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This paper examines the applicability of capacitive-loading-based size-reduction techniques to wideband and multi-band signal-interference planar filters. Using this approach, a miniaturized 0.96/1.84-GHz dual-band bandpass filter (BPF) shaped by a branch-line-coupler-type transversal filtering section (TFS) is built and measured. It features a 55.4% area decrease in relation to its fully-planar counterpart...
A four-pole tunable filter has been demonstrated at UHF frequencies which tunes 300 MHz to 700 MHz and exhibits mid-band losses between 0.5 dB and 0.9 dB. This filter incorporates piezo-electric tuning of capacitively-loaded cavities and frequency-tailored input/output coupling networks to maintain good impedance match across more than an octave tuning band. The unloaded quality factor of the filter...
Micro- and nano-scale gaps are likely to occur in miniaturized and high frequency devices. Large electric fields (∼10s V/μm) may result in such gaps even for relatively small voltages commonly found in existing electronics. These strong fields can potentially induce gas discharge, which may lead to performance degradation or even device failure. Gas discharge is due to generation and movement of charged...
This paper presents the design and fabrication of a new packaged MEMS capacitive temperature sensor for engine component health-monitoring applications and measurement results above 500–600°C. The multimorphs employed are thermal-SiO2/LPCVD-Si3N4/sputtered-Au beams designed for deflection at these temperatures. The mean initial capacitance of the sensors is 6.441 pF; with a standard deviation of 0...
Micro-Electro-Mechanical-Systems (MEMS) have emerged as a promising technology for the development of miniaturized low-cost and low-power switches, actuators, and sensors. However, there are a number of physical mechanisms that need more understanding and this remains as one of the biggest hurdles to widespread commercial adaptation of MEMS-based radio frequency (RF) electronics. In this work we study...
This paper presents a single-tunable-element matching network optimized for the GSM850 and GSM900 bands. A simple model for antenna detuning based on extensive measurements from literature is first presented. Single tunable element implementations for a planar inverted-F antenna as well as a proof-of-concept for the iPhone 4TM antenna are shown. Measured results indicate transducer gain improvements...
A unique GaN power amplifier (PA) with an integrated evanescent-mode filter as its output matching network is presented in this paper. This design yields a very narrowband PA response from 1.24–1.275 GHz (2.8%) which is comparable to the bandwidth of typical communication signals. The PA exhibits a state-of-the-art performance of 70% efficiency, 10 dB gain, 30 dBm output power, and second and third...
Tunable bandstop filters are demonstrated with wide tuning ranges, tunable bandwidth, and a variable number of dynamically allocated poles. The number of poles can be dynamically applied at different frequencies to maximize isolation for a given interference scenario. These filters are made with evanescent-mode cavities which use a new loading post geometry that results in greater external coupling...
In this paper we present a novel tunable RF MEMS resonator that is based upon electrostatic control over the morphology of a liquid metal droplet (LMD). We demonstrate a LMD evanescent-mode cavity resonator that simultaneously achieves wide analog tuning from 12 to 18 GHz with a measured quality factor of 1400–1840. A droplet of 250-um diameter is utilized and the applied bias is limited to 100V....
We present, for the first time, an all-silicon magnetostatically-tunable evanescent-mode cavity resonator that is capable of analog tuning from 9.5 to 17 GHz (1∶1.8) while maintaining a high unloaded quality factor (Q) of 650–950 (70–80% of the simulated results). The resonator is fabricated using silicon micromachining and is tuned by moving a gold-covered single-crystal silicon diaphragm over the...
This paper demonstrates the concept of a field-programmable filter array which can be configured in the field after fabrication. The proposed array is composed of tunable resonators and can have multiple functionalities by rerouting signals from input ports to output ports. Signal rerouting can be achieved by controlling the inter-resonator coupling with a wide tuning ratio of coupling coefficients.
This paper details how a distributed proof mass can be used to achieve an increased operational bandwidth in a low-frequency, meandering piezoelectric vibration energy harvester. The fabricated device features two closely spaced resonant modes at 33 Hz and 43.3 Hz with measured RMS output powers of 107.3 µW and 74.9 µW, respectively, at a peak acceleration magnitude of 0.2 g. The output power of this...
For periodic and event-driven applications with long standby times, controlling leakage is essential. This paper investigates using MEMS switches for power gating processors, which eliminates standby leakage power and allows for highly scalable processing. We show that when power gating with a MEMS switch, low technology nodes and low threshold voltages, which offer low switching energy and high speeds,...
This paper presents the first system-level characterization of the effects of bias noise on the performance of high-Q electrostatic RF MEMS tunable filters. By looking at the system-level performance of such a tunable filter, this paper shows that bias noise, if not well controlled, can degrade the RF performance of the tunable filter. Quantified by error vector magnitude measurement, such system...
This paper reports the performance of a wireless MEMS bimorph temperature sensor integrated on a bearing for component health monitoring applications. The sensor consists of a robust array of bimorphs consisting of gold and thermally-grown oxide operable to at least 300°C. Fabrication details are included, as well as the hermetic packaging information. Speed of actuation results from a high-speed...
This paper presents the first near-contact aerodynamic damping model based on rarefied flow modeling for use in dynamic simulations of large-displacement motion and contacting behavior of microbeams. The damping model is constructed based on high-fidelity simulations of rarefied gas flow around microbeams based on the Boltzmann kinetic equation with the Ellipsoidal Statistical Bhatnagar-Gross-Krook...
Direct experimental evidence of field emission currents in metallic MEMS devices is presented. For the first time, high resolution I-V curves have been demonstrated for micro-gaps in MEMS-based capacitor/switch-like geometries. The I-V dependence shows a good agreement with the Fowler-Nordheim theory, supporting the hypothesis that field emission plays a significant role in charging phenomena in MEMS...
A new topology for significantly improving the linearity of RF MEMS varactors is reported in this paper. A single MEMS varactor subject to a low frequency noise and/or modulating signal is the main structure under consideration. The key idea is to separate the single varactor into two varactors in parallel which are anti-biased. This leads to the opposing vibration of two beams under the influence...
In this paper, the viscoelastic behavior of a tunable RF-MEMS resonator and its impacts are studied by means of direct RF measurements for the first time. This tunable resonator consists of one lambda/2 coplanar waveguide (CPW) Resonator and two nanocrystalline-Ni RF-MEMS varactors. S-parameters of this tunable resonator have been measured for 80 hours under a bi-state bias condition of 0 and 40 V...
A fast and power efficient phase difference and frequency offset estimation technique for collaborative beamforming in a wireless sensor network is presented. Common radio blocks are used to implement the phase difference estimation technique and we present an analytical expression for the phase difference estimation accuracy in an AWGN channel. The analysis including the effect of noise and multipath...
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