Phase shifter is one of the core components for phased-array antennas which find wide applications in satellite systems,
telecommunications, wireless systems, radar systems and tracking systems. The current high-frequency phase shifters
are mainly built upon active semiconductor technologies which suffer from high fabrication and assembly costs. In this
work, we propose a cost-effective approach to fabricate distributed MEMS transmission line phase shifters on a
polymer-glass substrate. The fabrication procedure is compatible with CMOS and post-CMOS processes. The polymerglass
phase shifter was characterized from DC to 26 GHz. The measurements show a phase shift of 120° and a 2.5-dB
insertion loss at 26 GHz.
This paper discussed modeling, design, fabrication and characterization of a new cantilever-type electrostatic zipping
actuator. The actuator was designed to achieve high displacements and fabricated using multi-layer polysilicon foundry
fabrication process PolyMUMPS. The high out-of-plane displacement is to satisfy the requirements in specific optical
applications. In this paper we presented the design considerations in displacement, electrostatic forces and electrostatic
stability. The electrostatic force between the curved cantilever and the bottom electrode on the substrate pulls the
cantilever down. With a warped cantilever, the force closes the gap from the anchor end and gradually the zipping effect
actuates the entire cantilever without increasing the biasing voltages. Previous electrostatic zipper actuators require a
thin layer of dielectric material on top of the bottom electrode to prevent electrical shorting. They may have an issue
with electrical breakdown of the thin dielectric layer due to the film quality. We designed a new mechanical structure to
avoid the electrical shorting problem without a layer of dielectric material. Our analysis and experimental results
demonstrated that the proposed design can withstand high voltages without shorting and is capable of high deflection.
The vertical displacements of different device configurations were found ranging from 30.4μm to 450μm while the
actuation voltages varied in the range from 12V to 45.3V for complete actuation. The pull-in voltages for various
configurations were analyzed and presented.
RF phase shifters find wide applications in telecommunications, satellite systems, personal wireless
communication systems, radar systems, tracking systems, and sensors. They have been conventionally
manufactured by semiconductor technologies which suffer from high insertion losses due to high RF series
resistances. They are expensive due to fabrication and assembly costs.
The RF MEMS phase shifters provide low insertion losses, low fabrication costs and high linearity compared
with the semiconductor ones. Furthermore, polymer materials have demonstrated low material costs and low
RF attenuations. In this work, we proposed to build RF MEMS phase shifters on polymer substrates. The
proposed devices were successfully manufactured and tested from DC to 26 GHz. Our experimental results
indicated more than 35 degrees phase shifts and low insertion losses.
In this paper, reconfigurable antenna design consideration is discussed. The antenna design constrains are base on the use of radio frequency microelectromechanical system (RF MEMS) switches. The design consideration includes practical issues in using the switches to either change the antenna feeding networks or change the antenna topologies. In the first design, a coplanar waveguide (CPW)-to-microstripline transition technique is used to integrate the small switches onto the antenna feeding networks to achieve beam steering. In the second design, the switches are used to change the antenna ground plane topology to achieve frequency switching. Both antennas are modeled using our Finite-Difference Time-Domain (FDTD) simulator. The beam steering antenna will be capable of more than 60° scanning angles and the frequency switching antenna can operate at 2.4GHz and 5.8 GHz for WLAN applications.
The advantages of polymers have made them popular choices in many micro device applications. The benefits of low material and fabrication costs have been demonstrated in many micro-fluidic devices. The low conductivities and low dielectric constants of polymers provide potentials for high quality-factor RF MEMS applications. Nevertheless, the extension of using polymers for electronic components has not been well explored. In this work, we investigated the fabrication processes and RF performances of coplanar waveguide (CPW) transmission lines, with which many RF MEMS phase shifters, tuners, switches and interconnects are built, on polymer dielectric layers. In order to achieve optimum results, the CPW transmission lines were fabricated on benzocyclobutene (BCB), kapton and polyimide polymers. Our experimental results indicated very low insertion losses of CPW transmission lines with BCB as a dielectric layer and with kapton as substrate, and a moderate insertion loss with polyimide as a dielectric layer.
Recently, millimeter-wave devices have been attracted more attentions in applications owing to their short wavelengths, higher resolutions, broader bandwidths and higher environmental tolerance. The great challenges of high fabrication and assembly costs, bulky volumes, and heavy weights of millimeter-wave systems call for new integrated manufacturing techniques. The hot embossing technique could address these challenges. In this paper, a review of micro plastic hot embossing was given for the fabrication of miniaturized millimeter-wave systems. The micro hot embossing on plastic materials demonstrated its advantages on significant costs, volume and weight reduction, while maintaining high performances. We have designed, fabricated and characterized a W-band rectangular waveguide and a W-band iris waveguide filter with integrated plastic flanges using micro hot embossing and selective electroplating. In this paper, we reviewed the results and discussed the design methodology in details for the micromachined components. The prototype devices showed promise for the system designs.