Network Analyzer and Spectrum Analyzer Measurements of Antennas and RF Components

Transcription

1 Network Analyzer and Spectrum Analyzer Measurements of Antennas and RF Components قياسات أنظمة أإلتصاالت ألعامله بألترددات ألراديويه وألميكرويفيه وتحليل وفحص ألهوائيات محمد ألنظامي by: Dr. Mohamed K. Nezami Tuesday, May 12, Hijjawi د.

2 RF/Microwave Measurements Presentation Outline Network Analyzer measurements S-Parameters X-Parameters Return loss Insertion loss Reflection loss VSWR Power Meter Impedance Analyzer Transmission line Time domain reflectometry measurements RF/Microwave Connector Types Waveguide Components

3 Antenna basic parameters Antenna Measurements Presentation Outline Antenna Laboratory measurements: Radiation pattern Bandwidth and Bandwidth Gain, efficiency, and Directivity VSWR, return loss, and input impedance Antenna Examples: Horn Antennas Parabolic Antennas Satellite Antenna Wire Antenna Corner Reflector Antenna BiQuad Antenna Cubical Quad Antenna Cubical Quad Antenna Bow Tie Antenna Circular Polarization Antenna Tactical Antennas Aircraft Antenna Cellular & WLAN Antennas Helical Antenna Yagi-Antenna Loop Antenna Log-Periodic Antennas Vertical/Horizontal Stacking of Antennas Printed Antennas (Microstrip Antennas) RFID (wire loop) Antenna Fun Free Antenna Designs د. محمد ألنظامي -- Nezami, Dr. Mohamed K.

4 Analysis Examples: TV satellite LNB/dish/receiver system to explain. Movies: short movies about RF system and Antenna measurements.

5 VSWR, Reflection Coefficient (r), Mismatched Loss (ML), and Return loss (RL) Voltage along line Transmission line

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7 Network Analyzer د. محمد ألنظامي -- Nezami, Dr. Mohamed K.

8 Network Analyzer

9 The X-parameters

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11 S-Parameters S-parameters measure the complex magnitude and phase relationship between small signals at the same frequency at different ports. Unlike S-parameters, X-parameters contain detailed and useful information including the magnitudes and phases of distortion products generated by the nonlinear component in response to large-signal conditions.

12 The X-parameters Generated from a circuit-level design in Advanced Design System (ADS) software. Measured using the Nonlinear Vector Network Analyzer. X-parameters can be easily imported into ADS and then dropped into a component or system to start the design process or for use with ADS linear, harmonic balance or circuit envelope simulation.

13 The X-parameters Created or Measured, X-parameters capture the frequency dependence and asymmetry of the intermodulations. X-parameters can be used to create a simulatable model for design with frequency-dependent distortion, like memory in PA. X-parameters allows you to measure and simulate nonlinear component behavior as a function of impedance, input power, bias and frequency at all load impedances.

14 Principle of S-parameters

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16 Principle of S-parameters

17 Extracting Input/Output impedance from S-parameters

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19 Network Analyzer SWR Network Analyzer method

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24 RF Impedance/ Material Analyzer

25 RF impedance/material analyzer This Equipment is used to characterize impedance or material at high frequency capacitance

26 RF impedance/material analyzer

27 RF/Microwave Power Meter

28 RF Power Meter Power sensors, or Bolometers measures RF power by measuring the change in resistance due converting RF or microwave energy into heat within the bolometric element. Coaxial thermistor sensors

29 RF Power Meter

30 RF Power Meter

31 RF Power Meter Remotely monitoring transmitter output power

32 Time Domain Reflectometer (TDR)

33 Time Domain Reflectometer The TDR works on the same principle as radar. A pulse of energy is transmitted down a cable. When that pulse reaches the end of the cable, or a fault along the cable, part or all of the pulse energy is reflected back to the instrument

34 Time Domain Reflectometer Applications Characterize and locate faults in cables (twisted wire pairs, coaxial cables, and Microstrip). To locate discontinuities in a connectors, printed circuit board traces, or any other electrical path. To determine electrical length of lines. Determine cable unknown loads.

