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IFIP-UNU ADVANCED COURSE ON NETWORKING AND SECURITY Module II-Wireless Communications Section 7

IFIP-UNU ADVANCED COURSE ON NETWORKING AND SECURITY Module II-Wireless Communications Section 7. Antennas. Overview.

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IFIP-UNU ADVANCED COURSE ON NETWORKING AND SECURITY Module II-Wireless Communications Section 7

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  1. IFIP-UNU ADVANCED COURSE ON NETWORKING AND SECURITYModule II-Wireless CommunicationsSection 7 • Antennas

  2. Overview This module will cover basic antenna theory, including directional and omni directional antenna selection. After discussing antenna theory and types of antennas, cables, connectors and accessories for antennas will be discussed. Additionally, important antenna design considerations, such as link engineering, path planning, and installation are also discussed.

  3. Learning Objectives • Define how an antenna is used to propagate an RF signal. • Define basic facts of EIRP. • Define facts on FCC regulations for UNII-1, UNII-2 and UNII-3. • Identify what an isotropic antenna is and why it is used as a reference for other antennas. • Identify Cisco Aironet antennas, their coverage patterns, and the proper polarization of each antenna.

  4. Key terms • Lobes • Directional • Omnidirectional • Beamwidth and Bandwidth • Polarization • Vertical • Horizontal • Diversity • Plane (H and E) • Fresnel Zone

  5. Definition of Terms • dB- Decibel- Ratio of one value to another • dBx where x = • m = compared to 1 milliwatt (0 dBm=1 mW) • i = compare to isotropic antenna • d = compared to dipole antenna • w = compared to 1 watt (0 dBw = 1 watt)

  6. Antennas

  7. Important Antenna Concepts

  8. Beamwidth

  9. Cisco Aironet 802.11b Antennas • FCC requires that ALL antennas sold by a spread spectrum vendor be certified with the radio they are to be sold with • All Cisco Aironet 802.11b supplied cables, RF devices and antennas have reverse polarity TNC (RP-TNC) connectors • Cisco Aironet supplied antennas meet all FCC rules • Wide variety of 802.11b antennas for most applications

  10. Cisco Aironet 802.11a Antennas • FCC requires that all radios utilizing the UNII-1 Band (5.15 GHz – 5.25 GHz) must have non-removable or integrated antennas • FCC allows radios utilizing the UNII-2 Band (5.25 GHz – 5.35 GHz) to have external or removable antennas • The Cisco Aironet 802.11a radios utilize both UNII-1 and UNII-2 bands, therefore cannot have external or removable antennas • Cisco 802.11a antennas are integrated into the radio module • Cisco 1400 radios utilize UNII-3 bands, therefore have external or removable antennas

  11. Antenna Concepts • Directionality • Omni (360º coverage) directional • Directional (limited range of coverage) • Gain • Measured in dBi and dBd (0 dBd = 2.14 dBi) • More gain means more coverage - in certain directions • Polarization • Antennas are used in the vertical polarization

  12. Antenna Issues (cont.) • Antennas have gain in particular directions • Direction other than the main intended radiation pattern, are typically related to the main lobe gain

  13. Antenna Gain • If the gain of an antenna goes up, the coverage area or angle goes down • Coverage areas or radiation patterns are measured in degrees • Angles are referred to as beamwidth • Horizontal measurement • Vertical measurement

  14. Beamwidth vs. Gain

  15. Antenna Theory • A theoretical isotropic antenna has a perfect 360º vertical and horizontal beamwidth • This is a reference for ALL antennas

  16. Side View (Vertical Pattern) Vertical Beamwidth New Pattern (with Gain) Top View (Horizontal Pattern) Antenna Theory- Dipole • Energy lobes are ‘pushed in’ from the top and bottom • Higher gain • Smaller vertical beamwidth • Larger horizontal lobe • Typical dipole pattern

  17. High Gain Omni-Directionals • More coverage area in a circular pattern • Energy level directly above or below the antenna will become lower

  18. Side View (Vertical Pattern) Top View (Horizontal Pattern) Directional Antennas • Lobes are pushed in a certain direction, causing the energy to be condensed in a particular area • Very little energy is in the back side of a directional antenna

  19. FCC Part 15 Antenna Requirements • 802.11b antenna • Must use a unique, or proprietary connector • Cisco Aironet products use RP-TNC connector • Part 15 standards • Approved antenna may exceed • Exceeding may lead to interference problems • Penalties could result in fines • FCC standards apply to Part 15 users in the United States • Different countries will have similar standards

  20. 2.4 GHz EIRP Rules for FCC Governed Areas • Point-to-Multipoint • FCC allows increasing the gain of an antenna/cable system if the transmitter power is reduced below 30 dBm in a 1:1 ratio • Reduce Transmit Power below maximum of 30 dBm by 1 dBm and increase antenna/cable system gain by 1dBi • Point-to-Point • Maximum of 36 dBm EIRP • Installations – 30 dBm maximum transmitter power with 6 dBi in gain attributed to antenna and cable combination • FCC allows exceeding the 36 dBm EIRP in Point-to-Point installations using the 3:1 rule • Reduce Transmit Power below maximum of 30 dBm by 1 dBm and increase antenna/cable system gain by 3 dBi

