Compact Helix PCB Antenna for Capsule Orientation Changes
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Solution Overview
Problem
Conventional swallowable capsules with linearly polarized antennas face communication degradation due to changing orientations within the GI tract, and existing helix antennas are unsuitable for small devices due to impedance mismatch issues and size constraints, limiting data transmission rate and efficiency.
Innovation Solution
A compact helix antenna structure integrated with a printed circuit board (PCB) that includes a middle section with multilayered PCB conductive traces and bridging sections, allowing for orthogonal antenna feeding lines to optimize impedance matching and support RF power amplification, enabling circular polarization and efficient data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linearly polarized antenna is used in a swallowable capsule, then the antenna structure is simple and small, but communication performance degrades due to changing orientations in the GI tract
Solution Approach 1:
The patent transitions from a linear antenna (1D) to a helical antenna (3D structure), adding spatial dimensionality to achieve circular polarization. The helical structure wraps around an axis, creating a three-dimensional configuration that radiates electromagnetic waves with circular polarization, thereby maintaining communication reliability despite orientation changes in the GI tract.
2Reliability
If a conventional helix antenna is used to improve communication performance, then circular polarization is achieved, but the antenna size becomes too large for small in-vivo devices
Solution Approach 1:
The patent embeds the helical antenna structure within a compact cylindrical housing, nesting the antenna turns inside a confined space. The helical conductor is arranged in multiple turns around a central axis, with each turn nested within the spatial envelope of the overall antenna structure, enabling a compact form factor suitable for small in-vivo devices while maintaining the circular polarization characteristics.
Solution Approach 2:
The patent modifies key parameters of the helical antenna including reducing the diameter of the helix, optimizing the spacing between turns, and adjusting the number of turns to achieve the desired circular polarization performance within a compact size. By carefully controlling the helical pitch, conductor diameter, and turn density, the antenna maintains communication reliability while fitting within the volume constraints of small in-vivo devices.
3Reliability
If transmission power is increased to reduce communication gaps, then data transmission reliability improves, but battery operation time is shortened
Solution Approach 1:
The patent employs a simple LC oscillator transmitter design rather than more complex modulation schemes, accepting limited data transmission capabilities in exchange for extremely low power consumption. The transmitter uses a minimal component count with a parallel resonant circuit and switching transistor, enabling the capsule to operate for extended periods (7-10 hours) on a small battery while maintaining adequate communication performance for transmitting image data.
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 enhances communication performance by maintaining data transmission efficiency despite orientation changes and impedance matching, allowing for increased data transmission rates and reduced power consumption, suitable for small in-vivo devices like swallowable capsules.
Implementation Method 1
the antenna currently used by capsules cannot interoperate with a PA due to impedance mismatch issues... incorporation of a PA in a swallowable capsule (in order to facilitate OFDM communication) calls for a new antenna design... A compact helix antenna structure integrated with a printed circuit board (PCB) that includes a middle section with multilayered PCB conductive traces and bridging sections, allowing for orthogonal antenna feeding lines to optimize impedance matching and support RF power amplification, enabling circular polarization
Data Source
AI summary
A helix antenna structure includes loop antennas and a multilayered printed circuit board including printed circuit board layers. Each printed circuit board layer includes a peripheral loop antenna and each adjacent two loop antennas are electrically connected by a connection bridge functioning as a monopole antenna. A selected printed circuit board layer physically and electrically accommodates a transmitter inside ‘its’ peripheral loop antenna, and it further includes a first antenna feeding line which is connected to the loop antenna that is disposed on the selected printed circuit board layer and electrically connectable to a first output terminal of the transmitter. A second antenna feeding line is disposed on another printed circuit board layer and electrically connected to its loop antenna and connectable to another output terminal of the transmitter. The two antenna feeding lines lie in a plane perpendicular to an axis of the printed circuit board after its folding.