Bandpass Filter With Three Resonators For Wide Frequency Band
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Solution Overview
Problem
Existing bandpass filters face limitations in using wide frequency bands and have a small degree of freedom in designing passbands, as they typically rely on two or three resonance peaks formed by even-mode and odd-mode resonance, which restricts their application in wireless communication devices.
Innovation Solution
A bandpass filter design incorporating a laminated body with dielectric layers, strip-shaped resonance electrodes, and coupling electrodes that allow for electromagnetic coupling between resonators, enabling the formation of three resonance peaks with adjustable frequencies, thereby expanding the frequency band and design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bandpass filter uses two resonance peaks (even-mode and odd-mode resonance) to form a passband, then the filter structure is simple, but the frequency band coverage is limited
Solution Approach 1:
The filter is divided into multiple independent resonators (first, second, and third resonators with different resonance frequencies) that can be independently designed and adjusted. Each resonator is formed by separate resonance electrodes (31a, 31b, 31c) that can be individually tuned to specific frequencies, allowing the passband to cover a wider frequency range by combining multiple resonance peaks rather than relying on a single even-mode or odd-mode resonance structure
Solution Approach 2:
The invention transitions from a two-dimensional resonance structure (even-mode and odd-mode in the same plane) to a three-dimensional configuration by stacking resonators at different interlayers (first interlayer for resonators 1 and 3, second interlayer for resonator 2). This vertical arrangement allows independent frequency tuning of each resonator while maintaining compact horizontal footprint, thereby expanding frequency band coverage without proportionally increasing device area
2Adaptability or versatility
If a bandpass filter uses three resonance peaks to expand frequency band, then the frequency band coverage increases, but the degree of freedom in designing passband decreases
Solution Approach 1:
The filter design incorporates adjustable and reconfigurable elements including variable capacitors and inductors within each resonator circuit, allowing the resonance frequencies of the three resonators to be dynamically tuned. The electromagnetic coupling coefficients between resonators can also be adjusted by changing the position and orientation of coupling electrodes, providing dynamic control over passband characteristics and maintaining high design flexibility despite using three resonators
Solution Approach 2:
The invention provides preliminary design configurations with standardized interlayer arrangements and pre-defined coupling electrode positions that simplify the passband design process. By establishing predetermined geometric relationships between resonators at different interlayers, designers can achieve desired passband characteristics through parameter optimization rather than complex structural redesign, thus maintaining ease of design while utilizing three resonance peaks
3Area of stationary object
If resonance electrodes are arranged in the same interlayer, then the filter structure is compact, but the electromagnetic coupling between resonators is insufficient
Solution Approach 1:
The filter structure nests resonators at different interlayers vertically, with the second resonator positioned between the first and third resonators in the stacking direction. This nested arrangement allows strong electromagnetic coupling between adjacent resonators (first-second and second-third) while maintaining a compact horizontal footprint. The coupling electrodes extend vertically across interlayers to establish reliable electromagnetic connections without requiring large lateral spacing
Solution Approach 2:
Coupling electrodes serve as intermediary elements that facilitate electromagnetic coupling between resonators separated by dielectric layers. These coupling electrodes are positioned at strategic locations to maximize coupling efficiency while maintaining compact dimensions. The intermediary coupling structure enables reliable electromagnetic interaction without requiring direct contact or large spacing between resonator elements
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 achieves a wide frequency band operation with enhanced design flexibility, allowing for the formation of a passband using three resonance peaks, which improves transmission characteristics and reduces attenuation poles outside the passband, enhancing performance in wireless communication devices.
Implementation Method 1
first to third resonance electrodes sequentially arranged side-by-side, as viewed in the stacking direction, on the same interlayer or different interlayers of the laminated body such that the first to third resonance electrodes are electromagnetically coupled to each other
Implementation Method 2
first to third resonators... having different resonance frequencies from each other, and used to produce a passband
Data Source
AI summary
[Object] An object is to provide a bandpass filter that can be used for a wide frequency band and has a large degree of freedom in designing a passband, and a wireless communication module and a wireless communication device that use the bandpass filter.[Solution] A bandpass filter includes first to third resonance electrodes 31a, 31b, and 31c sequentially arranged side-by-side such that they are electromagnetically coupled to each other, the first to third resonance electrodes 31a, 31b, and 31c being grounded at one end and constituting first to third resonators, respectively; a first input/output coupling electrode 40a facing the first resonance electrode 31a and electromagnetically coupled thereto; a second input/output coupling electrode 40b facing the second resonance electrode 31b and electromagnetically coupled thereto; and a resonator coupling electrode 43 configured to provide electromagnetic coupling between the first resonance electrode 31a and the third resonance electrode 31c. The first and second resonators have the same resonance frequency which is different from a resonance frequency of the third resonator. The first to third resonators are used to produce a passband. The bandpass filter can be used for a wide frequency band and has a large degree of freedom in designing the passband.