  21. 2.4 GHz EIRP Rules for FCC Governed Areas (cont.) Point-to-Multipoint Transmitter Power Transmitter dBm Maximum Gain EIRP 6 dBi 36 dBm FCC Maximum 30 dBm 1 Watt 36 dBm Cisco Maximum 16 dBi 100 mW 20 dBm The above values reflect the 1:1 rule Point-to-Point Transmitter Power Transmitter dBm Maximum Gain EIRP 6 dBi 36 dBm FCC Maximum 30 dBm 1 Watt 56 dBm Cisco Maximum 36 dBi 100 mW 20 dBm The above values reflect the 3:1 rule

  22. 2.4 GHz EIRP Rules for ETSI Governed Countries • Currently ETSI stipulates a maximum of 20 dBm EIRP on Point-to-Multipoint and Point-to-Point installations –17 dBm maximum transmitter power with 3 dBi in gain attributed to antenna and cable combination • Professional installers are allowed to increase the gain of an antenna/cable system if the transmitter power is reduced below 17 dBm in a 1:1 ratio • Reduce Transmit Power below maximum of 17 dBm by 1 dBm and increase antenna/cable system gain by 1 dBi

  23. 2.4 GHz EIRP Rules for non-FCC Governed Bodies Governing bodies with 20 dBm ceiling on EIRP: ETSI, France/Singapore, Israel, Mexico Point-to-Multipoint and Point-to-Point Transmitter Power Transmitter dBm Maximum Gain EIRP 3 dBi 20 dBm Gov. Body Maximum 17 dBm 50 mW 2.2 dBi 19.2 dBm 50 mW Cisco Integrated Antennas 17 dBm Reduced TX Power 20 dBm 30 mW 15 dBm 5 dBi Reduced TX Power 20 mW 20 dBm 13 dBm 7 dBi 5 mW 7 dBm 13 dBi Reduced TX Power 20 dBm Reduced TX Power 1 mW 0 dBm 20 dBm 20 dBi The above values reflect the 1:1 rule

  24. 802.11a and FCC 5 GHz Specifications • FCC regulations for UNII-1 and UNII-2 • UNII-1 • FCC max 50 mW • 802.11a max 40 mW • With max 6 dBi antenna gain • 802.11a max of 40 mW complies with all countries except Singapore (20 mW) • UNII-2 • FCC max 250 mW • 802.11a max 200 mW

  25. FCC Rules for 802.11a - Antennas • FCC requires that all radios utilizing the UNII-1 Band (5.15 GHz – 5.25 GHz) must have non-removable or integrated antennas • FCC allows radios utilizing the UNII-2 Band (5.25 GHz – 5.35 GHz) to have external or removable antennas • FCC requires radios operating in both UNII-1 and UNII-2 bands must comply with antenna rules regulating UNII-1 band (including indoor use only) • The Cisco Aironet 802.11a radios utilize both UNII-1 and UNII-2 bands, therefore cannot have external or removable antennas and must be used indoors only • Cisco 802.11a antennas are integrated into the radio module

  26. Omni directional Antennas

  27. 2.4 GHz Omni-Directional Antennas • 2 dBi Dipole "Standard Rubber Duck"

  28. 2.4 GHz Omni-Directional Antennas • 5.2 dBi Mast Mount Vertical

  29. 2.4 GHz Omni-Directional Antennas • 5.2 dBi Ceiling Mount

  30. 2.4 GHz Omni-Directional Antennas • 5.2 dBi Pillar Mount Diversity

  31. 2.4 GHz Diversity Omni-Directional Antennas • 2 dBi Diversity Omni-Directional Ceiling Mount

  32. 2.4 GHz Omni-Directional Antennas • 12 dBi Omni-Directional (Outdoor only)

  33. 5 GHz Omni-Directional Antennas • 9 dBi omni (Vertical polarization)

  34. 5 GHz Integrated Antenna Innovative 5 GHz Combo Antenna: • Wall Mount: Fold antenna flat against access point housing for 6 dBi gain patch antenna • Ceiling Mount: Fold antenna out at a 90° angle for 5 dBi gain omni antenna In 6 dBi patch position In 5 dBi omni position

  35. Cisco Aironet 1100 Series Internal View 2.2 dBi Omni-Directional Diversity Antennas Mini-PCI Radio • Option 1: 802.11b

  36. Cisco Aironet 1100 Series Antenna Details Cone of reduced coverage Sphere of influence Sphere of influence Cone of reduced coverage

  37. Cisco Aironet 1100 Series Antenna Details (cont.) H-Plane Pattern E-Plane Pattern Floor Top View Side View

  38. Directional Antennas

  39. 2.4 GHz Diversity Antennas • 6.5 dBi Diversity Patch Wall Mount – 55 degree

  40. 2.4 GHz Directional Antennas (cont.) • 6 dBi Patch Antenna – 65 degree

  41. 2.4 GHz Directional Antennas (cont.) • 8.5 dBi Patch Antenna – 60 degree

  42. 2.4 GHz Directional Antennas (cont.) • 13.5 dBi Yagi Antenna – 25 degree

  43. 13.5 dBi Yagi Antenna—Inside view

  44. 2.4 GHz Directional Antennas (cont.) • 21 dBi Parabolic Dish Antenna – 12 degree

  45. 5 GHz Omni-Directional Antennas • 28 dBi dish (H or V polarization)

  46. 5 GHz Antenna • 9.5 dBi sector (H or V polarization)

  47. Cable and Accessories

  48. 2.4 GHz Accessories

  49. RP-TNC Connectors

  50. Lightning Arrestor To Antenna • Designed to protect LAN devices from static electricity and lightning surges that travel on coax transmission lines • RP-TNC connectors used on all Cisco Antennas Lug Lockwasher Nut Ground Wire From RF Device

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