Multiband Yagi Antenna Layout for High Gain in Separate Bands
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Solution Overview
Problem
Existing multiband antennas are either too large for consumer use, offer insufficient gain for long-range applications, or are limited to single frequency bands due to coupling effects between directors and reflectors, making them unsuitable for simultaneous transmission/reception across non-overlapping frequency bands like Wi-Fi at 2.4 GHz and 5 GHz.
Innovation Solution
A Yagi-type multiband antenna design featuring a dipole and multiple director bars, each designed for specific frequency bands, with adjustable distances and angles between them, and optional reflector elements, allowing configuration for multiple frequency bands without the need for multiple antennas, enabling flexible frequency response and gain adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate antennas are used to cover different frequency bands, then each frequency band can be handled independently with optimal performance, but the overall device size and volume become too large for consumer use
Solution Approach 1:
The patent combines multiple Yagi antennas designed for different frequency bands (2.4 GHz, 5 GHz, and other bands) into a single integrated antenna structure. The director bars from different frequency-specific antennas are merged into one common structure, allowing the antenna to cover multiple non-overlapping frequency bands simultaneously while maintaining compact dimensions suitable for consumer devices like routers and access points.
2Adaptability or versatility
If a log-periodic antenna is used to achieve broadband coverage, then the antenna can receive signals across a wide frequency range, but the gain is limited to maximum 9-10 dBi which is insufficient for long-range applications
Solution Approach 1:
Instead of using a single log-periodic antenna structure that compromises gain for bandwidth, the patent segments the antenna into multiple frequency-specific Yagi sub-antennas, each optimized for a particular band. Each segment (director bar) is designed with specific dimensions and spacing optimized for its target frequency band, allowing each to achieve high gain (up to 18 dBi) while the collection of segments provides multiband coverage.
3Power
If a Yagi-Uda antenna is designed for a specific frequency band with optimized director bar dimensions, then high gain up to 18 dBi is achieved, but the antenna becomes narrowband and cannot operate across multiple frequency bands
Solution Approach 1:
The patent creates a universal Yagi antenna structure where the same physical framework supports multiple frequency-specific director bar configurations. The antenna can be adapted to different frequency bands by adjusting the dimensions and spacing of the director bars while maintaining the same basic Yagi-Uda geometry, thus achieving both high gain and multiband functionality through a single versatile design.
4Volume of moving object
If director bars for different frequency bands are placed close together in a combined antenna structure, then the overall antenna size is reduced, but coupling effects between directors and reflectors limit the number of directors to one or two for lower frequency bands
Solution Approach 1:
The patent resolves coupling issues by arranging director bars for different frequency bands in three-dimensional space rather than simply stacking them linearly. Director bars are positioned at different heights and angular orientations around the common reflector, utilizing vertical and angular dimensions to separate the electromagnetic fields of different frequency bands. This spatial separation reduces coupling effects while maintaining a compact overall 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 higher gain and directivity across multiple frequency bands, eliminating the need for multiple antennas and improving performance in specific frequency applications, while maintaining a compact design suitable for consumer use.
Implementation Method 1
a dipole (1) designed for a bandwidth that includes all working bands of the antenna, so that it allows multiband reception
Implementation Method 2
The directors 21, on the other hand, are elements located in the front area of the dipole that reinforce the field in said front area, increasing the directivity of the antenna
Implementation Method 3
reflector elements 4 located behind the dipole to reduce the level of the signal received at the back of the antenna and, at the same time, reinforce the signal received by the front of the antenna thus increasing directivity
Data Source
Figure 1~2b
Figure 3~4
Figure 5~6
AI summary
The invention relates to a Yagi-type multiband antenna comprising a dipole 1 connected to an input/output cable, a plurality of n director bars 2 (n>=2), each of them designed for a frequency band and fastening and supporting means 3 to which the director bars 2 are attached at one of their ends. The dipole 1 is designed for a bandwidth that includes all working bands of the antenna, so that it allows multiband reception. For their part, the director bars 2 meet each other at distances d1, d2,.., dn-1 this distance measured in the supporting element(s), and form angles α1, α2, ..., αn-1 with each other. This antenna is characterized in that at least two director bars 2 are designed for different frequency bands.