Compact Resonator With Local Dielectric Concentration
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Solution Overview
Problem
Conventional resonators face challenges in miniaturization, leading to deterioration in electrical characteristics such as decreased resonant frequency and Q value, particularly when attempting to shrink size by filling the shield case with a dielectric body or placing a dielectric body between the columnar conductor and the shield case.
Innovation Solution
A compact resonator design featuring a shield conductor with a cavity, a columnar body, and a dielectric body, where the columnar body is positioned inside the cavity and surrounded by the dielectric body, maintaining a significant clearance to prevent sharp decreases in resonant frequency and Q value, while allowing for miniaturization without compromising electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the shield case is filled with a dielectric body or a dielectric body is placed between the columnar conductor and the shield case to miniaturize the resonator, then the size is reduced, but the resonant frequency and Q value sharply decrease
Solution Approach 1:
The dielectric body is positioned only in the lower portion of the resonator with a specific height ratio (0.2 ≤ h1/H ≤ 0.8), creating local dielectric concentration rather than full filling. This localized approach provides miniaturization benefit while controlling the impact on resonant frequency and Q value
Solution Approach 2:
The invention optimizes the height ratio parameter (h1/H) of the dielectric body to achieve the best balance between miniaturization and electrical characteristics. By adjusting this critical parameter, the resonator achieves compact size while maintaining acceptable resonant frequency and Q value
2Volume of moving object
If the resonator is miniaturized by filling with dielectric material, then the volume is reduced, but the difference between fundamental-mode and higher-order mode resonant frequencies decreases
Solution Approach 1:
Partial filling with dielectric material in the lower portion creates asymmetric field distribution that helps maintain frequency separation between modes while achieving miniaturization
Solution Approach 2:
The invention introduces the height ratio dimension (h1/H) as a new design parameter to control the three-dimensional distribution of the dielectric body, enabling independent optimization of volume reduction and mode frequency separation
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 design achieves a compact resonator with excellent electrical characteristics, including a distinct difference between fundamental-mode and higher-order mode resonant frequencies and high Q values, facilitating both miniaturization and high-yield manufacturing.
Implementation Method 1
a dielectric body 12, wherein the dielectric body 12 surrounds a predetermined portion of the columnar body 21
Implementation Method 2
a resonator comprising: a shield conductor 10; a columnar body 21 having a columnar shape, placed inside a cavity 19 of the shield conductor 10, joined to a first conductor 13, and having an end in a positive z-direction positioned apart from the shield conductor 10
Data Source
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AI summary
There are provided a compact resonator having excellent electrical characteristics, and a filter and a communication device that employ the resonator. A resonator includes a shield conductor (10), a columnar body (21), and a first dielectric body (12). The shield conductor (10) includes a first conductor (13) located on a negative z-direction side and a second conductor (14) located on a positive z-direction side, and has a cavity (19) therein. The columnar body (21) is composed of a dielectric body or a conductor and has a columnar shape, and is placed inside the cavity (19), an end in the negative z-direction thereof being joined to the first conductor (13), an interval being provided between an end in the positive z-direction of the columnar body and the shield conductor (10). The first dielectric body (12) is placed inside the cavity (19), an end in the positive z-direction thereof being joined to the second conductor (14), an interval being provided between an end in the negative z-direction of the first dielectric body and the shield conductor (10), the first dielectric body surrounding the columnar body (21) so as to be apart from each other.