Switched Capacitive Patch Antenna for Multi-Band RF
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Solution Overview
Problem
Existing RF antennas in cellular handsets require multiple antennas and complex circuitry to cover multiple cellular bands, leading to increased space and complexity, which is undesirable for smaller, more capable devices.
Innovation Solution
A single feed antenna system utilizing a multi-resonant design with capacitive patches and switching devices that selectively couple to a ground plane to cover multiple RF bands, minimizing physical volume and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antennas are used to cover multiple cellular bands, then bandwidth capabilities are improved, but device volume and circuit complexity increase
Solution Approach 1:
The patent implements a single antenna structure that can operate across multiple cellular bands (GSM 850, 900, 1800, 1900 MHz) by incorporating switchable capacitive patches. The antenna element and ground plane are designed to provide universal coverage for multiple frequency bands, eliminating the need for separate antennas for each band while maintaining adaptability across different cellular standards
Solution Approach 2:
The patent uses electronic switching mechanisms (SPDT switches) to dynamically reconfigure the antenna's electrical characteristics. By switching between different capacitive patch configurations, the antenna can adapt its resonant frequencies to match different cellular bands in real-time, providing dynamic bandwidth adjustment without physical changes to the antenna structure
2Adaptability or versatility
If multiple antennas are used to cover multiple cellular bands, then bandwidth capabilities are improved, but circuit complexity increases
Solution Approach 1:
The patent employs a single feed line and shared ground plane that serve multiple frequency bands, reducing the need for separate feed circuits for each antenna. The capacitive patches are electrically connected to the same feed point, allowing one circuit to perform multiple band operations rather than requiring separate circuits for each band
Solution Approach 2:
The switching circuitry uses SPDT switches to dynamically connect different capacitive patches to the feed line based on the desired operating band. This dynamic reconfiguration allows a single circuit to adapt to multiple bands rather than requiring permanent connections for each band, reducing overall circuit complexity while maintaining multi-band capability
3Volume of moving object
If a single feed antenna is used, then device volume is reduced, but bandwidth capabilities deteriorate
Solution Approach 1:
The patent divides the ground plane into multiple segmented regions, each associated with a specific capacitive patch. These segmented ground plane portions allow the single antenna to electrically distinguish between different frequency bands by switching which ground plane segment is active, thereby maintaining bandwidth capabilities despite using a single physical antenna structure
Solution Approach 2:
The patent changes the electrical parameters of the antenna by switching between different capacitive patch configurations. By altering the capacitance values connected to the feed line through the SPDT switches, the resonant frequency and impedance of the single antenna are adjusted to match different cellular bands, enabling multi-band operation from a single element
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 reception and transmission across multiple RF bands with minimal physical volume, reducing complexity and enhancing bandwidth capabilities while maintaining a low profile format.
Implementation Method 1
one or more capacitive patches, each of which is selectively coupleable to the ground plane
Implementation Method 2
a multi-resonant feed leg
Data Source
AI summary
An antenna system (102) for receiving and transmitting radio frequency (RF) signals within a plurality of predetermined RF bands includes a ground leg (202), a feed leg (206), one or more capacitive patches (212) and one or more switching devices (214). The feed leg (206) is coupled to the ground leg (202) at one portion thereof. Each of the one or more switching devices (214) is associated with one capacitive patch (212) and selectably couples its associated capacitive patch (212) to a ground plane (204) in order to receive and transmit RF signals within an associated predetermined RF band.