Adjustable Multiband Antenna Switch Reactance
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Solution Overview
Problem
Existing multiband antennas face challenges in adjusting resonance frequencies to cover multiple radio systems' frequency ranges due to space constraints in small mobile devices, leading to reduced bandwidth and difficulties in maintaining optimal radio connection quality.
Innovation Solution
The antenna design incorporates a switch-based adjusting circuit with variable components and a thin dielectric substrate, allowing independent adjustment of lower and upper operating bands by changing the reactance between the adjusting point and ground, which reduces space requirements and improves efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the antenna bandwidth is increased to cover multiple radio systems' frequency ranges, then the operating band coverage is improved, but the device thickness must be increased which contradicts the miniaturization trend
Solution Approach 1:
The patent implements dynamic adjustability of the antenna's resonance frequency through an electrical switching mechanism. The antenna structure includes a switchable connection between the radiating plane and ground plane, allowing the resonance frequency to be changed electrically. This enables the antenna to adapt to different frequency ranges (e.g., GSM1800 and GSM1900) without requiring physical size changes, thus maintaining thin device profile while achieving multi-band coverage.
2Volume of moving object
If the distance between the radiating plane and ground plane is reduced to achieve compact size, then the device form factor is improved, but the antenna bandwidth decreases
Solution Approach 1:
The patent compensates for the reduced bandwidth caused by compact dimensions through dynamic frequency adjustment capability. By implementing switchable connections that allow electrical tuning of the resonance frequency, the antenna can optimize its performance for specific frequency ranges even with reduced physical dimensions. This dynamic adaptation enables the compact antenna to maintain adequate bandwidth for its intended operating bands.
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 design achieves desired band displacements with low current losses, enhancing radiation characteristics and matching in both bands without reshaping the radiator, while maintaining a compact form factor.
Implementation Method 1
the antenna resonance frequency becomes higher and the operating band corresponding to the resonance frequency is displaced upwards
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3c
AI summary
An adjustable multiband antenna especially intended to mobile terminals. The antenna structure comprises a radiator (320), a feed element (330) and an adjusting circuit (350). The radiator is a conductive part of the outer cover (COV) of a radio device or conductive coating of the cover. It is fed electromagnetically by a feed element which is isolated from the radiator by a relatively thin dielectric substrate. The feed element is connected either directly or through an intermediate element (340) to the antenna port of the device and to the ground plane (310), and it is shaped so that the antenna has at least two operating bands. The adjusting circuit is connected to an adjusting point (AP) in the feed element, and the reactance between the adjusting point and ground and thus the electric size of the antenna can be changed by means of a switch (SW) in the adjusting circuit. Among other things, the component values of the adjusting circuit and the distance between the short-circuit (SP) and adjusting (AP) points in the feed element are variables from the point of view of the antenna adjustment. Displacements, which have desired directions and lengths, are obtained for at least two operation bands of the antenna independently from each other by changing the switch state. The efficiency of the antenna is better than of the corresponding known antennas, and its matching can be made good both in lower and upper operating band of the antenna.