Rectangular Waveguide Notch Filter With Narrow Cavity Section
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Solution Overview
Problem
Notch filters with cavities in waveguides struggle to efficiently remove high-frequency electromagnetic waves, leading to noise interference due to their design, which allows high-frequency waves to pass through while inadequately blocking target frequencies.
Innovation Solution
A rectangular waveguide with a narrow path portion and cavities protruding perpendicular to the E plane, where the dimensions of the short sides are reduced to enhance the removal of specific frequency bands, stabilizing the transmission of target frequencies and improving attenuation of higher frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional waveguide with cavity is used to remove specific frequency electromagnetic waves, then the structure is simple and easy to manufacture, but high-frequency electromagnetic waves pass through efficiently causing noise interference and the target frequency removal is inefficient
Solution Approach 1:
The waveguide cross-section is divided into two distinct regions: a first cross-section with larger dimensions for the input/output portions, and a second cross-section with smaller dimensions for the intermediate portion where the cavity is located. This local variation in geometry creates different electromagnetic field distributions in different sections, enabling the intermediate section to effectively trap high-frequency waves while the input/output sections maintain good signal coupling.
Solution Approach 2:
The patent changes the geometric parameters of the waveguide cross-section along its length. Specifically, the width and height of the waveguide are reduced in the intermediate portion compared to the input and output portions. This parameter change modifies the cutoff frequency and field distribution, creating a region that is particularly effective at trapping electromagnetic waves at the target frequency while attenuating high-frequency noise.
2Stability of the object's composition
If the waveguide dimensions are optimized for a specified frequency band, then the specified frequency passes through stably, but high-frequency waves beyond the specified band are not effectively attenuated
Solution Approach 1:
The waveguide is segmented into three functional sections: an input section with larger cross-section for signal coupling, an intermediate section with smaller cross-section for frequency-selective trapping, and an output section with larger cross-section for signal extraction. This segmentation allows each section to perform its specific function optimally while working together to achieve both stable transmission of the specified frequency band and effective attenuation of higher frequencies.
Solution Approach 2:
The patent introduces variation in the cross-sectional dimensions of the waveguide along its length, adding a spatial dimension to the frequency selection mechanism. By changing the width and height of the waveguide cross-section in the intermediate portion, the patent creates a three-dimensional structure that provides both stable transmission characteristics for the specified frequency and enhanced attenuation for higher frequencies through modified field confinement.
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 configuration significantly improves the efficiency of removing specific frequency bands by stabilizing the transmission of target frequencies and attenuating higher frequencies, effectively functioning as a notch filter with enhanced performance.
Implementation Method 1
A cavity corresponding to a frequency of the electromagnetic wave that is to be removed is mounted to such a waveguide. This cavity serves to trap the electromagnetic wave
Implementation Method 2
The waveguide is configured to allow only an electromagnetic wave of a specified frequency to pass therethrough, according to the shape of an opening formed therein
Data Source
AI summary
The present disclosure aims to improve the performance of a notch filter using a rectangular waveguide and a cavity. A notch filter has a rectangular opening that is formed in an end face thereof. Inside of the notch filter, a waveguide is connected with circular cavities and by connecting pipes. In a planar shape of the waveguide, from an inlet side thereof, a wide path portion, a tapered portion and a narrow path portion are formed and are further connected with a tapered portion and a wide path portion. The circular cavities and designed according to the frequency of the electromagnetic wave that is to be trapped are provided in the middle of the narrow path portion. The configuration of decreasing the width of the waveguide in a location where the circular cavities are provided improves the performance of removal of the electromagnetic wave by the circular cavities.