Passive Field Probe for Phaseless Antenna Pattern Measurement

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Solution Overview

Problem

Conventional antenna measurement setups require complex and expensive arrangements involving phase-stable cables, rotary joints, connectors, amplifiers, and mixers to measure electromagnetic waves, making them costly and cumbersome, especially for phase-sensitive measurements like near-field to far-field transformations.

Innovation Solution

A field probe with an antenna arrangement of three or four antennas sharing a common center point, connected directly to RF circuitry that adds and subtracts measured RF waves to determine magnitude and phase patterns without needing phase information, using passive components and simplified cabling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional measurement arrangements with phase-stable cables, rotary joints, connectors, amplifiers, and mixers are used, then phase information can be measured, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvephase measurement capabilityVSAvoidmeasurement arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the magnitude information from the electromagnetic signals while discarding the phase information. By using multiple antennas arranged in specific geometries and measuring only signal magnitudes, the system achieves antenna pattern measurements without requiring phase-stable cables, rotary joints, or complex phase measurement equipment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, phase-stable measurement equipment with simple, inexpensive magnitude detectors. The measurement system uses basic RF detectors that measure only signal strength, eliminating the need for costly phase-stable cables, precision connectors, and complex signal processing equipment while still achieving the measurement objective.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If phase-stable cables and specialized cabling arrangements are used for near field to far field transformation, then phase information is preserved, but the cost and complexity of the test arrangement increase

Engineering Contradiction:
Improvephase information preservationVSAvoidtest arrangement setup
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts magnitude information from the electromagnetic field using multiple antennas with fixed geometric arrangements. By calculating antenna patterns based on magnitude measurements from antennas positioned at known locations, the system performs near-field to far-field transformation without requiring phase-stable cable connections or complex cabling arrangements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/physical phase-stability system (phase-stable cables, precision connectors, rigid cabling arrangements) with a computational approach. The system uses software algorithms to process magnitude measurements from multiple antennas and reconstruct the antenna pattern, substituting physical phase preservation with mathematical calculation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If multiple expensive components such as RF amplifiers, mixers, and switches are used to transfer signals, then signal measurement capability is enhanced, but the cost and complexity of the measurement system increase

Engineering Contradiction:
Improvesignal measurement capabilityVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential measurement information (antenna pattern) by measuring only signal magnitudes with simple detectors. This approach eliminates the need for RF amplifiers, mixers, and switches that would be required for traditional phase-sensitive measurements, as magnitude detection can be performed with much simpler and fewer components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, active RF components (amplifiers, mixers, switches) with simple, passive magnitude detectors. The measurement system uses basic RF detection elements that measure signal strength without requiring active signal processing components, significantly reducing both component count and system cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables cost-effective, simplified antenna measurements by determining magnitude and phase patterns through phaseless measurements, reducing the need for expensive components and allowing near-field analysis without phase-stable cables, thus streamlining the measurement process.

Implementation Method 1

Each of the antennas is configured to measure radio frequency waves emitted by a device under test

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Electromagnetic Induction

Implementation Method 2

The RF circuitry is configured to add the measured RF waves, and to subtract the measured RF waves

Methodology Applied
Scientific EffectWave interference: Interference

Data Source

PatentEP3945325B1Field probe and method for conducting antenna measurements
Publication Date: 2024.03.27 ROHDE & SCHWARZ GMBH & CO KG
  • EP3945325B1 patent drawingFigure 1~2
  • EP3945325B1 patent drawingFigure 3~4

AI summary

Field probe for conducting antenna measurements by phaseless measurements. An antenna arrangement comprises three or four antennas for measuring RF waves. The measured RF waves are pairwise added and subtracted. Based on the result of the adding and subtracting operations, magnitude patterns and phase patterns are determined. In this way, magnitude and phase patterns of electromagnetic waves emitted by a device under test can be determined by a completely passive device.