35 Time Domain Reflectometer Applications

36 Summary of Test Equipments

37 Summary of Test Equipments

38 RF/Microwave Connector Types BNC, TNC, N, UNF, Mini UHF, SMA, SMB, SMZ, F, MCX, MMCX, 1.5/5.6, FME, Twin axial, 1.0/2.3 DIN, 7/16 DIN

39 Waveguide Components

40 Antenna RF waveguide components

41 Measuring Antenna Parameters Input VSWR Input Impedance Radiation pattern Gain Beam-width Bandwidth Directivity Side Lope level Reciprocity

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43 Measuring Antenna Input Parameters Input impedance for matching purposes Zin Return loss (S11) VSWR Efficiency

44 Measuring Antenna Transmission (Gain) Parameters

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46 Antenna Measurements

47 Antenna Measurements

48 Antenna Measurements with the Network Analyzer S21 S11 The magnitude of the transfer function of an antenna system can be obtained by measuring the S21 parameter of the antenna using a network analyzer. Ideally this should be done in an anechoic chamber to provide accurate and repeatable results

49 Antenna Measurements with the Network Analyzer Network Analyzer

50 Antenna pattern measurement on transmit power and receiver sensitivity for notebooks, PCMCIA cards, and other terminals with WiMAX. The goal of the product certification process is to assure that WiMAX-enabled products perform as expected and provide the customer with a reliable communication experience. The RPT is one portion of this process that measures transmit power and receive sensitivity of WiMAX devices.

51 Principle of Gain Measurement using the Network Analyzer Connect Network Analyzer port 1 to any antenna with the same polarization as the AUT. Connect Network Analyzer port 2 to a calibrated reference a dipole Antenna with the same polarization as the AUT. Measure S21 (transmission coefficient of reference Antenna) with reference dipole antenna. P dbm) P ( dbm) G ( db) G ( db) PL( db) Replace the calibrated reference dipole with AUT, and measure S21 with AUT. P rx( tx tx _ Ant cal _ Ant rx ( dbm) Ptx( dbm) Gtx _ Ant ( db) GAUT _ The difference between the two S21 is the gain in dbd of your AUT Ant ( db) PL( db)

52 Gain Measurement using the Network Analyzer Dr. Mohamed K. Nezami, د. يماظنلأ دمحم -- كومريلأ ةعماج ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( db G db G dbm P dbm P db G db G dbm P dbm P db PL db G db G dbm P dbm P db PL db G db G dbm P dbm P Ant AUT Ant cal AUT rx cal rx Ant AUT Ant cal AUT rx cal rx Ant AUT Ant tx tx AUT rx Ant cal Ant tx tx cal rx ) ( ) ( ) ( ) ( db G dbm P dbm P db G Ant cal cal rx AUT rx Ant AUT ant cal tx cal rx tx cal rx S dbm P dbm P watts P P _ 21 ) ( ) ( log 10 ant AUT tx AUT rx tx AUT rx S dbm P dbm P watts P P _ 21 ) ( ) ( log 10 ant AUT ant cal cal rx AUT rx S S dbm P dbm P _ _ ) ( ) ( ) ( ) ( db G S S db G Ant cal ant AUT ant cal Ant AUT

53 Gain Measurement using the Network Analyzer Example: S G G 21_ cal _ ant cal _ Ant AUT _ Ant S ( db) ( db) 21_ AUT _ ant 10dB 4dB 4dB 10( db) 6dB

54 Measurement using the Network Analyzer Beam and Band Width Side Lobe level Front-to-Back ratio Directivity

55 Travelling Wave Antennas Helical Antenna Yagi-Uda Antenna Dipole & Monopole Microstrip Antennas Microstrip Antennas Planar Antennas Reflector Antennas Corner Reflector Parabolic Reflector (Dish Antenna) Wire Antenna Aperture Antennas Slot Antenna Waveguide Antenna Horn Antenna Antenna Types

