Dielectric Filter Stepped Resonant Holes Signal Leakage
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Solution Overview
Problem
Existing TEM dielectric filters face issues with unstable welding due to different thermal expansion coefficients of materials and high background noise, leading to signal leakage and weak noise suppression capabilities.
Innovation Solution
A dielectric filter design featuring stepped resonant through holes with conductor layers and loop gaps that form capacitance to lower resonant frequency, reducing volume and preventing signal leakage, while all surfaces being covered with conductor layers enhance shielding and noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal shielding cover is used to shield electromagnetic signals and reduce filter volume, then shielding effectiveness and miniaturization are improved, but welding stability deteriorates due to different thermal expansion coefficients of materials
Solution Approach 1:
The patent removes the separate metal shielding cover from the filter structure. Instead, the dielectric body itself is designed with conductive layers on its surfaces that provide the shielding function, thereby eliminating the welding connection between different materials while maintaining electromagnetic shielding effectiveness.
Solution Approach 2:
The shielding function is merged into the dielectric body by adding conductive layers to its surfaces. This integration eliminates the need for a separate shielding cover and its associated welding connections, resolving the thermal expansion mismatch problem while maintaining shielding effectiveness.
2Ease of operation
If a gap is reserved between the shielding cover and dielectric body for assembly, then ease of assembly is improved, but signal leakage increases and noise suppression capability deteriorates
Solution Approach 1:
The shielding function is integrated directly onto the dielectric body surfaces through conductive layers, eliminating the gap between separate components. This integration ensures continuous shielding coverage that prevents signal leakage while maintaining ease of assembly as a single-unit structure.
3Object-affected harmful factors
If conductor layers cover all surfaces of the dielectric body, then shielding effectiveness and noise suppression are improved, but manufacturing complexity increases
Solution Approach 1:
The conductive layers serve multiple functions simultaneously: they provide electromagnetic shielding on the dielectric body surfaces and form capacitive structures with the resonant holes for frequency tuning. This multi-functionality achieves improved noise suppression without proportionally increasing manufacturing complexity.
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 effectively prevents signal leakage, improves noise suppression, and avoids unstable welding, achieving a background noise suppression level of -80 dB, compared to -60 dB in existing filters, while allowing for miniaturization of the filter.
Implementation Method 1
A loop gap not covered with the conductor layer is provided on the stepped surface, and the loop gap is arranged around the stepped small hole so that a capacitance is formed between the conductor layer of the inner wall of the stepped small hole and the conductor layer of the inner wall of the stepped large hole
Implementation Method 2
After being input from the input pad 05, an electromagnetic wave signal is transmitted through resonant coupling between the plurality of metalized resonant holes 03 and finally output from the output pad 06. In the series of resonance process, only electromagnetic waves whose frequency components are near a resonant frequency are allowed to pass
Implementation Method 3
The surfaces of the dielectric block are covered with conductor layers... because all surfaces of the dielectric block are provided with the conductor layer, the conductor layer can effectively shield a signal, to prevent signal energy leakage and interference from an external signal
Data Source
AI summary
This application provides an example dielectric filter and an example communications device. The dielectric filter includes a dielectric block. At least two resonant through holes that are parallel to each other are provided in the dielectric block. The resonant through hole is a stepped hole. The stepped hole includes a large stepped hole and a small stepped hole that are arranged coaxially and that are in communication. The small stepped hole passes through a first surface of the dielectric block. The large stepped hole passes through a second surface of the dielectric block. A stepped surface is formed between the large stepped hole and the small stepped hole. The surfaces of the dielectric block are covered with conductor layers. The conductor layers cover the surfaces of the dielectric block and inner walls of the large stepped hole and the small stepped hole. A conductor layer of the inner wall of the large stepped hole is short-circuited with a conductor layer of the second surface. A conductor layer of the inner wall of the small stepped hole is short-circuited with a conductor layer of the first surface. A loop gap that does not cover the conductor layers is provided on the stepped surface. The loop gap is arranged around the small stepped hole.