Hybrid Resonant Ceramic Filter for Multi-Band Suppression
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Solution Overview
Problem
Existing ceramic filters are limited in functionality, primarily functioning as either band-stop or band-pass filters, unable to effectively utilize frequency bands across the full frequency demand, lacking versatility in frequency selection and suppression.
Innovation Solution
A structured hybrid different-wavelength resonant ceramic filter is designed with a ceramic substrate featuring multiple resonant cavities of varying lengths and diameters, arranged to form both band-pass and band-stop filters, allowing for integrated multi-cavity functionality, with metal-coated inner walls and electrodes for precise frequency control and suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-function ceramic filter (band-pass or band-stop) is used, then the filter structure is simple, but the frequency band usage is limited and cannot meet full frequency demand
Solution Approach 1:
The patent combines multiple resonant cavities with different functions (band-pass and band-stop) into a single integrated ceramic filter structure. The first, second, and third resonant cavities are arranged and coupled to simultaneously provide both band-pass and band-stop filtering functions, enabling the filter to handle multiple frequency bands and meet diverse frequency demands within one device.
Solution Approach 2:
The integrated ceramic filter is designed to perform multiple functions: it provides band-pass filtering for specific frequency bands while simultaneously providing band-stop filtering for other frequency bands. This multi-functional design allows the single filter to meet full frequency demand across different application scenarios, replacing what would traditionally require multiple separate filters.
2Adaptability or versatility
If multiple separate filters are used to meet full frequency demand, then the frequency band coverage is comprehensive, but the device complexity and size increase
Solution Approach 1:
Instead of using multiple separate filters, the patent merges multiple resonant cavities into a single integrated ceramic substrate structure. The first, second, and third resonant cavities share the same physical housing and are coupled through controlled electromagnetic interactions, achieving comprehensive frequency band coverage while maintaining a compact form factor equivalent to a single filter.
Solution Approach 2:
The patent employs a nested arrangement where multiple resonant cavities are positioned and coupled within a shared ceramic substrate structure. The cavities are arranged to utilize space efficiently, with their electromagnetic fields interacting through the substrate, thereby achieving multi-functionality without proportionally increasing the overall device volume.
3Productivity
If traditional single-function filters are used, then the manufacturing process is simple, but the debugging and frequency adjustment time is long
Solution Approach 1:
The filter is designed with segmented resonant cavities (first, second, and third cavities) that can be independently adjusted during manufacturing. Each cavity group corresponds to specific filtering functions, allowing for modular frequency tuning and simplifying the debugging process by enabling targeted adjustments to specific frequency bands without affecting the entire filter system.
Solution Approach 2:
The patent employs parameter adjustments of the resonant cavities (such as cavity dimensions, positioning, and coupling coefficients) to optimize filtering performance. By designing the cavities with adjustable parameters, the filter can be tuned during manufacturing to achieve precise frequency characteristics, reducing debugging time while maintaining manufacturing feasibility.
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 filter achieves excellent suppression at both low and high frequencies, suitable for pass bandwidths of 1 GHz to 1.8 GHz with high attenuation slopes, and effectively suppresses harmonics above −20 to −50 dB, enabling usage up to 5 GHz with high suppression attenuation, while simplifying structural design and reducing debugging time.
Implementation Method 1
five of the first resonant cavities and two of the third resonant cavities are coated with metal at one end located on the second surface. The input/output electrode is disposed at the first surface, and are electrically connected to two of the second resonant cavities. Five of the first resonant cavities are coupled to form a fifth-order band-pass filter. Each of the second resonant cavities is coupled to an adjacent one of the third resonant cavities to form a band-stop filter.
Data Source
AI summary
Disclosed is a structured hybrid different-wavelength resonant ceramic filter, comprising a ceramic substrate and an input/output electrode, wherein the ceramic substrate comprises a first surface and a second surface opposite to the first surface, five first resonant cavities, two second resonant cavities and two third resonant cavities are formed between the first surface and the second surface in a horizontal direction; the five first resonant cavities are located in the middle of the first surface of the ceramic substrate, the two second resonant cavities are respectively located at both sides of the five first resonant cavities, and the two third resonant cavities are respectively located lateral relative to the two second resonant cavities. With the present disclosure, filters with various forms and functions are integrated into a multi-cavities filter, and it is simple in structure.