Dielectric Cavity Notch Filter Using Second-Order TE Mode
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Solution Overview
Problem
Existing band stop filters face challenges in achieving deep notch attenuation, high quality factor, temperature stability, and compact size, which are crucial for applications in systems like radar and communication systems.
Innovation Solution
A dielectric cavity band stop filter is designed with a dielectric cavity resonator magnetically coupled to a transmission line through a coupling aperture, exciting the resonator in a second order transverse electric (TE) mode, using ceramic material for high dielectric constant and quality factor, and optimized dimensions for resonance frequency, allowing for deep notch attenuation and narrow band rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric cavity resonator is used to achieve deep notch attenuation and high quality factor, then the filter performance is improved, but the device size increases
Solution Approach 1:
The patent changes the excitation mode parameter from fundamental mode to second-order TE mode, which fundamentally alters the resonance characteristics. This parameter change enables the resonator to achieve the same quality factor with a significantly reduced physical volume, directly resolving the contradiction between filter performance and device size
Solution Approach 2:
The patent utilizes the coupling aperture positioned at a specific location on the resonator surface to excite the second-order TE mode. This spatial dimensionality approach allows selective mode excitation that achieves deep notch attenuation while maintaining compact dimensions, effectively resolving the size-performance tradeoff
2Volume of moving object
If the resonator dimensions are reduced to achieve compact size, then the device volume decreases, but the temperature stability and quality factor deteriorate
Solution Approach 1:
By changing the excitation mode to second-order TE mode, the patent achieves a different relationship between physical dimensions and resonant properties. This parameter change allows the resonator to maintain high quality factor and temperature stability even at reduced dimensions, as the higher-order mode provides better field confinement and less sensitivity to dimensional variations
Solution Approach 2:
The patent replaces the traditional fundamental mode resonance mechanism with a second-order TE mode resonance mechanism. This substitution fundamentally changes how the resonator stores and releases energy, enabling compact dimensions while preserving temperature stability and quality factor through the unique field distribution characteristics of the higher-order mode
3Manufacturing precision
If a coupling aperture is used to magnetically couple the resonator to the transmission line, then the selectivity is improved, but the device complexity increases
Solution Approach 1:
The patent extracts only the essential coupling function by using a simple aperture in the resonator surface, eliminating the need for complex coupling structures. This extracted coupling mechanism achieves high selectivity through the second-order TE mode excitation while keeping the overall device complexity low, as the aperture is a straightforward structural feature rather than a complex assembly
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 achieves a deep notch attenuation, high selectivity, and temperature stability, enabling effective signal rejection across a wide frequency range while maintaining a compact size, suitable for integrated circuits and circuit boards.
Implementation Method 1
a coupling aperture configured to magnetically couple the dielectric cavity resonator to the transmission line
Implementation Method 2
The waves are confined by a discontinuity in permittivity at boundaries of the resonator
Implementation Method 3
Resonators resonate at a frequency determined by the overall physical dimensions of the resonator and the dielectric constant
Implementation Method 4
Resonators can be used to control the frequency of EM waves and bandpass filters among other applications
Data Source
AI summary
A band stop filter can include a circuit board having a first surface and an opposing second surface. The circuit board can have a transmission line on the first surface. The band stop filter can include a dielectric cavity resonator physically coupled to the second surface of the circuit board. The dielectric cavity resonator can have a coupling aperture configured to magnetically couple the dielectric cavity resonator to the transmission line, and to cause excitation of the dielectric cavity resonator in a second order transverse electric (TE) mode.