(s):

C Leela Mohan, Et. al.

Keyword(s):

Dielectric Layer ◽

Rf Mems ◽

Coplanar Waveguides ◽

Rf Mems Switch ◽

High Isolation ◽

Mems Switch ◽

Power Handling ◽

Mems Technology ◽

Rf Signal ◽

Selection Of

This paper aimed to design and analysis of non-uniform meander capacitive shunt RF MEMS switch. The less pull in voltage is obtained in flexure type membrane by proposed RF MEMS Switch. The selection of materials for the beam and dielectric layer is expressed in this paper and also shown the performance depends on materials utilized for the design. The high isolation of -31.15dB actuating at the pull-in voltage of 7.69V with a spring constant of 3.28N/m produced the switch and is obtained by the optimization process. Capacitive contact switches have capability of power handling. The actuated switch state provides an excellent isolation. It shorts the ground by RF signal. MEMS technology is the integration of electrical and mechanical components on single platform i.e. substrate [10]. From the literature, various researchers have proposed different RF MEMS Switch, but still there few challenges on optimization of the Switch for best performance. The electromechanical analysis such as Upstate, Downstate capacitances and stress analysis have been carried out. The performance of the switch is analyzed by taking appropriate materials selected by Ashby’s approach. These optimized dimensions are feasible to fabricate. The substrate height, material for the substrate and coplanar waveguides are used for the impendence matching. For obtaining the less pull in voltage overlapping area is to be increased.

Download Full-text

Design and Fabrication of a Ka Band RF MEMS Switch with High Capacitance Ratio and Low Actuation Voltage

Micromachines ◽

10.3390/mi13010037 ◽

2021 ◽

Vol 13 (1) ◽

pp. 37

Author(s):

Kun Deng ◽

Fuxing Yang ◽

Yucheng Wang ◽

Chengqi Lai ◽

Ke Han

Keyword(s):

Rf Mems ◽

Dielectric Material ◽

Actuation Voltage ◽

Rf Mems Switch ◽

Ka Band ◽

High Capacitance ◽

Mems Switch ◽

Capacitance Ratio ◽

Metal Insulator Metal ◽

State Capacitance

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.

Download Full-text