Multi-band Antenna with Cone Element for Low Profile
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Solution Overview
Problem
Existing multi-band radio frequency antennas face challenges in operating across non-harmonically related frequency bands, often resulting in phase reversal and azimuth pattern distortion due to bulky designs that are not suitable for various environments and devices with different functionalities.
Innovation Solution
A multi-band antenna design featuring a cone-shaped high-frequency antenna element with a tip electrically isolated from the ground plane and three low-frequency antenna elements extending between the cone's base and the ground plane, providing a compact and symmetric structure that maintains uniform radiation patterns across 700 MHz to 8.5 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a monopole antenna with choke and patch antenna is used to achieve multi-band operation, then frequency band coverage is improved, but antenna height increases and causes phase reversal and pattern distortion
Solution Approach 1:
The antenna is segmented into distinct functional elements: a low-band monopole element and a high-band patch element with slots, each optimized for specific frequency ranges. This segmentation allows each element to operate independently in its designated band without interfering with the other, achieving multi-band coverage without the phase reversal issues of unified monopole designs.
Solution Approach 2:
The patent transitions from a one-dimensional monopole structure to a two-dimensional patch antenna structure for high-band operation. The patch element lies in the same plane as the ground plane, reducing the overall antenna height while maintaining effective high-frequency radiation through the slot configurations.
2Adaptability or versatility
If patch antenna exceeds 1/4 wavelength in high band frequencies, then high frequency operation is achieved, but azimuth pattern distortion increases
Solution Approach 1:
The patch antenna incorporates slots with specific local geometries and positions that are optimized for their local electromagnetic field distribution. The slots are strategically placed to create localized current paths that maintain symmetric radiation patterns even when the overall patch dimensions exceed traditional wavelength guidelines.
3Device complexity
If monopole antenna is used for high frequency operation, then simple structure is achieved, but phase reversal occurs causing elevation pattern split
Solution Approach 1:
The patent extracts the high-frequency radiation function from the monopole structure and places it in a separate patch antenna element. This removes the source of phase reversal from the overall antenna system, as the patch element operates independently with its own current distribution that does not exhibit the phase reversal characteristic of monopole antennas at high frequencies.
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 a bandwidth of 12:1 with a VSWR of less than 1.7 and symmetric azimuth patterns, significantly exceeding Chu-Wheeler-McLean predictions, while maintaining a low profile and minimizing pattern distortion.
Implementation Method 1
a cone-shaped relatively high frequency antenna element with a tip of the high frequency antenna disposed adjacent to but electrically isolated from the ground plane
Implementation Method 2
at least three relatively low frequency antenna elements electrically connected to and extending between the base of the cone-shaped antenna element and the ground plane
Data Source
AI summary
A multi-band antenna is provided that operates in at least two non-harmonically related frequency bands. The antenna includes a ground plane, a cone-shaped relatively high frequency antenna element with a tip of the high frequency antenna disposed adjacent to but electrically isolated from the ground plane with a base of the cone-shaped antenna element extending away from the ground plane, and at least three relatively low frequency antenna elements electrically connected to and extending between the base of the cone-shaped antenna element and the ground plane.