Multiband Antenna Resolving Size and Bandwidth Trade-off
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Solution Overview
Problem
Conventional antennas in communications terminals, such as inverted F antennas and ring antennas, typically support only a few frequency bands, necessitating multiple antennas to accommodate various communication frequencies, which increases the terminal's size and deviates from miniaturization trends.
Innovation Solution
A multiband antenna design featuring a high-frequency radiator and a low-frequency radiator, where the high-frequency radiator has an electrical length of half a wavelength and shares routing with a ring radiator, allowing the communications terminal to operate across multiple frequency bands without increasing the number of antennas, by utilizing a printed circuit board with conductive and non-conductive areas and connecting the radiators in specific configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the quantity of antennas is increased to support multiple frequency bands, then the frequency band coverage is improved, but the size of the communications terminal increases
Solution Approach 1:
The patent combines multiple antenna functions into a single integrated antenna structure. The antenna includes a first antenna element with first and second arms, a second antenna element with third and fourth arms, and a third antenna element with fifth and sixth arms, all sharing common feeding and grounding structures. This merging of multiple antenna elements into one unified structure enables support for multiple frequency bands while maintaining a compact terminal size, directly resolving the contradiction between frequency band coverage and terminal size.
Solution Approach 2:
The single antenna structure is designed to perform multiple functions by supporting operation across different frequency bands. The antenna elements are configured with specific electrical lengths and impedance characteristics that enable them to resonate at multiple frequencies, making the antenna universal for various communication standards and frequency bands, thereby eliminating the need for multiple separate antennas.
2Volume of moving object
If conventional IFA or ring antennas are used, then the terminal size is kept compact, but the number of supported working frequency bands is limited
Solution Approach 1:
The antenna is segmented into multiple independent antenna elements (first, second, and third antenna elements) with distinct arm configurations. Each element can be optimized for specific frequency ranges while working together as a unified structure. The first antenna element with its two arms, the second antenna element with its two arms, and the third antenna element with its two arms provide segmented functionality that collectively achieves broad frequency coverage within a compact form factor.
Solution Approach 2:
The patent employs planar inverted-F antenna (PIFA) structures that utilize the surface area of the printed circuit board in two dimensions. The antenna elements are arranged in a planar configuration with arms extending in different directions, effectively using the available board space to achieve multiple resonant frequencies without increasing the terminal's three-dimensional volume.
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
Enables the communications terminal to support multiple frequency bands while maintaining a compact size, enhancing its operational bandwidth and reducing interference, thus aligning with miniaturization trends.
Implementation Method 1
a high-frequency radiator working at a high frequency band of 1710 MHz-2690 MHz, and a low-frequency radiator working at a low frequency band of 698 MHz-960 MHz
Implementation Method 2
an electrical length between the two ends of the high-frequency radiator is half of a wavelength of the high frequency band
Data Source
Figure 1~2
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Figure 5~6
AI summary
Embodiments of the present invention provide a multiband antenna, including a feed point, a ground point, a high-frequency radiator working at a high frequency band, and a low-frequency radiator working at a low frequency band. One end of the high-frequency radiator is electrically connected to the feed point, the other end of the high-frequency radiator is electrically connected to the ground point, and an electrical length between the two ends of the high-frequency radiator is half of a wavelength of the high frequency band; the high-frequency radiator is connected, in a first position, to the low-frequency radiator, and a length from the first position to the feed point is less than a length from the first position to the ground point.