Multi-Band Antenna Circuit With Harmonic Filtering
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Solution Overview
Problem
Existing antenna designs struggle to provide simultaneous access to multiple standard frequency bands, particularly the 698-960 MHz band, due to their narrow bandwidth and mutual interference issues when trying to cover extended frequency ranges.
Innovation Solution
An antenna circuit comprising multiple antennas tuned to different fundamental frequencies, each with its own filter to attenuate unwanted frequency components, and a passive recombination element to combine these filtered paths into a single feed, ensuring isolation and efficient coverage of multiple bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna is used to cover multiple frequency bands, then the device complexity is reduced, but the bandwidth coverage remains narrow and cannot simultaneously cover all standard bands
Solution Approach 1:
The patent divides the antenna system into multiple independent antenna elements (first antenna, second antenna, etc.), each tuned to different fundamental frequencies. This segmentation allows each antenna to specialize in specific frequency bands while collectively covering all required bands simultaneously, resolving the contradiction between simple device structure and broad frequency coverage.
Solution Approach 2:
The patent creates a universal antenna circuit that can simultaneously operate across all standard frequency bands (698-960 MHz, 1710-1990 MHz, 2110-2170 MHz, and LTE bands) by combining multiple antennas with different resonant frequencies. The system achieves multi-functionality where a single antenna circuit serves multiple frequency bands that would otherwise require separate antenna systems.
2Adaptability or versatility
If multiple antennas are used to cover extended frequency ranges, then the bandwidth coverage is improved, but mutual interference occurs between antennas
Solution Approach 1:
The patent introduces filters as intermediary components between multiple antennas and the common feed. Each filter is configured to pass only the fundamental frequency and harmonics of its associated antenna while attenuating other frequencies. This intermediary filtering mechanism prevents mutual interference between antennas by selectively allowing only desired frequency components to reach the common feed.
Solution Approach 2:
The patent applies local quality by giving each antenna-filter path unique characteristics tailored to its specific frequency band. Each filter is customized to match its associated antenna's fundamental frequency, creating localized frequency selectivity that prevents interference while maintaining optimal performance for each band.
3Adaptability or versatility
If antenna tuning circuits are used to modify matching over larger frequency bands, then the bandwidth is extended, but the narrow-band nature of the antenna is not changed and all frequencies cannot be covered simultaneously
Solution Approach 1:
Instead of using a single tuning circuit to attempt broad coverage, the patent segments the system into multiple independent antenna elements, each optimized for specific frequency bands. This segmentation allows simultaneous operation across all bands without the trade-offs inherent in single-antenna tuning approaches.
Solution Approach 2:
The patent merges multiple narrow-band antenna systems into a single multi-band system by combining them through a common feed with filtering. This merging approach maintains the reliability of each individual antenna's narrow-band performance while achieving broad simultaneous frequency coverage that neither antenna could achieve alone.
4Adaptability or versatility
If the fundamental frequency is lowered to cover the 698-960 MHz band, then the frequency coverage is improved, but the antenna arm size becomes oversized and integration into mobile phones becomes problematic
Solution Approach 1:
The patent segments the low-frequency coverage requirement from the physical antenna structure by using harmonic frequencies. Instead of requiring a physically large antenna for low fundamental frequencies, the system uses higher-frequency antennas operating at their harmonic modes to achieve equivalent low-frequency coverage, maintaining compact dimensions while covering the 698-960 MHz band.
Solution Approach 2:
The patent changes the operational parameter of the antennas from fundamental frequency operation to harmonic frequency operation for low-band coverage. By utilizing the second or third harmonics of higher-frequency antennas, the system achieves coverage of the 698-960 MHz band without requiring physically oversized antenna elements, thus maintaining mobile phone integration feasibility.
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
This solution allows for simultaneous access to all standard frequency bands, including the challenging 698-960 MHz band, with improved bandwidth coverage and reduced mutual interference, enabling effective operation across a wider range of frequencies.
Implementation Method 1
a first filter having a first terminal connected to the first antenna, and configured to attenuate the frequency components outside of a band defined by the first fundamental frequency or its harmonics
Implementation Method 2
a first passive recombination element coupling the second terminals of the two filters to a first common terminal
Data Source
AI summary
An antenna circuit includes a first antenna tuned to a first fundamental frequency and a second antenna tuned to a second fundamental frequency different from the first fundamental frequency. A first filter has a first terminal connected to the first antenna and attenuates the frequency components outside of a band defined by the first fundamental frequency or its harmonics. A second filter has a first terminal coupled to the second antenna and attenuates the frequency components outside of a band defined by the second fundamental frequency or its harmonics. A passive recombination element couples the second terminals of the two filters to a common terminal.