Multilayer Bandpass Filter Layout for Coupling and Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing band pass filters with multistage LC parallel resonators face limitations in adjusting coupling degrees and freedom due to narrow resonator intervals, leading to decreased attenuation characteristics and isolation between input and output terminals.
Innovation Solution
A filter device with a configuration of two filters connected by main and sub-paths, utilizing magnetic and electric field couplings between resonators, and adjusting coupling through ground vias, to enhance attenuation characteristics in non-pass bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resonators are arranged sequentially with more resonators to improve attenuation characteristics, then the number of resonators increases, but the interval between resonators becomes narrower limiting coupling adjustment range
Solution Approach 1:
The patent introduces a sub-path that bypasses some resonators (jump coupling between resonators separated by one or more resonators), adding a dimensional aspect to the signal transmission path. This allows coupling adjustment without requiring narrow intervals between adjacent resonators, resolving the contradiction between having more resonators for attenuation and maintaining adjustment range.
2Area of stationary object
If input terminal and output terminal are disposed adjacent to each other to compact the structure, then device size is reduced, but isolation between input and output terminals decreases
Solution Approach 1:
The patent divides the filter into two separate filter sections (first filter with resonators R1-R4 and second filter with resonators R5-R8) connected in cascade. This segmentation allows the input and output terminals to be positioned at opposite ends of the cascaded structure, improving isolation while maintaining compact overall size through the shared resonator coupling mechanism.
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
Improves attenuation characteristics in non-pass bands by adding attenuation poles, increasing design freedom, and enhancing isolation between input and output terminals.
Implementation Method 1
The first inductor circuit and the second inductor circuit are magnetically coupled, the second inductor circuit and the third inductor circuit are magnetically coupled, and the third inductor circuit and the fourth inductor circuit are magnetically coupled
Implementation Method 2
first to third capacitor circuits, a first capacitor, and a second capacitor
Implementation Method 3
band pass filter having a multistage configuration of a plurality of LC parallel resonators
Data Source
AI summary
A filter device includes a multilayer body, an input terminal, an output terminal, a first filter including first resonators, and a second filter including second resonators. In the first filter, a signal from the input terminal is transmitted to the second filter through the first resonators. In the second filter, the signal from the first filter is transmitted to the output terminal through the second resonators. Jump coupling is formed between one of the first resonators and one of the second resonators. One main coupling of the coupling between a first pair of the first and second resonators and the coupling between a second pair of the first and second resonators is magnetic coupling, and the other main coupling is electric field coupling.