Switchable Gain Antenna Using Selective Impedance Transformers
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Solution Overview
Problem
Current antenna systems for wireless access points face challenges in designing a small-size antenna system with switchable radiation gain due to signal reflection and multipath fading in indoor environments.
Innovation Solution
The antenna system incorporates a signal feeding element, first and second antenna elements, diodes, switch elements, and impedance transformers to selectively adjust radiation gain by switching between different impedance transformers and enabling/disabling antenna elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antenna elements and impedance transformers are added to achieve switchable radiation gain, then adaptability is improved, but device complexity increases
Solution Approach 1:
The antenna system employs switchable impedance transformers that can dynamically change their impedance transformation ratio based on operating conditions. The first impedance transformer has a first transformation ratio and the second impedance transformer has a second transformation ratio, allowing the system to adapt between different radiation gain states (approximately 3 dBi and 9 dBi) by switching between transformers or combining them in different configurations.
Solution Approach 2:
The antenna system is divided into multiple independent antenna elements (first antenna element and second antenna element) that can be selectively activated. Each antenna element can be independently controlled through diodes and switch elements, allowing the system to segment the radiation function and activate only the necessary portions based on communication requirements.
2Power
If antenna elements are enabled to increase radiation gain, then power is improved, but loss of energy increases due to signal reflection and multipath fading
Solution Approach 1:
The system changes the impedance transformation ratio parameter to optimize power transfer and minimize reflections. By selecting between different impedance transformers with different transformation ratios, or by switching their connection configurations, the system adapts the impedance matching to combat multipath fading and reduce energy loss from signal reflections in indoor environments.
Solution Approach 2:
The switchable impedance transformer configuration enables the system to respond to channel conditions by selecting appropriate impedance transformations. This feedback mechanism allows the antenna system to adapt to varying signal propagation conditions, reducing the impact of multipath fading by optimizing the radiation pattern and impedance matching based on current operating conditions.
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 allows for adjustable radiation gain, providing either low (about 3 dBi) or high (about 9 dBi) gain depending on the selected impedance transformer and diode state, enhancing communication quality and adaptability.
Implementation Method 1
The first diode has an anode coupled to the first connection point, and a cathode coupled to the second connection point
Implementation Method 2
The selected first target transformer is coupled between the first connection point and the signal feeding element
Data Source
AI summary
An antenna system with switchable radiation gain includes a signal feeding element, a first antenna element, a second antenna element, a first diode, a first switch element, a second switch element, a first impedance transformer, and a second impedance transformer. The first antenna element is coupled to a first connection point. The second antenna element is coupled to a second connection point. The first diode has an anode coupled to the first connection point, and a cathode coupled to the second connection point. The first switch element and the second switch element are configured to select either the first impedance transformer or the second impedance transformer as a first target transformer, and the selected first target transformer is coupled between the first connection point and the signal feeding element.