Dielectric Filter Bandwidth via Conductor Positioning
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Solution Overview
Problem
Conventional dielectric filters face challenges in increasing fractional bandwidths, particularly in high-frequency bands required for 5G communication systems, where filters with large fractional bandwidths are necessary to manage increasing traffic and communication speed effectively.
Innovation Solution
The design of a dielectric filter with a resonator body and a surrounding dielectric portion, where the input/output conductor portion is strategically positioned to enhance electromagnetic coupling, reducing external Q and thereby increasing fractional bandwidth. This includes specific dimensions and orientations of the resonator and conductor components, as well as the use of a shield conductor portion to manage electromagnetic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional dielectric filter structures are used, then the filter can operate at high frequencies (10 GHz or higher), but the fractional bandwidth remains limited and cannot be increased sufficiently
Solution Approach 1:
The patent positions the input/output conductor portion in a specific spatial relationship with the resonator body, extending along a direction substantially perpendicular to the resonator's longitudinal axis. This dimensional arrangement allows the conductor to interact with multiple resonant modes simultaneously, thereby increasing the fractional bandwidth without adding complex internal structures to the resonator itself.
Solution Approach 2:
The surrounding dielectric portion is configured with specific local properties (different permittivity than the resonator body) in strategic locations around the resonator. This local differentiation of dielectric properties enables control over the electromagnetic field distribution, allowing bandwidth enhancement while maintaining a relatively simple overall filter structure.
2Quantity of substance
If the resonator body dimensions are increased to expand bandwidth, then the fractional bandwidth increases, but the external Q value increases which degrades filter performance
Solution Approach 1:
The input/output conductor portion acts as an intermediary element that couples the external circuit to the resonator body. By optimizing the conductor's position and dimensions, the patent achieves strong electromagnetic coupling that lowers the external Q value. This allows the resonator to maintain its original dimensions while still achieving increased fractional bandwidth through enhanced coupling mechanisms.
Solution Approach 2:
The patent optimizes specific parameters of the input/output conductor portion, including its length (0.05 to 0.2 times the resonator's longitudinal dimension), position (distance of 0.01 to 0.05 times the resonator's longitudinal dimension from the resonator surface), and cross-sectional dimensions. These parameter adjustments enable control over the coupling strength and external Q value while achieving the desired fractional bandwidth expansion.
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 solution effectively increases the fractional bandwidth of dielectric filters, improving their performance in high-frequency applications by reducing external Q and enhancing electromagnetic coupling between the conductor and resonator bodies.
Implementation Method 1
a surrounding dielectric portion present around the resonator body and formed of a dielectric material having a relative permittivity lower than that of the dielectric material used to form the resonator body
Implementation Method 2
an input/output conductor portion formed of a conductor and configured to perform at least one of supply of an electromagnetic wave to the resonator body and reception of an electromagnetic wave from the resonator body
Implementation Method 3
a resonator body formed of a dielectric material
Data Source
AI summary
A dielectric filter includes: a resonator body formed of dielectric material; surrounding dielectric portion present around the resonator body and formed of dielectric material having a relative permittivity lower than the dielectric material used to form the resonator body; and an input/output conductor portion formed of a conductor and configured to perform at least one supply of an electromagnetic wave to the resonator body and reception of an electromagnetic wave from the resonator body. The resonator body has a first end face and a second end face located at opposite ends in a first direction. The input/output conductor portion is located either at least part of the input/output conductor portion is contained in a space formed by shifting a virtual plane corresponding to the first end face in the first direction away from the second end face, or the input/output conductor portion is in contact with the space.