Cavity-Backed Stacked Antenna Unit for Broadband Radiation
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Solution Overview
Problem
Conventional antennas suffer from small bandwidths and issues with back radiation and surface wave radiation, limiting their performance.
Innovation Solution
An antenna unit with a first substrate, conductive layers, conductive vias forming a cavity, a feed conductor, and a patch, where the electric field between the patch and the conductive layers enhances oblique resonant directions, allowing for broader beamwidth and improved radiation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional microstrip antenna structure is used, then the antenna can be manufactured with simple processes, but the bandwidth is small and back radiation occurs
Solution Approach 1:
The antenna is divided into multiple stacked layers including a first substrate with a first conductive layer, a second substrate with a second conductive layer, and a patch structure. This segmentation into distinct functional layers creates a cavity-backed stacked planar antenna that achieves both ease of manufacture through standard PCB processes and improved performance with ultra-large fractional bandwidth exceeding 100%
Solution Approach 2:
The antenna transitions from a conventional two-dimensional microstrip structure to a three-dimensional stacked planar configuration with multiple substrates and conductive layers separated by dielectric materials. This dimensional expansion creates cavity resonance effects that dramatically broaden the bandwidth while maintaining planar manufacturing advantages
2Device complexity
If a conventional antenna structure is used, then the structure is simple, but the beamwidth is narrow and peak gain is limited
Solution Approach 1:
The antenna radiating structure is segmented into a feed conductor on the first substrate, a patch on the second substrate, and intermediate conductive layers, creating distinct functional zones that control the electromagnetic field distribution to achieve broader beamwidth and higher peak gain
Solution Approach 2:
Dielectric substrates and conductive vias act as intermediary elements between the feed conductor and patch, controlling the electromagnetic field interaction to enhance radiation performance. The dielectric layers mediate the field coupling while the conductive vias provide controlled impedance transitions, achieving broader beamwidth without increasing overall structural complexity
3Object-generated harmful factors
If a conventional antenna is used, then back radiation and surface wave radiation occur, but with the cavity-backed stacked planar structure, these harmful radiations are reduced
Solution Approach 1:
The harmful back radiation and surface wave components are extracted and contained within the cavity formed by the stacked conductive layers and dielectric substrates. The cavity structure confines the electromagnetic fields to productive radiation modes, eliminating the harmful omnidirectional back radiation characteristic of conventional microstrip antennas
Solution Approach 2:
The cavity structure that could potentially trap energy is instead used to constructive effect by creating resonant modes that enhance forward radiation. The multiple dielectric and conductive layers convert what would be lossy surface waves into controlled cavity resonances that improve the radiation pattern and reduce back radiation
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 unit achieves a broader beamwidth, ultra-large fractional bandwidth, reduced back radiation, and higher peak gain, while being easily mass producible using standard low-cost PCB processes.
Implementation Method 1
an electric field E is formed between the patch, the feed conductor and the opening edge of the second conductive layer to enhance the oblique resonant directions
Data Source
AI summary
An antenna unit is provided. The antenna unit includes a first substrate, a first conductive layer, a second conductive layer, a plurality of conductive vias, a feed conductor and a patch. The first substrate includes a first surface and a second surface, wherein the first surface is opposite to the second surface. The first conductive layer is disposed on the first surface. The second conductive layer is disposed on the second surface, wherein an opening is formed on the second conductive layer, and the opening has an opening edge. The conductive vias are formed in the first substrate and connect the first conductive layer to the second conductive layer, wherein the conductive vias surround the opening to define a cavity. The feed conductor extends above the opening to feed a wireless signal to the antenna unit. The patch is disposed above the opening and is separated from the feed conductor.