Radio Frequency Microelectromechanical Systems in Defence and Aerospace
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
The Damped Harmonic Oscillator
THE DAMPED HARMONIC OSCILLATOR Reading: Main 3.1, 3.2, 3.3 Taylor 5.4 Giancoli 14.7, 14.8 Free, undamped oscillators – other examples k m L No friction I C k m q 1 x m!x! = !kx q!! = ! q LC ! ! r; r L = θ Common notation for all g !! 2 T ! " # ! !!! + " ! = 0 m L 0 mg k friction m 1 LI! + q + RI = 0 x C 1 Lq!!+ q + Rq! = 0 C m!x! = !kx ! bx! ! r L = cm θ Common notation for all g !! ! 2 T ! " # ! # b'! !!! + 2"!! +# ! = 0 m L 0 mg Natural motion of damped harmonic oscillator Force = mx˙˙ restoring force + resistive force = mx˙˙ ! !kx ! k Need a model for this. m Try restoring force proportional to velocity k m x !bx! How do we choose a model? Physically reasonable, mathematically tractable … Validation comes IF it describes the experimental system accurately Natural motion of damped harmonic oscillator Force = mx˙˙ restoring force + resistive force = mx˙˙ !kx ! bx! = m!x! ! Divide by coefficient of d2x/dt2 ! and rearrange: x 2 x 2 x 0 !!+ ! ! + " 0 = inverse time β and ω0 (rate or frequency) are generic to any oscillating system This is the notation of TM; Main uses γ = 2β. Natural motion of damped harmonic oscillator 2 x˙˙ + 2"x˙ +#0 x = 0 Try x(t) = Ce pt C, p are unknown constants ! x˙ (t) = px(t), x˙˙ (t) = p2 x(t) p2 2 p 2 x(t) 0 Substitute: ( + ! + " 0 ) = ! 2 2 Now p is known (and p = !" ± " ! # 0 there are 2 p values) p t p t x(t) = Ce + + C'e " Must be sure to make x real! ! Natural motion of damped HO Can identify 3 cases " < #0 underdamped ! " > #0 overdamped ! " = #0 critically damped time ---> ! underdamped " < #0 # 2 !1 = ! 0 1" 2 ! 0 ! time ---> 2 2 p = !" ± " ! # 0 = !" ± i#1 x(t) = Ce"#t+i$1t +C*e"#t"i$1t Keep x(t) real "#t x(t) = Ae [cos($1t +%)] complex <-> amp/phase System oscillates at "frequency" ω1 (very close to ω0) ! - but in fact there is not only one single frequency associated with the motion as we will see. -
The Q of Oscillators
The Q of oscillators References: L.R. Fortney – Principles of Electronics: Analog and Digital, Harcourt Brace Jovanovich 1987, Chapter 2 (AC Circuits) H. J. Pain – The Physics of Vibrations and Waves, 5th edition, Wiley 1999, Chapter 3 (The forced oscillator). Prerequisite: Currents through inductances, capacitances and resistances – 2nd year lab experiment, Department of Physics, University of Toronto, http://www.physics.utoronto.ca/~phy225h/currents-l-r-c/currents-l-c-r.pdf Introduction In the Prerequisite experiment, you studied LCR circuits with different applied signals. A loop with capacitance and inductance exhibits an oscillatory response to a disturbance, due to the oscillating energy exchange between the electric and magnetic fields of the circuit elements. If a resistor is added, the oscillation will become damped. 1 In this experiment, the LCR circuit will be driven at resonance frequencyωr = , when the LC transfer of energy between the driving source and the circuit will be a maximum. LCR circuits at resonance. The transfer function. Ohm’s Law applied to a LCR loop (Figure 1) can be written in complex notation (see Appendix from the Prerequisite) Figure 1 LCR circuit for resonance studies v( jω) Ohm’s Law: i( jω) = (1) Z - 1 - i(jω) and v(jω) are complex instantaneous values of current and voltage, ω is the angular frequency (ω = 2πf ) , Z is the complex impedance of the loop: 1 Z = R + jωL − (2) ωC j = −1 is the complex number The voltage across the resistor from Figure 1, as a result of current i can be expressed as: vR ( jω) = Ri( jω) (3) Eliminating i(jω) from Equations (1) and (3) results into: R v ( jω) = v( jω) (4) R R + j(ωL −1/ωC) Equation (4) can be put into the general form: vR ( jω) = H ( jω)v( jω) (5) where H(jω) is called a transfer function across the resistor, in the frequency domain. -
Arxiv:1704.05328V1 [Cond-Mat.Mes-Hall] 18 Apr 2017 Tuning the Mechanical Mode Frequencies by More Than Silicon Wafers
