Dielectric Resonator Filter Size Reduction via Mode Segmentation

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Solution Overview

Problem

Current dielectric resonator filters and multiplexers face challenges in achieving size reduction and simplified design due to complex tuning and coupling schemes, especially in quadruple-mode resonators, which are bulky and require independent control over multiple modes.

Innovation Solution

A dielectric resonator assembly comprising a half-cut or full cylindrical dielectric resonator with specific dimensions and geometry, allowing for coupling between HEH11 and HEE11 modes, enabling operation in dual or quad modes with independent control over resonant frequencies and simplified coupling mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If quadruple-mode dielectric resonators are used to reduce size, then the physical resonator can support multiple field distributions, but the fabrication and tuning complexity increases significantly requiring independent control over four modes with large number of tuning and coupling screws

Engineering Contradiction:
Improveresonator sizeVSAvoidcoupling scheme complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The invention divides the quadruple-mode resonator into two separate dual-mode resonators, each supporting two field distributions. This segmentation reduces the complexity of controlling four modes simultaneously while achieving the same size reduction benefit, as each dual-mode resonator requires fewer tuning and coupling elements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each dual-mode resonator is designed to support multiple field distributions (dual-mode operation), allowing a single resonator structure to perform the function of what would traditionally require multiple resonators. This multi-functionality maintains size reduction while simplifying the overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If triple-mode and quadruple-mode dielectric resonators are used, then size reduction is achieved by overloading one physical resonator with multiple electrical resonators, but the design complexity becomes even more pronounced compared to single-mode and dual-mode resonators

Engineering Contradiction:
Improvefilter sizeVSAvoidtuning scheme complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The invention segments the high-order mode resonator into lower-order dual-mode resonators, reducing the number of modes that must be controlled within a single resonator structure. This segmentation maintains compact size while reducing tuning complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces adjustable coupling mechanisms between resonators that allow dynamic control of mode coupling strength. This enables flexible tuning of the system response without requiring complex fixed coupling structures, simplifying the overall design

Inventive Principle:
Principle #15Dynamics

3Reliability

If dielectric resonators are used instead of lumped element or microstrip resonators, then superior Q values are achieved in the range of 3,000 to 40,000 at 1GHz, but the resonators become bulkier in size and more complex in design

Engineering Contradiction:
ImproveQ valueVSAvoidresonator size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The invention combines multiple resonant modes within dual-mode resonators, allowing a single physical resonator structure to provide the functionality of multiple resonators. This merging maintains the high Q values of dielectric resonators while reducing the overall filter size

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention exploits the three-dimensional field distributions within dielectric resonators to support multiple resonant modes. By utilizing different spatial field configurations (dimensions) within the same physical volume, the system achieves size reduction while maintaining high Q performance

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

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 configuration results in compact, efficient dielectric resonator filters and multiplexers with improved size reduction and simplified design, achieving effective mode control and reduced spurious performance.

Implementation Method 1

The resonant frequency of a resonator is defined as any frequency at which the stored electric and magnetic energies in the resonator are equal, and at that frequency the resonator is said to be in resonance

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a dielectric resonator formed in a unitary piece of high-permittivity dielectric substrate

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2151885B1Method of operation, and construction of dual-mode filters, quad-mode filters, dual band filters, and diplexer/multiplexer devices using full or half cut dielectric resonators
Publication Date: 2012.02.08 COM DEV INTERNATIONAL
  • EP2151885B1 patent drawingFigure 1A~1B
  • EP2151885B1 patent drawingFigure 2A~2B
  • EP2151885B1 patent drawingFigure 2C~2D

AI summary

Novel quadruple-mode, dual-mode, and dual-band filters as well multiplexers are presented. A cylindrical dielectric resonator sized appropriately in terms of its diameter D and length L will operate as a quadruple-mode resonator, offering significant size reduction for dielectric resonator filter applications. This is achieved by having two mode pairs of the structure resonate at the same frequency. Single-cavity, quad-mode filters and higher order 4n-pole filters are realizable using this quad-mode cylindrical resonator. The structure of the quad-mode cylinder can be simplified by cutting lengthwise along its central axis to produce a half-cut cylinder suitable for operation in either a dual-mode or a dual-band. Dual-mode, 2n-pole filters are realizable using this half-cut cylinder. Dual-band filters and diplexers are further realizable using the half-cut structure and full cylinder by carrying separate frequency bands on different resonant modes of the structure. These diplexers greatly reduce size and mass of many-channel multiplexers at the system level, as each two channels are overloaded in one physical branch. Full control of center frequencies of resonances, and input and inter-resonator couplings are achievable, allowing realization of microwave filters with different bandwidth, frequency, and Return Loss specifications, as well as advanced filtering functions with prescribed transmission zeros. Spurious performance of the half-cut cylinder can also be improved by cutting one or more through-way slots between opposite surfaces. Size and mass reduction achieved by using the full and half-cut resonators described, provide various levels of size reduction in microwave systems, both filter level, and multiplexer level.