Cavity Filter Terminal Assembly for Compact Massive MIMO Mounting

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Solution Overview

Problem

Existing cavity filters for Massive MIMO antennas are bulky and difficult to assemble, leading to increased size and variability in frequency characteristics when mounted, which complicates their integration into base station antennas.

Innovation Solution

A slim and compact cavity filter design with an improved RF connector structure, featuring a terminal unit with an elastic connector and dielectric bush, which reduces assembly tolerances and maintains uniform frequency characteristics by securely connecting to a printed circuit board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a traditional cavity filter structure is used, then the filter provides stable frequency characteristics, but the filter size is large and assembly is difficult

Engineering Contradiction:
Improvecavity filter sizeVSAvoidassembly difficulty
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The cavity filter is divided into multiple modular components including a first casing containing the resonant element, a second casing covering one surface, and separate assembly units with terminal insertion holes. This segmentation allows each component to be manufactured and tuned independently, then assembled together, reducing overall size while maintaining assembly feasibility

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connector structure is reoriented from a lateral connection to a vertical connection through the thickness direction of the cavity filter body. Terminal units pass through the first casing in the thickness direction, with assembly units protruding from the lower surface, enabling compact integration along the Z-axis rather than requiring lateral space

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multiple cavity filters are assembled, then filtering capacity increases, but cumulative assembly tolerances cause frequency characteristic variability

Engineering Contradiction:
Improvefilter assembly capacityVSAvoidfrequency characteristic uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The terminal unit incorporates an elastic member that automatically adjusts and maintains optimal electrical contact between the pin member and the electrode pad on the PCB. This self-adjusting mechanism compensates for assembly tolerances without requiring high-precision manual adjustment, ensuring consistent frequency characteristics across multiple assembled filters

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The connector design includes an elastic member that changes its mechanical parameter (elastic force) to maintain stable electrical connection. The elastic force dynamically compensates for variations in assembly position and contact pressure, keeping electrical parameters consistent across multiple filters even with cumulative tolerances

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If a compact cavity filter design is implemented, then mounting space is reduced, but connection stability under vibration and thermal deformation decreases

Engineering Contradiction:
Improvemounting spaceVSAvoidconnection stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The connector employs an elastic member that provides dynamic adjustment capability. When vibration or thermal deformation occurs, the elastic member deforms elastically to maintain optimal contact pressure between the pin member and electrode pad, ensuring stable electrical connection despite external disturbances or compact mounting constraints

Inventive Principle:
Principle #15Dynamics

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 enables a more compact antenna system with rapid and reproducible verification of individual cavity filters, facilitating easier mounting and maintaining consistent frequency characteristics even under vibration and thermal deformation.

Implementation Method 1

a terminal body through which the pin member passes, and which is installed together with the pin member in the terminal insertion hole, the terminal body having an elastic member accommodated therein to apply an elastic force to the pin member

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a resonator, which is composed of a resonant rod as a conductor, and the like, inside a box structure made of a metallic conductor, so that only an electromagnetic field having a natural frequency exists so as to allow only a characteristic frequency of ultra-high frequencies to pass through the filter by resonance

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3748766B1Cavity filter
Publication Date: 2024.06.12 KMW INC
  • EP3748766B1 patent drawingFigure 1~2
  • EP3748766B1 patent drawingFigure 3~4
  • EP3748766B1 patent drawingFigure 5

AI summary

The present invention relates to a cavity filter and, particularly, to a cavity filter comprising: a resonance element including a coupling block; a first case including the resonance element therein; a second case arranged so as to cover one surface of the first case; a terminal unit penetrating the first case such that one end thereof is protrndingly provided so as to be connected to an electrode pad of an external member provided on the outside of the first case and the other end thereof is electrically connected to the coupling block of the resonance element provided to be close to the second case, wherein the terminal unit is electrically insulated from the first case; and an assembly unit provided on either one side or both sides in the lengthwise direction of the case, and having a terminal insertion hole in which the terminal unit is insertedly provided, wherein the assembly unit is formed to protrude to the outside from a lower surface of the first case.