Multiband Mobile Antenna Using Coupled Radiating Branches
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Solution Overview
Problem
Conventional coupling-feed mechanisms in mobile communication devices cannot effectively cover all required operating bands for 8-band LTE/GSM/UMTS operations, including 3-band LTE700/GSM850/900 and 5-band GSM1800/1900/UMTS/LTE2300/2500 frequencies, while maintaining a small antenna size.
Innovation Solution
A multiband mobile communication device antenna design featuring a monopole, a shorted radiating portion, and multiple radiating branches that generate multiple resonant modes through capacitive coupling, forming two wide-band operating bands to cover the necessary frequency ranges, with a compact footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional coupling-feed mechanism is used, then the antenna can be kept small, but it cannot cover all required operating bands for 8-band LTE/GSM/UMTS operations
Solution Approach 1:
The antenna is divided into multiple independent radiating elements (first radiating element, second radiating element, third radiating element, and fourth radiating element) that can be independently designed and tuned to resonate at different frequency bands. Each element is fed through separate feeding points, allowing independent impedance matching and resonance frequency adjustment, thereby achieving comprehensive 8-band coverage without requiring a single complex structure.
Solution Approach 2:
The antenna elements are arranged in a nested configuration where multiple radiating elements are positioned within a compact footprint on the device chassis. The elements are strategically placed to utilize available space efficiently, with some elements positioned adjacent to each other and others stacked, achieving multiband functionality within a small overall antenna structure.
2Adaptability or versatility
If the antenna structure is simplified, then manufacturing is easier, but it cannot generate multiple resonant modes for multiband operations
Solution Approach 1:
Each radiating element is designed with specific local geometric characteristics (different lengths, widths, and shapes) that are optimized for resonating at particular frequency bands. The feeding points are positioned at specific locations on each element to achieve desired impedance values. This localized optimization of geometric parameters allows each element to be independently tuned for its target frequency band, achieving multiband resonance through relatively simple individual structures.
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 design efficiently covers 8-band LTE/GSM/UMTS operations, achieving a compact size suitable for slim mobile devices by generating multiple resonant modes that correspond to specific frequency bands, ensuring effective multiband operation.
Implementation Method 1
The shorted radiating portion has one end as a shorting end electrically connected to the ground plane, while the other end is left open. The shorted radiating portion is extended along the monopole and has a coupling gap to the monopole. The shorted radiating portion generates a second resonant mode of the antenna by the coupling excitation of the monopole.
Implementation Method 2
The monopole generates a first resonant mode of the antenna. The shorted radiating portion generates a second resonant mode of the antenna by the coupling excitation of the monopole. The first radiating branch generates a third resonant mode. The second radiating branch generates a fourth resonant mode.
Data Source
AI summary
A multiband mobile communication device has a ground plane and an antenna. The antenna is disposed on a dielectric substrate. The antenna includes a monopole, a shorted radiating portion, a first radiating branch, and a second radiating branch. The monopole includes a feeding end, and the feeding end is the feeding point of the antenna. The shorted radiating portion has a shorting end electrically connected to the ground plane, and its other end is left open. The shorted radiating portion is extended along the monopole and has a coupling gap to the monopole. The first radiating branch has an end electrically connected to the shorted radiating portion, and its other end is left open. The first radiating branch is extended toward the shorting end of the shorted radiating portion and located on the opposite side of the monopole. The second radiating branch has an end electrically connected to the shorted radiating portion, and its other end is left open. The second radiating branch is extended along the first radiating branch, with the first radiating branch located between the second radiating branch and the shorted radiating portion.