1 Microwave Engineering - Department of Electrical Communication ...

13 downloads 1441 Views 454KB Size Report
Microwave Engg. RF transmission lines: theory, high freq effects (4). 7. Sections of ... D.M. Pozar, Microwave Engineering 2nd ed., John Wiley 2003. 2. M. Madou  ...
Microwave Engineering & RF MEMS http://ece.iisc.ernet.in/~kjvinoy/rfmems/rfmems.htm Instructor Dr. K.J. Vinoy, Asst Professor, ECE Dept. Detailed Course Outline 1. 2. 3. 4.

Introduction to MEMS, general concepts on miniaturization and fabrication (1) MEMS Materials, Fabrication and Processes: Silicon, other substrates, ceramics (1) Lithography, Deposition techniques, Etching techniques (2) Bulk micromachining, Surface micromachining (2)

5. 6. 7. 8.

Actuation Mechanisms in MEMS, Electrostatic actuation, Comb drive actuators (3) Intro. Microwave Engg. RF transmission lines: theory, high freq effects (4) Sections of transmission lines: special cases, Transmission line examples: microstrip, CPW(4) S-parameter theory, ABCD, parameter extraction, Introduction to RF MEMS (4)

9. 10. 11. 12. 13. 14. 15. 16.

RF MEMS Switches: Intro, basic design guidelines RF switch design case studies, Performance improvement approaches Micromachined passive components, theory, features, tunable capacitors, inductors RF resonators & filters RF Filter design concepts Mechanical filters: design approaches, RF filters with MEMS, mmwave filters, SAW, BAW filters Phase Shifters: introduction, basic theory, applications RF MEMS Phase shifters, Distributed MEMS phase shifters, Ferroelectric phase shifters

17. 18. 19. 20.

Micromachining concepts for antennas: Antenna parameters, Microstrip antennas, Microstrip antenna design, key factors affecting performance Micromachined antennas, Micromachined Txn lines and components Reliability & packaging, RF MEMS Packaging (5)

Grading Policy

Evaluation: Tests & Home Works Test 1 Aug, 24 2005 Test 2 Sept 14 2005 Test 3 Oct. 26 2004 Homework/Project* Finals

% Marks 91-100 81-90 66-80 51-65 40-50

15% 15% 15% 5% 50%

*Email submissions only, due at 5PM on Nov 18 Policy on Late Submission of Home works First 5 working days after deadline @ 5 % per day Afterwards add 15 % per week Absolutely no excuses!

Grade S A B C D

Suggested Text Books 1. D.M. Pozar, Microwave Engineering 2nd ed., John Wiley 2003 2. M. Madou, Fundamentals of Microfabrication 2nd ed., CRC Press, 2002 3. V.K. Varadan, K.J. Vinoy and K.A. Jose, RF MEMS and their Applications, John Wiley, 2002.

1

Other Reference Books Microwave Engineering 4. I Bahl, Lumped Elements for RF and Microwave Circuits, Artech House 5. R.E. Collin, Foundations for Microwave Engineering, IEEE Press 6. R. Mongia, I.J. Bahl, and P. Bhartia, RF and Microwave Coupled-Line Circuits, Artech House, 1999. 7. I. Bahl & P. Bartia, Microwave Solid State Circuit Design, Wiley Inter Science, 2003. Microfabrication & MEMS 8. S. Senturia, Microsystem Design, Kluwer, 2001. 9. J.W. Gardner , V.K. Varadan , O.O. Awadelkarim, Microsensors, MEMS & Smart Devices John Wiley, 2001. 10. S. Campbell, The Science and Engineering of Microelectronic Fabrication, Oxford Univ. Press, 2001 11. N Maluf An Introduction to Microelectromechanical Systems Engineering, Artech House 12. M Elwenspoek R. Wiegerink, Mechanical Microsensensors, Springer 2001 13. G.T. Kovacs, Micromachined Transducers Sourcebook, McGraw Hill Science, 1998 14. M. Gad El Hak The MEMS Handbook, CRC Press 2001. RF MEMS 15. G. Rebeiz, RF MEMS: Theory, Design, and Technology, Wiley/IEEE Press, 2003 16. H.J. De Los Santos, Introduction to Microelectromechanical (MEM) Microwave Systems, Artech house, 1999. 17. H.J. De Los Santos, RF MEMS Circuit Design for Wireless Communications, Artech House, 2003 Journals of Interest IEEE/ASME J. Microelectromechanical Systems IEEE Trans. Microwave Theory & Techniques J. Micromechanics and Micromachining (IOP) IEEE Microwave & Wireless Components Letters Websites of Interest 18. http://www.nexus-mems.com/ E 19. http://guernsey.et.tudelft.nl/indexold.html 20. http://guernsey.et.tudelft.nl/farlinks.html 21. http://www.dimes.tudelft.nl/ 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35.

