Wireless IC Device Radiation Plate Antenna Gain
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Solution Overview
Problem
RFID wireless IC devices face challenges in achieving sufficient antenna gain, especially at higher frequency bands and require close proximity to readers-writers due to small antenna size and impedance matching issues.
Innovation Solution
A wireless IC device with a power supply circuit and a two-surface-open type radiation plate that externally radiates and receives signals, connected via electric or magnetic fields, allowing for increased antenna gain and operation at higher frequency bands by adjusting the size and shape of the radiation portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna coil is formed on the wireless IC chip substrate, then the device size is reduced, but the antenna gain is reduced and the operating distance is limited
Solution Approach 1:
The antenna system is divided into two separate components: a small antenna coil on the wireless IC chip and a separate radiation plate. This segmentation allows each component to perform its optimized function - the coil provides compactness while the radiation plate provides high gain, resolving the contradiction between device size and antenna gain.
Solution Approach 2:
The radiation plate extends the antenna structure into a third dimension by being positioned opposite to the antenna coil with spacing between them. This dimensional extension enables the system to achieve high antenna gain without increasing the planar footprint of the wireless IC chip, thus maintaining small device size while improving power.
2Adaptability or versatility
If a closed loop antenna is used on the substrate, then impedance matching is achieved in lower frequency bands, but impedance matching becomes difficult in frequency bands greater than UHF
Solution Approach 1:
The system changes the fundamental parameters of the antenna structure by transitioning from a single closed loop to a dual-component open structure with a radiation plate. This parameter change enables impedance matching across higher frequency bands including those greater than UHF, while maintaining reliability through the complementary nature of the coil and radiation plate configuration.
3Area of moving object
If the antenna coil is made very small on the chip, then the chip size is reduced, but the antenna gain is insufficient and close proximity to reader-writer is required
Solution Approach 1:
The radiation plate acts as an intermediary element that bridges the small antenna coil on the chip and the external reader-writer. This intermediary structure amplifies the electromagnetic field, enabling the small chip to communicate at sufficient distances without requiring close proximity to the reader-writer.
4Volume of moving object
If the power supply circuit area is reduced, then the device size is reduced, but the antenna gain is reduced
Solution Approach 1:
The system segments the antenna function from the power supply circuit, allowing the power supply circuit to remain compact on the chip while the radiation plate provides the necessary antenna gain. This segmentation resolves the contradiction by assigning different functions to different components.
Solution Approach 2:
The radiation plate serves multiple functions: it acts as the radiating element for high gain, provides impedance matching for high frequency bands, and enables operation at extended distances. This multi-functionality allows the compact power supply circuit to be paired with a high-performance antenna system.
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 enables the wireless IC device to operate effectively at a sufficient distance from readers-writers and supports use in frequency bands higher than UHF, with adjustable gain and resonant frequency, while maintaining efficiency and flexibility in design and attachment.
Implementation Method 1
a radiation plate that externally radiates a transmission signal supplied from the power supply circuit and that supplies a reception signal externally transmitted to the power supply circuit
Implementation Method 2
The radiation plate is connected to the power supply circuit via an electric field
Implementation Method 3
the radiation plate is coupled to the power supply circuit via a magnetic field
Implementation Method 4
a power supply circuit including a resonant circuit having a predetermined resonant frequency
Data Source
AI summary
A wireless IC device includes a wireless IC chip having a power supply circuit including a resonant circuit having a predetermined resonant frequency and a radiation plate that externally radiates a transmission signal supplied from the power supply circuit and that supplies a reception signal externally transmitted to the power supply circuit. The radiation plate is connected to the power supply circuit via an electric field or the radiation plate is coupled to the power supply circuit via a magnetic field. The radiation plate is a two-surface-open type radiation plate including at least one radiation portion arranged to externally exchange a transmission-reception signal and a power supply portion arranged to exchange a transmission-reception signal with the power supply circuit.