56 Horn Antennas Parabolic Antennas Satellite Antenna Wire Antenna Corner Reflector Antenna BiQuad Antenna Cubical Quad Antenna Cubical Quad Antenna Bow Tie Antenna Circular Polarization Antennas Tactical Antennas Aircraft Antenna Cellular & WLAN Antennas Helical Antenna Yagi-Antenna Loop Antenna Log-Periodic Antennas Vertical/Horizontal Stacking of Antennas Printed Antennas (Microstrip Antennas) RFID (wire loop) Antenna Satellite TV Reception Example Fun Free Antenna Designs References

57 Monopole and Dipole Antennas

58 Dipole & Monopole 4 2 GND radials b) Monopole

59 Half Wave Dipole Antenna 4 Construction 4 4 4

60 Characteristics of Dipoles and Monopoles A ½ λ dipole has an impedance of about 73 Ω. Vee A ½ λ dipole has a gain of 3dBi Monopole and Dipole are omnidirectional (in azimuth, or horizontal). Monopole has a gain of 1.64 (or G = 2.15 dbi) Loop A 1/4 λ Monopole has an impedance of about 73/2=36 Ω. A ½ λ folded dipole has an input impedance of about 300 Ω. A ½ λ folded dipole is used as the driving element in many other types of antennas. Loop fed Yagi 300/75 Ohm Balun

61 Characteristics of Dipoles and Monopoles Most TV receivers are equipped with two indoor antennas, one to cover the VHF band and the other the UHF band. The most common VHF antennas are the extendible monopole and vee dipole colloquially known as the rabbit ears. Rabbit ears (Vee) Antenna is available with either a 75 Ω or 300 Ω impedance and has a typical gain of -4 db with respect to a ½ λ dipole. The common UHF antennas are the circular loop with impedance of 300 Ω.

62 Marconi Monopole Antenna Construction Radially-dispersed wire radial system to enhance the ground conductivity

63 Quarter Wave Ground Plane ( Ground elements are bent 30 to 45 degrees down. This set of elements, called radials, is known as a ground plane. If used as car antenna, car body serves as ground plane. The gain is in the order of 2-4 dbi. Marconi Antenna) The input impedance is half the dipole input impedance, 36Ohms. This is a simple and effective antenna that can capture a signal equally from all directions (Omni in horizontal plane). When used in cellular telephones, the metal back plate of the phone serves as the ground plane.

64 Radiation pattern of Dipoles and Monopoles The azimuthal pattern of Dipole is a circle. The azimuthal pattern of is a circle.

65 Radiation pattern of Dipoles and Monopoles

66 Antenna Polarization The polarization of an antenna is determined by the orientation of the the electrical component of the wave.

67 Antenna Polarization Vertical Vertical Vertical Horizontal

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69 Shortening Monopole Antennas

70 Multi-Band Monopole Antennas

71 Horn Antennas

72 A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct the radio waves. Horn antennas are commonly used as the active element in a dish antenna..

73 Horn Configurations This horn antenna is flared in the E-plane This horn is flared in the H-plane Most popular Pyramid Horn is flared in both planes

74 Horn RF Signal Coupling Single polarization feed Dual polarization feed

75 Parabolic Antennas

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79 n is the efficiency or the effectiveness of illumination of the dish by the feed

80 Dual offset feed

81 Satellite Antenna

82 Satellite Antenna

83 Wire Antenna

84 Wire Antenna the feedpoint impedance is about Mhz full-wave loop is 100-ohms, so a 2:1 matching transformer is required when using 50 coax

85 Corner Reflector Antenna

86 Corner reflector antenna comprised of one or more dipole elements in front of a corner reflector.

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88 BiQuad Antenna

89 BiQuad Antenna simple to build and offers good directivity and gain for Point-to-Point communications a beamwidth of about 70 degrees gain in the order of dbi sed as stand-alone antenna or as feeder for a Parabolic Dish

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91 D is the Distance from the Dipole to the Reflector Dr. Mohamed K. Nezami, -- د. محمد ألنظامي

92 Cubical Quad Antenna

93 A quad loop is a pair of dipole antennas mounted one above the other A quad fed at the bottom is horizontally polarized and this is usual on the HF bands. Fed at the side the quad will be vertically polarized.

