Antenna Loop Electrode Segmentation for Impedance Matching
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Solution Overview
Problem
Existing RFID antennas face issues where radiation characteristics such as directivity and gain are altered during impedance adjustment, affecting performance.
Innovation Solution
The design incorporates a first loop electrode as a radiation portion and a second loop electrode as an impedance matching portion, coupled through a coupling electrode, ensuring independence and maintaining radiation characteristics during impedance adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance adjustment is performed by modifying the shape of a slit or adjusting conductor pattern lengths, then impedance matching is improved, but radiation characteristics such as directivity and gain are changed
Solution Approach 1:
The antenna is divided into two separate loop electrodes: a first loop electrode dedicated to radiation and a second loop electrode dedicated to impedance matching. This segmentation allows each component to perform its specific function independently, preventing changes in radiation characteristics during impedance adjustment.
Solution Approach 2:
A coupling electrode is introduced as an intermediary component to connect the first loop electrode (radiation) and the second loop electrode (impedance matching). This mediator allows the two functional parts to interact while maintaining their independence, enabling impedance adjustment without directly affecting the radiation portion.
2Reliability
If a portion of the dipole antenna is used for impedance adjustment, then impedance matching is achieved, but radiation characteristics are altered
Solution Approach 1:
The antenna structure is segmented into distinct functional portions: the first loop electrode for radiation and the second loop electrode for impedance matching. This clear division simplifies the design process by assigning specific roles to each component, making it easier to manufacture and adjust without affecting overall performance.
3Reliability
If the first conductor pattern is directly electrically connected to the second and third conductor patterns, then impedance adjustment is enabled, but radiation characteristics change
Solution Approach 1:
The coupling electrode serves as an intermediary connection between the first loop electrode and the second loop electrode. This intermediate connection enables impedance adjustment through the second loop electrode while preventing direct electrical connection that would cause radiation characteristics to change, thus resolving the contradiction between adjustability and stability.
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 allows for stable radiation characteristics and efficient transmission and reception of circularly polarized waves, maintaining directivity and gain without altering the antenna's radiation properties during impedance matching.
Implementation Method 1
an antenna (radiation body) that transmits and receives a high-frequency signal
Implementation Method 2
a coupling electrode that couples the first loop electrode and the second loop electrode to each other
Data Source
AI summary
An antenna and a wireless communication device which are suitable for an RFID system and in which radiation characteristics are prevented from being changed as a result of impedance adjustment are configured such that the antenna includes a first loop electrode that has an external shape of a regular polygon or circle and that includes a pair of open ends, feeding portions arranged inside the first loop electrode, a second loop electrode connected to the feeding portions, and a coupling electrode that couples the first loop electrode and the second loop electrode to each other. The wireless communication device is obtained by coupling the wireless communication element which processes a high-frequency signal to the feeding portions.