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This study discusses the exploitation of a full-3D methodology for the electromagnetic simulation of a Wafer-Level Packaging solution featuring Through Silicon Vias (TSVs) for the redistribution of electrical signal from the in-package (RF-MEMS) passive devices to the external world. In particular, the Finite Element Method full-3D model is parameterised and allows analysing the influence of the most relevant Degrees of Freedom (DoFs) available in the package design, on the RF characteristics of encapsulated RF-MEMS passive devices. A previous part of this work, already published, discussed the validation of the mentioned full-3D model, comparing the results of simulations against experimental S-parameters datasets for a certain variety of Coplanar Waveguide test structures, in a frequency range from 50 MHz up to 30 GHz. Such a comparison showed good accuracy in predicting the behaviour of physical devices. Therefore, the soundness of the optimisation approach can be regarded as proven and consolidated for the optimisation purposes of the current work. [ABSTRACT FROM AUTHOR]

Packaging of Radio Frequency MicroElectroMechanical-Systems (RF-MEMS) and other passive components is a delicate issue, especially in the riverbed of upcoming application contexts like 5G and the Internet of Things, in which frequencies of operation are getting closer to mm-Waves (millimetre waves). In fact, when dealing with RF signals, the package, beyond protecting encapsulated devices, has also to exert an influence as limited as possible on their electromagnetic characteristics and performance. Therefore, the package design phase has to be performed with particular care. Given such a frame of reference, this study discusses the validation against experimental data of a full-3D methodology for the electromagnetic simulation of a Wafer-Level Packaging solution featuring Through Silicon Vias for the redistribution of electrical signal from the in-package (RF-MEMS) passive devices to the external world. In particular, the results of the full-3D finite element method RF simulations will be compared against experimental S-parameters datasets for a certain variety of Coplanar Waveguide test structures, in a frequency range from 50 MHz up to 30 GHz, showing good accuracy in predicting the behaviour of physical devices. For the sake of brevity, this work will be followed by a standalone second part in which the full-3D model, here validated, will be parameterised and exploited to analyse the influence of the most relevant Degrees of Freedom available in the package design, on the RF characteristics of encapsulated RF-MEMS passive devices. [ABSTRACT FROM AUTHOR]

RF-MEMS, i.e. micro electro mechanical-systems (MEMS) for radio frequency (RF) passive components, started to make their way into mass-market applications in the telecommunication segment. One critical aspect to ensure easy employment of such devices within systems and sub-systems is that of packaging and encapsulation. In packaging of RF-MEMS, next to the protection of the fragile movable structures and membranes, optimisation of the package electrical performance plays a very important role. In this work, a wafer-level packaging process is investigated and optimised in order to minimise its electrical parasitic effects. The capping silicon substrate resistivity, the substrate thickness and the geometry of through-silicon vias are optimised relying on finite element method electromagnetic simulations. Moreover, a preliminary analysis on the electromagnetic effects of the wafer-to-wafer bonding techniques (i.e. solder bump reflow and Isotropic or anisotropic conductive adhesive – ICA/ACA) is presented. [ABSTRACT FROM AUTHOR]

Simulation of MEMS-based, microelectromechanical-systems, radio frequency (RF) passive components, i.e. RF-MEMS, is not an easy task, as it involves the coupling of different physical domains (mechanical, electrical, electromagnetic). This work discusses the exploitation of a software library of elementary MEMS behavioural models, in order to predict the multi-physical behaviour of a complex RF-MEMS switch geometry, i.e. a toggle-switch. The elementary models developed and available in the software library are implemented in an HDL (hardware description language) programming code and can therefore be exploited within standard development environments for integrated circuits. [ABSTRACT FROM AUTHOR]

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, divided in the previous Part 1 and the current Part 2, a novel design concept of an 8-bit reconfigurable power attenuator manufactured in the RF-MEMS technology available at the CMM-FBK, in Italy, is presented, tested and discussed. As reported in Part 1, 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 eight cascaded stages (i.e. 8-bit), thus implementing 256 different network configurations. In the current Part 2, fabricated samples are measured (S-parameters) from 10 MHz to 110 GHz in a wide range of different configurations, and modelled/simulated in a full 3D Finite Element Method (FEM) environment. Despite the attenuator complexity, the simulation approach leads to accurate prediction of the experimental behaviour. The device exhibits attenuation levels (S21) in the range from − 10 to − 60 dB, up to 110 GHz. In particular, the S21 shows flatness from 15 down to 3–5 dB, from 10 MHz to 50 GHz, while less linear traces up to 110 GHz. A comprehensive discussion is developed around the voltage standing wave ratio (VSWR), employed as quality indicator for the attenuation levels. Finally, margins of improvement at design level are also discussed, in order to overcome the limitations of the presented RF-MEMS device. [ABSTRACT FROM AUTHOR]

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, a novel design concept of an 8-bit reconfigurable power attenuator manufactured in the RF-MEMS technology available at the CMM-FBK, in Italy, is tested and discussed. In the current Part 1 of the contribution, the RF-MEMS power attenuator design concept is discussed. 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 eight cascaded stages (i.e. 8-bit), thus implementing 256 different network configurations. In Part 2 of the article, fabricated samples are measured (S-parameters) from 10 MHz to 110 GHz in a wide range of different configurations, and modelled/simulated in with a Finite Element Method software tool. Despite the attenuator complexity, the simulation approach leads to accurate prediction of the experimental behaviour. The device exhibits attenuation levels (S21) in the range from − 10 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. A comprehensive discussion is developed around the voltage standing wave ratio, employed as quality indicator for the attenuation levels. Finally, margins of improvement at design level are also discussed, in order to overcome the limitations of the presented RF-MEMS device. [ABSTRACT FROM AUTHOR]

Microelectromechanical-systems technology (MEMS) applied to radio frequency (RF) and microwave systems (i.e. RF-MEMS) has recently started to exhibit its market potential in applications centred on telecommunications and consumer segments. As evolution towards the 5G (5th generation of mobile communications) and the Internet of things (IoT) is progressing, more agile, reconfigurable and multi-functional RF passive components and networks will be necessary. In this work, an entirely RF-MEMS-based impedance matching network (IMN) is reported and discussed, taking the global system for mobile communications (GSM) protocol as testing scenario. The mentioned RF-MEMS IMN was designed in order to perform proper impedance conversion between a CMOS class-E power amplifier (PA) and the transmitting/receiving antenna of a GSM system. In the following pages, the RF-MEMS IMN will be discussed in details against its design solution, working principles, as well as electromechanical and RF simulated and measured characteristics. [ABSTRACT FROM AUTHOR]

RF-MEMS technology is emerging as a key enabling solution to address demanding requirements that upcoming 5G standards pose upon passive devices and networks. In this letter, we demonstrate experimentally—to the best of our knowledge, for the first time—, RF-MEMS 2-state basic attenuator modules, from nearly dc up to 110 GHz. Physical samples are realized in the CMM-FBK RF-MEMS technology, and design variations are tested. Resistive loads are placed in series or shunt configuration on the RF line, and the attenuation is ON/OFF switched by electrostatically driven MEMS micro-relays. Tested devices show attenuation levels (S21) from −5 to −10 dB, depending on the resistive load, with flatness of 2–3 dB from 10 MHz to 50 GHz and of $\sim 2$ dB from 60 up to 110 GHz. When OFF, the attenuator modules introduce loss (S21) better than −1 dB up to 50 GHz and better than −6 dB up to 110 GHz. [ABSTRACT FROM PUBLISHER]