Quantitative Determination of the Mechanical Properties of Nanomembrane Resonators by Vibrometry In Continuous Light Fan Yang,∗ Reimar Waitz,y and Elke Scheer Department of Physics, Universit¨atKonstanz, 78464 Konstanz, Germany We present an experimental study of the bending waves of freestanding Si3N4 nanomembranes using optical profilometry in varying environments such as pressure and temperature. We introduce a method, named Vibrometry in Continuous Light (VICL) that enables us to disentangle the response of the membrane from the one of the excitation system, thereby giving access to the eigenfrequency and the quality (Q) factor of the membrane by fitting a model of a damped driven harmonic oscillator to the experimental data. The validity of particular assumptions or aspects of the model such as damping mechanisms, can be tested by imposing additional constraints on the fitting procedure. We verify the performance of the method by studying two modes of a 478 nm thick Si3N4 freestanding membrane and find Q factors of 2 × 104 for both modes at room temperature. Finally, we observe a linear increase of the resonance frequency of the ground mode with temperature which amounts to 550 Hz=◦C for a ground mode frequency of 0:447 MHz. This makes the nanomembrane resonators suitable as high-sensitive temperature sensors. I. INTRODUCTION frequencies of bending waves of nanomembranes may range from a few kHz to several 100 MHz [6], those of Nanomechanical membranes are extensively used in a thickness oscillation may even exceed 100 GHz [21], re- variety of applications including among others high fre- quiring a versatile excitation and detection method able quency microwave devices [1], human motion detectors to operate in this wide frequency range and to resolve [2], and gas sensors [3]. -
Adobe Corporate Campus Utah, Usa – Structure Becomes the Architecture
ADOBE CORPORATE CAMPUS UTAH, USA – STRUCTURE BECOMES THE ARCHITECTURE GEOFF S SHARP Senior Project Engineer, Holmes Consulting Group LP SUMMARY Phase one of Adobe Corporation’s new corporate campus is an example of where the thoughtful selection of structural system and construction materials allowed for seamless integration of engineering and architecture. Constructed of post tensioned and conventionally reinforced concrete the office structure showcases what can be achieved when the structure becomes the architecture. At over 200 metres in length and boasting cantilevered frames and a 25 metre “bridge” the use of concrete was essential to the success of this new office building. INTRODUCTION In late 2012, United States based software giant Adobe Corporation moved into their new 28,000 square metre campus in Lehi, Utah. The decision to expand away from their long standing Silicon Valley home required their new facility to make a statement. It needed to attract a new class of outdoors-loving young professionals. Located approximately 50km south of Salt Lake City, the resulting buildings form stage one of their impressive new home on the “Silicon Slopes” of Utah. Challenges included a highly sloped site with significant variation in subsoil conditions and a dual carriage roadway dividing the property. Figure 1 below shows a rendering of the phase one buildings Figure 1 - Phase 1 Adobe Campus Rendering, courtesy of WRNS Studio The lead architects for the project were WRNS Studio of San Francisco with structural engineering delivered through a collaboration between Holmes Culley in San Francisco and Dunn Associates in Salt Lake City. The design process between architect and engineer was very successful due to an open and collaborative approach. -
Cantilever Bridges: the Governor Harry W
CANTILEVER BRIDGES: THE GOVERNOR HARRY W. NICE MEMORIAL BRIDGE From a technical perspective, cantilever construction of a bridge defines a specific form of support of the bridge rather than a particular bridge type such as the truss or girder. Simply supported bridges are directly supported on piers and abutments, while continuous structures, as developed in both metal and reinforced concrete during the late nineteenth and early twentieth centuries, include spans that are continuous across one or more intermediate supports. By contrast, the cantilever form of support occurs when the support is at one end and the other end of the span is free. Cantilever bridges consist of a series of cantilevered spans including a main span and two anchor spans which flank it (Pennsylvania Historical and Museum Commission, and Pennsylvania Department of Transportation 1986:124). Based on historical research alone, cantilever bridges in Maryland appear to be represented by only one bridge, which may be briefly described in order to provide historic technological context for the evaluation of that bridge, the 1940 Governor Harry W. Nice Memorial Bridge carrying U.S. 301 over the Potomac River. Bridge historian J.A.L. Waddell noted that "the development of the cantilever. did not proceed very far until modern times, when the truss form of structure had become established and when iron and steel constituted the materials of construction" (Waddell 1916:7). Waddell and subsequent technological historians dated the major advent of modern cantilever bridges to the design and construction of the high bridge over the Kentucky River at Dixville in 1876-1877. -
