Planar Antenna Multi-Frequency Control via Switching
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Solution Overview
Problem
Conventional planar antennas in handheld devices require multiple radiators to operate at multiple central frequencies, leading to increased size and volume, making it difficult to change operating frequencies without redesigning the antenna structure, which contradicts the trend of miniaturization and complicates supporting multiple frequency bands.
Innovation Solution
A planar antenna with a single radiator and a control element, featuring short connectors and switches, allows the antenna to operate at multiple central frequencies by changing the resonant path through electrical coupling, enabling operation at different frequencies without altering the basic structure or increasing volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple radiators are provided in a conventional planar antenna to operate at multiple central frequencies, then the antenna can support multiple frequency bands, but the antenna structure becomes more complex and the volume increases
Solution Approach 1:
The patent applies dynamics by making the antenna structure adjustable through switching elements. A single radiator is configured with multiple switching elements that can change the effective electrical length and resonance characteristics of the antenna, enabling it to operate at multiple central frequencies (e.g., 900 MHz, 1800 MHz, 2100 MHz) without requiring multiple separate radiators. This dynamic reconfiguration allows the antenna to adapt its electrical properties while maintaining a compact physical structure.
Solution Approach 2:
The patent implements universality by designing a single radiator that can perform multiple functions - supporting operation across multiple frequency bands. The radiator is equipped with switching elements that enable it to function as different resonant structures (e.g., half-wave dipole, quarter-wave monopole) depending on the switching state, thereby replacing what would traditionally require multiple specialized radiators for different frequency bands.
2Ease of manufacture
If the antenna structure is fixed for a determined central frequency, then the antenna design is simplified, but it becomes difficult to change the operating frequency without redesigning the entire antenna structure
Solution Approach 1:
The patent resolves this contradiction by introducing switching elements that enable dynamic reconfiguration of the antenna's electrical characteristics. The switching elements can change the effective length and resonance properties of the single radiator, allowing frequency adjustment from 900 MHz to 2100 MHz without physical redesign. This maintains manufacturing simplicity while achieving frequency adaptability.
Solution Approach 2:
The patent applies parameter changes by using switching elements to alter the electrical parameters (effective length, capacitance, inductance) of the antenna structure. By changing these parameters through switching, the resonance frequency can be adjusted without changing the physical dimensions or basic structure of the radiator, enabling frequency reconfiguration while maintaining design simplicity.
3Reliability
If the clearance area size remains constant while antenna volume is reduced, then communication quality improves due to reduced interference from external electronic components, but the arrangement of internal space becomes less flexible
Solution Approach 1:
The patent's dynamic switching capability allows the antenna to optimize its performance within the given clearance area by electronically adjusting its resonant properties rather than requiring physical space changes. This enables the antenna to achieve better communication quality through reduced interference while maintaining design flexibility for internal space arrangement.
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 solution enables handheld devices to support multiple frequency bands with improved communication quality by reducing the antenna's volume and minimizing the influence of external electronic components, while maintaining flexibility in internal space arrangement and reducing the need for multiple radiators.
Implementation Method 1
the planar antenna operates at a first central frequency when the first switch is turned off and operates at a second central frequency when the first switch is turned on
Data Source
AI summary
A handheld device and a planar antenna thereof are provided. The planar antenna comprises a radiator having a feeding point, a first short point and a second short point. The feeding point is coupled to a circuit board of the handheld device so that the handheld device transmits and receives a RF (radio frequency) signal through the radiator. The first short point is coupled to a ground of the circuit board so as to be grounded. A control element is disposed on the handheld device or the planar antenna in order to control the second short point to be selectively electrically coupled to the ground so that the planar antenna can operate at two different central frequencies. Furthermore, the planar antenna can operate at multiple central frequencies by changing a position of the second short point contacted to the radiator.