uropean microsys net Silicon Microoptics in Delft

DIMES delft institute of microelectronics and submicron technology http://www.postech.ac.kr/~khkang/Links.htm MEMS links http://www.darpa.mil/MTO/MEMS/ DARPA MEMS http://www.memsnet.org/ MEMS and Nanotechnology Clearinghouse ISI MEMS clearinghouse http://transducers.stanford.edu/ Stanford transducers lab http://www-bsac.eecs.berkeley.edu/ Berkeley Sensor & Actuator centre http://mems.jpl.nasa.gov/home.html JPL-MEMS http://www.analog.com/index.html look up MEMS technology at Analog devices http://www.mcnc-rdi.org/index.cfm MCNC research home page http://www.mems.louisville.edu UofL MicroTechnology Web Site http://www.dbanks.demon.co.uk/ueng/ Introduction to Microengineering by Dr. Daniel Banks http:/www.dbanks.demon.co.uk/ueng/ Microsystems, Microsensors & Microactuators by Dr. Daniel Banks http://www.ee.surrey.ac.uk/Personal/D.Banks/roughgui.html Introduction to Microengineering http://www.memsrus.com/cronos/svcsmumps.html MUMPS Design Handbook www.memsrus.com/cronos/mumps.pdf

The course material will be from various resources listed above.

2

Electromagnetic spectrum of relevance HF 3-30 MHz VHF 30-300 MHz UHF 300-1000 MHz L 1-2 GHz S 2-4 GHz‫ﭕ‬ C 4-8 GHz X 8-12 GHz Ku 12-18 GHz K 18-27 GHz Ka 27-40 GHz V 40-75 GHz W 75-90 GHz mm wave 30-300 GHz

RF Microwave

Wavelength & frequency

λ=

c 30 → λ[cm] = f f GHz

History/ Evolution/ Trends in RF Engineering Popular application Early 20th century Radios mid- 20th century TV late 20th century Mobile phones early 21st century (Wireless systems) Bluetooth/ WLAN Next?? Future generation (?)

Frequency ~ MHz 100’s MHz ~ 1 GHz 2-5 GHz 20-50 GHz (?)

Behavior RLC Components at High Frequencies All components (passive, active, and even interconnects) need to be viewed as distributed parameter networks. We will consider resistors, capacitors, inductors, and the skin effect in conductors. Recall some fundamental principles: Resistance - occurs in any conducting medium (except superconductors) and limits the flow of current. Capacitance - occurs whenever two conductors are separated by a dielectric. Inductance - occurs whenever magnetic flux links a conductor. The physical dimensions and material properties of the components determine the equivalent distributed parameter network and we model the component as a network of discrete components.

Resistor

3

Capacitor

Inductor

Observe that • All components have resistance, capacitance, and inductance. • At low frequencies, the unintended components are insignificant. • At high frequencies, these unintended components become significant. • The unintended components are distributed throughout the device. These devices should therefore be modeled with a network of discrete devices. • As a rule of thumb, when the average size of a discrete component is more than a tenth of the wavelength, the distributed parameter network model, i.e., transmission line theory, should be used. (Use the wavelength in the medium, not the free-space wavelength)

Some of the issues with Conventional RF/Microwave Circuits Issue Poor modeling Poor Q-factor

Poor line-to line isolation

Low package density

Result Discontinuity effects Radiation leakage to, and/or out of the substrate Formation of multiple modes Excess bandwidth, reduced selectivity of filters, increasing input noise power Excess insertion loss, reduced output power, efficiency Excess localization of heat dissipation (requiring thermal management) Excess noise temperature, reducing sensitivity of receivers Low directivity, reducing efficiency of directional couplers High cross-talk, increasing stability problems in amplifiers and oscillators Increasing mutual coupling between antenna elements Stray coupling between standards, increasing measurement uncertainty. Excess line lengths, further increasing insertion loss Excess chip sizes, increasing cost

4

This course addresses the possibility of Microfabricated components and their use in RF engineering What are RF MEMS? • Components used for RF, Microwave and millimeter wave systems • Small devices, with feature size of micron order • Fabricated by micro- (and nano-) technologies • These are devices for RF applications, made by microfabrication route Common Advantages of RF MEMS • Miniaturization • Integration capability • Increased performance (reduced parasitics, reduced losses) • Reduced power/voltage (for actuation) requirements • Batch production Æ reduced cost • Potential for system-on-a-chip Some RF MEMS Components • Micro-Switches/Micro-relays • Capacitors and Inductors • Resonators and Filters • Phase Shifters • Antennas, Planar transmission lines

