Modeling and Manufacturing of Micromechanical RF Switch with Inductors

Abstract

This study presents the simulation, fabrication and characterization of micromechanical radio frequency (RF) switch with micro inductors. The inductors are employed to enhance the characteristic of the RF switch. An equivalent circuit model is developed to simulate the performance of the RF switch. The behaviors of the micromechanical RF switch are simulated by the finite element method software, CoventorWare. The micromechanical RF switch is fabricated using the complementary metal oxide semiconductor (CMOS) and a post-process. The post-process employs a wet etching to etch the sacrificial layer, and to release the suspended structures of the RF switch. The structure of the RF switch contains a coplanar waveguide (CPW), a suspended membrane, eight springs and two inductors in series. Experimental results reveal that the insertion loss and isolation of the switch are 1.7 dB at 21 GHz and 19 dB at 21 GHz, respectively. The driving voltage of the switch is about 13 V.

Manufacture of Radio Frequency Micromachined Switches with Annealing

“…To obtain excellent membrane flatness, this study adopts an annealing process to improve the residual stress of the membrane. The insertion loss and isolation of this work exceed that of the previous works [10,21]. In addition, the membrane has many etching holes as shown in Figure 2a, in order to reduce the etching time during the post-process.…”

Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology

“…Then, the electrical parameters are inputted into the The Agilent ADS (Agilent Technologies, Santa Clara, CA, USA) and the Ansoft Q3D extractor (Ansoft Technologies, New Delhi, DL, USA) were used to simulate the electrical properties of the switch. First, the Ansoft Q3D extractor [23] extracts the electrical parameters of the switch in accordance with the structure and dimensions as shown in Figure 1. The extracted results reveal that the membrane and springs have an inductance of 0.25 nH; the capacitance between the membrane and the signal line is 0.03 pF; the membrane and springs have a resistance of 2 Ω; the silicon substrate has a resistance of 250 Ω; the insulated capacitance under the CPW lines is 45 fF; the capacitance of silicon substrate 32 fF.…”

Novel low-voltage RF-MEMS switch: Design and simulation

“…It clearly shows that the membrane exhibits a uniform out-of-plane displacement of 2.9µm. The maximum von Mises stress of 13.2MPa is located at the end of the folded beams of the switch which is much lower than the yield strength of aluminum of 124MPa [8]. Therefore, the switch operates in the elastic range.…”

“…On the contrary, without the applied DC voltage, the membrane is at up-state position; the RF signal can be propagated from an input port to an output port, which is called the switch-on state. This pull-in voltage can be calculated by (1) [8]; and the relationship between the pull-in voltage (Vp) and spring constant (k) can be plotted in Fig. 2.…”