RF-MEMS Load Sensors with Enhanced Q-Factor and Sensitivity In
Microelectronic Engineering 88 (2011) 247–253 Contents lists available at ScienceDirect Microelectronic Engineering journal homepage: www.elsevier.com/locate/mee RF-MEMS load sensors with enhanced Q-factor and sensitivity in a suspended architecture ⇑ Rohat Melik a, Emre Unal a, Nihan Kosku Perkgoz a, Christian Puttlitz b, Hilmi Volkan Demir a, a Departments of Electrical Engineering and Physics, Nanotechnology Research Center, and Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey b Department of Mechanical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, CO 80523, USA article info abstract Article history: In this paper, we present and demonstrate RF-MEMS load sensors designed and fabricated in a suspended Received 31 August 2009 architecture that increases their quality-factor (Q-factor), accompanied with an increased resonance fre- Received in revised form 7 July 2010 quency shift under load. The suspended architecture is obtained by removing silicon under the sensor. Accepted 29 October 2010 We compare two sensors that consist of 195 lm  195 lm resonators, where all of the resonator features Available online 9 November 2010 are of equal dimensions, but one’s substrate is partially removed (suspended architecture) and the other’s is not (planar architecture). The single suspended device has a resonance of 15.18 GHz with 102.06 Q-fac- Keywords: tor whereas the single planar device has the resonance at 15.01 GHz and an associated Q-factor of 93.81. Fabrication For the single planar device, we measured a resonance frequency shift of 430 MHz with 3920 N of applied IC Resonance frequency shift load, while we achieved a 780 MHz frequency shift in the single suspended device. -
Teaching the Difference Between Stiffness and Damping
LECTURE NOTES « Teaching the Difference Between Stiffness and Damping Henry C. FU and Kam K. Leang In contrast to the parallel spring-mass-damper, in the necessary step in the design of an effective control system series mass-spring-damper system the stiffer the system, A is to understand its dynamics. It is not uncommon for a the more dissipative its behavior, and the softer the sys- well-trained control engineer to use such an understanding to tem, the more elastic its behavior. Thus teaching systems redesign the system to become easier to control, which requires modeled by series mass-spring-damper systems allows an even deeper understanding of how the components of a students to appreciate the difference between stiffness and system influence its overall dynamics. In this issue Henry C. damping. Fu and Kam K. Leang discuss the diff erence between stiffness To get students to consider the difference between soft and damping when understanding the dynamics of mechanical and damped, ask them to consider the following scenario: systems. suppose a bullfrog is jumping to land on a very slippery floating lily pad as illustrated in Figure 2 and does not want to fall off. The frog intends to hit the flower (but he simple spring, mass, and damper system is ubiq- cannot hold onto it) in the center to come to a stop. If the uitous in dynamic systems and controls courses [1]. TThis column considers a concept students often have trouble with: the difference between a “soft” system, which has a small elastic restoring force, and a “damped” system, x c which dissipates energy quickly. -
Using a Cmos-Biomems Cantilever Sensor For
