Multiband Monopole Slot Antenna for Mobile Devices
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Solution Overview
Problem
Existing antennas embedded in notebook computers are primarily designed for WLAN operation and are not suitable for multiband mobile communication systems due to their size, making it difficult to fit into mobile communication devices that require coverage of GSM850/900/DCS/PCS/UMTS bands.
Innovation Solution
A multiband monopole slot antenna is designed with a ground plane, dielectric substrate, and a microstrip feedline, featuring three monopole slots and a step-shaped microstrip feedline that allows series-fed operation across GSM850, 900, and DCS/PCS/UMTS bands, enabling compact integration in mobile devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual-band antenna is designed on a ground plane built in the backplane of the LCD display, then WLAN operation is achieved, but the antenna size is too large to fit into mobile communication devices
Solution Approach 1:
The antenna is divided into three separate monopole slots (first, second, and third monopole slots) with different lengths, each resonating at different frequency bands. This segmentation allows the antenna to cover multiple frequency bands (GSM850/900 and DCS/PCS/UMTS) while maintaining a compact overall structure that fits within mobile communication devices.
Solution Approach 2:
Each monopole slot has a different length to create local variations in resonant frequency. The first monopole slot is longest for lower frequency bands, the second is shortest for higher frequency bands, and the third is intermediate. This local quality differentiation enables multiband operation within a small total area.
2Volume of moving object
If the antenna structure is simplified for compact size, then integration into mobile devices is improved, but achieving multiband operation becomes difficult
Solution Approach 1:
The microstrip feedline is designed with a step shape that dynamically adjusts the feeding positions for different monopole slots. The feedline includes sections parallel to each monopole slot at different distances from the ground plane, allowing the same compact structure to resonate at multiple frequency bands by adjusting which slots are excited and how.
3Adaptability or versatility
If three monopole slots are arranged to cover multiple frequency bands, then multiband operation is achieved, but the antenna structure becomes more complex
Solution Approach 1:
Three monopole slots and a step-shaped microstrip feedline are merged into a single integrated structure printed on one side of the substrate. The feedline serves all three slots simultaneously, and the slots are arranged in parallel to share common grounding, reducing overall structural complexity compared to separate antenna elements.
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 multiband operation with adjusted resonant modes and impedance matching, covering GSM850/900 and DCS/PCS/UMTS bands, with measured return loss and radiation efficiency suitable for mobile communication devices.
Implementation Method 1
The first monopole slot can generate a resonant mode near a quarter wavelength of a lower frequency at about 900 MHz, the second monopole slot can generate a resonant mode near a quarter wavelength of a higher frequency at about 1900 MHz
Implementation Method 2
The microstrip feedline is on the surface opposite to the metal surface of the dielectric substrate and can be printed or etched on the dielectric substrate. A first end of the microstrip feedline is connected to a signal source
Data Source
AI summary
A multiband monopole slot antenna includes a ground plane, a dielectric substrate, a radiating portion, and a microstrip feedline. The dielectric substrate is connected to an edge of the ground plane and extends toward the opposite direction of the ground plane. The radiating portion is on the metal surface of the dielectric substrate and includes a first monopole slot, a second monopole slot and a third monopole slot. The microstrip feedline is on the surface opposite to the metal surface of the dielectric substrate. A first end of the microstrip feedline is connected to a signal source, and a second end of the microstrip feedline is an open end. The microstrip feedline passes over the first, second, and third monopole slots. A section of the microstrip feedline which passes over the third monopole slot is parallel to the third monopole slot, and the microstrip feedline is generally of a step shape.