Micropatch Antenna Cavity Design for Multipath Rejection
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Solution Overview
Problem
Conventional micropatch antennas face challenges in achieving a balance between small size, wide bandwidth, and low sensitivity to multipath reception, particularly when the ground plane length is on the order of 1-1.5 wavelengths, leading to increased sensitivity to multipath reflections.
Innovation Solution
A broadband micropatch antenna system is designed with a ground plane featuring a cavity structure, where the radiating element has a height from both the top and bottom surfaces optimized to reduce multipath sensitivity while maintaining high bandwidth, with the height from the bottom surface not exceeding 0.05λ, and a dual-band configuration is achieved by stacking radiating elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of the radiating element above the ground plane is increased to achieve wider bandwidth, then the bandwidth increases, but the sensitivity to multipath reception increases and the radiation pattern in the backward hemisphere increases
Solution Approach 1:
The ground plane is segmented into two distinct surfaces: a first surface (top surface) and a second surface (bottom surface) separated by a cavity. The radiating element is positioned within this cavity structure, creating distinct height measurements from each surface. This segmentation allows independent optimization of the height from the first surface for bandwidth and the height from the second surface for multipath rejection, resolving the technical contradiction between bandwidth and multipath sensitivity.
2Object-affected harmful factors
If the length of the ground plane is increased to reduce multipath reflections, then the ground plane size increases, but the radiation pattern in the backward hemisphere increases and sensitivity to multipath reception increases when length is 1-1.5 wavelengths
Solution Approach 1:
Instead of solving the multipath problem by extending the ground plane length in one dimension (which creates backward hemisphere radiation), the invention transitions to a three-dimensional cavity structure. By controlling the height of the radiating element from the bottom surface of the cavity to be no greater than 0.05λ, the design achieves multipath rejection through vertical dimension control rather than horizontal extension, thereby avoiding increased backward hemisphere radiation.
3Object-affected harmful factors
If edge ground elements are used to filter multipath radiation, then multipath filtration is improved, but the design is inefficient for broadband radiators with ground plane lengths of 1-1.5 wavelengths
Solution Approach 1:
The invention changes the critical parameter from horizontal ground plane extension to vertical height control within a cavity structure. By specifying that the height from the bottom surface of the cavity be no greater than 0.05λ, the design achieves effective multipath filtration for broadband applications without relying on edge ground elements, thereby resolving the inefficiency of previous designs for broadband radiators with ground plane lengths of 1-1.5 wavelengths.
Data Source
AI summary
A micropatch antenna system with simultaneous high bandwidth and low sensitivity to multipath radiation is achieved by positioning a radiating element within a cavity in a ground plane. Bandwidth and sensitivity to multipath radiation may be varied by varying the height of the radiating element above the bottom of the cavity and above the top of the ground plane. The electromagnetic and physical characteristics of the antenna system may be further controlled by introducing dielectric solids or wave-slowing structures between the bottom of the cavity and the radiating element. A dual-band micropatch antenna system with simultaneous high bandwidth and low sensitivity to multipath radiation may be similarly configured by stacking a second radiating element on top of the first radiating element.