USING A CMOS-BIOMEMS CANTILEVER SENSOR FOR ORCHID VIRUS DETECTION Lu-Hsun Cheng1, Ya-Chun Chang2, Wen-Chi Hu2, Hsin-Hao Liao3, Hann-Huei Tsai3,Ying-Zong Juang3 and Yen-Wen Lu1 1Dept. of Bio-Industrial Mechatronics Engineering, 2Dept. of Plant Pathology & Microbiology, National Taiwan University, Taipei Taiwan, ROC, 3National Chip Implementation Center (CIC), Hsinchu, Taiwan, R.O.C ABSTRACT We present a preliminary study on utilizing cantilever biosensors to detect Odontoglossum ringspot tobamovirus (ORSV) - one of the most prevalent viruses affecting the health of orchids. The cantilever surfaces of the biosensor are immobilized by ORSV-antibody (Ab) as the recognition probe for ORSV detection. Implemented by using commercially available CMOS technology and post-processed for bio-MEMS capability, the biosensors are embedded with piezoresistors, which can realize surface stress changes due to cantilever deflection coming from the specific bioaffinity between the antigen (Ag) and the antibody. The result shows -0.7% and +0.6% resistivity change when ORSV-Ab and ORSV are respectively presented. KEYWORDS: Cantilever, Odontoglossum ringspot tobamovirus, Piezoresistor, CMOS BioMEMS INTRODUCTION Cantilever biosensors have been used as a sensitive and label-free diagnostic platform for malignant disease diagnosis by detecting DNA mismatch or protein biomarkers [1-3]. Figure 1 depicted the schematics of our device that contained an array of cantilevers with imbedded piezoresistors. The detection is normally achieved by modifying the surface of the cantilever with recognition molecules. The specific interaction between the recognition molecules and the target biomarkers generates surface stress and makes the deflection of the cantilever. The deflection, which is normally several nanometers, can be measured using either optical or piezoresistive readouts. -
Lab 4: Prelab
ECE 445 Biomedical Instrumentation rev 2012 Lab 8: Active Filters for Instrumentation Amplifier INTRODUCTION: In Lab 6, a simple instrumentation amplifier was implemented and tested. Lab 7 expanded upon the instrumentation amplifier by improving circuit performance and by building a LabVIEW user interface. This lab will complete the design of your biomedical instrument by introducing a filter into the circuit. REQUIRED PARTS AND MATERIALS: Materials Needed 1) Instrumentation amplifier from Lab 7 2) Results from Prelab 3) Oscilloscope 4) Function Generator 5) DC Power Supply 6) Labivew Software 7) Data Acquisition Board 8) Resistors 9) Capacitors 10) Dual operational amplifier (UA747) PRELAB: 1. Print the Prelab and Lab8 Grading Sheets. Answer all of the questions in the Prelab Grading Sheet and bring the Lab8 Grading Sheet with you when you come to lab. The Prelab Grading Sheet must be turned in to the TA before beginning your lab assignment. 2. Read the LABORATORY PROCEDURE before coming to lab. Note: you are not required to print the lab procedure; you can view it on the PC at your lab bench. 3. For further reading consult class notes, text book and see Low Pass Filters http://www.electronics-tutorials.ws/filter/filter_2.html High Pass Filters http://www.electronics-tutorials.ws/filter/filter_3.html BACKGROUND: Active Filters As their name implies, Active Filters contain active components such as operational amplifiers or transistors within their design. They draw their power from an external power source and use it to boost or amplify the output signal. Operational amplifiers can also be used to shape or alter the frequency response of the circuit by producing a more selective output response by making the output bandwidth of the filter more narrow or even wider. -
Basic Structures
Basic Structures What is a structure? The structure of a building is the part which is responsible for maintaining the original shape of the building under the influence of the forces, loads and other environmental factors to which is subjected. Examples of structural components include: _Steel beams, columnsm roof trusses ans space frames _Reinforced concrete beams, columns, retaining walls and foundations Below picture shows the Lower Manhattan skyline in New York, one of the greatest concentrations of high-rise buildings in the world. Space limitations on the island meant building construction had to proceed upwards rather than outwards, and the presence of solid rock made foundations for these soaring structures feasible. [Image below: Lower Manhattan skyline in New York, USA] Structural understanding The basic function of a structure is to transmit loads from the position of application of the load to the point of support and thus to the foundations in the ground. Any structure must satisfy the following criteria: 01// Aesthetics (it must look nice). 