Multiband Folded Loop Antenna for Dual-Band GSM Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional loop antennas face challenges in simultaneously covering GSM850/900 dual-band operation due to limited size and bandwidth, and existing solutions for single-band operation are not applicable to dual-band mobile phone antennas.
Innovation Solution
A multiband folded loop antenna design using a metal strip bent into a three-dimensional structure with a 0.5-wavelength resonant mode for the lower band and higher-order resonant modes for the upper band, combined with a matching circuit for dual-resonant characteristics and a tuning patch for improved impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the loop antenna size is greatly reduced to fit mobile phone space constraints, then the antenna can be embedded in mobile phones, but it has difficulty in simultaneously covering GSM850/900 dual-band operation
Solution Approach 1:
The patent transforms the conventional planar loop antenna into a three-dimensional folded structure. The loop strip is folded along specific axes to create a compact 3D configuration that maintains the electrical length required for dual-band operation while significantly reducing the occupied volume. This dimensional transformation allows the antenna to achieve both small size and adequate bandwidth coverage simultaneously.
Solution Approach 2:
The folded loop structure effectively nests the antenna elements within a compact volume. The loop strip is folded back on itself multiple times, creating a nested configuration where the antenna occupies minimal space while maintaining the necessary electrical path length for GSM850/900 dual-band operation.
2Adaptability or versatility
If conventional monopole antenna or PIFA antenna uses wide metal strip to increase bandwidth, then the bandwidth is improved, but the antenna size increases and cannot achieve compact design
Solution Approach 1:
The patent changes the geometric parameters of the antenna structure by folding the loop strip into a three-dimensional configuration. This parameter change allows the antenna to achieve increased bandwidth through the folded structure's resonant characteristics while maintaining a compact size, avoiding the need for wide metal strips used in conventional monopole or PIFA antennas.
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 five-band operation covering GSM850/900/1800/1900/UMTS bands with a smaller size than conventional antennas, maintaining high impedance matching and return loss above 6 dB across all bands, while saving space in mobile devices.
Implementation Method 1
the 0.5-wavelength resonant mode of the loop strip is used for the lower band of the antenna, and the higher-order resonant modes of the loop strip are formed into a wide upper band
Data Source
AI summary
The present invention relates to a multiband folded loop antenna comprising a dielectric substrate, a ground plane, a radiating portion and a matching circuit. The ground plane is located on the dielectric substrate and has a grounding point. The radiating portion comprises a supporter, a loop strip, and a tuning patch. The loop strip has a length about a half-wavelength of the central frequency of the antenna's first resonant mode. The loop strip has a feeding end and a grounding end, with the grounding end electrically connected to the grounding point on the ground plane. The loop strip is folded into a three-dimensional structure and is supported by the supporter. The tuning patch is electrically connected to the loop strip. The matching circuit is located on the dielectric substrate with one terminal electrically connected to the feeding end of the loop strip and another terminal to a signal source.