Dielectric Resonator Filter with Internal Coupling for Mode Control
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Solution Overview
Problem
There is a continuous need for microwave or RF filters with larger bandwidth and lower pass-through attenuation while maintaining steep slopes, and existing filters are often bulky and lack flexibility.
Innovation Solution
A microwave or RF bandpass filter design utilizing a dielectric resonator with a cylindrical shape and a conductive housing, featuring adjustable coupling elements and tuning rods to achieve quad-mode operation, allowing for compact and robust filters with adjustable frequency tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional rectangular and circular waveguide resonators are used, then the filter structure is simple, but the filter size and volume are large
Solution Approach 1:
The patent changes the resonator type from conventional waveguide resonators to dielectric resonators, utilizing the high dielectric constant material property to concentrate electromagnetic fields and reduce filter volume while maintaining functional performance
Solution Approach 2:
The patent employs composite structure combining dielectric resonator material with metal enclosure, where the dielectric resonator concentrates fields and the metal housing provides shielding and structural support, achieving compact size without excessive complexity
2Volume of moving object
If dielectric resonators with high dielectric constant are used, then the filter volume is reduced, but the Q-factor is limited by dielectric loss
Solution Approach 1:
The patent applies local quality by using high dielectric constant material only in the resonator regions where field concentration is needed, while the surrounding metal enclosure provides low-loss transmission paths, optimizing both size reduction and loss performance
3Reliability
If filters are designed for large bandwidth with low pass-through attenuation, then the filter performance is improved, but the filter size increases
Solution Approach 1:
The patent utilizes three-dimensional dielectric resonator structures with optimized height-to-diameter ratios, exploiting the vertical dimension for field confinement and mode control, achieving large bandwidth performance in a compact volume
4Adaptability or versatility
If fixed structure filters are used, then the manufacturing is simple, but the tuning flexibility is limited
Solution Approach 1:
The patent incorporates adjustable coupling elements and tuning mechanisms that allow dynamic adjustment of resonator coupling and frequency tuning after manufacturing, providing flexibility without compromising manufacturing simplicity
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 design achieves a compact, robust, and highly adjustable filter with a large bandwidth and low pass-through attenuation, enabling steep slope performance and flexible tuning capabilities.
Implementation Method 1
The resonator is mounted inside a metal enclosure. The electromagnetic field is concentrated mainly in the dielectric cylinder. Therefore, the Q-factor of the resonator is determined largely by the loss tangent of the dielectric material of the resonator.
Implementation Method 2
at least one first internal coupling element is provided which provides coupling between a HEEx mode and a HEEy mode of the resonator
Data Source
AI summary
A quad-mode microwave or RF bandpass filter comprises a housing of a conductive material defining a cylindrical cavity and containing a cylindrical dielectric resonator defined by a parallel pair of face surfaces. The dielectric resonator is held within the housing between a pair of support plates of a dielectric material. Internal coupling elements are provided above and/or below the dielectric resonator for coupling between resonating modes. Further mode coupling elements are protruding into the housing.