Foldable Antenna Layout With Parasitic Decoupling for Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Foldable electronic devices experience poor antenna performance and isolation in the mid or low band when in a folded state compared to the unfolded state.
Innovation Solution
A foldable electronic device with an antenna system featuring two same-band antennas spaced apart by a gap, a decoupling structure connected in series between them, and a parasitic structure on the other side that forms a half-wavelength resonance when folded, offsetting induced electric fields to enhance isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two same-band antennas are disposed close to each other on the first body, then the device complexity is reduced, but the isolation between antennas deteriorates when the electronic device is in a folded state
Solution Approach 1:
A decoupling structure is introduced as an intermediary element connected between the two same-band antennas. This decoupling structure acts as a mediator to block coupling paths and reduce mutual interference between the antennas, thereby improving isolation without requiring the antennas to be placed far apart or on different bodies.
Solution Approach 2:
The patent utilizes the third dimension by placing a parasitic structure on the second body that overlaps with the antennas on the first body when folded. This vertical stacking approach (another dimension) allows the antennas to be closely positioned while maintaining isolation through the decoupling structure and parasitic element interference management.
2Reliability
If a decoupling structure is added between the two same-band antennas, then the antenna isolation is improved, but the device complexity increases
Solution Approach 1:
The decoupling structure is merged with the existing antenna feed network or grounding system, allowing it to perform multiple functions: both decoupling the antennas and serving as part of the impedance matching or feeding structure. This integration reduces the overall complexity compared to adding a completely separate decoupling component.
Solution Approach 2:
The parasitic structure on the second body serves multiple functions: it acts as a reflector to control radiation patterns, provides additional coupling paths for signal distribution, and helps manage interference between the folded bodies. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
3Reliability
If the parasitic structure is positioned to overlap the antennas when folded, then the antenna isolation is enhanced through resonance, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs adjustable parameters in the parasitic structure design, such as variable length, position, and geometric configuration, that can be tuned to achieve the desired resonance effect and isolation performance. By providing design flexibility through parameter adjustments, the system can accommodate reasonable manufacturing tolerances while maintaining effective isolation.
Solution Approach 2:
The coupling between the parasitic structure and the antennas is designed to be dynamically effective only in the folded state, where the overlapping geometry creates the necessary resonance conditions. In the unfolded state, the coupling is naturally minimized. This dynamic behavior reduces the need for extremely precise positioning across all states, as the critical alignment is only required when folded.
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 achieves high isolation and ideal antenna performance in both unfolded and folded states, ensuring effective wireless communication functions.
Implementation Method 1
the parasitic structure and the two same-band antennas are coupled to form resonance in a half-wavelength mode
Implementation Method 2
A direction of an induced electric field formed between one side of a middle of the parasitic structure and a reference ground near the parasitic structure and a direction of an induced electric field formed between the other side of the middle of the parasitic structure and the reference ground near the parasitic structure are opposite to each other
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
This application provides a foldable electronic device and an antenna system for same. The antenna system includes two same-band antennas disposed on a first body, a decoupling structure connected in series between the two antennas, and a parasitic structure disposed on a second body. The two antennas are spaced apart by a gap. In a folded state, the parasitic structure at least partially overlaps both the two antennas. The parasitic structure is a 1/2 wavelength antenna structure. The wavelength is an operating wavelength of the two same-band antennas. In the folded state, when any one of the two antennas is operating, the parasitic structure is coupled to the any one antenna to form resonance in a 1/2 wavelength mode, and an induced electric field is formed between one side of a middle of the parasitic structure and a reference ground and an induced electric field in an opposite direction is formed between the other side of the middle of the parasitic structure and the reference ground, to offset an electric field coupled from the any one antenna to the other antenna. This suppresses radiated energy on the any one antenna from being coupled to the other antenna through the reference ground on the second body. In this way, a problem of a poor isolation between the two same-band antennas in an unfolded state and the folded state can be resolved effectively.