Watch Antenna Layout for Multiband Signal Isolation in Metal Cases
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Solution Overview
Problem
The challenge is to design an antenna device for a timepiece that can efficiently transmit and receive signals across multiple frequency bands within a limited space, while being integrated into a watch case without increasing its volume, which is constrained by the need for insulation and the presence of metal parts.
Innovation Solution
The antenna device features two separate antenna circuits on a flexible printed circuit substrate, with a duplexer/rejector filtering circuit and a unique configuration that allows for optimal signal transmission and reception across Bluetooth and satellite location networks, utilizing a two-strand architecture for Bluetooth and a folded configuration for satellite networks, along with electromagnetic shielding and mechanical integration that leverages the watch's metal frame for improved radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an antenna of optimal length is used for full-power signal transmission, then communication performance is improved, but the device volume increases beyond acceptable limits for a watch
Solution Approach 1:
The antenna is folded back on itself multiple times to create a compact structure that fits within the watch case. The optimal-length antenna is nested within the limited space by creating loops and folds, allowing the full signal transmission capability to be achieved without increasing the external dimensions of the watch.
Solution Approach 2:
The antenna transitions from a straight linear configuration to a three-dimensional folded structure. By utilizing vertical and lateral dimensions within the watch case, the antenna achieves its optimal electrical length while maintaining a compact footprint that fits within the constrained watch volume.
2Adaptability or versatility
If multiple communication devices are integrated into the same watch case, then communication versatility is improved, but antenna isolation becomes difficult to maintain
Solution Approach 1:
A ground plane is introduced as an intermediary structure between multiple antennas. This ground plane acts as a shielding layer that isolates the antennas from each other, preventing mutual interference while allowing multiple communication protocols to operate simultaneously within the same watch case.
Solution Approach 2:
Different regions of the antenna structure are assigned different functional qualities. The antenna is divided into separate radiating elements and ground plane sections, with each region optimized for its specific function. This local differentiation allows multiple antennas to coexist with proper isolation while maintaining individual performance characteristics.
3Reliability
If the antenna is insulated from metal parts to prevent interference, then signal quality is improved, but the available space for antenna integration is reduced
Solution Approach 1:
The antenna structure is merged with the metal caseband of the watch. Instead of treating the metal case as an obstacle requiring insulation, the design integrates the antenna directly with the caseband, using the metal structure itself as part of the antenna system. This eliminates the need for additional insulation space while maintaining signal quality through proper electromagnetic coupling.
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 enables full-power signal transmission and reception across multiple frequency bands, maintaining the compact size of the watch while ensuring isolation and efficient mechanical integration, enhancing the antenna's performance and compatibility with various communication protocols.
Implementation Method 1
a remote communication system provided with a multi-band antenna device (1)
Implementation Method 2
an antenna device (1) comprising a substrate (10) produced in the form of a flexible printed circuit
Implementation Method 3
utilizing a two-strand architecture for Bluetooth and a folded configuration for satellite networks, along with electromagnetic shielding
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a timepiece comprising a case formed of a metallic case (40) in which are arranged a metallic dial and a remote communication system provided with a multi-band antenna device (1) arranged above said dial, the communication system comprising a bracelet (49) of said timepiece connected at its ends to said case and comprising a body formed of a plurality of attachment elements having different electrical conductivity properties, the arrangement of said attachment elements in the body of the bracelet (49) being configured to achieve a broadening of the radiation pattern of said antenna device (1).