Zeroth-Order Resonant Antenna Layout to Suppress Ground Plate Resonance
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Solution Overview
Problem
Existing wireless communication devices using zeroth-order resonant antennas face issues with current leakage to communication cables due to resonance of the ground plate at frequencies near the target frequency.
Innovation Solution
A wireless communication device configuration that includes a ground plate with a specific rectangular shape, a zeroth-order resonant antenna element with a counter conductor plate and short circuit portion, and a circuit module. The ground plate is positioned such that its length in the lengthwise direction deviates from integer multiples of λ/4, and the counter conductor plate is offset by a predetermined distance to suppress current excitation in the ground plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ground plate is used in a zeroth-order resonant antenna, then the antenna can achieve resonance at the target frequency, but current leakage to communication cables occurs due to ground plate resonance at frequencies near the target frequency
Solution Approach 1:
The ground plate is designed with an asymmetric rectangular shape where the length in the lengthwise direction is specifically controlled to deviate from integer multiples of λ/4, while the width in the widthwise direction is kept less than λ/2. This asymmetric dimensional design prevents resonance at frequencies near the target frequency, thereby reducing current leakage to communication cables while maintaining the zeroth-order resonance function.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the dimensional parameters of the ground plate. The length in the lengthwise direction is set to satisfy L ≥ λ/2 and L < (N + 0.25)λ (where N is an integer), and the width in the widthwise direction is set to W < λ/2. By adjusting these parameters to specific ranges, the ground plate resonance frequency is shifted away from the target frequency, eliminating current leakage while preserving antenna functionality.
2Power
If the ground plate dimensions are increased to improve antenna performance, then resonance characteristics may be enhanced, but the risk of ground plate resonance at nearby frequencies increases, causing current leakage
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges for the ground plate dimensions. The length in the lengthwise direction is constrained to L ≥ λ/2 and L < (N + 0.25)λ, while the width in the widthwise direction is constrained to W < λ/2. These parameter changes ensure that the ground plate maintains sufficient size for effective antenna operation while preventing resonance at frequencies near the target frequency, thus eliminating current leakage.
Solution Approach 2:
The patent converts the potential harmful effect of ground plate resonance into a beneficial design constraint. By deliberately designing the ground plate dimensions to avoid resonance conditions (L < (N + 0.25)λ and W < λ/2), the design transforms what could be a problematic resonance issue into a controlled parameter specification that ensures both effective antenna operation and elimination of current leakage.
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 proposed configuration effectively reduces current leakage to communication cables by preventing ground plate resonance, thereby enhancing the stability and efficiency of wireless communication.
Implementation Method 1
the zeroth-order resonant antenna element and the ground plate are configured to cause parallel resonance at the target frequency
Data Source
AI summary
A wireless communication device for transmitting and receiving radio waves of a target frequency includes a ground plate having a rectangular shape, a zeroth-order resonant antenna element arranged at a position shifted from a center of the ground plate in a lengthwise direction of the ground plate, and a circuit module configured to transmit and receive signal via the zeroth-order resonant antenna element. The zeroth-order resonant antenna element includes a counter conductor plate arranged at a predetermined distance from the ground plate and having a feed point connected to a feedline, and a short circuit portion electrically connecting the counter conductor plate and the ground plate. The ground plate, the counter conductor plate and the short circuit portion are configured to cause parallel resonance at the target frequency and satisfy a condition that resonance caused by the ground plate is reduced.