Hoang-Nam Nguyen

Bio: Hoang-Nam Nguyen is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 3 citations.

Technique alternative de test pour les interrupteurs MEMS RF

Abstract: 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.

Low Frequency Test for RF MEMS Switches

Abstract: In order to envision fault-tolerant SiPs and SoCs containing RF MEMS switches, this paper studies easily embedded low frequency tests for capacitive switches. The correlation between high frequency (S parameters) and low frequency (envelope of the high frequency signal) responses of a capacitive RF MEMS switch is analysed. This has been done by modeling both the electromechanical and RF behaviours of the switch and by a statistical simulation of the switch with Monte Carlo method. Next, it has been possible to predict the insertion loss, return loss and isolation of the switch from the low frequency measurements for a broad frequency range. Furthermore, by using the obtained correlations for two different frequencies, it was possible to recreate the S-parameters for the entire frequency spectrum with good agreement.

Laterally-driven RF microswitch with high isolation

Abstract: Most of MEMS microswitches that have been so far reported utilize a movable electrode moving vertically to a substrate. Especially, few researches have been made to apply a lateral motional MEMS microswitch to a high frequency range (above several GHz). Although the insertion loss is kept low in a wide range up to a high frequency, the isolation usually becomes worse with the increase of the signal frequency. We have improved the isolation in a high frequency by using lateral motion in mutually opposite directions. In addition, this lateral movement is effective to alleviate the adhesion of a contact area. We also consider about the feasibility of a silicon RF transmission line, which helps the process very easy because of keeping the overall structure simple. The microswitch under investigation has a simple structure and can be fabricated by the easy process. Its isolation is excellent as well as insertion loss even for a use in RF range. Rapid growing demands for more data traffic flow in mobile-phones and wireless LAN's tend to use a higher frequency band. Although the current microswitch has several improvements left, its excellent feature will make it more useful near the future.

A Comparative Study of RF MEMS Switch Test Methods

Abstract: Micro-ElectroMechanical Systems, often abbreviated as MEMS are miniaturized elements, multiplied components and microelectronics that can capture and act on the environment in order to perform a number of missions. They have a small size, limited energy capacity and low memory capacity. MEMS applications exceed the scaling limits of current computational paradigms, posing serious challenges and new opportunities for information technology. The heart of the MEMS switches is a moving electrode that, by contacting a fixed electrode, creates modifications in an RF circuit. The movable electrode is often formed of a suspended beam exerting movement. Another form of the moving electrode is a thin disk suspended above the electrode system disposed on the substrate. The movement of the moving electrode is generated by an actuating force that is often electrostatic, but it can be thermal, piezoelectric, or magnetic. The purpose of the test is to discriminate between the good devices that respect its specifications and the faulty ones that are not functional. In general, the failures occur due to deviations in the parameters of the manufacturing process or the presence of manufacturing defects. This problem cannot be solved by a single method, but requires several complementary techniques. This paper will present a comparison between the test techniques of RF MEMS Switches. Thus, the proposed method is based on machine learning to create predictive models for testing devices. This reliable test strategy helps to overcome the necessity of sophisticated test equipment, as well as the access difficulties to measure embedded points.