Balanced Band-Pass Filter With Asymmetric Resonator Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional balanced band-pass filters struggle to form abrupt attenuation poles in specific frequency ranges while maintaining balance characteristics, particularly in fifth-generation mobile communication systems.
Innovation Solution
A balanced band-pass filter configuration with an unbalanced port and a pair of balanced ports, utilizing first to third resonators with specific electromagnetic couplings and capacitive connections, including magnetic and capacitive couplings between resonators, to create abrupt attenuation poles in designated frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional balanced band-pass filters are used, then balance characteristics are maintained, but abrupt attenuation poles cannot be formed in specific frequency ranges
Solution Approach 1:
The patent applies asymmetry by configuring the resonators in a non-symmetric arrangement where the first resonator has a different coupling relationship with the second and third resonators compared to their mutual coupling. Specifically, the first resonator is coupled to the second resonator with a first coupling coefficient and to the third resonator with a second coupling coefficient, where these coefficients are deliberately made different to create the desired attenuation pole characteristics while maintaining overall balance performance
Solution Approach 2:
The patent utilizes parameter changes by adjusting the coupling coefficients between resonators and the resonant frequencies of individual resonators. By controlling the coupling coefficients (k12, k13, k23) and resonant frequencies (f1, f2, f3) as independent parameters, the design achieves both abrupt attenuation poles at specific frequencies and good balance characteristics across the operating band
2Manufacturing precision
If abrupt attenuation poles are formed in vicinity ranges, then frequency selectivity is improved, but balance characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating different coupling characteristics in different parts of the filter structure. The first resonator is designed with asymmetric coupling to the second and third resonators, where the coupling strength and frequency response are locally optimized to form attenuation poles. This localized asymmetric coupling does not degrade the overall balance characteristics because the asymmetry is confined to specific coupling paths rather than affecting the entire filter structure uniformly
3Manufacturing precision
If multiple resonators with complex coupling are used, then attenuation pole formation is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the filter into three distinct resonator units (first, second, and third resonators) that can be independently designed and optimized. Each resonator is configured with specific resonant frequency and coupling characteristics, allowing the complex attenuation pole formation to be achieved through modular assembly of simpler individual components rather than a single complex resonant structure
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 proposed filter design effectively forms abrupt attenuation poles in both lower and higher vicinity ranges relative to the pass band, while ensuring good amplitude and phase balance characteristics, enhancing its performance in mobile communication systems.
Implementation Method 1
The second resonator and the third resonator are adjacent to each other in the circuit configuration, and electromagnetically coupled by magnetic coupling as main coupling
Implementation Method 2
The first resonator is provided closer to the second resonator than to the third resonator in the circuit configuration, and jump-coupled to the third resonator
Data Source
AI summary
A band-pass filter includes an unbalanced port, a first balanced port, a second balanced port, and first to third resonators provided between the unbalanced port and the first and second balanced ports. The second resonator and the third resonator each are a resonator with both ends open. The second resonator and the third resonator are adjacent to each other in a circuit configuration, and electromagnetically coupled by magnetic coupling as main coupling. The first resonator is provided closer to the second resonator than to the third resonator, and jump-coupled to the third resonator.