Yu Yuan-wei

Bio: Yu Yuan-wei is an academic researcher. The author has contributed to research in topics: Surface micromachining & Microelectromechanical systems. The author has an hindex of 2, co-authored 3 publications receiving 22 citations.

Monolithic silicon micromachined Ka-band filters

Abstract: This paper describes a novel kind of filter at Ka-band on silicon substrate, which is based on the substrate integrated waveguide (SIW) design and MEMS fabrication process. Inductively coupled plasma (ICP) deep etching is used to form the square via-holes of SIW cavities. A 5-pole micromachined filter is made from rectangular cavities integrated into a silicon substrate and is fed by coplanar waveguide(CPW) transmission-lines through current probes. Measured results show a 0.5 dB loss with a 6.5% bandwidth at a center frequency of 30.9 GHz. The final size of the filter chip is 10.0 mm x 2.7 mm x 0.4 mm. This micromachined filter gives compact size and outstanding performance with relatively mature batch process.

Millimeter-wave design of aperture-coupled micromachined patch antennas

Abstract: An aperture-coupled patch antenna using micromachining technology on high resistivity silicon substrates has been studied in this paper. A finite ground coplanar waveguide-microstrip line (FGCPW-MS) is used to feed this antenna. The effects of varying several key physical parameters of the structure are investigated to get the maximum improvement in bandwidth and HFSS software is used to optimize this model. The simulated results show that bandwidth of 6.34%, gain of 5.8 dB and efficiency of 74% has been achieved. Fabrication is done using micromachining technologies. And due to fabrication error and measurement method the measured results show a bandwidth of 4.19%. However, it still shows good agreement in simulation and measurement. Besides its small physical size, this kind of antenna is also easy to integrate with other active components.

Design of single crystal silicon based RF MEMS switch with high contact force

Abstract: A metal contact RF MEMS switch based on single crystal silicon is presented in this article. Performance of the switch is demonstrated numerically in simulations. The mN-level contact and release forces are achieved. Pull-in voltage is calculated to be 40V. 1.5mN contact force and 1.2mN release force are achieved when actuation voltage is 50V. The isolation and insertion loss are better than -30.8dB and -0.09dB respective between DC and 10GHz. The fabrication process is presented as well.

Substrate Integrated Waveguide Filters: Design Techniques and Structure Innovations

Abstract: Because of the inherent structural flexibility in coupling design and topological arrangement, substrate integrated waveguide (SIW) filter topologies enjoy better out-of-band frequency selectivity and/or in-band phase response with the allocation of finite transmission zeros (FTZs). In the first article in this series, basic design rules and fundamental electrical characteristics have been presented that indicate the superior performances of SIW structures and their filter applications. Advanced design techniques and innovative structure features have recently been reported in a large number of publications. They include cross couplings realized by physical and nonphysical paths and SIW filters with dual-mode or multimode techniques. Miniaturization-enabled techniques including low-temperature cofired ceramic (LTCC) technology have been developed and applied to the development of SIW filters to reduce the size for low-gigahertz applications using nontransverse electromagnetic (non-TEM) modes. Wideband SIW filters, multiband SIW filters, and reconfigurable SIW filters have also been reported by various research groups. This article reviews these advanced and innovative SIW filter technologies, and related examples are presented and discussed.

10–60-GHz Electromechanical Resonators Using Thin-Film Lithium Niobate

Abstract: This work presents a new class of microelectromechanical system (MEMS) resonator toward 60 GHz for the fifth-generation (5G) wireless communications. The wide range of the operating frequencies is achieved by resorting to different orders of the antisymmetric Lamb wave modes in a 400-nm-thick Z-cut lithium niobate thin film. The resonance of 55 GHz demonstrated in this work marks the highest operating frequency for piezoelectric electromechanical devices. The fabricated device shows an extracted mechanical $Q$ of 340 and an $f\times Q$ product of $1.87\times 10^{13}$ in a footprint of $2 \times 10^{-3}$ mm2. The performance has shown the strong potential of LiNbO3 antisymmetric mode devices for front-end applications in 5G high-band.

Mems mass-spring-damper systems using an out-of-plane suspension scheme

Abstract: MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) using an out-of-plane (or vertical) suspension scheme, wherein the suspensions are normal to the proof mass, are disclosed. Such out-of-plane suspension scheme helps such MEMS mass-spring-damper systems achieve inertial grade performance. Methods of fabricating out-of-plane suspensions in MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) are also disclosed.

Aluminum Nitride Combined Overtone Resonators for the 5G High Frequency Bands

Abstract: This work presents a new acoustic MEMS resonator technology, dubbed Aluminum Nitride (AlN) Combined Overtone Resonator (COR), capable of addressing the filter requirements for the 5G high frequency bands in the 6-40GHz range. The COR exploits the multimodal excitation of two higher-order Lamb waves ( $2^{\mathbf {nd}}$ and $3^{\mathbf {rd}}$ order Asymmetrical Lamb Waves) in a suspended thin-film AlN plate to transduce a 2-dimensional vibration mode with high electromechanical coupling coefficient $k_{t}^{2}$ (up to 1.9%) and quality factor $Q>1100 $ at twice the frequency of a fundamental thickness-extensional mode in the same structure. Analytical and finite-element method (FEM) models are developed to describe the working principle of the COR technology and predict the achievable $k_{t}^{2}$ , Q and lithographic frequency tunability. An 8.8 GHz COR prototype was fabricated showing a high $k_{t}^{2}~\sim ~0.3$ % (using a simple top-electrode-only configuration with a 2-mask process) and a groundbreaking $Q\sim {1100}$ which is the highest ever achieved among piezoelectric resonators above 6 GHz. The $f - Q$ product $\sim 1\times 10 ^{\mathbf {13}}$ is the highest among all demonstrated piezoelectric resonators with metallic coverage >50%. Additionally, the capability of the COR technology to deliver contiguous filters with bandwidths between 355 and 592 MHz (aggregated BW >2GHz) in the mmWave spectrum, with relaxed lithographic requirements, is demonstrated by FEM. [2019-0229]

Novel linearly and circularly polarized 60 GHz MEMS antennas on low- and high-resistivity silicon

Abstract: Two novel MEMS antennas for 60 GHz applications are introduced in this paper. The first antenna is radiating linearly polarized wave, while circularly polarized wave can be radiated from the second antenna. Both antennas possess good isolation from the driving circuit via the presence of ground metal plane. The fabrication process requires only one silicon wafer with no need for wafer bonding or hybrid integration. The two antennas are radiating mainly from one side of the substrate, as indicated by high front-to-back ratio. They enjoy good polarization purity characterized by low cross-polarization level. Both high- and low-resistivity silicon are considered as substrates for each antenna. The first solution is associated with very high radiation efficiency and gain, and hence suitable for applications requires considerable distance between transmitter and receiver. On the other hand, the much cheaper and more electronics-compatible low-resistivity silicon solution offers relatively low radiation efficiency and gain, which makes it more suitable for in-door communication systems.