Spiral Antenna Coil Layout for Longer-Range Transponders
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Solution Overview
Problem
Existing transponders with spiral antennas face limitations in communication distance, which are not adequately addressed by adding a second antenna in parallel, necessitating further enhancements for specific applications like contactless payments in small devices.
Innovation Solution
A transponder design with a spiral antenna featuring two sets of coils, where the first set is connected and the second set extends outside the connection points, enhancing communication distance by 10-20% without increasing size, and optionally incorporating a resonant circuit with a capacitor for an additional 30-40% increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the antenna dimensions are increased to improve communication distance, then the communication distance is improved, but the terminal size increases
Solution Approach 1:
The patent applies the nesting principle by arranging multiple spiral antennas in a concentric configuration where inner antennas are nested within outer antennas. This allows multiple antennas to occupy a compact radial space while collectively providing extended communication distance through cooperative operation, thus improving communication range without proportionally increasing terminal size.
Solution Approach 2:
The patent transitions from a single-dimensional linear antenna to a two-dimensional spiral configuration, and further to a multi-dimensional nested arrangement of multiple spiral antennas at different radii. This dimensional expansion allows the system to achieve greater effective antenna length and communication distance while maintaining a compact footprint area.
2Length of stationary object
If a second antenna is added in parallel to increase communication distance, then the communication distance increases, but the device complexity increases
Solution Approach 1:
The patent merges multiple spiral antennas into a unified nested structure where they share common mounting space and coordinate their electromagnetic fields. The antennas are configured to operate cooperatively with their respective electronic systems, creating a combined radiation pattern that extends communication distance while avoiding the complexity of completely separate antenna systems.
Solution Approach 2:
Each spiral antenna in the nested configuration serves multiple functions: it acts as both an emitter and receiver, operates at its resonant frequency while contributing to the overall communication distance, and can be independently tuned. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity.
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 enhanced transponder design achieves improved communication distances suitable for contactless payment systems in small devices, such as watches, by optimizing energy storage and transmission range.
Implementation Method 1
The antenna is of major importance for determining the emitting/receiving operating distance between the terminals
Implementation Method 2
The second antenna operates as a resonant circuit, such that the nominal frequency of the set of both antennas does not change with respect to the nominal frequency of the spiral portion alone
Data Source
AI summary
A transponder (1) including an electronic system (3) for managing the sending and receiving of data and a spiral antenna (2), the spiral antenna (2) including a wound strip forming a plurality of coils (11), the electronic system (3) being connected to the spiral antenna (2) by two connection points (6) arranged on the strip. The coils (11) included between the two connection points (6) form a first set of coils (4), the spiral antenna (2) including a second set of coils (5) extending outside the connection points (6). Also, an electronic device, particularly a timepiece including such a transponder (1).