Electromagnetic Wave Filter With Stub Conductors for Antenna Radiation Preservation
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Solution Overview
Problem
Existing electromagnetic wave filter apparatuses fail to maintain antenna radiation characteristics while suppressing undesired noise radiation, particularly at specific frequencies, leading to degradation in radiation patterns and increased interference.
Innovation Solution
An electromagnetic wave filter apparatus comprising a ground conductor with strip conductors and bandstop filters, where the bandstop filters are open-circuited stub conductors configured to block specific frequencies, maintaining radiation characteristics by preventing current flow at predetermined frequencies and reducing low-frequency noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield structure is used to suppress undesired electromagnetic wave radiation, then noise radiation is reduced, but the radiation pattern of the antenna is degraded
Solution Approach 1:
The shield structure is segmented into multiple frequency-selective screen portions, each with apertures of different sizes and configurations. This segmentation allows different frequency ranges to be filtered independently, enabling suppression of undesired radiation while preserving the desired radiation pattern at operating frequencies.
Solution Approach 2:
Different regions of the shield structure are assigned different aperture characteristics. The frequency-selective screen portions have locally optimized aperture sizes, shapes, and distributions tailored to specific frequency ranges, allowing selective suppression of noise frequencies while maintaining transmission characteristics at the antenna operating frequency.
2Object-affected harmful factors
If the aperture width is reduced to improve noise blocking, then low-frequency noise suppression is enhanced, but the antenna gain is reduced
Solution Approach 1:
The aperture structure is divided into multiple frequency-selective screen portions with different aperture dimensions. Smaller apertures are used for blocking low-frequency noise, while larger apertures or differently configured apertures are used to maintain antenna gain at the operating frequency, thus segmenting the frequency filtering function across different aperture types.
Solution Approach 2:
The aperture parameters (width, length, shape, distribution) are changed across different frequency-selective screen portions to achieve frequency-selective filtering. By varying these parameters, the shield structure can suppress low-frequency noise while maintaining adequate aperture size for desired signal transmission and antenna gain.
3Object-affected harmful factors
If a conventional shield structure is used, then electromagnetic wave blocking is achieved, but the radiation characteristics change from the original design
Solution Approach 1:
The shield structure incorporates frequency-selective screen portions with apertures specifically designed to maintain transmission characteristics at the antenna operating frequency. These locally optimized regions ensure that the desired radiation characteristics are preserved while other frequency ranges are blocked.
Solution Approach 2:
The aperture parameters are carefully selected and optimized to maintain the radiation characteristics at the operating frequency while providing blocking at other frequencies. By changing aperture size, shape, and distribution parameters in a controlled manner, the shield structure achieves frequency selectivity without degrading the intended radiation pattern.
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 maintains radiation characteristics and suppresses low-frequency noise, preventing interference and ensuring reliable communication without degrading the antenna's radiation pattern, thus enhancing communication equipment performance.
Implementation Method 1
each of the bandstop filters prevents a current with the predetermined frequency from flowing through a corresponding strip conductor due to an electromagnetic wave with the predetermined frequency passing through the electromagnetic wave filter apparatus
Data Source
AI summary
An electromagnetic wave filter apparatus includes: a shield conductor; a shield aperture provided in the shield conductor; a plurality of strip conductors, each of which is connected to the shield conductor at both ends thereof, and which divide the shield conductor into a plurality of apertures; and a plurality of stub conductors provided at intervals on each of the strip conductors. Each of the stub conductors prevents a current with a predetermined frequency from flowing through a corresponding strip conductor due to an electromagnetic wave with the predetermined frequency passing through the electromagnetic wave filter apparatus. Thus, the electromagnetic wave filter apparatus passes the electromagnetic wave with the predetermined frequency without exerting a substantial influence on radiation of the electromagnetic wave with the predetermined frequency.