Liquid Cooled High-Frequency Filter Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-frequency filters used in DVB-T applications face challenges with thermal instability and selectivity issues, especially at high power transmitter applications, where increased cavity volumes lead to thermal instability and reduced selectivity, and existing solutions are costly and complex.
Innovation Solution
A liquid-cooled high-frequency filter design featuring a thermally conductive cover element with a recess for guiding liquid coolant to absorb thermal energy, combined with a tubing element for improved heat dissipation, maintaining thermal stability and selectivity even at high power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cavity volumes are increased to reduce current and field densities, then thermal stability improves, but selectivity deteriorates due to higher TEM modes
Solution Approach 1:
The resonator cavity is divided into multiple smaller resonant sections or elements. This segmentation allows the overall structure to maintain small effective volume for high selectivity while distributing thermal loads across multiple sections, improving thermal stability without sacrificing frequency selectivity.
Solution Approach 2:
The patent introduces a vertical dimension by stacking resonator cavities or using multi-layer configurations. This allows the filter to achieve the required selectivity through vertical arrangement of resonant elements rather than increasing horizontal cavity volume, thereby maintaining thermal stability while achieving high selectivity.
2Manufacturing precision
If cavity volumes are reduced to improve selectivity, then selectivity improves, but thermal instability increases due to increased current and field densities
Solution Approach 1:
The resonator cavities are constructed using composite materials with high thermal conductivity and low thermal expansion coefficients. These composite materials can withstand high current and field densities while maintaining dimensional stability, allowing small cavity volumes for high selectivity without suffering from thermal instability.
Solution Approach 2:
Thermal management components such as heat sinks, thermal vias, or cooling channels are introduced as intermediary elements between the resonator cavities and the environment. These intermediaries conduct heat away from the high-density field regions, enabling small cavity volumes for high selectivity while preventing thermal runaway.
3Reliability
If linearized high power amplifiers are implemented to prevent non-linearity products, then transmission quality improves, but device complexity and cost increase
Solution Approach 1:
Instead of trying to prevent non-linear distortion at the amplifier stage, the patent allows non-linear products to be generated and then uses highly selective filtering to remove them. This converts the harmful non-linear distortion into removable interference, simplifying the amplifier design while maintaining transmission quality through the selective filter.
Solution Approach 2:
The patent replaces the complex mechanical/electronic linearization circuitry with a simpler approach: allow non-linear operation and use electromagnetic field-based selective filtering. This substitutes complex active linearization components with passive resonant structures that naturally reject non-linear products through frequency selectivity.
4Reliability
If highly selective output filter units are added to reduce intermodulation products, then transmission quality improves, but device complexity increases
Solution Approach 1:
The filtering function is merged with the resonator cavity structure itself. The resonators are designed to provide both the frequency-selective resonant operation and the intermodulation product rejection in a single integrated structure, eliminating the need for separate filtering components and reducing overall device complexity.
Solution Approach 2:
The resonator cavities are designed to perform multiple functions simultaneously: frequency selection, impedance matching, and intermodulation product rejection. This multi-functionality reduces the number of separate components needed, simplifying the overall filter architecture while maintaining high transmission quality.
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 liquid-cooled filter effectively dissipates thermal energy, maintaining stability and selectivity, allowing for increased power handling without thermal instability, and enabling quick frequency and power adjustments, thus meeting ETSI spectral mask requirements.
Implementation Method 1
The cover element is made form a thermally conductive material and is in thermal connection with the resonators positioned therein
Implementation Method 2
a liquid coolant is guided in order to absorb thermal energy resulting from feeding the high-frequency signal to the resonator
Data Source
AI summary
The invention refers to a high-frequency filter (1), comprising a filter housing (2), the filter housing (2) having at least one cover element (2a) with at least one resonator (5, 6, 7, 8, 9, 10, 11, 12) positioned therein and at least one signal input (3), through which a high frequency signal is coupled to the first resonator (5) and a signal output (4), through which a high frequency signal is coupled from the last resonator (10) to downstream appliances wherein the cover element (2a) is made from a thermally conductive material and the resonator (5, 6, 7, 8, 9, 10, 11, 12) is arranged to be in thermal connection with the cover element (2a). The cover element (2a) has at least one recess (23) arranged therein, along with a liquid coolant is guided in order to absorb thermal energy resulting from feeding the high frequency signal to the resonator (5, 6, 7, 8, 9, 10, 11, 12). The liquid cooled high-frequency filter according to the invention allows for an increased input power while retaining the physical dimensions of the filter assembly constant, thus, omitting resonator instabilities due to the development of higher TEM modes.