Threadless Tuning Elements for Coaxial Resonators

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing high-frequency filters require complex and costly threaded connections for tuning, which are difficult to automate and can lead to metallic abrasion causing passive intermodulation issues.

Innovation Solution

A coaxial high-frequency filter design with a threadless tuning element that uses an axially displaceable tuning element within the inner conductor bore, secured by an adhesive connection after adjustment, eliminating the need for threads and reducing metallic abrasion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If threaded connections are used for tuning elements, then secure mechanical fixation is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemechanical fixationVSAvoidthreaded connection structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the threaded connection structure from the tuning element assembly. Instead of using threads to secure the tuning element to the resonator, the invention employs a simple push-fit arrangement where the tuning element is inserted directly into the resonator bore, eliminating the complex threaded interface while maintaining secure mechanical fixation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent divides the resonator structure into separate components: the resonator body with a bore and the separate tuning element. The tuning element can be independently inserted and adjusted within the bore, allowing for simplified assembly and disassembly without requiring threaded connections, thereby reducing device complexity.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If threaded connections are used for tuning elements, then adjustable tuning is achieved, but manufacturing automation becomes difficult

Engineering Contradiction:
Improvetuning adjustmentVSAvoidmanufacturing automation
Core Design Contradiction:
Adaptability or versatilityVSExtent of automation

Solution Approach 1:

The patent eliminates the threaded connection component from the tuning mechanism, replacing it with a direct push-fit arrangement. This simplification allows tuning elements to be automatically inserted and positioned by robotic assembly systems without requiring complex threading operations, significantly improving manufacturing automation capability while preserving full tuning adjustability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If threaded connections are used for tuning elements, then mechanical connection is achieved, but metallic abrasion occurs causing passive intermodulation

Engineering Contradiction:
Improvemechanical connectionVSAvoidpassive intermodulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the threaded interface between the tuning element and resonator, eliminating the source of metallic abrasion. The tuning element is instead inserted directly into the resonator bore without threads, preventing metal-to-metal contact and friction that would otherwise generate passive intermodulation products, while still achieving secure mechanical connection through the push-fit arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If precise thread matching is required, then secure connection is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveconnection securityVSAvoidthread matching precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent eliminates the threaded connection system entirely, replacing it with a push-fit arrangement where the tuning element is inserted into the resonator bore. This design tolerates greater dimensional variations and does not require precise thread matching, significantly reducing manufacturing precision requirements while maintaining secure mechanical connection through the interference fit of the push-fit interface.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3320578B1Threadless tuning elements for coaxial resonators, and method for tuning same
Publication Date: 2019.10.30 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3320578B1 patent drawingFigure 1A
  • EP3320578B1 patent drawingFigure 1B
  • EP3320578B1 patent drawingFigure 2A~2B

AI summary

The invention relates to a high-frequency filter (1) with a coaxial design, comprising at least one resonator (2) with a first inner conductor (3) and with an outer conductor housing (4). The outer conductor housing (4) comprises a housing base (5), a housing cover which is arranged at a distance from the housing base (6), and a peripheral housing wall (14) between the housing base (5) and the housing cover (6). The first inner conductor (3) is galvanically connected to the housing base (5) and extends axially from the housing base (5) in the direction of the housing cover (6). The resonator (2) comprises a second internal conductor (7) which is galvanically connected to the housing cover (6) and extends axially from the housing cover (6) in the direction of the housing base (5). The first and/or second inner conductor (3, 7) has an inner conductor bore (8, 25 15), and a tuning element (9) is arranged in one inner conductor bore (8, 15) in a thread-free axially movable manner. The tuning element (9) is arranged in a sleeve or bushing (31) and optionally or in addition thereto has an enlarged elastic region.