Annular Antenna Segmentation for GPS Frequency Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Miniaturization of antennas in electronic devices like electronic timepieces leads to a shift in resonant frequency, causing them to operate outside the desired frequency band.
Innovation Solution
The antenna is designed with an annular shape and features an inner peripheral edge with notches and a protruding edge, along with a dielectric resin case, to maintain frequency stability and reduce capacitive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna element is miniaturized to improve usability and reduce device size, then the device becomes more compact and wearable, but the resonant frequency shifts to higher frequencies causing the antenna to operate outside the desired frequency band
Solution Approach 1:
The annular antenna element is segmented by forming notches at specific positions along its circumference. These notches divide the continuous annular structure into sections, which modifies the current distribution and electrical length of the antenna. This segmentation allows the antenna to maintain the desired resonant frequency despite the reduced overall size, effectively resolving the frequency drift issue caused by miniaturization.
2Length of moving object
If the antenna element is made smaller to fit within the device case, then device miniaturization is achieved, but the resonant frequency increases beyond the desired operating band
Solution Approach 1:
The notches create segments in the annular antenna element, which modifies the current path and effective electrical length. This segmentation allows the physical dimensions to be reduced while the electrical length is adjusted to maintain the correct resonant frequency, thus resolving the contradiction between size reduction and frequency accuracy.
Solution Approach 2:
The notches are positioned at specific locations around the annular antenna element, creating local variations in the structure. These localized modifications affect the current distribution and impedance characteristics at specific points, allowing precise control over the resonant frequency while maintaining overall miniaturization.
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
An electronic device comprises an antenna that has an annular shape in a plan view from a first direction and has at least an outer peripheral edge and an inner peripheral edge, and a device case that accommodates the antenna inside. The antenna comprises at least one latch that is integral to the inner peripheral edge. The device case has a catch at a position corresponding to the latch of the antenna.