Conference
International Frequency Control Symposium
About: International Frequency Control Symposium is an academic conference. The conference publishes majorly in the area(s): Resonator & Phase noise. Over the lifetime, 4532 publications have been published by the conference receiving 30960 citations.
Papers published on a yearly basis
Papers
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29 Aug 2005
TL;DR: As vibrating RF MEMS devices are perceived more as circuit building blocks than as stand-alone devices, and as the frequency processing circuits they enable become larger and more complex, the makings of an integrated micromechanical circuit technology begin to take shape, perhaps with a functional breadth not unlike that of integrated transistor circuits.
Abstract: An overview on the vise of microelectromechanical systems (MEMS) technologies for timing and frequency control is presented. In particular, micromechanical RF filters and reference oscillators based on recently demonstrated vibrating on-chip micromechanical resonators with Q's > 10,000 at 1.5 GHz are described as an attractive solution to the increasing count of RF components (e.g., filters) expected to be needed by future multiband, multimode wireless devices. With Q's this high in on-chip abundance, such devices might also enable a paradigm shift in the design of timing and frequency control functions, where the advantages of high-Q are emphasized, rather than suppressed (e.g., due to size and cost reasons), resulting in enhanced robustness and power savings. Indeed, as vibrating RF MEMS devices are perceived more as circuit building blocks than as stand-alone devices, and as the frequency processing circuits they enable become larger and more complex, the makings of an integrated micromechanical circuit technology begin to take shape, perhaps with a functional breadth not unlike that of integrated transistor circuits. With even more aggressive three-dimensional MEMS technologies, even higher on-chip Q's are possible, such as already achieved via chip-scale atomic physics packages, which so far have achieved Q's > 107 using atomic cells measuring only 10 mm3 in volume and consuming just 5 mW of power, all while still allowing atomic clock Allan deviations down to 10-11 at one hour
776 citations
20 Apr 2009
TL;DR: The design approaches will be reviewed and optimal tag designs, as well as encoding methods, will be demonstrated, and ways to reduce the size and cost of SAW tags are discussed.
Abstract: SAW tags were invented more than 30 years ago, but only today are the conditions united for mass application of this technology. The devices in the 2.4-GHz ISM band can be routinely produced with optical lithography, high-resolution radar systems can be built up using highly sophisticated, but low-cost RF-chips, and the Internet is available for global access to the tag databases. The "Internet of Things," or I-o-T, will demand trillions of cheap tags and sensors. The SAW tags can overcome semiconductor-based analogs in many aspects: they can be read at a distance of a few meters with readers radiating power levels 2 to 3 orders lower, they are cheap, and they can operate in robust environments. Passive SAW tags are easily combined with sensors. Even the "anti-collision" problem (i.e., the simultaneous reading of many nearby tags) has adequate solutions for many practical applications. In this paper, we discuss the state-of-the-art in the development of SAW tags. The design approaches will be reviewed and optimal tag designs, as well as encoding methods, will be demonstrated. We discuss ways to reduce the size and cost of these devices. A few practical examples of tags using a timeposition coding with 106 different codes will be demonstrated. Phase-coded devices can additionally increase the number of codes at the expense of a reduction of reading distance. We also discuss new and exciting perspectives of using ultra wide band (UWB) technology for SAW-tag systems. The wide frequency band available for this standard provides a great opportunity for SAW tags to be radically reduced in size to about 1 x 1 mm2 while keeping a practically infinite number of possible different codes. Finally, the reader technology will be discussed, as well as detailed comparison made between SAW tags and IC-based semiconductor device.
251 citations
04 May 2003
TL;DR: This paper will survey the development of the thin film resonator technology and describe the core elements that give rise to resonators and filters for today's high performance wireless applications.
Abstract: The thin film resonator technology has been under development for over forty years in one form or another. Although the basic approach is derived from the desire to reach higher frequencies than those readily achieved by thinning bulk crystals, there have always been competing technologies or fundamental material or processing problems that have impeded the development. Finally, a point was reached in the wireless market wherein competing technologies appeared unable to meet the demands of modern wireless applications and thin film approaches began to receive some emphasis. This paper will survey the thin film resonator technology. Every effort will be made to provide an objective analysis of the technology in relation to applications and competing technologies, and point out obstacles and promises, as known, for further technology advancement to high frequencies.
169 citations
04 Mar 2010
TL;DR: This temperature-compensated AlN Lamb wave resonator based on a stack of AlN and SiO2 layers can achieve a zero first-order temperature coefficient of frequency (TCF) and is promising for future applications including thermally stable oscillators, filters, and sensors.
Abstract: In this paper, the temperature compensation of AlN Lamb wave resonators using edge-type reflectors is theoretically studied and experimentally demonstrated. By adding a compensating layer of SiO2 with an appropriate thickness, a Lamb wave resonator based on a stack of AlN and SiO2 layers can achieve a zero first-order temperature coefficient of frequency (TCF). Using a composite membrane consisting of 1 ?m AlN and 0.83 ?m SiO2, a Lamb wave resonator operating at 711 MHz exhibits a first-order TCF of -0.31 ppm/°C and a second-order TCF of -22.3 ppb/°C2 at room temperature. The temperature-dependent fractional frequency variation is less than 250 ppm over a wide temperature range from -55°C to 125°C. This temperature-compensated AlN Lamb wave resonator is promising for future applications including thermally stable oscillators, filters, and sensors.
168 citations
27 May 1998
TL;DR: In this article, the authors investigated surface acoustic wave (SAW) devices working at high temperatures and found that the frequency response disappeared completely at about 800/spl deg/C. The considered substrate materials are lithium niobate (LiNbO), quartz and langasite (La/sub 3/Ga/sub 5/SiO/sub 14/).
Abstract: Results of investigations of surface acoustic wave (SAW) devices working at high temperatures are presented in this paper. The considered substrate materials are lithium niobate (LiNbO/sub 3/), quartz and langasite (La/sub 3/Ga/sub 5/SiO/sub 14/). In addition, electrode materials and assembly, interconnect and packaging strategies are discussed or examined. Delay lines on LiNbO/sub 3/ had low SAW attenuation up to approx. 550/spl deg/C. The frequency response disappeared completely at about 800/spl deg/C. Delay lines on quartz had low SAW attenuation up to 500/spl deg/C, a temperature being significantly below the phase transition from /spl alpha/- to /spl beta/-quartz at 573/spl deg/C. Delay lines on La/sub 3/Ga/sub 5/SiO/sub 14/ withstand extreme temperatures: a SAW response was observed up to destruction of the packages used in these tests, however, resulted in a degradation of the device performance starting at about 600/spl deg/C. An identification (ID) tag on La/sub 3/Ga/sub 5/SiO/sub 14/, could be used as a wireless passive thermometer for measuring high temperatures in industrial process control applications.
148 citations