94 Bow Tie Antenna

95 Bow Tie Antenna

96 The side of the bowtie-triangle is a quarter-wavelength to the lowest frequency of interest. So technically, quarter-wave plus quarter-wave will make it a half-wavelength dipole, For example, for freq. = Mhz (ch 7), half wave = " The broader the angle, the broader the bandwidth. 60 to 90 degrees are common. It needs a BALANCED transmission line or a coax cable with a BALUN just like a normal dipole. BOW TIE has a OHM impedance this requires a 4:1 current balun for the un-balanced (50 OHM coax) feedline. BOW TIE provides a 3 db gain over a simple dipole If the antenna is mounted ¼ λ in front of a reflecting surface, the gain increases to approximately 9 db. Stacking two of them vertically one wavelength apart, increases the overall gain to about 12 db

97 Vertical Stacking

98 Vertical Stacking

99 Circular Polarization Antennas

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102 Tactical Antennas

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104 Aircraft Antenna

105 Aircraft Antenna

106 Cellular & WLAN Antennas

107 Panel antennas Tilting Sectoring

108 Panel antennas are made up of several dipoles mounted in front of a reflector so that gain can be achieved from both the horizontal and vertical plane.

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111 Backhauling Microwave Link Antennas

112 POLARIZATION DIVERSITY SPACE DIVERSITY

113 Polarization Diversity Space diversity uses 2 vertically polarized antennas as reception antennas and compares the signal level. Polarization diversity uses 2 orthogonally polarized antennas and compares the resulting signals. mobile telephone is never held exactly upright which means that all polarizations between vertical and horizontal are possible Dr. Mohamed K. Nezami, د. محمد ألنظامي --

114 If in addition the vertical path of the dual polarized antenna is fed via a duplexer for Rx and Tx, then only one antenna is needed per sector. As a result all 3 sectors can be supplied from one mast

115 Sector antenna system using Space Diversity Reception - 3 antennas, 3 feeders 3 to 5 db, Sector antenna system with Polarization Diversity Reception - 2 antennas, 3 feeders Sector antenna system with Polarization Diversity Reception using a duplex filter1 antenna, 3 feeders, 1 duplexer

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117 Helical Antenna

118 wide bandwidth easily constructed circularly polarized impedance is approximately 125 ohms so a matching transformer is required. The antenna is quite broadbanded. Beam widths of 50 Dr. and Mohamed a gain K. Nezami, of 12 dbi -- or greater are easily attained د. محمد ألنظامي

119 Online Helix Antenna Designer

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122 Yagi-Antenna

123 It can be constructed with one or more (usually one or two) reflector elements and one or more (usually two or more) director elements. approximately 0.2 to 0.5 wavelength on either side of it, are straight rods or wires called reflectors and directors A reflector is placed behind the driven element and is slightly longer (+5%) than half wavelength; a director is placed in front of the driven element and is slightly shorter (-5%)than half wavelength It consists of a half wave dipole (sometimes a folded one, sometimes not), a rear "reflector" and may or may not have one or more forward "directors". Yagi antennas are used primarily for Point-to- Point links, have a gain from 10 to 20 dbi and a horizontal beamwidth of 10 to 20 degrees. can be mounted to support either horizontal or vertical polarization

124 The antenna gain is a function of the number of dipole elements : GT = 1.66 * N where N is the number of elements in the Yagi antenna Maximum gain will be about 5.5 dbi for a two element Yagi to 10.5 dbi for five elements

125 Loop Antenna

126 Folded Dipole Full wave feedpoint impedance of 300 ohms half wave dipole is 75 ohms that the upper half wavelength dipole is voltage fed from the ends of the lower dipole; this is not a parasitic element broader bandwidth than a wire dipole VHF/UHF region. Folded dipole antennas were mainly used in conjuction with Yagi antennas.

127 The Loop Antenna directivity is about 3.5 db. The mid band gain is 3 db higher than a ½ λ dipole, but falls off to about 1 db at either end The dipole is typically 0.45 to 0.49 wavelengths long. The reflector is normally 0.55 wavelengths long and placed anywhere from 0.1 to 0.25 wavelengths behind the dipole. The reflector spacing has no affect on the forward gain, but does influence the front to back ratio and input impedance. The directors are normally 0.4 to 0.45 wavelengths long and are spaced at 0.3 to 0.4 wavelengths in front of the dipole. An antenna will usually have 6 to 12 directors.

