LTE Antenna Array Calibration via Out-of-Line Phase-Shifting Networks

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Solution Overview

Problem

Conventional calibration networks in multi-column antenna arrays introduce undesirable insertion losses, amplitude and phase errors, and passive intermodulation (PIM) effects due to their in-line configuration with signal paths.

Innovation Solution

The calibration network is reconfigured to be out-of-line, utilizing signal splitter/combiner networks with phase shifting capabilities and capacitive coupling to sample calibration signals at electrical midpoints, reducing direct interaction with transceiver signal sources and minimizing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the calibration network is configured in-line between the signal source and antenna array, then calibration and tuning functions are provided, but insertion losses, amplitude and phase errors, and passive intermodulation effects are introduced

Engineering Contradiction:

Improvecalibration functionVSAvoidinsertion loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The calibration network is extracted from the in-line signal path and reconfigured to be coupled to the antenna elements through separate coupling mechanisms. This allows the calibration function to be maintained while removing the source of insertion losses, amplitude errors, and phase errors that were introduced by having the calibration network directly in the signal path between the signal source and antenna array.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the calibration network is configured in-line between the signal source and antenna array, then calibration and tuning functions are provided, but amplitude and phase errors are introduced

Engineering Contradiction:

Improvecalibration functionVSAvoidamplitude and phase accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The calibration network is extracted from the in-line signal path and reconfigured to be coupled to the antenna elements through separate coupling mechanisms. This allows the calibration function to be maintained while removing the source of amplitude and phase errors that were introduced by having the calibration network directly in the signal path between the signal source and antenna array.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Coupling mechanisms such as coupling capacitors or electromagnetic coupling are introduced as intermediaries between the calibration network and the antenna elements. These intermediaries allow calibration signals to be transferred without directly interfering with the main signal path, thereby maintaining measurement precision while enabling calibration functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the calibration network is configured in-line between the signal source and antenna array, then calibration and tuning functions are provided, but passive intermodulation effects are increased

Engineering Contradiction:

Improvecalibration functionVSAvoidpassive intermodulation effects

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The calibration network is extracted from the in-line signal path and reconfigured to be coupled to the antenna elements through separate coupling mechanisms. This allows the calibration function to be maintained while removing the source of passive intermodulation effects that were generated by the additional circuitry, connectors, and solder joints in the in-line configuration.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Coupling mechanisms such as coupling capacitors or electromagnetic coupling are introduced as intermediaries between the calibration network and the antenna elements. These intermediaries minimize direct electrical connections and reduce the generation of passive intermodulation products by isolating the calibration network from the high-power signal path.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration reduces insertion losses, amplitude and phase errors, and PIM effects, while maintaining effective calibration and tuning functions for the antenna array.

Implementation Method 1

Each of the calibration signal sampling points is coupled electromagnetically or capacitively to a respective calibration source input of the calibration network

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

each of the signal splitter/combiner networks is embodied as a phase shifting network

Methodology Applied

Scientific EffectPhase shifting: Phase Modulation

Data Source

PatentEP3066717B1Methods and systems for calibrating LTE antenna systems

Publication Date: 2024.02.28 ALCATEL LUCENT SHANGHAI BELL CO LTD

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AI summary

Antenna array calibration systems and related methods include or utilize a plurality of signal splitter/combiner networks. Each of the signal splitter/combiner networks has a calibration signal sampling point in electrical communication with a signal input point, and signal output points. Each calibration signal sampling point may be capacitively coupled to a respective calibration source input of a calibration network. The signal splitter/combiner networks may be formed as phase-shifting networks.