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Antenna Measurements with the
Network Analyzer
Presented byErnie Jackson
RF/uW Applications Engineer
Agilent Technologies
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Slide 2
Purpose
During this presentation you will:
Learn about interface requirements between components.
Learn about issues related to selecting the equipment required tomake antenna measurements.
Learn how instruments can be integrated into your configuration.
Learn about New PNA-X Measurement Receiver and FrequencyConverter.
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Slide 3
Agenda
AUT
Positionercontroller
Provide bySystem Integrators
Overview of antenna applicationsAntenna Measurement Design Considerations
Transmit Site Configuration
Receive Site Configuration
Receiver Speed
Summary
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Slide 4
Key features for Antenna Measurements
High sensitivity.
Reduces measurement uncertainty (increase accuracy).
Enable the best device specifications.
Increased Speed.
Decrease test time and cost.
Flexibility.
Upgradable for future requirements
Security.
Enable multiple users to share test site
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Slide 5
Near-Field Vs Far-Field
Near-Field:The near-field test system measures the energy in the radiating near-fieldregion and converts those measurements by a Fourier transform into thefar-field result.
Far-Field:On a traditional far-field antenna range the transmit and receive antennasare typically separated by enough distance to simulate the intended
operating environment. The AUT is illuminated by a source antenna at adistance far enough to create a near-planar phase front over the electricalaperture of the AUT.
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Slide 6
Antenna does not
move (planar case)
Amplitude and Phase
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A
mplitude(dB)
Azimuth (deg)
Near-field MeasurementsBasic Concept:
Record amplitude and phase over a surface in the radiating near-field (~3 wavelengths)Process with an FFT to produce far-field data.
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Slide 7
Near-Field
Near-Field:There are three scan types
1. Planar near-field
Directional antennas
Gain > 15 dBi Max angle < 70
2. Cylindrical near-field
Fan beam antennas Wide side or back lobes
3. Spherical near-field
Low gain antennas Wide or omni-directional patterns
on any antennas
Cylindrical
Planar
Spherical
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Slide 8
Near-field Antenna Measurement Scan Summary
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Slide 9
Far-field Measurements
Basic Concept: Rotate antenna under test in azimuth and elevation coordinates
Record far-field data on plotter or computer
Receive antenna measures far-field
amplitude and or phase as test antenna
rotates
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Amplitude(dB)
Azimuth (deg)
Azimuth and
Elevation
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Slide 10
Near-Field Vs Far-Field
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Slide 11
Agenda
AUT
Positioner
controller
Provide bySystem Integrators
Overview of antenna applicationsAntenna Measurement Design Considerations
Transmit Site Configuration
Receive Site Configuration
Receiver Speed
Summary
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Slide 12
Antenna Characterization System Solution
Overview:
Antenna Characterization System Consists:
1. RF Subsystem Receiver, Sources and Convertor/Mixers2. Mechanical Subsystem Positioner, Anechoic Chamber
and Absorber Material
3. Measurement & Data Analysis Software
Agilent primary provides RF Subsystem only.
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Slide 13
Far-Field Distance determination
The mathematical expression for determining the minimum separation distance is: R