MIMO Antenna with Slits and Switching for Compact Diversity Reception
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Solution Overview
Problem
Conventional diversity antenna apparatuses face challenges in achieving high isolation between multiple antennas without switching, and existing MIMO antenna designs are limited in size due to the use of one-wavelength loop antennas, making them unsuitable for small, portable wireless communication devices.
Innovation Solution
A MIMO antenna apparatus with a radiating conductor having slits, multiple feed points, and a switching circuit that dynamically connects antennas based on signal measurement values to maintain high isolation and reduce correlation between antennas, allowing for high-quality and high-speed communication in a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-wavelength loop antenna is used to achieve high isolation and low correlation, then diversity effect is improved, but antenna size increases making it unsuitable for portable devices
Solution Approach 1:
The patent divides a single radiating conductor into multiple functional sections by providing multiple feed points and slits. The radiating conductor is segmented into first and second antenna elements that can be independently excited, enabling multiple antenna functions within a compact structure. This segmentation allows the antenna apparatus to achieve diversity reception without requiring multiple separate full-size antennas.
Solution Approach 2:
The patent combines multiple antenna functions into a single integrated radiating conductor structure. By providing multiple feed points on one radiating conductor, the patent merges first and second antennas into a unified structure, achieving space-efficient MIMO functionality while maintaining high isolation through proper feeding network design.
2Volume of moving object
If multiple antennas are arranged close to each other to reduce device size, then portability is improved, but isolation between antennas deteriorates
Solution Approach 1:
The patent introduces a switching circuit as an intermediary component between the feed points and the radiating conductor. This switching circuit enables dynamic control of antenna excitation, allowing the system to selectively activate different antenna elements and maintain high isolation even when antennas are closely spaced. The switching mechanism acts as a mediator that manages electromagnetic coupling between adjacent antenna elements.
3Reliability
If impedance adjustment units are added to achieve high isolation between antennas, then isolation is improved, but device complexity increases
Solution Approach 1:
The patent achieves impedance matching and isolation by dynamically changing the operational parameters of the antenna system through the switching circuit. By switching between different feed point configurations, the system adjusts electromagnetic parameters to optimize isolation without requiring additional impedance adjustment components. This parameter-based approach reduces structural complexity compared to adding physical impedance matching elements.
Data Source
AI summary
A MIMO antenna apparatus is provided with: an upper housing having slits; first feed points through which the upper housing itself is excited as first antennas; second feed points through which the slits are excited as second antennas; switch, each of which is connected to one of the first feed points and one of the second feed points, and connects one of the two feed points to an A/D converter circuit-; a signal level detector circuit detecting signal levels of received radio signals; and a controller that controls the switches to change a feed point connected to the A/D converter circuit, when the detected signal level is less than or equal to a predetermined threshold value. The slits are located between the first antennas.