Orthogonal Doppler Antenna Isolation via Vertical Stacking
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Solution Overview
Problem
Existing Doppler motion sensor devices face challenges in achieving sufficient isolation between transmission and reception antennas, leading to signal interference and increased device size due to the need for long antenna separation and multiple ground planes, resulting in unwanted power loss.
Innovation Solution
The Doppler motion sensor device employs a configuration where multiple antennas are disposed close to each other and coupled to the same common voltage plane, with orthogonal feed-in points and middle points at centroids, allowing for effective signal detection without the need for long distances or excessive ground planes, thereby enhancing isolation and reducing signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission antenna and reception antenna are separated by a long distance, then the isolation between antennas is improved, but the device size increases excessively
Solution Approach 1:
The patent transitions from separating antennas in the horizontal plane to positioning them in different vertical layers (first antenna layer and second antenna layer). This vertical stacking arrangement achieves high isolation between transmission and reception antennas without requiring large horizontal separation distance, thus reducing overall device footprint while maintaining reliability.
2Reliability
If multiple ground planes are used to increase antenna isolation, then the isolation between antennas is improved, but the device size and complexity increase
Solution Approach 1:
The patent merges the ground plane function into a single shared ground structure that serves both the first antenna layer and second antenna layer. Instead of implementing separate ground planes for each antenna layer, the design uses one common ground plane to provide reference potentials for all antennas, thereby reducing device complexity while maintaining the isolation benefits through vertical separation.
3Reliability
If longer conduction wires are used to connect antennas, then the antenna isolation is improved, but unwanted power loss increases
Solution Approach 1:
By stacking antennas vertically in different layers, the patent significantly shortens the conduction wire lengths required to connect antennas to the ground plane and to each other. This vertical arrangement eliminates the need for long horizontal runs of wire, thereby reducing resistive power losses while maintaining effective isolation between transmission and reception antennas through the layer separation.
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 achieves high isolation between antennas, minimizing signal interference and power loss while maintaining signal quality, allowing for efficient detection of object motion using the Doppler effect.
Implementation Method 1
The first antenna is configured to transmit or receive a first wireless signal
Implementation Method 2
The second antenna is configured to transmit or receive a second wireless signal
Implementation Method 3
The sensor circuit is configured to detect the motion of the object according to at least the first internal signal and the second internal signal
Data Source
AI summary
A Doppler motion sensor device is used for detecting a motion of an object. The Doppler motion sensor device includes a first antenna and a second antenna. The first antenna is used to transmit or receive a first wireless signal. The second antenna is used to transmit or receive a second wireless signal. A first straight line passing through a first feed-in point and a first middle point of the first antenna is orthogonal to a second straight line passing through a second feed-in point and a second middle point of the second antenna. One of the first wireless signal and the second wireless signal is a transmission signal. The transmission signal is reflected by the object to form the other one of the first wireless signal and the second wireless signal.