Looped Antenna with Nested Ground for Wideband MIMO
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Solution Overview
Problem
Current antenna designs for mobile devices face challenges in achieving both multiband operation and size reduction while maintaining high radiation efficiency, especially with strong electromagnetic coupling between antennas, which degrades transmission rates and requires a wide operating bandwidth.
Innovation Solution
The antenna apparatus features a looped radiation conductor with a capacitor and inductor positioned along its loop, where the distance between the radiation conductor and ground conductor increases from a feed point, forming resonant circuits at different frequencies to achieve dual-band operation with an ultra-wide bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the antenna size is reduced to increase distance among antennas, then electromagnetic coupling is reduced, but radiation efficiency degrades
Solution Approach 1:
The patent embeds a ground conductor within the looped radiation conductor structure. The ground conductor is positioned inside the loop, creating a nested configuration where the ground conductor and radiation conductor form an integrated resonant structure. This nesting allows the antenna to maintain compact size while achieving proper impedance matching and radiation efficiency through the coupled resonant modes of the nested structures.
Solution Approach 2:
The patent transitions from a planar two-dimensional antenna layout to a three-dimensional configuration by positioning the ground conductor in space within the loop formed by the radiation conductor. This spatial arrangement in the third dimension enables the antenna to achieve desired electrical characteristics and reduce coupling effects without simply increasing planar dimensions.
2Productivity
If multiple antennas are used for MIMO to increase transmission rate, then spatial division multiplexing is achieved, but electromagnetic coupling among antennas increases
Solution Approach 1:
The ground conductor nested within the looped radiation conductor creates a compact MIMO antenna structure where multiple antennas can be closely positioned without excessive coupling. The nested configuration provides natural isolation between adjacent antennas while maintaining small overall dimensions suitable for mobile devices requiring high data transmission rates.
3Volume of moving object
If looped radiation element is formed on dielectric or magnetic block to reduce size, then multiple bands operation is achieved, but impedance decreases and radiation characteristics degrade
Solution Approach 1:
The patent extracts the ground conductor from a traditional dielectric or magnetic block substrate and positions it freely within the loop formed by the radiation conductor. This extraction eliminates the negative impedance effects associated with dielectric/magnetic blocks while maintaining the compact loop structure. The ground conductor is held in position by a support structure rather than being embedded in a block, thereby improving radiation characteristics.
4Volume of moving object
If capacitance is formed by bringing open end close to feeding portion to achieve multiband operation, then size is reduced, but Q value becomes high and bandwidth is limited
Solution Approach 1:
The patent segments the traditional single-loop structure by introducing a ground conductor that divides the current path into multiple segments. This segmentation creates multiple resonant modes within the same physical structure, enabling wideband operation. The looped radiation conductor and nested ground conductor together form a multi-segment resonant system that achieves ultra-wide bandwidth without increasing overall antenna size.
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 configuration allows for a compact, efficient antenna that operates in multiple bands with reduced electromagnetic coupling, enhancing transmission rates and supporting a wide frequency range.
Implementation Method 1
forming resonant circuits at different frequencies to achieve dual-band operation
Implementation Method 2
the distance between the radiation conductor and ground conductor increases from a feed point
Data Source
AI summary
A radiator includes a looped radiation conductor, a capacitor, an inductor, and a feed point on a radiation conductor. In a portion where the radiation conductor and a ground conductor are close to each other, a distance between the radiation conductor and the ground conductor gradually increases as a distance from the feed point along the looped radiation conductor increases. When the radiator is excited at a low-band resonance frequency, a current flows along a first path extending along an inner perimeter of the looped radiation conductor and including the inductor and the capacitor. When the radiator is excited at a high-band resonance frequency, a second current flows through a second path including a section extending along an outer perimeter of the looped radiation conductor, and the section including the capacitor but not including the inductor, and the section extending between the feed point and the inductor.