5

6

Introduction to Microsystems Technology Definitions Microelectromechanical Systems (MEMS) Miniaturized device or an array of devices, combining electrical and mechanical components, fabricated using IC batch production techniques. Also called Microsystems, micromechanical systems, etc. MEMS is usually an integration of mechanical elements, sensors, actuators, and electronics on a common substrate (usually silicon) through microfabrication technology. While the electronics are fabricated using IC process sequences (e.g., CMOS (most common now), Bipolar, or BICMOS processes), the micromechanical components are fabricated using a set of "micromachining" processes that selectively etch away parts of the wafer or add new structural layers to form the mechanical and electromechanical devices. Actuator A device that generates force to manipulate itself, or another mechanical device, or the surrounding environment to perform some useful function Sensor A device that collects useful information from the surrounding environment, and provides one or more output variables to a measuring instrument Smart Sensor A sensor with built-in intelligence (usually integrated). This will have the necessary control and electronics built-in on-chip, or separately on another fabricated by IC technology, and packaged together. Substrate A material that supports (or forms part of) the device. (Usually silicon, ceramic, glass, or plastic) Note: if the substrate is semiconductor material such as Si, GaAs, the electronics may be built in. Another possibility: organic electronics) Structural Layer A layer of thin film material that comprises a mechanical device. The layer is fabricated on the sacrifical layer, and then released by etching it away. Sacrifical Layer A layer of material that is deposited between the structural layer and the substrate to provide mechanical separation and isolation between them. This is removed after the mechanical components on the structural layer are fully formed, by release etch. This approach facilitates the free movement of the structural layer with respect to the substrate. Minimum Feature Size The lateral dimension of the smallest feature on the structural layer Vertical Aspect Ratio Ratio of the height of the structural layer to the minimum feature size Die Footprint The total area on the substrate that the (entire) device occupies. MEMS Technology Milestones Credited to Physicist R. Feynmann “There’s plenty of room at the bottom” Bulk etching of Si wafers for pressure sensors Pioneering work: K. Peterson “Silicon as a structural material” (properties, etching data) Surface micromachined polysilicon, comb drive actuators, disc drive heads Optical Applications MOEMS RF/microwave applications RF MEMS Major Areas of MEMS Applications (industry-wise) • Automobile/Transportation • Defense, Space • Medical/Biological • Industrial/Control • Telecom (RF & Optical)

7

1956 1970s 1982 1980’s 1990’s 1990’s

MEMS Components for Automotive/Transportation Segment Micromachine Absolute pressure sensor Accelerometer Temperature sensors Level sensor Light sensor Solid state cameras Pressure sensors Rain sensors Parking sensors Oxygen sensor Air flow sensor Head-up display Alcohol sensor Humidity sensor Tire pressure sensor Torque sensors Battery sensor charge/density Contraband detector Azide sensor Driver identification Fuel flow sensor Gyros Spill detector Micro-nozzle system NOX Sensor Oil quality monitor Roadlbridge condition sensors Road sensors Smart windows

Application Manifold absolute pressure (MAP) sensing Air-bag release Inside and outside vehicle Oil and gas level Turn on the lights Looking behind truck or car e.g., for exhaust gas recirculation Automatic Collision avoidance Air/gas ratio Air/fuel ratio control Information on window Detection of alcohol level in blood of drivers Cabin climate Pressure reading on board Work Customs Air bag propellant Charge/density of electrolyte Theft prevention

Present Availability Status Available Available Available Available Available Available Available Available Available Available, but needs better Expensive, not micromachined Not affordable yet No reliable products available Unsatisfying products available Under development Under development Research Does not exist No good solutions No good solutions yet No inexpensive solutions No good solutions available

Navigation Truck accidents clearing Fuel injection Pollution control Engine protection Preventive road maintenance

Not available Not available Not available

Roughness, ice, rain Defog, clear view

Not available at cost Not available at low cost

Defense/Space Accelerometers Angular rate sensors/gyroscopes Micropropulsion systems Micropumps RF components for radar and communications IR imagers Medical/Bio Drug delivery systems Patches External and implantable pumps Smart pill Monitoring Point -of-care testing On-line monitoring of blood gases On-line monitoring of pressure

Cygnus GlucoWatch Biographer Debiotech micropump, ChipRx smart pill, i-STAT's hand-held blood analyzer See RT-MECSS from microbioncs Several disposable pressure sensors available (