Waveguide-Slit Antenna Structure for Surface Wave Suppression
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Solution Overview
Problem
Existing antenna devices that use artificial magnetic conductor (AMC) elements to suppress surface wave propagation require a large number of AMC elements, leading to increased antenna size and reduced gain.
Innovation Solution
An antenna device with a substrate having multiple insulating layers, a ground electrode, and a waveguide structure featuring a slit and conductor wall, where the waveguide structure's dimension in the magnetic field direction is greater than half a wavelength, and the length from the slit to its terminal is a quarter wavelength, effectively suppressing surface wave propagation and improving antenna gain while reducing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a certain number of AMC elements are used to suppress surface wave propagation, then antenna gain is improved, but device size increases
Solution Approach 1:
The invention divides the ground electrode into multiple regions with different impedance characteristics. Specifically, a first ground electrode region with higher impedance and a second ground electrode region with lower impedance are created, allowing selective suppression of surface waves without requiring numerous AMC elements throughout the entire structure.
Solution Approach 2:
Different regions of the ground electrode are assigned different electrical properties. The first ground electrode region under the radiation electrode has higher impedance to suppress surface waves in the critical radiation area, while the second region has lower impedance to maintain overall conductivity and reduce total device size.
2Volume of stationary object
If the number of AMC elements is reduced to decrease device size, then surface wave suppression becomes insufficient, but antenna gain improvement is maintained through alternative structure
Solution Approach 1:
The ground electrode is segmented into regions with different impedance values, creating a first region for surface wave suppression and a second region for maintaining conductivity. This segmentation allows effective surface wave control with fewer elements compared to uniform AMC structures.
Solution Approach 2:
The impedance parameter of the ground electrode is varied spatially by dividing it into regions with different numbers of via holes. The first region has higher impedance (fewer via holes) for surface wave suppression, while the second region has lower impedance (more via holes) for maintaining overall electrical continuity, achieving effective suppression with reduced element count.
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 solution enhances antenna gain while minimizing the overall device size by effectively interrupting surface wave currents and optimizing the waveguide structure's dimensions to improve directivity and reduce the number of AMC elements required.
Implementation Method 1
The waveguide structure has a slit and a conductor wall... A dimension of the waveguide structure in a magnetic field direction of the radiation electrode in the plan view is greater than 1/2 of a wavelength of a radio wave emitted by the radiation electrode in a medium of the substrate. A length from the slit to a terminal portion of the waveguide structure in the electric field direction of the radiation electrode in the plan view is about 1/4 of a wavelength of the radio wave emitted by the radiation electrode in the waveguide structure.
Implementation Method 2
a radiation electrode, and a waveguide structure... a wavelength of a radio wave emitted by the radiation electrode
Data Source
AI summary
An antenna device includes a substrate, a first ground layer, a radiation electrode, and waveguide structures. Each of the waveguide structures has a slit and a conductor wall. The slit is positioned in an electric field direction of the radiation electrode and provided in the first ground layer. The conductor wall surrounds the slit and extends in a thickness direction of the substrate. A dimension of the waveguide structure in a magnetic field direction in plan view is greater than ½ of a wavelength of a radio wave emitted by the radiation electrode in a medium of the substrate. A length from the slit to a terminal portion of the waveguide structure is about ¼ of a wavelength of the radio wave emitted by the radiation electrode in the waveguide structure.