Switchable Dual-Fed Antenna Element for Multi-Band Mobile Devices
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Solution Overview
Problem
Designing an antenna element that can efficiently cover multiple communication bands within the limited space of a mobile communication device while maintaining a compact size is a significant challenge.
Innovation Solution
A switchable dual-feed antenna element with an asymmetrical dipole structure, where the antenna is coupled to different matching circuits to operate in various bands by controlling the switch circuit's open and closed states, allowing the antenna to generate distinct resonant modes in high and low bands without interference between the feeding points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional single-feed antenna structure is used, then the antenna can be designed with simple structure, but it cannot efficiently cover multiple communication bands within limited space
Solution Approach 1:
The antenna element is divided into multiple feed points (first feeding point and second feeding point) along its length. Each feed point can be independently connected to different matching circuits, allowing the antenna to be segmented into different operational segments for different frequency bands, thereby achieving multi-band operation without requiring multiple separate antennas
Solution Approach 2:
The antenna system incorporates switchable matching circuits that can dynamically reconfigure the antenna's electrical characteristics. By switching between different matching circuits connected to different feed points, the antenna can adapt its impedance and resonant frequency to match different communication bands, providing dynamic adaptability across multiple bands
2Adaptability or versatility
If multiple separate antennas are used to cover different bands, then each band can be optimized independently, but the overall device size increases
Solution Approach 1:
A single antenna element is designed to serve multiple frequency bands by incorporating multiple feed points and switchable matching circuits. This universal antenna structure can be configured to operate in first communication bands (e.g., LTE/UMTS) and second communication bands (e.g., GSM/EDGE) independently or simultaneously, eliminating the need for separate dedicated antennas for each band and thereby reducing overall antenna system size
Solution Approach 2:
Multiple antenna functions for different frequency bands are merged into a single physical antenna element. The antenna element combines multiple feed points and associated matching circuits that can be selectively activated, allowing one antenna structure to perform the functions that would traditionally require multiple separate antennas, thus saving space within the mobile device
3Volume of moving object
If the antenna size is reduced to fit compact devices, then the device can maintain thin and small appearance, but the antenna's performance and coverage capability deteriorate
Solution Approach 1:
The antenna system uses switchable matching circuits to change the electrical parameters (impedance, resonant frequency, current distribution) of the antenna element depending on the operating band. This allows a compact antenna physical size to achieve optimal performance across different frequency bands by dynamically adjusting electrical parameters rather than relying on fixed physical dimensions
Solution Approach 2:
Different sections of the antenna element are designed with specific characteristics optimized for different frequency bands. By using multiple feed points at different locations along the antenna element, each feed point can excite different current distributions and resonant modes, allowing local optimization of antenna performance for specific bands while maintaining overall compact size
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
Enables multi-band operations in a compact form factor, achieving efficient antenna performance with reduced size, covering bands such as GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500, while maintaining high antenna efficiency across both bands.
Implementation Method 1
the antenna element generates a second resonant mode in a second band (lower band)... the antenna element generates a first resonant mode in a first band (higher band)
Data Source
AI summary
A communication device including a ground element and an antenna element is provided. An edge of the ground element has a notch, and the antenna element includes a metal element disposed inside the notch. The metal element of the antenna element has a first end and a second end. The first and second ends are spaced away from each other and are respectively positioned adjacent to two ends of a diagonal line of the notch. The first end is used as a first feeding point of the antenna element, and the second end is used as a second feeding point of the antenna element. The first feeding point is coupled through a switch and a first matching circuit to a first signal source, and the second feeding point is coupled through an inductive element and a second matching circuit to a second signal source.