Magnetically Coupled Slot Antenna for Wider Multi-Band Coverage
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Solution Overview
Problem
Slot antennas are not suitable for built-in applications in electronic devices that require operation in multiple frequency bands due to their resonant frequency being determined by the length of the slot.
Innovation Solution
An antenna device with a planar conductor and slots, featuring first and second excitation electrodes connected to magnetically coupled coils, which are connected to a feed circuit, allowing for additional resonance points and expanded frequency usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a slot antenna is used with a fixed slot length, then the resonant frequency is determined, but the antenna cannot operate in multiple frequency bands
Solution Approach 1:
The slot antenna is divided into multiple segments with different lengths (first slot segment, second slot segment, third slot segment) that can be independently controlled. Each segment can be selectively connected to the excitation electrode through switching elements, allowing the antenna to operate at different resonant frequencies by activating different segments, thus achieving multi-frequency band operation without increasing overall structural complexity
Solution Approach 2:
The antenna structure incorporates switching elements (such as PIN diodes or MEMS switches) that can dynamically change the electrical configuration of the slot segments. By controlling the switching states, the effective electrical length of the antenna can be changed in real-time, enabling frequency reconfiguration and multi-band operation while maintaining a compact fixed physical structure
2Adaptability or versatility
If the slot length is increased to cover lower frequencies, then the frequency band is widened, but the antenna size increases
Solution Approach 1:
The slot is divided into multiple segments of different lengths arranged in a compact configuration. By selectively activating different segments through switching elements, the antenna can achieve different effective electrical lengths corresponding to different frequency bands without requiring a single large slot structure, thus maintaining compact size while covering wide frequency range
Solution Approach 2:
The slot segments are arranged in a nested or folded configuration where shorter segments are positioned within or alongside longer segments. This allows the antenna to achieve multiple effective lengths (and thus multiple frequency bands) without increasing the overall bounding box size, as the segments are space-efficiently arranged in a nested manner
3Adaptability or versatility
If multiple slot antennas are used to cover different frequency bands, then frequency coverage is improved, but the device complexity increases
Solution Approach 1:
Instead of using multiple separate slot antennas, a single slot antenna is segmented into multiple electrically independent sections. Each segment can be independently controlled by switching elements, allowing the same physical structure to function as multiple frequency-specific antennas by activating different segments, thus achieving multi-frequency operation without increasing the number of antenna elements
Solution Approach 2:
The single slot antenna structure is designed to perform multiple functions by selectively activating different segments. The same physical antenna structure can operate at different frequency bands depending on the switching configuration, making it a universal antenna that replaces what would traditionally require multiple specialized antennas, thereby reducing overall device complexity
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 provides additional resonance points, enabling the antenna to operate in a wider frequency band, specifically covering bands from approximately 2.4 GHz to 7 GHz.
Implementation Method 1
the first coil and the second coil are positioned to be magnetically coupled with each other
Data Source
AI summary
An antenna device includes a conductor with a planar shape and a slot, first and second excitation electrodes at positions corresponding to the slot, and first and second coils. A first end of the first coil is electrically connected to the first excitation electrode, and a second end of the first coil is connected to a feed circuit. One end of the second coil is electrically connected to the second excitation electrode. The first and second coils are positioned to be magnetically coupled with each other.