Antenna Isolation Using Phase Shifter for Compact Wireless Devices
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Solution Overview
Problem
Forming electronic device antenna structures with desired attributes is challenging, particularly when multiple antennas are present, as they can adversely affect each other's performance, leading to bulky designs or inefficient frequency coverage.
Innovation Solution
The use of a primary and secondary antenna in a diversity arrangement, where the secondary antenna is coupled with a phase shifter to adjust signal phase and avoid efficiency degradation of the primary antenna, sharing a common ground plane formed from the electronic device's metal housing, ensuring efficient operation across various communications bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple antennas are placed close together to reduce device size, then device compactness is improved, but antenna performance degrades due to mutual coupling
Solution Approach 1:
A phase shifter is introduced as an intermediary component between the secondary antenna and the transceiver circuitry. This phase shifter actively manipulates the electromagnetic signals to create destructive interference in the coupling paths between antennas, thereby reducing mutual coupling effects and maintaining antenna performance in compact configurations.
Solution Approach 2:
The phase shifter dynamically changes the phase parameter of signals connected to the secondary antenna based on the operating frequency band. By adjusting the phase shift amount according to different communication bands (e.g., LTE bands), the system optimizes antenna isolation and maintains reliable performance across multiple frequency ranges while keeping antennas in close proximity.
2Reliability
If antennas are separated by large distances to reduce coupling, then antenna performance is maintained, but device size increases
Solution Approach 1:
The phase shifter serves as an active intermediary that electronically compensates for the close physical proximity of antennas. By introducing controlled phase shifts, it creates virtual isolation between antennas, allowing them to be placed close together without sacrificing performance, thus avoiding the need for large physical separations.
Solution Approach 2:
The invention replaces the mechanical solution of physically separating antennas with an electronic solution using a phase shifter. Instead of relying on physical distance to reduce coupling, the system uses electronic phase manipulation to achieve the same isolation effect, enabling compact device design while maintaining antenna performance.
3Reliability
If antenna designs are modified to reduce coupling, then antenna isolation is improved, but frequency range coverage is limited
Solution Approach 1:
The phase shifter is designed as a dynamic component that can be reconfigured for different operating conditions. It includes switching elements that allow the phase shift characteristics to be changed based on the active communication band, enabling the system to maintain effective antenna isolation across multiple frequency ranges rather than being optimized for a single frequency.
Solution Approach 2:
The system changes the phase shift parameter dynamically according to the selected communication band. Different phase shift amounts are applied for different LTE bands and other frequency ranges, allowing the antenna isolation mechanism to remain effective across a broad frequency spectrum while maintaining versatility and adaptability.
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 maintains primary antenna efficiency by adjusting the phase shifter to prevent adverse effects from the secondary antenna, allowing for effective wireless communication without bulkiness or frequency inefficiencies.
Implementation Method 1
The phase shifter may impose a phase shift on signals carried between the secondary antenna and the transceiver that avoids primary antenna efficiency degradation associated with the presence of the secondary antenna in the vicinity of the primary antenna
Data Source
AI summary
An electronic device may be provided with a primary antenna that is used for transmitting and receiving signals and a secondary antenna that is used for receiving signals. The primary and secondary antennas may be used together in a diversity arrangement when receiving signals. The electronic device may have a transceiver. A phase shifter may be interposed between the transceiver and the secondary antenna. Control circuitry may select a communications band of interest for transmitting signals with the primary antenna. The control circuitry can adjust the phase shifter in real time based on which communications band of interest has been selected for transmission with the primary antenna. The phase shifter may impose a phase shift on signals carried between the secondary antenna and the transceiver that ensures that primary antenna efficiency degradation associated with the presence of the secondary antenna in the vicinity of the primary antenna is avoided.