02// Ease of maintenance. 03// Durability. This means that the materials used must be resistant to corrosion, spalling (pieces falling off), chemical attack, rot. 04// Fire resistance. While few materials can completely resist the effects of fire, it is important for a building to resist fire long enough for its occupants to be safely evacuated. [Image below: Roof structure of Quartier 206 shopping mall, Berlin, Germany] Safety and serviceability There are two main requirements of any structure: it must be safe and it must be serviceable. Safe means that the structure should not collapse Serviceability means that the structure should not deform unduly under the effects of defl ection, cracking or vibration. -
Modified Chebyshev-2 Filters with Low Q-Factors
J KAU: Eng. Sci., vol. 3, pp. 21-34 (1411 A.H.l1991 A.D.) Modified Chebyshev-2 Filters with Low Q-Factors A. M. MILYANI and A. M. AFFANDI Department ofElectrical and Computer Engineering, Faculty ofEngineering, King Abdulaziz University, Jeddah, Saudi Arabia. ABSTRACT A modified low pass maximally flat inverse Chebyshev filter is suggested in this paper, and is shown to have improvement over previous known Chebyshev filters. The coefficients of this modified filter, using a higher order polynomial with multiplicity of the dominant pole-pair, have been determined. The pole locations and the Q factors for different orders of filters are tabulated using an optimization algorithm. 1. Introduction Recently, there has been a great deal of interest in deriving suboptimal transfer func tions with low Q dominant poles[1-3J. The suboptimality of these functions allows for low precision requirements in both active RC-filters and digital filters. It is, however, noted that the minimal order filter is not necessarily the least complex filter. In a recent article, Premoli[11 used the notion of multiplicity in the dominant poles to obtain multiple critical root maximally flat (MUCROMAF) polynomials for low pass filters. An alternative method for deriving these functions, referred to as mod ified Butterworth functions, has been presented by Massad and Yariagaddal2J . Also a new class of multiple critical root pair, equal ripple (MUCROER) filtering func tions, having higher degree than the filtering functions, has been presented by Premoli[1l. By relaxing the equal ripple conditions, Massad and Yarlagadda derived a new algorithm to find modified Chebyshev functions which have lower Qdominant polesl21 . -
Quality-Factor Considerations for Single Layer Solenoid Reactors
Quality-factor considerations for single layer solenoid reactors M. Nagel1*, M. Hochlehnert1 and T. Leibfried1 1University of Karlsruhe, Institute of Electrical Energy Systems and High-Voltage Technology Engesserstr. 11, 76131 Karlsruhe, Germany *Email: [email protected] Abstract: As it is commonly known, rating and build- are affecting the performance of existing equipment. ing a reactor is not the easiest thing to do. Numerical High frequency noise is subjected to components, pre- solutions of complex magnetic field distributions need viously only fed with clean sine waves of 50/60Hz. to be calculated to verify the design. This is getting even This noise, mainly superimposed by power elec- more challenging, when the quality-factor (Q-factor) of tronic equipment like used in Flexible AC transmission a resonator is of major importance. This problem is for systems (FACTS) build with IGBT valves, is thereby a example appearing, when building resonance circuits new stress to the equipment and poorly investigated yet. with low losses for high voltage and high frequency While in the above mentioned case, the large slew rates (HF) experiments. Coreless, one layer solenoid, or like- of the switching pulses is generating the noise, more wise, reactors are needed there to meet both frequency longer known is high frequent noise to arise by trans- and voltage requirements. Coreless because of the hys- former switching over longer lines. teresis losses of magnetic materials at high frequency In common for all the cases of high frequency noise and only one layer, due to the maximum applicable field at standard equipment is the present lack of knowledge strength per winding, which is dropping significantly at about the performance of the insulation system.