Compact Multi-Band Loop Antenna with Branch Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Designing antennas for modern mobile communication devices that are both compact and capable of supporting multiple wireless communication bands is challenging due to limited space and the need for wide-band coverage.
Innovation Solution
A small-size, wide-band/multi-band loop antenna element is designed with a loop metal element and a branch metal element, utilizing capacitive and inductive elements to generate resonant modes that cover LTE/WWAN frequency ranges, including an inverted L-shape configuration to increase bandwidth and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to fit limited device space, then the device compactness is improved, but the bandwidth coverage capability deteriorates
Solution Approach 1:
The patent employs a nested structure where the loop metal element is positioned adjacent to the ground element, forming a compact configuration. The branch metal element is coupled to the loop metal element at a connection point, creating a nested arrangement that maximizes space utilization while maintaining electrical performance for multi-band operation
Solution Approach 2:
The patent utilizes capacitive and inductive elements to modify the electrical parameters of the antenna structure. By adjusting the capacitance and inductance values, the antenna achieves resonance at multiple frequency bands (including LTE bands) despite the reduced physical size, thereby maintaining bandwidth coverage capability
2Ease of manufacture
If the antenna structure is simplified for ease of manufacture, then the manufacturing complexity is reduced, but the multi-band resonance capability deteriorates
Solution Approach 1:
The antenna is divided into distinct functional segments: the loop metal element for basic resonance, the branch metal element for additional resonance modes, and the capacitive/inductive elements for parameter tuning. This segmentation allows each part to be optimized independently while maintaining overall multi-band capability
Solution Approach 2:
The loop metal element serves multiple functions by supporting both a low-frequency resonant mode and two higher-order resonant modes. The branch metal element coupled through the inductive element provides additional resonance capability, enabling the single antenna structure to cover multiple LTE and WWAN frequency bands simultaneously
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 element achieves efficient coverage of multiple bands with a low-profile and small-size structure, providing average antenna efficiency of approximately 50% in the first band and 80% in the second band, meeting practical application requirements.
Implementation Method 1
The low-frequency resonant mode is excited using a capacitance provided by the capacitive element
Implementation Method 2
The loop metal element can generate one low-frequency resonant mode and two higher-order resonant modes
Implementation Method 3
at least two higher-order resonant modes of the loop metal element together form a wide band using an inductance provided by the first inductive element
Implementation Method 4
the inductance causes the bandwidth of the second (high-frequency) band of the antenna element to be increased
Data Source
AI summary
A communication device includes a ground element and an antenna element. The antenna element includes a loop metal element and a branch metal element. The loop metal element is adjacent to an edge of the ground element. The loop metal element has a feeding end and a grounding end. The grounding end is coupled to the ground element. The feeding end is coupled through a capacitive element and a first inductive element to a signal source. A closed region is enclosed by the loop metal element and the edge of the ground element. The branch metal element is coupled through a second inductive element to a connection point on the loop metal element. The connection point is at the front-half portion of the loop metal element. The front-half portion includes the feeding end. The branch metal element substantially extends along an outer periphery of the loop metal element.