Antenna Conductor Layout With Capacitive Coupling for High Isolation
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Solution Overview
Problem
Existing antenna designs face challenges in achieving sufficient isolation between antennas while reducing return loss, particularly with the use of stub patterns.
Innovation Solution
The antenna device incorporates first and second antenna conductor patterns in a ground clearance area on a substrate, connected by a capacitive element within a specific range relative to the center position of the radiation pattern, to cancel inductive coupling and improve isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stub pattern is used to adjust coupling between antennas, then coupling adjustment is achieved, but sufficient isolation between antennas cannot be achieved
Solution Approach 1:
A capacitive element is introduced as an intermediary component between the first and second antenna conductor patterns. This capacitor mediates the coupling between the antennas, providing a controlled impedance path that achieves both coupling adjustment and sufficient isolation. The capacitive element acts as a bridge that manages the electromagnetic interaction between the two antennas more effectively than a stub pattern alone.
Solution Approach 2:
The invention changes the coupling mechanism by introducing a capacitive element with specific capacitance values. By adjusting the capacitance parameter of the inserted capacitor, the coupling between antennas can be precisely controlled while maintaining isolation. This parameter-based approach allows for fine-tuning of the antenna system performance without compromising isolation.
2Area of stationary object
If antenna patterns are arranged in ground clearance area, then space utilization is improved, but isolation between antennas deteriorates
Solution Approach 1:
The capacitive element serves as a mediator that enables close spacing of antenna patterns in the ground clearance area while maintaining isolation. By inserting the capacitor between the antenna conductor patterns, the electromagnetic coupling is controlled even when the antennas are positioned close together for space efficiency.
Solution Approach 2:
The invention extracts the isolation function from the physical spacing between antennas and transfers it to the capacitive element. This allows the antenna patterns to be positioned close together in the ground clearance area for space utilization, while the capacitor handles the isolation requirement independently of the physical distance.
3Reliability
If capacitive element is connected at center position of radiation pattern, then isolation is improved, but return loss characteristics deteriorate
Solution Approach 1:
The invention applies local quality by positioning the capacitive element at an offset location rather than the center of the radiation pattern. This asymmetric positioning creates different electrical characteristics at different locations, allowing the capacitor to provide isolation while the overall antenna structure maintains good return loss characteristics. The offset position optimizes the local electromagnetic field distribution.
Solution Approach 2:
The capacitive element is intentionally positioned asymmetrically relative to the radiation pattern center, within a specific range from the center position. This asymmetric arrangement breaks the symmetry of the antenna structure, enabling independent optimization of isolation and return loss characteristics. The asymmetric positioning allows the capacitor to affect coupling without being the sole determinant of return loss.
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
This configuration achieves high isolation and satisfactory return loss, gain, and radiation efficiency, while allowing for miniaturization and reduced return loss.
Implementation Method 1
a capacitive element connecting the first and second antenna conductor patterns
Implementation Method 2
connected by a capacitive element within a specific range relative to the center position of the radiation pattern, to cancel inductive coupling and improve isolation
Data Source
AI summary
Disclosed herein is an antenna device that includes a substrate, a ground conductor formed on the substrate, first and second antenna conductor patterns arranged in a ground clearance area on the substrate, and a capacitive element connecting the first and second antenna conductor patterns. The first antenna conductor pattern includes a first radiation pattern extending in a first direction from a first feed point. When a wavelength with respect to a center frequency of an electromagnetic wave in wireless communication using the first antenna conductor pattern is λ, the capacitive element is connected within a range between +λ/20 from a center position of the first radiation pattern in the first direction.