Wideband RF Device Characterization Using Overlapping Sub-bands

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Wideband RF devices are challenging to characterize accurately due to hardware influences on frequency responses, and existing methods with narrowband reference sources or receivers face issues with phase coherency and the need for repetitive signals.

Innovation Solution

A method that divides the wideband RF device's bandwidth into overlapping sub-bands, using narrowband measurements to calculate continuous amplitude and phase responses without requiring phase coherency between the reference and the device, allowing for calibration of wideband RF devices using a single-port measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a narrowband reference source or receiver is used to characterize a wideband RF device, then the measurement setup becomes simpler and more accessible, but the bandwidth coverage is insufficient and multiple measurements are required

Engineering Contradiction:

Improveavailability of reference equipmentVSAvoidbandwidth coverage

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The wideband frequency range is divided into multiple overlapping sub-bands, each measured by the narrowband reference device. The segmentation allows the narrowband device to cover the entire wideband range through multiple sequential measurements while maintaining measurement accuracy in each sub-band.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple narrowband measurements across different sub-bands are merged into a single continuous wideband frequency response characterization. The overlapping regions between sub-bands are used to ensure continuity and consistency when combining the measurements.

Inventive Principle:

Principle #5Merging (Combining)

2Area of stationary object

If multiple measurements at different frequencies are performed with a narrowband reference receiver, then the entire bandwidth can be covered, but phase offset variations between measurements make combining results difficult

Engineering Contradiction:

Improvebandwidth coverageVSAvoidphase response accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

A phase reference signal is introduced as an intermediary element that is present in all measurements. This reference signal provides a common phase reference across all sub-band measurements, allowing phase responses to be combined accurately despite frequency changes. The phase offset between measurements is determined relative to this common reference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If a power sensor is used for frequency response characterization, then the amplitude response can be measured, but the phase response cannot be characterized

Engineering Contradiction:

Improveamplitude measurement capabilityVSAvoidphase response information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The electrical measurement system is enhanced by using a vector network analyzer or similar device that can measure both magnitude and phase of the frequency response. This replaces the limitation of simple power sensing with a more sophisticated measurement capability that captures the complete complex frequency response.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If a reference source or receiver with the same bandwidth as the wideband RF device is used, then accurate frequency response characterization is achieved, but such high-bandwidth reference equipment is often unavailable

Engineering Contradiction:

Improvefrequency response accuracyVSAvoidavailability of reference equipment

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of requiring a single high-bandwidth reference device, the approach segments the bandwidth measurement into multiple narrowband measurements. This makes the reference equipment requirements much more accessible while achieving the same overall characterization accuracy through systematic measurement and combination of results.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11489599B1Wideband frequency response characterization with a narrowband source or receiver

Publication Date: 2022.11.01 ROHDE & SCHWARZ GMBH & CO KG

AI summary

The present disclosure relates to a method (10) for characterizing a wideband RF device-under-test (DUT) by means of a narrowband RF source or a narrowband RF receiver, the method (10) comprising: selecting (11) a bandwidth of the wideband RF DUT to be analyzed; dividing (12) the selected bandwidth into at least two overlapping sub-bands, the respective sub-bands having a frequency range that corresponds to a bandwidth of the narrowband RF source or the narrowband RF receiver; acquiring (13) a response of the wideband RF DUT for each of the at least two overlapping sub-bands by means of at least two narrowband measurements using the narrowband RF source or the narrowband RF receiver; and calculating (14) a continuous amplitude response and a continuous phase response of the wideband RF DUT in a frequency range that corresponds to the combined bandwidth of the at least two overlapping sub-bands, said calculation making use of the overlap of the sub-bands.