Loop Antenna Feed Layout for Impedance Matching and Isolation
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Solution Overview
Problem
The impedance mismatch between the antenna conductor and the power feeder in existing antenna devices with loop antennas can lead to insufficient matching, and the arrangement of power feeders perpendicular to loop antennas may cause induced current issues.
Innovation Solution
The antenna module includes a dielectric substrate with loop-shaped radiation elements and power feeding wires that supply high-frequency signals via flat electrodes offset in the polarization direction, with vias connected to these electrodes, allowing for fine adjustment of impedance and overlap with radiation elements to prevent deterioration in isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the power feeder length is limited, then the antenna module size is reduced, but the impedance matching between antenna conductor, power feeder and transmitter/receiver becomes insufficient
Solution Approach 1:
The patent transitions from a conventional vertical power feeder arrangement to a planar configuration where the power feeder extends in the same plane as the loop antenna. The flat electrode is positioned to overlap with the loop antenna in the planar view, creating a capacitive coupling structure that enables effective power transfer within a limited length while maintaining proper impedance matching.
Solution Approach 2:
The patent modifies the geometric parameters of the power feeder, specifically using a flat electrode with dimensions (length and width) that are optimized for capacitive coupling with the loop antenna. The offset distance between the flat electrode center and the loop antenna center is carefully controlled to achieve the desired impedance matching characteristics.
2Adaptability or versatility
If multiple loop antennas are arranged concentrically, then the antenna module achieves multi-frequency operation, but the isolation between antennas may be compromised
Solution Approach 1:
The patent applies different geometric configurations to different antennas in the concentric arrangement. Each loop antenna has its own optimized power feeder with specific flat electrode dimensions and offset distances. This localized optimization allows each antenna to maintain proper impedance matching and isolation characteristics while operating at different frequencies.
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 facilitates impedance matching and suppresses isolation deterioration between radiation elements, improving antenna characteristics by adjusting the length and overlap of power feeding wires with radiation elements.
Implementation Method 1
a first flat electrode disposed apart from the first radiation element in the first direction, and a first conductor connected to the first flat electrode
Implementation Method 2
high-frequency signals are supplied to a plurality of loop-shaped radiation elements disposed on a dielectric substrate via flat electrodes offset in the polarization direction
Data Source
AI summary
An antenna module includes a dielectric substrate, loop antennas, and power feeding wires that transmit high-frequency signals to the antennas. One loop antenna is positioned inside the loop of another in plan view from the winding axis direction. Each power feeding wire has a flat electrode and a via extending along the winding axis. The flat electrodes partially overlap with their respective loop antennas but not with others. At least one via connects to its corresponding flat electrode at a position offset from the antenna in the polarization direction.