Band-pass filter partition for waveguide mode suppression
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Solution Overview
Problem
Band-pass filters designed for quasi-millimeter and millimeter wave bands face degradation in attenuation characteristics due to unwanted resonance from the lowest-order waveguide mode and harmonic resonance mode, which are close to the passband, leading to poor performance in frequency regions above the passband.
Innovation Solution
Incorporating a partition within the band-pass filter that divides the space defined by the shield into smaller sections, allowing for shorter resonator lengths and higher resonance frequencies, thereby preventing degradation by the lowest-order waveguide and harmonic resonance modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resonator length is increased to achieve the desired passband frequency, then the passband performance is improved, but the space defined by the shield becomes larger, causing the lowest-order waveguide mode resonance frequency to decrease and degrade attenuation characteristics
Solution Approach 1:
The patent introduces a partition wall that divides the shielded space into multiple smaller sections. This segmentation reduces the effective space dimension, thereby increasing the resonance frequency of the lowest-order waveguide mode above the passband. The partition wall is electrically connected to the shield and extends in the direction intersecting the resonator length, effectively segmenting the cavity without interfering with the resonator operation.
2Measurement precision
If the resonator length is increased to achieve the desired passband frequency, then the passband performance is improved, but the harmonic resonance mode frequency decreases and degrades attenuation characteristics in the frequency region above the passband
Solution Approach 1:
The partition wall segments the shielded space, which increases the effective electrical length required for harmonic resonance modes. This segmentation raises the harmonic resonance mode frequencies above the passband, preventing them from causing attenuation degradation. The partition creates additional electrical boundaries that affect the standing wave patterns of harmonic modes.
3Object-affected harmful factors
If a partition is added to increase waveguide mode resonance frequency, then the attenuation characteristic is improved, but the device complexity increases
Solution Approach 1:
The partition wall is implemented as a thin conductive structure that is electrically connected to the shield. This thin-film approach minimizes the additional material and structural complexity while effectively achieving the desired electromagnetic separation. The partition can be formed as a thin conductor layer or mesh that provides the necessary electrical boundary without adding significant structural complexity.
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 raises the resonance frequency of the lowest-order waveguide mode and harmonic resonance mode, preventing attenuation characteristic degradation in the frequency region above the passband, thus enhancing the filter's performance.
Implementation Method 1
the shield and a dielectric material inside the shield constitute a structure similar to a waveguide, thereby generating at least one propagation mode for electromagnetic waves
Implementation Method 2
the waveguide mode produces unwanted resonance having a resonance frequency in a frequency region above the passband
Implementation Method 3
The resonance frequency of the lowest-order waveguide mode varies depending on the shape of the space defined by the shield. Typically, the larger the space, the lower the resonance frequency
Data Source
AI summary
A band-pass filter includes a main body formed of a dielectric, a plurality of resonators, a shield, and a partition formed of a conductor. Each of the plurality of resonators includes a resonator conductor portion. The resonator conductor portion has a first end and a second end opposite to each other in the longitudinal direction. The first end is connected to a ground, and the second end is open. The partition extends to pass through between the respective resonator conductor portions of two resonators, and is electrically connected to the shield.