平面小型化三频微带天线

针对多频天线结构复杂,天线尺寸较大,设计了一款紧凑型结构的三频单极性微带贴片天线。该天线的辐射单元由双C型结构和加载倒L型结构构成,利用低频段的高次模,从而产生天线的高频段。该方法可以有效实现多频特性,并能够有效地减小天线尺寸。天线尺寸仅为20×31×1.6 mm3。实测频段为2.40~2.50 GHz,3.17~3.90 GHz,4.67~5.83 GHz。该天线具有体积小,结构简单,辐射特性良好的优点,实现了对3.5/5.5 GHz WIMAX频段和2.4/5.2/5.8 GHz WLAN频段的全覆盖,能够很好的适用于无线通信系统的应用。     

3D-printed membrane microvalves and microdecoder

A microfluidic system for multichannel switching and multiphase flow control has potential uses in pneumatic soft robotics and biological sampling systems. At present, the membrane microvalves used in microfluidic systems are mostly constructed using a multilayer bonding process so that the device cannot withstand high pressures. In this paper, we demonstrate a design method and the properties of a bondless membrane microvalve fabricated using a commercial 3D printer. We used a multijet (MJP) 3D printer to print a 100-μm-thick and 6-mm-diameter membrane from a relatively hard material (1700 MPa). The membrane’s high toughness ensures that it does not need negative pressure to reopen. The measured operation frequency was less than 2.5 Hz under a pneumatic pressure of 14.5 kPa. We also 3D-printed an integrated Quake-style microfluidic decoder network by combining 8 valves in series to demonstrate the integrability of the microvalve. The decoder chip was demonstrated to control the ON/OFF state of the four coded fluidic channels, with the droplets being generated from selected channels according to the valve action. Therefore, such 3D-printed microvalves are highly integrable, have a high manufacturing efficiency, and can be applied in pneumatic controllers, sample switchers and integrated print heads.