Radio frequency (RF) microelectromechanical systems (MEMS) have been pursued for more than a decade as a solution of high-performance on-chip fixed, tunable and reconfigurable circuits. This paper reviews our research work on RF MEMS switches and switching circuits in the past five years. The research work first concentrates on the development of lateral DC-contact switches and capacitive shunt switches. Low insertion loss, high isolation and wide frequency band have been achieved for the two types of switches; then the switches have been integrated with transmission lines to achieve different switching circuits, such as single-pole-multi-throw (SPMT) switching circuits, tunable band-pass filter, tunable band-stop filter and reconfigurable filter circuits. Substrate transfer process and surface planarization process are used to fabricate the above mentioned devices and circuits. The advantages of these two fabrication processes provide great flexibility in developing different types of RF MEMS switches and circuits. The ultimate target is to produce more powerful and sophisticated wireless appliances operating in handsets, base stations, and satellites with low power consumption and cost.

/pdf/rf-mems-switches-and-integrated-switching-circuits-2vsihyk7su.pdf

RF MEMS Switches and Integrated Switching Circuits

The present disclosure provides for a microelectromechanical switch including a first port (e.g., input port), one or more second ports (e.g., output ports), a cantilever beam, and a mechanical spring connected to the cantilever beam for providing a mechanical force to move the cantilever beam. The cantilever beam extends from a first end, which is in contact with either the first port or one of the second ports, to a second end that is switchably connectable to the other of the first port or said one of the second ports. The first and second ports and cantilever beam may be formed in a coplanar waveguide.

High performance switch for microwave mems

Ce travail vise a trouver une technique de test rapide et peu onereuse pour les interrupteurs MEMS RF embarques dans les SiPs (System-in-Package). La complexite des SiPs RF exige une strategie de conception en vue du test (DFT, Design-for-Test) afin d'eviter l'utilisation d'equipements sophistiques de test, aussi bien que de surmonter les difficultes d'acces aux points de mesure embarques. L'approche proposee utilise le principe du test alternatif qui remplace des procedures de test a base des specifications conventionnelles. L'idee de base est d'extraire les performances haute frequence de l'interrupteur a partir des caracteristiques basse frequence du signal d'enveloppe de la reponse. Ces caracteristiques, qui incluent le temps de montee, le temps de descente, ou les amplitudes maximales du signal dans les etats ON et OFF, sont alors utilisees dans un processus de regression pour predire des specifications RF comme les parametres /S/. Un banc de test a ete configure et utilise pour evaluer une dizaine d'echantillons d'un commutateur commercial. Des mesures experimentales ont ete realisees avec un kit d'evaluation developpe par notre partenaire industriel et un kit d'evaluation du developpeur. Les mesures de basse frequence comme le temps de transition ON/OFF et les amplitudes RF de la sortie sont utilisees comme regresseurs pour l'algorithme de regression multivariee qui construit une liaison non-lineaire entre les caracteristiques de basse frequence et les performances RF de l'interrupteur. Ainsi, des performances conventionnelles comme les parametres /S/ sont predites a partir de ces mesures par la regression non-lineaire. Les resultats ont expose une bonne correlation entre les performances RF et les mesures de basse frequence. La validation experimentale a seulement ete realisee pour un petit echantillon d'interrupteurs. Les resultats de simulation ont aussi ete utilises pour evaluer cette correlation.

/pdf/technique-alternative-de-test-pour-les-interrupteurs-mems-rf-4s5n0wcvk7.pdf

Technique alternative de test pour les interrupteurs MEMS RF

This paper presents a Single-Pole Double-Throw (SPDT) microelectromechanical system (MEMS) waveguide switch operating at 500–750 GHz. The switch consists of a U-bend waveguide surrounded by an electromagnetic bandgap (EBG) surface. The EBG surface is used to prevent propagation of electromagnetic waves without mechanical or electrical contact. The U-bend is placed on a rotating arm, that moves between two waveguide connections. The arms movement is controlled by a rotating MEMS motor that can rotate ±4.5° at 90 V. The switch is fabricated using silicon micromachining and is designed to be in-plane with the connecting waveguides. Thus, allowing it to be implemented into a silicon micromachined waveguide network. Since the electromagnetic wave can be isolated with the EBG surface without the need for electrical or mechanical contact, the MEMS waveguide switch rotates freely between two contactless states, circumventing common MEMS switch issues such as stiction. 

A Mems Contactless Rotating Terahertz Waveguide Switch

In this paper, a simulation-based particle swarm optimization (PSO) approach is developed to optimize the operational parameters of a 15.12 GHz single pole double throw (SPDT) switch. The Agilent Advance Design System (ADS) is used to synthesize the performance of the switch design while PSO is employed as the optimizer for achieving the required switch performance. The performance of the designed SPDT switch is assessed in terms of insertion loss and isolation. Simulation results show that the proposed component values of SPDT switch is manage to fulfill the required specifications, achieving 25.978dB of isolation loss and 3.077dB of insertion loss.

An optimization of 15.12 GHz SPDT switch using particle swarm optimization algorithm

A low-loss single-pole-double-throw (SPDT) switch circuit using lateral RF MEMS switches has been developed on glass to operate from DC to 20 GHz. High compactness and low loss can be obtained by use of the lateral switches and coplanar waveguide (CPW) configuration. The circuit provides > 24-dB isolation and < 0.9-dB insertion loss up to 20 GHz. The pull-in voltage of the switch is only 12.4 V, with a switching-on time of 35 mus and a switching-off time of 36 mus. A single-mask silicon-on-glass (SiOG) fabrication process has been developed to fabricate the SPDT switch circuit on glass, which has the advantages of low loss and high yield. The whole circuit has a size of 1.64 mm times 1.3 mm.

https://nocweba.ntu.edu.sg/laq_mems/conference/transducers/a low-loss single-pole double-throw (spdt) switch circuit.pdf

M. Tang

Papers

A Low-Loss Single-Pole-Double-Throw (SPDT) Switch Circuit