Multilayer RF Filter Coupling Layout for Band-Pass Isolation
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Solution Overview
Problem
Existing filter devices struggle to achieve a desired band-pass characteristic while preventing signal interference between different frequency bands, particularly in communications systems with varied frequency usage.
Innovation Solution
A filter device with a multilayer body containing multiple LC parallel resonators, each connected to a ground terminal, and a connection conductor that overlaps a portion of another conductor, allowing for adjustable electromagnetic field coupling through capacitors and inductors, enhancing the adjustability of electromagnetic field coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic field coupling is used between non-adjacent LC parallel resonators to increase attenuation at attenuation pole, then band-pass characteristic is improved, but adjustability of electromagnetic field coupling is limited
Solution Approach 1:
A connection conductor is introduced as an intermediary element between non-adjacent LC parallel resonators. This connection conductor enables both magnetic field coupling (through proximity to conductors) and electric field coupling (through overlapping regions forming capacitive coupling), providing enhanced adjustability of electromagnetic field coupling while maintaining improved band-pass characteristics.
Solution Approach 2:
The connection conductor is designed with adjustable positioning and configuration, allowing dynamic adjustment of coupling strength. By changing the position, shape, or overlapping area of the connection conductor, the electromagnetic field coupling between resonators can be tuned to achieve desired filter characteristics for different frequency bands.
2Reliability
If multiple LC parallel resonators are arranged to achieve desired band-pass characteristic, then signal filtering capability is improved, but device complexity increases
Solution Approach 1:
Multiple LC parallel resonators are integrated into a compact multilayer structure where they share common ground terminals and are interconnected through connection conductors. This merging approach achieves desired band-pass characteristics with multiple resonators while reducing overall device complexity through shared components and compact arrangement.
Solution Approach 2:
The filter device utilizes a multilayer configuration where LC parallel resonators and connection conductors are distributed across different layers. This three-dimensional arrangement allows complex electromagnetic coupling relationships to be achieved with simpler planar conductor patterns on each layer, reducing manufacturing complexity while maintaining filtering performance.
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 enables precise adjustment of electromagnetic field coupling, allowing for improved band-pass characteristics and reduced signal interference between frequency bands.
Implementation Method 1
The connection conductor includes a first region that overlaps a portion of the second conductor in plan view of the multilayer body seen in the stacking direction
Implementation Method 2
a first via including one end connected to the first conductor and another end connected to the connection conductor, and a second via including one end connected to the third conductor and another end connected to the connection conductor
Implementation Method 3
three or more LC parallel resonators are arranged. In the band-pass filter, two non-adjacent LC parallel resonators are coupled to each other by magnetic field coupling
Data Source
AI summary
A filter device includes a multilayer body in which multiple dielectric layers are stacked, a ground terminal, and a first LC parallel resonator, a second LC parallel resonator, and a third LC parallel resonator located in the multilayer body and magnetically coupled to each other. The first LC parallel resonator includes a first conductor, the second LC parallel resonator includes a second conductor, and the third LC parallel resonator includes a third conductor. The filter device further includes a connection conductor on a layer different from a layer on which the second conductor is located, a first via including one end connected to the first conductor and another end connected to the connection conductor, and a second via including one end connected to the third conductor and another end connected to the connection conductor. The connection conductor includes a first region that overlaps a portion of the second conductor in plan view of the multilayer body seen in a stacking direction.