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

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.

RESEARCH OF METHODS FOR DECREASE OF THE CAPACITANCE RATIO IN THE STW-RESONATORS

This paper presents the research of methods for decrease of the capacitance ratio in the STW-resonators without significant degradation of the quality factor by use of the external inductors and topology change: IDT division on parts and their series connection. The calculated and experimental data are presented for 416 MHz and 766 MHz STW-resonators with quality factors Q = 7000–7978. The capacitance ratio has been reduced from 1200 to 301.

Design and Analysis of Shunt Configuration-Based RF MEMS Switch

In this paper a shunt type RF MEMS switch design and analysis for tunable applications is presented. Switch works based on the electrostatic actuation principle. Theoretical calculated Switch parameters are compared with the electromechanical and electromagnetic simulation results. The effect of various materials like conductor and dielectrics & parameters like airgap, beam width on the electromechanical parameters of the switch is analyzed to get low pull-in voltage, high switching speed, better capacitance ratio, return loss, insertion loss, and isolation loss. The switch up and down state capacitance are 40.9fF and 4.45pF respectively. Down to up state capacitance ratio of this switch is 108.69. The designed switch has an actuation voltage of 32V. RF performance is simulated from 1-10GHz. In ON state switch has return loss of -35dB, insertion loss of -0.1dB. In the OFF-state switch has return loss of -1dB and an isolation loss of -11dB.