A study on bonding packaging of a SP4T series RF MEMS switch with metal-to-metal contact is presented. The switch, with the total die size of 3580pm x2740gm, consists of a coplanar waveguide (CPW), SiON dielectric bridge membranes and broadside actuation electrodes. In order to protect the movable structures from the mechanical damage as well as the particle contaminations, a high-resistivity silicon cap with a rectangular cavity of 50pm depth is designed, fabricated via etching in KOH solution at 800 C, and bonded on top of the switch with epoxy resin. The results show the bonding between the cap and the switch support substrate is mechanically robust and the degradation of the isolation is in the range of 5%-010% in the frequency band from 1-10 GHz.

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Antibiotics have been an emerging concern due to the potential adverse threat on the environment and human health. Studies on the presence and fate of antibiotics in Chinese aqueous environments have increased in the past few years. Nevertheless, the distribution of antibiotics contributing to the development and dissemination of antibiotic resistance in China nationwide remains unclear. This review summarizes the temporal and spatial distribution of antibiotics in different aqueous environmental systems across the China in the last decade. In all, 79 antibiotics with the concentration range of 0.04 ng/L~6.54 μg/L have been detected in the aquatic environment in China. The Bohai Sea had the highest annual average concentration of total antibiotics ranging from 5.66 to 1552.59 ng/L. The peak of antibiotics in four typical water systems occurred in different years. Antibiotics in the surface water of Northern China accounted for 47.0% of the total annual average concentrations in four regions. Sulfonamides, tetracyclines and fluoroquinolones were the dominant compounds both for seawater and surface water. In contrast, β-lactams, sulfonamides and fluoroquinolones were the most abundant for the wastewater treatment plants. That indicated that β-lactams were from human medicine and tetracyclines were from veterinary antibiotics. The risk assessment demonstrated ofloxacin, norfloxacin and enrofloxacin had posed the higher risk than other antibiotics. The review provides an improved understanding on aquatic antibiotics pollution to outline the Chinese scenario and addresses the prospects for future research relating to the issues requiring urgent attention.

Presented is a DC-contact radio-frequency (RF) microelectromechanical system symmetric toggle switch for broadband power applications. Based on the lever principle, the proposed switching structure can be toggled upwards with extra restoring force using push electrodes. This push mechanism greatly improves the isolation and efficiently avoids the down-state stiction of the contacts which leads to enhancement of the power-handling capability. The measured actuated voltage is 33.4 V and the contact resistance of the switch can be further decreased to 0.18 Ω under a pull in voltage of 60 V, which results in the improvement of insertion loss. The switch can be properly restored with a voltage of 30 V applied to the push electrode. In addition, the substrate loss is reduced by using a Boroloat™ glass substrate. The RF measurement results show that the switch can handle a minimum 1 W incident RF signal power with isolation and an insertion loss of better than −30 and −0.24 dB from DC to the X-band.