Tunable Loop Antenna with Switchable Inductor for Multi-Band Wireless
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Solution Overview
Problem
Conventional antenna structures in small electronic devices face challenges in covering multiple wireless communications bands due to limited bandwidth, making it difficult to fit efficient wireless communications circuitry in compact form factors.
Innovation Solution
The implementation of a loop antenna design with tunable matching circuitry, including a switchable inductor circuit, tunable matching network, and variable capacitor circuit, which allows the antenna to resonate across different frequency bands by adjusting impedance matching and capacitance, minimizing sensitivity to touch events and external objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional antenna structures are used in small electronic devices, then the device form factor remains compact, but the antenna bandwidth becomes too narrow to cover all communications bands of interest
Solution Approach 1:
The patent applies dynamics by making the antenna system adjustable through switching circuitry that can change the effective electrical length and impedance of the antenna. The antenna includes switchable components that allow it to be reconfigured for different frequency bands, transforming a static antenna into a dynamic, multi-band capable structure that adapts to different communication requirements while maintaining a compact form factor
Solution Approach 2:
The patent changes physical parameters of the antenna system by incorporating variable capacitance and inductance elements that can be switched to alter the resonant frequency and bandwidth. By changing these electrical parameters through switching circuitry, the antenna can operate across multiple frequency bands (including GSM, UMTS, and LTE bands) without requiring a larger physical structure
2Volume of moving object
If the antenna is confined to a small volume, then the device size is reduced, but the operating bandwidth becomes narrower
Solution Approach 1:
The patent implements nesting by integrating the antenna structure within the device housing, utilizing the housing itself as part of the antenna structure. The antenna is nested within the compact device form factor, with conductive elements integrated into the housing walls, allowing the antenna to achieve larger effective electrical dimensions while occupying minimal physical space
Solution Approach 2:
The patent applies dynamics by making the antenna system adjustable through switching circuitry that can change the effective electrical length and impedance of the antenna. The antenna includes switchable components that allow it to be reconfigured for different frequency bands, transforming a static antenna into a dynamic, multi-band capable structure that adapts to different communication requirements while maintaining a compact form factor
3Ease of manufacture
If the antenna structure is simplified for compact design, then manufacturing becomes easier, but the ability to cover multiple communications bands is compromised
Solution Approach 1:
The patent applies universality by designing a single antenna structure that can perform multiple functions across different frequency bands. The antenna system uses switching circuitry to reconfigure the same physical structure for different communications standards (GSM, UMTS, LTE), eliminating the need for separate antennas for each band and simplifying manufacturing while maintaining multi-band capability
Solution Approach 2:
The patent applies dynamics by making the antenna system adjustable through switching circuitry that can change the effective electrical length and impedance of the antenna. The antenna includes switchable components that allow it to be reconfigured for different frequency bands, transforming a static antenna into a dynamic, multi-band capable structure that adapts to different communication requirements while maintaining a compact form factor
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
Enables efficient operation across multiple wireless communications bands, including GSM, LTE, and UMTS, while maintaining performance and reducing sensitivity to user interaction, thus supporting a wide range of wireless communications standards in compact devices.
Implementation Method 1
An inductive element may be formed in parallel with the antenna feed terminals, whereas a capacitive element may be formed in series with one of the antenna feed terminals. The switching inductor circuit, the tunable matching circuit, and the variable capacitor serve as antenna tuning circuitry that can be used to allow the antenna to resonate at different frequency bands.
Implementation Method 2
radio-frequency transceiver circuitry that is coupled to the antenna using a transmission line
Data Source
AI summary
Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antenna structures. A parallel-fed loop antenna may be formed from portions of a conductive bezel and a ground plane. The antenna may operate in multiple communications bands. The bezel may surround a peripheral portion of a display that is mounted to the front of an electronic device. The bezel may contain a gap. Antenna feed terminals for the antenna may be located on opposing sides of the gap. A variable capacitor may bridge the gap. An inductive element may bridge the gap and the antenna feed terminals. A switchable inductor may be coupled in parallel with the inductive element. Tunable matching circuitry may be coupled between one of the antenna feed terminals and a conductor in a coaxial cable connecting the transceiver circuitry to the antenna.