Antenna Device Sharing Radiation Element for UHF and HF Bands
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Solution Overview
Problem
In small communication terminal apparatuses with metalized housings, embedding an antenna is challenging due to signal blocking, and securing space for HF band RFID antennas is difficult, especially when trying to integrate antennas for multiple frequency bands.
Innovation Solution
An electronic apparatus with an antenna device that includes a radiation element and a ground conductor forming a loop unit, where the radiation element functions as a field emission element in one frequency band and a magnetic field emission element in another, allowing sharing of the antenna for both bands with magnetic field coupling, and using reactance elements to optimize impedance for each band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an antenna is embedded inside a metalized housing, then the mechanical strength is improved, but the signal is blocked by the metal
Solution Approach 1:
The housing is segmented into metal portions and nonmetal portions, allowing the antenna to be positioned in the nonmetal region where signals can radiate freely while the metal portions provide structural strength and shielding for other components
2Volume of moving object
If the housing is made smaller and thinner, then the device size is reduced, but the mechanical strength degrades
Solution Approach 1:
The housing uses a composite structure combining metal and nonmetal materials, where the metal portions reinforce the housing to maintain mechanical strength despite reduced overall size and thickness
3Device complexity
If antennas for multiple frequency bands are integrated, then the device complexity is reduced, but the space requirement increases
Solution Approach 1:
The same radiation element serves multiple functions by operating in different frequency bands (UHF and HF) through impedance transformation, eliminating the need for separate antenna structures for each band and reducing overall device complexity and space requirements
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 the antenna to be shared across different frequency bands, reducing the size of the antenna device and enabling effective communication in both UHF and HF bands without affecting signal quality.
Implementation Method 1
the radiation element functions as a field emission element in one frequency band
Implementation Method 2
the radiation element functions as a magnetic field emission element in another frequency band
Implementation Method 3
with magnetic field coupling
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An electronic apparatus comprises an antenna device, a first feeder circuit that feeds a communication signal of a first frequency band to the antenna device, and a second feeder circuit that feeds a communication signal of a second frequency band that is lower than the first frequency band to the antenna device. The antenna device includes a radiation element of an electric field type antenna and a ground conductor disposed so as to face the radiation element. At least one first reactance element is connected between the radiation element and the ground conductor, the radiation element, the first reactance element, and the ground conductor forming a loop unit of a magnetic field type antenna. The radiation element is an antenna element for the first frequency band, and the loop unit is an antenna element for the second frequency band. The entirety of the radiation element is used as an antenna element for the first frequency band.