Example: bachelor of science

UNDERSTANDING AND FINDING THE INVISIBLE …

Henry W. OttHOCELECTROMAGNETICCOMPATIBILITY2000 ByHenry W. OttHenry Ott ConsultantsLivingston, NJ 07039(973) AND FINDING THE INVISIBLEANTENNAS IN YOUR DESIGNANT - 0000 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYCONVEN TIONAL WISDOMANT - 010281998 Conventional Wisdom Says: If it Looks Like a Duckand If it Walks Like a Duck and it Quacks Like aDuck, it Probably is a DuckEMC Wisdom Says: If it Radiates Like an Antennaand it Receives Like an Antenna and it Doesn t LookLike an Antenna, it Probably Still is an Antenna Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYOVERVI EW!Describe the Basic Types of Antennas!Understand What Configurations (Electrical &Mechanical) Form Antenna Structures!Learn to Look at Your Design as if it Was anAntenna!Understand What Parameters Affect theRadiation!Learn to Avoid Using Antenna Configurationsin Your Design!If You Must Use an Antenna Structure, KnowHow to Minimize it s Radiation EfficiencyANT - 010331998 Henry W.

©Henry W. Ott HOC ELECTROMAGNETIC COMPATIBILITY OVERVIEW! Describe the Basic Types of Antennas! Understand What Configurations (Electrical & Mechanical) Form Antenna Structures

Tags:

  Understanding, Findings, Invisible, Understanding and finding the invisible

Information

Domain:

Source:

Link to this page:

Please notify us if you found a problem with this document:

Other abuse

Transcription of UNDERSTANDING AND FINDING THE INVISIBLE …

1 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITY2000 ByHenry W. OttHenry Ott ConsultantsLivingston, NJ 07039(973) AND FINDING THE INVISIBLEANTENNAS IN YOUR DESIGNANT - 0000 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYCONVEN TIONAL WISDOMANT - 010281998 Conventional Wisdom Says: If it Looks Like a Duckand If it Walks Like a Duck and it Quacks Like aDuck, it Probably is a DuckEMC Wisdom Says: If it Radiates Like an Antennaand it Receives Like an Antenna and it Doesn t LookLike an Antenna, it Probably Still is an Antenna Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYOVERVI EW!Describe the Basic Types of Antennas!Understand What Configurations (Electrical &Mechanical) Form Antenna Structures!Learn to Look at Your Design as if it Was anAntenna!Understand What Parameters Affect theRadiation!Learn to Avoid Using Antenna Configurationsin Your Design!If You Must Use an Antenna Structure, KnowHow to Minimize it s Radiation EfficiencyANT - 010331998 Henry W.

2 OttHOCELECTROMAGNETICCOMPATIBILITYMISC. ANTENNASANT - 010011998 Slot AntennaPatch or MicrostripAntennaSleeve AntennaMetallic PatchAbove Ref. PlaneReference PlaneSlot in a Metal PlateUnshielded CenterConductorFringing FieldsProduce Radiation Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYBASIC ANTENNA STRUCTURES!Wire Antennas Dipole Loop!Aperture Antennas Slot HornANT - 010021998 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYCHARAC TERISTICS OF ANTENNAS!Size!Bandwidth!Polarization!Ant enna Factor or Gain!Radiation Pattern!Front to Back Ratio!Effective Height orAperture!Radiation ResistanceANT - 010071998 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYDIPOLE ANTENNA!A Dipole Requires Two Parts!What About a Monopole?!If You Do Not Provide the Second Part, The Antenna WillFind Something to Serve the Purpose (Usually The LargestPiece of Metal Nearby)!It is Better to Provide the Second Half of The DipoleIntentionally, at Least Then You Know What and Where it is!

3 The Way to Make an Antenna, is to Have an rf PotentialBetween Two Different Pieces of Metal!To Prevent the Radiation, Tie the Two Halves of theAntenna Together So That They Are at the Same Potentialand, Therefore, Cannot - 010031998 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYINTENT IONAL RADIATORSANT - 010371997 VVVD ipoleMonopoleTop HatRadiates as Goodas a Dipole & isHalf as LongRadiates BetterThan a Monopole(Up to Twice as Much) Reference PlaneReference Plane Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYMONOPO LE CURRENT DISTRIBUTIONANT - Current Along AntennaReference PlaneTipFeedPointMONOPOLEIS hort Antenna (< /10)Long Antenna ( /4) Sinusoidal Current (Current Shown For /4) Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYUNINTE NTIONAL MONOPOLESANT - 01038A1997 VGPCBC hassisGnd WireMother BoardRibbonCableDaughter BoardVG Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYLOOP ANTENNA!For Small Loops the Shape of the Loop DoesNot Matter!

4 All Loops of the Same Area Will Radiate theSameANT - 010311998 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYFAR FIELD RADIATION FROM A SMALL ANTENNA!Loop (Differential-Mode)!E = K f2 A I!Radiation is Proportional tothe Square of the Frequency!Area is the Basic ControlParameter!Dipole (Common-Mode)!E = K f L I!It only Takes 5 A of Currentin a 1-Meter Antenna to FailFCC Class B Requirements!Current is the Basic ControlParameter2000 ANT - 01039 Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYREDUCI NG ANTENNA RADIATION EFFICIENCY!LOOP Reduce Area Canceling Loops Dithering of Frequency!DIPOLE / MONOPOLE Reduce Dipole Current Short Out The Two Halves of the Antenna!APERTURE Minimize the Max. Linear Dimension Form into a Waveguide Below CutoffANT - 01034A1998 Note: In All Cases Reducing the Frequency and/or Rise Time is Effective in Reducing Radiation Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYEXAMPL ES OF UNINTENTIONAL DIPOLESANT - 010241998 VGPCB GroundVGPCB With CablesLaptop ComputerAnalog With SeparateAnalog & Digital DisplayChassisPower CordI/O CableEnclosure Henry W.

5 OttHOCELECTROMAGNETICCOMPATIBILITYEXAMPL ES OF UNINTENTIONAL MONOPOLESANT - 010251998 ChassisPCBG roundWirePCB Separated From Chassis& Connected With a Ground WireMother BoardDaughter BoardMother/ Daughter BoardChipVGround PlaneUngrounded HeatsinkPCBICT raceLong Unterminated TraceVgPCB With CableAttachedCablePCBPCBU ngrounded Metalizationon PCB (Patch Antenna) Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYEXAMPL ES OF UNINTENTIONAL LOOPSANT - 010271998C1C2 Decoupling CapacitorsICLarge ICs ( 1 )Clocks on PCBsSignalGroundIPCB Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYEXAMPL ES OF UNINTENTIONAL APERTUREANTENNASANT - 010261998 Cooling HolesSeams Henry W. OttHOCELECTROMAGNETICCOMPATIBILITYSUMMAR Y!Many Structures That We Use as Part of OurSystems & PCB Designs Are Antennas!As Much as Possible We Would Like to Eliminatethe Use of These Structures!If We Cannot Eliminate These Structures,Minimize their Radiation Efficiency!Learn to Look at Your Design From an AntennaPoint of View!

6 Remember Your Electronic Systems areAntennas, and What You Don t Know About ThemCould Hurt YouANT - 010181998


Related search queries