Shorted Monopole Antenna With Closed Loop Radiator For Eight LTE Bands
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Solution Overview
Problem
Traditional mobile communication device antennas struggle to cover the eight operating bands of LTE/GSM/UMTS systems due to insufficient bandwidth, particularly in miniaturized designs.
Innovation Solution
A shorted monopole antenna with a coupling feed and a closed loop radiating structure, including a first and second radiating portion, a feeding portion, and a shorting portion, which generates two wide operating bands covering LTE700/GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500 frequencies, suitable for slim-type devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional antenna designs are used, then the antenna structure is simple, but the operating bandwidth is insufficient to cover eight LTE/GSM/UMTS bands
Solution Approach 1:
The antenna is divided into multiple functional segments: a radiating element with specific geometric shape, a feeding portion with coupling gap, and a shorting portion. This segmentation allows each part to contribute to different frequency band coverage while maintaining overall broadband performance across eight LTE/GSM/UMTS bands.
Solution Approach 2:
The radiating element incorporates a three-dimensional structure with a coupling gap dimension, transforming a planar antenna design into a volumetric structure. This dimensional change enables the antenna to achieve broadband operation across multiple frequency bands by utilizing the coupling gap for impedance matching and resonance control.
2Volume of moving object
If antenna size is reduced for miniaturization, then the device becomes more compact, but the operating bandwidth decreases
Solution Approach 1:
The antenna employs a thin-film structure where the radiating element and feeding portion are constructed as planar conductive patterns on a substrate. This thin-film approach enables antenna miniaturization while the strategically designed coupling gap and shorting portion maintain broadband performance by creating resonant modes that extend the operating bandwidth despite the reduced physical dimensions.
Solution Approach 2:
The antenna design utilizes parameter optimization including the coupling gap width (less than 1 mm), the length and geometry of the radiating element, and the position of the shorting portion. By carefully adjusting these parameters, the antenna achieves broadband operation across eight frequency bands while maintaining a compact form factor suitable for modern mobile devices.
3Volume of moving object
If the coupling gap is reduced to less than 1 mm for compact design, then the antenna size is minimized, but the electromagnetic coupling efficiency must be optimized
Solution Approach 1:
The feeding portion creates an electromagnetic coupling mechanism where the coupling gap acts as a capacitive coupling structure. By designing the gap dimensions and positioning, the antenna achieves effective electromagnetic energy transfer from the feeding portion to the radiating element despite the sub-1 mm gap size, maintaining coupling efficiency while minimizing overall antenna volume.
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 antenna effectively covers three and five operating bands respectively in lower and higher frequency ranges, achieving broadband operation and impedance matching, thus enabling eight operating bands within a compact size suitable for mobile communication devices.
Implementation Method 1
The radiating portion comprises a first radiating portion and a second radiating portion... The closed loop has a total length at least equal to one tenth of a wavelength of a center frequency of the first operating band of the antenna
Implementation Method 2
The feeding portion couples the electromagnetic energy to the radiating portion through a coupling gap, which is less than 1 mm
Data Source
AI summary
A mobile communication device includes a ground plane, a dielectric substrate, and an antenna. The antenna is disposed on one surface of the dielectric substrate and includes a radiating portion, a feeding portion, and a shorting portion. The radiating portion includes a first radiating portion and a second radiating portion. The first radiating portion has at least one bending. One end of the first radiating portion is left open. The second radiating portion is a shunt metal strip. Both ends of the second radiating portion are electrically connected to the first radiating portion such that the second radiating portion forms a closed loop with a segment of the first radiating portion. The feeding portion couples the electromagnetic energy to the radiating portion through a coupling gap, and one end of the feeding portion is the antenna's feeding point. One end of the shorting portion is electrically connected to the radiating portion, and the other end of the shorting portion is electrically connected to the ground plane.