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MEMS resonators have been discussed as replacements for quartz crystals in electronics timing applications for more than 40 years. The emergence of high-quality, low-cost packaging for MEMS resonators has enabled the first demonstrations of long-term stability and opened the door for commercial applications.
This paper reports internal dielectric transduction of the 41st radial bulk-mode of a ring resonator at 2.79 GHz with a quality factor exceeding 11,500 in air. The transducer electrodes are integrated within the vibrating structure in a dense serpentine pattern, with the dielectric-filled gaps strategically placed on the nodal lines to excite the 41st order bulk radial mode. The serpentine dielectric...
This paper reports fine frequency selection techniques for aluminum nitride (AlN) Lamb wave mode resonators (LWR) to control the relative frequency of resonators in an array to 0.1%. The technique that works the best is by adjusting the so-called AlN “overhang” dimension, OH, measured from the center of the outermost electrode to the edge of AlN plate independently of the interdigital transducer (IDT)...
This paper reports on the first demonstration of single-ended-to-differential and differential-to-differential (S2D and D2D) channel-select filters based on single-layer (SL) and dual-layer-stacked (DLS) AlN contour-mode MEMS resonators. The key filter performances in terms of insertion loss (as low as 1.4 dB), operating frequency (250-1280 MHz), and out-of-band rejection (up to 60 dB) constitute...
Sensing platforms (5mm*5mm) containing 5 piezoelectric membranes have been fabricated by standard micromachining techniques starting with a Silicon-On-Insulator wafer. Each membrane (circular, with radius varying from 360 microns to 440 microns) could be individually actuated through a PZT 1-micron thick film and sensed either via the same piezoelectric patch or via two terminal piezoresistances (obtained...
We present the fabrication and characterization of a 90μm × 40μm × 885nm piezoelectric micro-cantilever resonator containing a 50nm thick Aluminum Nitride (AlN) piezoelectric film for transduction. Material characterizations demonstrate that our AlN deposition technique enables the fabrication of ultra-thin films with high piezoelectric coefficient e31 = 0.78C.m-2. Fully electrical actuation and detection...
A monolithic and unpackaged silicon die is presented as a frequency source suitable for quartz crystal resonator (XTAL) and oscillator (XO) replacement. The frequency source is referenced to a free-running, frequency-trimmed and temperature-compensated 3 GHz RF LC oscillator. A programmable divider array enables the device to provide frequencies ranging from 6 to 133 MHz. A post-processed Faraday...
We describe a novel architecture for realization of a miniature all-optical atomic clock. We show theoretically that a hyperparametric oscillator based on a whispering gallery mode resonator can be used as a miniature frequency divider for the clock. Such a frequency divider allows for transferring the long term frequency stability from the optical frequency domain to the RF frequency domain. We present...
The characteristics of microcantilevers vibrating in the in-plane flexural mode (also known as lateral vibration) in viscous liquid media are investigated. A numerical model was utilized to determine a correction to Stokes' solution for an infinite plate to obtain an analytical expression for the hydrodynamic forces acting on a laterally vibrating microcantilever as a function of both Reynolds number...
In this article, we describe the simultaneous digital measurement of both phase (PM) and amplitude (AM) noise of VHF and microwave sources by the direct digitization of the signal-under-test. Our measurement approach takes advantage of a commercially-available, high-dynamic-range analog-to-digital converter driven by a high-performance clock to digitize the signal-under-test with high fidelity. Following...
Experimental results of a pulsed mode electrostatic excitation on a Double Ended Tunning Fork (DETF) MEMS resonator at 11 MHz fabricated on a commercial standard 0.35um CMOS technology are described. Using small pulse widths of 4 ns, a ten percent power safe and a reduction of the MEMS non-linearities are achieved.
We describe the design of a low-phase modulated (PM) noise 40 GHz oscillator that uses a conventional air-dielectric cavity resonator as a frequency discriminator to clean up the PM noise of a commercial 10 GHz dielectric resonator oscillator (DRO) multiplied by four. The main features of this design incorporate (1) unloaded cavity quality factor (Q) of 30,000, (2) high coupling coefficient, (3) large...
Newer systems require improved noise performance in order to detect and track targets at great distances in difficult clutter environments. Typically, phase noise is an area that is closely watched as a main contributor to overall system noise performance. Amplitude noise is often treated as a second order effect because systems are often operated in amplitude compression during transmits to maximize...
Among the crystals belonging to the langasite family, the langatate one (La3Ga5.5Ta0.5O14 also called LGT) seems the best candidate to substitute to the quartz crystal for frequency and time applications. Pairs of LGT crystal resonators prototypes working at 10 MHz have been measured on an advanced phase noise measurement system. The LGT crystal resonators noise has been measured according to various...
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