Aspects of Achieving 10 v/m Field Uniformity over 1-6GHz with Single, Multiple and Cassegrain Antennas. Tom Mullineaux

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1 Aspects of Achieving 10 v/m Field Uniformity over 1-6GHz with Single, Multiple and Cassegrain Antennas Tom Mullineaux

2 EN Edition GHz, 10 3 meters

3 Field Generation Fundamentals

4 10v/m 1.5m 1.5m Test Field of a Prescribed Field Strength Across a Defined Plane

5 Equipment Under Test (EUT) One Face of EUT is Placed at the Plane EUT Is Monitored for Degradation in Performance when Exposed to Test Field Repeat for All Faces

6 Test Field Generation RF Input Power P Bore Sight Field E (v/m) Horn Antenna Gain G Test Plane Distance d

7 E = (30.P.G) / d Field Strength in v/m RF Power at Antenna Connector Gain of Antenna (Linear, not db) Distance from Antenna Fiddle Factor?

8 Area of Sphere 4πR 2 S = P/4πR 2 P Power Density S = E 2 /Z o S = E 2 /120π Impedance of Free Space Zo is 120π (377 Ohms)

9 P/4πR 2 = E 2 /120π E 2 = 120π.P / 4πR 2 E 2 = 30.P / R 2 E = (30.P) / R E = (30.P.G) / d

10 IMPLICATIONS P = d 2 E 2 / 30G RF Power Required at Antenna Connector Implication #1: Two Times the Gain Means HALF the RF Power is Required Implication #2: Double the Distance Means FOUR times the RF Power is Required Implication #3: Two Times the Field Strength Means FOUR times the RF Power is Required

11 Characteristics of High Gain / Low Gain Antennas

12 Test Plane Illumination Falls with Distance Bore Sight Max E(v/m)

13 Medium Gain Horn Illumination E/ 2 Bore Sight Max E(v/m) Beam Width (Degrees) E/ 2

14 High Gain Horn Illumination E/ 2 Bore Sight Max E(v/m) E/ 2 Beam Width (Degrees)

17 10v/m, -0dB, +6dB 1.5m 16 points all between 1.5m 10v/m and 20 v/m

18 Test Plane Illumination 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB Bore Sight

19 Effect of Higher Gain 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB Bore Sight

20 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

21 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

22 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

23 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

24 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

25 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

26 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

27 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

28 16 points all between 10 and 20 v/m 10v/m, -0dB, +6dB

29 EQUIVALENT TO??

30 Beam Width is Becoming Important - Some Standards Now Insist the EUT Fits Inside the Antenna Beam Width EUT Must Fit Here Half-Power Density = E/ 2 Emax

31 Advantages / Disadvantages of Each Antenna Type

32 High Gain Horn Advantage Reduced RF Power Requirement

33 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area

34 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?)

35 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic

36 Wanted Test Frequency Harmonic Signal, Un-Wanted Test Frequency

37 High Gain at Harmonic Frequency E/ 2 (-6dB) E (v/m) Measured Field is Sum of Wanted Field and Un-Wanted Field E/ 2 (-6dB)

38 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic

39 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic Less Bandwidth so More Antennas Required

40 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic Less Bandwidth so More Antennas Required Medium Gain Horn Advantage Large Illumination Area

41 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic Less Bandwidth so More Antennas Required Medium Gain Horn Advantage Large Illumination Area Less Field Contribution from Harmonic

42 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic Less Bandwidth so More Antennas Required Medium Gain Horn Advantage Large Illumination Area Less Field Contribution from Harmonic Wider Bandwidth, One Antenna Required

43 High Gain Horn Advantage Reduced RF Power Requirement High Gain Horn Disadvantage Smaller Illumination Area (equivalent?) Higher Field Contribution from Harmonic Less Bandwidth so More Antennas Required Medium Gain Horn Advantage Large Illumination Area Less Field Contribution from Harmonic Wider Bandwidth, One Antenna Required Medium Gain Horn Disadvantage Higher RF Power Requirement

44 Field Uniformity Through Use of Multiple High-Gain Antennas

45 Multiple High-Gain Horn Illumination

46 HIRF Multiple Horn Illumination

47 16 points all between 10 and 20 v/m

48 16 points all between 10 and 20 v/m 14v/m 14v/m 10v/m 12v/m 10v/m 14v/m 14v/m One Test Run Only

49 EQUIVALENT TO??

50 Reduced Risk of Corona Effect Due to Power Sharing 200v/m

64 Use of Shaped Reflector Plate

65 Beamwidth Spreading

67 Calculating the Illumination Diameter BW

68 D/2 BW/2 3m D/2 = 3 Tan BW/2

69 D/2 BW/2 3m D/2 = 3 Tan BW/2 D = 6 Tan BW/2

70 At 3m Test Distance Beam Width Diameter 40 degrees 2.2m 30 degrees 1.6m 20 degrees 1.05m 10 degrees 0.5m

71 At 1m Test Distance Beam Width Diameter 40 degrees 1.8m 30 degrees 1.2m 20 degrees 0.8m 10 degrees 0.4m

72 Worked Example Using 3115

80 Aspects of Achieving 10 v/m Field Uniformity over 1-6GHz with Single, Multiple and Cassegrain Antennas QUESTIONS? Tom Mullineaux

Aspects of Achieving 10 v/m Field Uniformity over 1-6GHz with Single, Multiple and Cassegrain Antennas. Tom Mullineaux

Aspects of Achieving 10 v/m Field Uniformity over 1-6GHz with Single, Multiple and Cassegrain Antennas Tom Mullineaux EN61000-4-3 Edition 3 1-6 GHz, 10 volts/meter @ 3 meters HEALTH WARNING Field Generation