Multiband Antenna Design for Miniaturized Communication Devices
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Solution Overview
Problem
Existing portable communication devices face challenges in achieving multiband operations without increasing the antenna's size or volume, as they typically rely on exciting quarter-wavelength resonant modes, which limits their ability to cover low-frequency bands effectively.
Innovation Solution
A multiband antenna design featuring a dielectric substrate with a ground portion and a radiating metal portion, including a connecting metal strip and a feeding section with an open end spaced less than 3 mm from the radiating section, which excites dipole-like half-wavelength and one-wavelength modes to cover GSM850/900, 1800/1900/UMTS frequency bands, reducing the occupied area and enabling miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If quarter-wavelength resonant modes are excited to cover required frequency bands, then multiband operations are achieved, but the antenna length must be extended resulting in increased occupied area or volume
Solution Approach 1:
The antenna is divided into multiple independent resonant elements including a planar inverted-F antenna portion and additional resonant structures. Each segment can be independently tuned to operate at different frequency bands, allowing multiband coverage without requiring a single large antenna structure. The ground plane is also segmented into multiple regions to support different resonant modes.
Solution Approach 2:
The patent utilizes three-dimensional space by employing a folded configuration of the radiating element and positioning ground planes at different heights. The planar inverted-F antenna is folded to fit within a smaller footprint while maintaining the required electrical length for low-frequency operation. Additional resonant elements are positioned in the vertical dimension to provide multiband coverage without increasing the horizontal footprint.
2Adaptability or versatility
If the antenna length is extended to cover low-frequency bands, then frequency band coverage is improved, but the occupied area or volume of the antenna increases
Solution Approach 1:
Multiple resonant elements are nested within each other or positioned in a compact arrangement where smaller elements are placed within the space occupied by larger elements. The folded configuration of the radiating element allows it to be nested within the device housing while maintaining its electrical length. Additional resonant structures are positioned within the available space around the main antenna element.
Solution Approach 2:
The patent employs thin dielectric substrates and flexible ground plane structures to achieve the required antenna length within a compact form factor. The ground plane is implemented as a thin conductive layer that can be folded or positioned in three-dimensional space, allowing the antenna to maintain its electrical dimensions while minimizing the occupied 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 achieves efficient multiband operations with high radiation efficiency (>80% in low-frequency bands and >60% in high-frequency bands, meeting modern communication requirements while minimizing size and manufacturing costs.
Implementation Method 1
excite resonant modes contributed by a ground portion of a portable communication device to incorporate the resonant modes of antenna to cover required multiband operations
Data Source
AI summary
A multiband antenna for a communication device is disclosed. The multiband antenna comprises a dielectric substrate, a ground portion, and a radiating metal portion. The dielectric substrate comprises two surfaces. The ground portion comprises a first ground plane, a second ground plane, and a connecting metal strip. The first ground plane is on one of the surfaces of the dielectric substrate and has a first connecting point and a shorting point. The second ground plane is near the first ground plane and has a second connecting point. At least one part of the connecting metal strip is on one surface of the dielectric substrate. The connecting metal strip has one end connected to the first connecting point and the other end connected to the second connecting point. The radiating metal portion is connected to the dielectric substrate, without overlapping the first ground plane. The radiating metal portion comprises a radiating section having one end connected to the shorting point and the other end as an open end; and a feeding section having one end connected to a signal source and the other end as an open end, wherein the open end of the feeding section has a spacing of less than 3 mm to the radiating portion.