Power Sensor Thermal Management via Segmented Substrate

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Solution Overview

Problem

Conventional power sensors face challenges with temperature-dependent zero-point resistance and noise behavior of diode detectors, leading to inaccurate measurements and high energy consumption due to their large mass and thermal capacity.

Innovation Solution

A power meter with an integrated power detector on a monolithic chip, featuring a thermally insulating signal input on a plastic substrate and a temperature control device on the chip's backside, achieving uniform temperature control with low thermal coupling, thus minimizing thermal capacity and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metallic housing with high mass is used for the power sensor, then mechanical strength and structural stability are improved, but thermal capacity increases leading to high time constant and high energy consumption for temperature control

Engineering Contradiction:
Improvemechanical strengthVSAvoidenergy consumption for temperature control
Core Design Contradiction:
StrengthVSUse of energy by stationary object

Solution Approach 1:

The patent divides the housing into a metallic structural housing and a separate thermal management substrate. The power detector is mounted on a substrate with low thermal capacity rather than directly on the metallic housing, separating the mechanical support function from the thermal management function. This allows the metallic housing to provide strength while the substrate provides low thermal capacity for efficient temperature control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The substrate acts as an intermediary between the metallic housing and the power detector. It provides thermal isolation from the high thermal capacity housing while maintaining mechanical support. The substrate has low thermal capacity to enable fast temperature response and low energy consumption for temperature control, while the metallic housing provides structural strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the power detector is thermally coupled to the housing for stable temperature, then temperature stability is improved, but response time to temperature changes increases due to high thermal capacity

Engineering Contradiction:
Improvetemperature stabilityVSAvoidresponse time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent segments the thermal system by mounting the power detector on a separate substrate with low thermal capacity rather than directly coupling it to the metallic housing. This allows the detector to have fast response time (low time constant) while the substrate provides sufficient thermal isolation to maintain temperature stability during normal operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the thermal capacity parameter of the mounting structure by using a substrate with low thermal capacity instead of direct mounting on the metallic housing. This parameter change enables the system to achieve both fast response time and temperature stability through the low thermal mass of the substrate.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If compensation circuits are added to correct temperature-dependent errors, then measurement accuracy is improved, but device complexity and residual errors increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional approach of using complex electronic compensation circuits with a thermal management approach. By actively controlling the temperature of the power detector through a temperature control device, the system eliminates temperature-dependent errors physically rather than compensating for them electronically, thereby reducing circuit complexity and improving accuracy.

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

Solution Approach 2:

The patent converts the harmful effect of temperature dependence into a beneficial controlled parameter. Instead of compensating for temperature effects, the system actively maintains constant temperature conditions, transforming the temperature variable from a source of error into a controlled parameter that improves measurement accuracy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Stability of the object's composition

If the signal input is thermally coupled to the power detector for stable temperature, then temperature stability is improved, but thermal capacity increases leading to higher energy consumption

Engineering Contradiction:
Improvetemperature stabilityVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by stationary object

Solution Approach 1:

The patent segments the thermal path by using a substrate with low thermal capacity to mount the power detector. The signal input is coupled to the detector through this low thermal capacity substrate rather than through a thermally conductive path, enabling temperature stability with minimal energy consumption for temperature control.

Inventive Principle:
Principle #1Segmentation

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 design enables precise, low-energy power measurement with reduced thermal effects, allowing for a lower zero-point resistance and constant noise behavior, resulting in improved measurement accuracy and reduced manufacturing complexity.

Implementation Method 1

The power detector (12) is integrated as an integrated circuit on a monolithic chip and converts a high-frequency measurement signal into a signal that indicates the power of the high-frequency measurement signal

Methodology Applied
Scientific EffectDiode detection: Diode

Implementation Method 2

The signal input is connected to the power detector (12) in a thermally insulating manner by means of a first line on a plastic substrate

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

The constant temperature is advantageously achieved by low thermal coupling of the power detector to the rest of the power meter

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2641096B1Thermally stabilized power sensor
Publication Date: 2016.02.10 ROHDE & SCHWARZ GMBH & CO KG
  • EP2641096B1 patent drawingFigure 1~3
  • EP2641096B1 patent drawingFigure 4
  • EP2641096B1 patent drawingFigure 5

AI summary

The invention relates to a power measuring device having a power detector (12) and a temperature control device (25). The power detector is integrated on a monolithic chip as an integrated circuit. Said detector converts a high-frequency measurement signal into a signal indicating the power of the high-frequency measurement signal. The power measuring device further has a signal input. The temperature control device (25) is thereby disposed outside of the monolithic chips on a side of the monolithic chip facing away from the integrated circuit. The signal input is connected to the power detector (12) by means of a first conductor (13) on a plastic substrate (34). The signal input feeds the high-frequency measurement signal to the power detector (12) by means of the first conductor (13).