[paper] RF-MEMS for Future Mobile Applications: Experimental Verification of a Reconfigurable 8-Bit Power Attenuator up to 110 GHz

RF-MEMS for Future Mobile Applications: Experimental Verification of a Reconfigurable 8-Bit Power Attenuator up to 110 GHz
Jacopo Iannacci¹ and Christian Tschoban^2
1Center for Materials and Microsystems - CMM, Fondazione Bruno Kessler , Trento, ITALY
²Fraunhofer Institut für Zuverlässigkeit und Mikrointegration IZM , Berlin, GERMANY
Journal of Micromechanics and Microengineering
Accepted Manuscript online 8 February 2017

Abstract

RF-MEMS technology is indicated as a key enabling solution to realise the high-performance and highly-reconfigurable passive components that future 5G communication standards will demand for. In this work, we present, test and discuss a novel design concept of an 8-bit reconfigurable power attenuator manufactured in the RF-MEMS technology available at the CMM-FBK, in Italy. The device features electrostatically controlled MEMS ohmic switches, in order to select/deselect resistive loads (both in series and shunt configuration) that attenuate the RF signal, and comprises 8 cascaded stages (i.e. 8-bit), thus implementing 256 different network configurations. Fabricated samples are measured (S-parameters) from 10 MHz to 110 GHz in a wide range of different configurations, and modelled/simulated in Ansys HFSS. The device exhibits attenuation levels (S21) in the range from -10 dB to -60 dB, up to 110 GHz. In particular, the S21 shows flatness from 15 dB down to 3-5 dB, from 10 MHz to 50 GHz, while less linear traces up to 110 GHz. Comprehensive discussion is developed around the Voltage Standing Wave Ratio (VSWR), employed as quality indicator for the attenuation levels. Margins of improvement at design level are also discussed, in order to overcome the limitations of the presented RF-MEMS device. The results of S-parameter simulations performed in the Quite Universal Circuit Simulator (QUCS: qucs.sourceforge.net) for a few significant configurations of the RF-MEMS attenuator from 10MHz to 110GHz are reported, too. [read more...]