Switched Inductor Array for RF Antenna Frequency Tuning
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Solution Overview
Problem
Modern wireless communication devices face interference issues due to energy leakage from hardware circuitry, which can render certain radio frequency bands unusable, especially in compact designs where RF antenna performance is critical across multiple frequency bands.
Innovation Solution
The implementation of a switchable inductor array and RF isolation shield to dynamically adjust the inductance of the RF antenna's return path and shield conductive objects from interfering with the antenna, allowing optimal performance across different frequency bands without altering the connector length or return path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed length connector is used for the RF antenna return path, then the device structure is simplified and manufacturing is easier, but the RF antenna cannot be tuned to optimal frequency without changing the connector length
Solution Approach 1:
The patent applies parameter changes by introducing a switchable inductor array that modifies the electrical inductance parameter of the return path without changing the physical length of the connector. This allows the RF antenna's resonant frequency to be tuned by changing the inductance value dynamically, resolving the contradiction between fixed connector manufacturing simplicity and frequency tuning adaptability
Solution Approach 2:
The switchable inductor array serves as an intermediary element between the fixed connector and the RF antenna. It mediates the frequency tuning requirement by providing variable inductance that compensates for the fixed connector length, enabling frequency adaptation without modifying the connector itself
2Reliability
If a stiffener is added to provide structural support and electrical grounding, then device reliability and safety are improved, but the stiffener interferes with nearby RF antenna performance
Solution Approach 1:
An RF isolation shield is introduced as an intermediary element positioned between the stiffener and the RF antenna. This shield mediates the interaction by providing electrical isolation, allowing the stiffener to maintain its grounding and structural functions while preventing harmful RF interference with the antenna
Solution Approach 2:
The patent applies segmentation by dividing the space between the stiffener and RF antenna with an isolation shield. This creates separate electromagnetic zones, allowing the stiffener to provide grounding without directly interfering with the RF antenna's electromagnetic field
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 solution effectively tunes the RF antenna to optimize performance across various frequency bands, reducing interference and maintaining RF antenna integrity, even in the presence of conductive objects, thereby enhancing wireless communication capabilities.
Implementation Method 1
determining a target inductance of the fixed length short pin that resonates with the RF antenna characteristic. The method can also include transitioning a state of a switch that is coupled to the fixed length short pin to change an inductance of the fixed length short pin to the target inductance
Implementation Method 2
The assembly can further include a shield assembly positioned between the stiffener and the enclosure. The shield assembly can include a conductive layer positioned between adhesive layers so that the shield assembly adheres the stiffener to the enclosure and provides shielding to the RF antenna
Data Source
AI summary
A consumer electronic product includes a switchable inductor array coupled to the RF antenna, the switchable inductor array comprising inductive elements and a switch circuit coupled to the inductor array to select at least one of the inductive elements and couple the selected inductive element with the RF antenna. The product can further include an assembly having a mesh that is strengthened by a stiffener. A multi-layer adhesive have a conductive layer that can be used to shield the RF antenna and adhesive layers that can provide adhesion between the stiffener and the housing of the product. The assembly can be covered by a cowling that is made of metal to provide further shielding. To reduce potential coupling between the RF antenna and the cowling, the cowling can have a portion that is formed of plastic to distance its metal portion from the antenna.