Compact Multiband Antenna Using Slit Excitation for WLAN WiMAX
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multiband antennas, such as inverted-F antennas, are too large to be effectively integrated into mobile communication devices for simultaneous WLAN and WiMAX operations, limiting their applicability in modern wireless communication devices.
Innovation Solution
A multiband shorted monopole antenna with a coupling feed structure, comprising a substrate, ground plane, and a radiating metal element with a feeding portion, radiating portion, and shorting portion, where a slit is used to excite a rejected frequency band, generating multiple operating frequency bands, including WLAN and WiMAX frequencies, while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inverted-F antennas are used for WLAN operation, then WLAN functionality is achieved, but the antenna size becomes too large to fit in mobile communication devices
Solution Approach 1:
The antenna is divided into multiple functional segments: a radiating element with multiple arms extending in different directions, each arm contributing to different frequency bands. The radiating element includes a first arm for lower frequency bands and a second arm for higher frequency bands, allowing each segment to be optimized for specific frequency ranges while collectively achieving multiband operation in a compact form
Solution Approach 2:
The antenna structure transitions from a planar inverted-F configuration to a three-dimensional configuration with arms extending in multiple directions (x, y, and z dimensions). This spatial distribution allows the antenna to achieve multiband operation by utilizing different spatial orientations for different frequency bands, reducing the overall footprint area while maintaining functionality
2Area of moving object
If the antenna length is reduced to achieve compact size, then the antenna can fit in mobile devices, but impedance matching becomes difficult to achieve across multiple frequency bands
Solution Approach 1:
The antenna design utilizes variable parameters including arm lengths, arm widths, spacing between arms, and ground plane dimensions to achieve impedance matching across multiple frequency bands. By adjusting these geometric parameters, the antenna maintains proper impedance characteristics (close to 50 ohms) across WLAN and WiMAX bands despite the compact overall size
Solution Approach 2:
The ground plane serves as an intermediary element that facilitates impedance matching between the radiating arms and the feeding structure. The ground plane's specific dimensions and positioning help establish proper current distribution and electromagnetic field patterns that enable consistent impedance matching across different frequency bands in the compact antenna structure
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 impedance matching and operates in multiple frequency bands (2.4/5.2/5.8 GHz WLAN and 2.5/3.5/5.5 GHz WiMAX) with a small size (9×13 mm2), enabling seamless integration into mobile devices and efficient wireless communication.
Implementation Method 1
a radiating metal element (13) disposed on a surface (111) of the substrate (11)... an antenna feeding point (141) at one end (141) of the feeding portion (14) for electrically connecting to a signal source (18)
Implementation Method 2
a slit (17) for exciting a rejected frequency band to generate a operating frequency band for the multiband antenna (1)
Data Source
AI summary
A multiband antenna comprises a ground plane, a substrate, and a radiating metal element, wherein a side of the substrate is substantially adjacent to a side of the ground plane; the radiating metal element is on a surface of the substrate. The radiating metal element comprises a radiating portion having a slit, a shorting portion having a first end electrically connected to the radiating portion and a second end electrically connected to the ground plane, and a feeding portion; the feeding portion comprises an antenna feeding point for electrically connecting to a signal source, wherein a first spacing is formed between the feeding portion and the radiating portion, and a second spacing is formed between the feeding portion and the shorting portion.