128 Log-Periodic Antennas

129 Log-Periodic Antenna is comprised of a set of dipoles, all active, that vary in size from smallest at the front to largest at the rear. Broadband, and its front-to-back gain ratio is high.

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131 Vertical/Horizontal Stacking of Antennas

132 By connecting single, and vertically stacked dipoles at a middle distance of one wavelength the half power beamwidth can be reduced. As a result the horizontal gain is increased. Each doubling of the number of dipoles results in a gain increase of 3 db. Vertical Dipole Stacking

133 Vertical Dipole Stacking

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135 Printed Antennas (Microstrip Antennas)

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137 inverted F antenna [5], [6] is similar to a freestanding quarter-wave monopole above a ground plane

138 The positions of the two conductors determine the impedance and bandwidth as well as the field pattern. Inverted-L antenna Inverted-F antenna

139 The vertical arm is a stub tuning device to tune out the capacitance of the cross arm The cross arm is a quarter wavelength the configuration is treated as a small loop inductor, consisting of the feed probe and the inverted-l element behind the feed, resonated with the capacitance of a horizontal wire above a ground plane. The addition of the extra inverted-l element behind the feed tunes the input impedance of the antenna. [4] The -- ألنظامي impedance د. محمد is adjusted by changing جامعة point. أليرموكtap the Dr. Mohamed K. Nezami,

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143 approximately 7dBi gain. Impedance of the antenna input is 50 Ω 2.4 GHz Yagi PCB Directional Antenna Test Board

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145 PCB Material: FR4 PWB Thickness: 15 mils Red represents vertical polarization and blue represents horizontal polarization both measured in dbi

146 RFID (wire loop) Antenna

147 RFID (wire loop) Antenna

148 Satellite TV Reception Example

149 BADR Ku BAND SIGNALS

150 Diseq switch

151 Low Band: 10.7GHz to 11.7GHz High Band: 11.7GHz-12.7GHz IF:.95GHz-2.15GHz

152 IF_Low=10.7GHz-9.75GHz=0.95Ghz IF_High=11.7GHz-9.75GHz=1.95Gh IF_Low=11.7GHz-10.6GHz=1.1Ghz IF_High=12.75GHz-10.6GHz=2.15Ghz Digital Satellite Equipment Control (DiSEqCä ). The signal (voltage and 22-kHz tone) is generated by the satellite receiver to switch the target LNB between H/V polarizations, and between the low and high bands received (22 khz absent/present). The DSU is through-hold for this signal.

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154 A OUT B 22 khz amplitude-modulated signaling)

155 Dual Horn Fed Parabolic Dish

156 LNB Voltage Regulators zener diode

157 High/Low Local Oscillator frequency, Horizontal/Vertical polarization and two satellite locations. SAT-A/SAT-B Polarization Horz/Ver Local Oscillator High /Low

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160 Image Rejection BPF Filter

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162 IF-AMP IMAGE FIL DRO Vertical IF-AMP Horizontal

163 Vertical MIXER/IFAMP RF-IN Horiz DRO BPF Inter-digital filter

164 Hair Pin filter

165 Edge coupled filter

166 DRO MIXER BPF IF-AMP Hair Pin filter

167 The radial stub has wider bandwidth and therefore less manufacturing tolerance problems. The disadvantage is the board surface area it takes up

168 Hair Pin filter BPF DRO Horiz RF-IN Vertical MIXER/IFAMP

169 Hair Pin filter

170 Edge coupled filter Mixer

171 Microwave Mixer Implementation

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173 Edge coupled filter

174 Image filter response: Grundig AUN3S Inter-digital filter

175 Hair Pin filter

176 Fun Free Antenna Designs

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179 Cantenna

180 References

181 1. C.A. Balanis,.Antenna Theory: Analysis and Design., third edition, John Wiley & Sons, 2005, pp R.C. Johnson and H. Jasik,.Antenna Engineering Handbook., second edition, McGraw-Hill Book Company, ?metc=mtsz3m