Band-Stop Antenna Feed Network for Compact Wi-Fi Isolation
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Solution Overview
Problem
Modern wireless access points face challenges in achieving efficient isolation between multiple antennas operating in different frequency bands due to the size constraints of compact form-factors and interference from parasitic radiation, with existing filters being costly and large in size, and deploying multiple filters further complicates the task.
Innovation Solution
The proposed antenna design incorporates a narrowband band-stop filter with conducting line resonators that filter specific frequency bands, providing a low-cost, compact, and efficient solution with a steep-slope band rejection, suitable for wireless communication devices like Wi-Fi access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filters are used to achieve frequency band isolation, then filtering performance is improved, but the filter size becomes large and cost increases
Solution Approach 1:
The patent changes the fundamental parameter of the filter structure by using a conducting line resonator with length equal to an integer multiple of quarter wavelength of the stopband frequency, rather than conventional filter designs. This parameter change enables compact size while maintaining effective frequency band isolation
Solution Approach 2:
The patent replaces conventional mechanical filter structures with an electromagnetic resonator-based filter. The conducting line resonator utilizes electromagnetic resonance at specific frequencies to achieve band-stop filtering, substituting traditional mechanical filter components with an electromagnetic field-based solution that is more compact
2Adaptability or versatility
If multiple filters are deployed to handle different polarizations, then filtering coverage is improved, but device complexity increases
Solution Approach 1:
The patent designs the conducting line resonator filter to be polarization-independent, enabling a single filter structure to handle both vertical and horizontal polarizations effectively. This universal design eliminates the need for separate filters for different polarizations, reducing device complexity while maintaining comprehensive polarization coverage
Solution Approach 2:
The patent segments the filtering function into frequency-based isolation rather than polarization-based isolation. By using a conducting line resonator that creates deep nulls at specific frequency bands, the filter achieves isolation through frequency selectivity rather than requiring separate filters for each polarization, simplifying the overall system architecture
3Reliability
If conventional coupled line filters are used, then filtering function is achieved, but parasitic radiation increases reducing isolation performance
Solution Approach 1:
The patent converts the potential harmful effect of the conducting line resonator into a beneficial filtering mechanism. By carefully designing the resonator length as an integer multiple of quarter wavelength, the patent creates constructive interference at stopband frequencies to produce deep nulls, while the same structure inherently suppresses parasitic radiation through its resonant characteristics
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 enhances isolation between antennas, allowing multiple radios to coexist efficiently within the same device by effectively rejecting unwanted frequency bands, thereby improving performance and reducing interference.
Implementation Method 1
The conducting line resonator is configured to filter the input signal in at least one stopband and has a length that is an integer multiple of the quarter wavelength of a stopband frequency
Data Source
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AI summary
An antenna for a wireless communication device, in particular a wireless access point is disclosed. The antenna comprises at least one radiating element configured to radiate electromagnetic radiation in response to an input signal, wherein the input signal extends over an operating frequency band, a feeding network configured to feed the input signal from an input port of the feeding network to the at least one radiating element for driving the at least one radiating element with the input signal to radiate electromagnetic radiation and a narrowband band-stop filter configured to filter the input signal. The narrowband band-stop filter comprises a conducting line resonator coupled to the feeding network, wherein the conducting line resonator is configured to filter the input signal in at least one stopband of the operating frequency band and has a length that is an integer multiple of the quarter wavelength of a stopband frequency.