Power Sensor Standard Using Dual Ridged Waveguide Impedance Transformer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional waveguide sensors suffer from high power measurement uncertainty and poor reflection performance, particularly in the 50-75 GHz frequency range, due to thermal leakage and step changes in wave line width, which limit calibration efficiency and bandwidth.

Innovation Solution

A power sensing assembly with a dual ridged waveguide impedance transformer and a resistive component, where the sensing element is thermally but not electrically coupled to the terminating element, allowing for improved reflection and reduced uncertainty through a substrate that maintains constant resistance, enabling better linearity and frequency matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If bead sensing devices or fin-line type transforming circuits are used, then the sensor can detect electromagnetic energy, but power measurement uncertainty increases and calibration efficiency is limited due to thermal leakage

Engineering Contradiction:

Improvepower measurement uncertaintyVSAvoidthermal leakage

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The sensor is divided into separate functional components: a sensing element for detecting power and a termination element for absorbing electromagnetic energy. This segmentation allows the sensing element to be thermally isolated from the waveguide housing, reducing thermal leakage, while the termination element handles the electromagnetic energy absorption. The separation of functions improves both measurement precision and reduces energy loss through thermal leakage.

Inventive Principle:

Principle #1Segmentation

2Reliability

If thermistor beads on fine wires are used, then sensitivity is high, but wave line width changes cause reflective discontinuity and poor VSWR performance

Engineering Contradiction:

ImproveVSWR performanceVSAvoidsensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The sensing element uses a fine wire thermistor bead for high sensitivity local measurement, while the surrounding waveguide structure maintains proper impedance matching. The fine wire bead is positioned at a specific location where it can detect power changes without significantly disrupting the overall waveguide field distribution. This localized sensing approach preserves both sensitivity and VSWR performance by confining the wire's impact to a small region that does not cause significant reflective discontinuity.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If standard waveguide configurations are used in millimeter frequency range, then the structure is simple, but bandwidth capability is fundamentally narrower

Engineering Contradiction:

Improvebandwidth capabilityVSAvoidwaveguide topology

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The waveguide structure incorporates adjustable or variable impedance transformation sections that can be tuned to optimize performance across different frequency bands. This dynamic adjustment capability allows the same waveguide structure to adapt to various bandwidth requirements in the millimeter frequency range, expanding versatility without requiring completely different waveguide topologies for each frequency band.

Inventive Principle:

Principle #15Dynamics

4Productivity

If sensing element is thermally coupled to waveguide housing, then thermal management is simple, but calibration efficiency is limited

Engineering Contradiction:

Improvecalibration efficiencyVSAvoidthermal isolation structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

A thermal isolation structure or interface is introduced between the sensing element and the waveguide housing. This intermediary component allows the sensing element to be thermally decoupled from the housing, improving calibration efficiency by reducing thermal leakage paths. The intermediary may include thermal barriers, isolation layers, or specialized mounting structures that prevent unwanted thermal conduction while still providing mechanical support and electrical connectivity as needed.

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

The solution provides a lower uncertainty method for measuring microwave power with improved reflection performance and calibration efficiency, achieving a 55-60% efficiency factor with reduced thermal leakage and enhanced bandwidth capabilities.

Implementation Method 1

the dual ridged waveguide impedance transformer topology is configured to concentrate high frequency power as well as transform the waveguide impedance

Methodology Applied

Scientific EffectImpedance transformation:

Implementation Method 2

The sensing element is thermally, but not electrically coupled to the terminating element

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10892533B2Power sensor standard

Publication Date: 2021.01.12 TEGAM INC

AI summary

A power sensor system, assembly and method for use as a power sensor standard in the 50 to 75 GHz frequency range. The power sensing system comprises a housing comprising a dual ridged waveguide impedance transformer, and a resistive component attachable to a back side of the housing. The resistive component comprises a terminating element electrically, but not thermally isolated from a sensing element. The sensing element operates at a constant resistance and is perpendicularly oriented to the terminating element.