Switchable Parasitic Element Antenna for SAR Reduction
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Solution Overview
Problem
The challenge in cellular devices is to miniaturize multi-functional wireless communications devices while minimizing the specific absorption rate (SAR) and improving hearing aid compatibility (HAC), as internal antennas are close to the user's head and can cause interference with other components, complicating design and performance.
Innovation Solution
A multiple-band antenna design featuring a first radiator with a parasitic element that can be switched between floating and grounded states, and a second radiator insulated from the first, supported by a non-planar dielectric substrate, allowing independent tuning of low and high band frequencies and controlling resonance and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If internal antennas are used to reduce device size, then device footprint is reduced, but specific absorption rate (SAR) increases due to close proximity to user's head
Solution Approach 1:
The antenna system is divided into multiple independent radiators (first radiator, second radiator, third radiator) that can be independently controlled and tuned. This segmentation allows each radiator to be optimized for specific frequency bands while maintaining compact overall device size, thereby reducing SAR exposure compared to a single large internal antenna.
Solution Approach 2:
The patent employs switchable parasitic elements that can be dynamically switched between connected and disconnected states to tune the antenna resonance frequencies. This dynamic tuning capability allows the antenna system to adapt to different operating conditions and frequency bands, optimizing performance while maintaining small device footprint and controlling SAR.
2Volume of moving object
If internal antennas are used to reduce device footprint, then device size is reduced, but hearing aid compatibility (HAC) is negatively affected
Solution Approach 1:
The antenna system is divided into multiple independent radiators (first radiator, second radiator, third radiator) that can be independently controlled and tuned. This segmentation allows each radiator to be optimized for specific frequency bands while maintaining compact overall device size, thereby reducing SAR exposure compared to a single large internal antenna.
Solution Approach 2:
The patent employs switchable parasitic elements that can be dynamically switched between connected and disconnected states to tune the antenna resonance frequencies. This dynamic tuning capability allows the antenna system to adapt to different operating conditions and frequency bands, optimizing performance while maintaining small device footprint and controlling SAR.
3Adaptability or versatility
If multiple antennas are installed to support multi-functional devices, then functionality is improved, but device complexity and size increase
Solution Approach 1:
The patent designs a multiband antenna system where multiple radiators can operate across different frequency bands (GSM 850, GSM 1900, PCS 1900, etc.). The switchable parasitic elements enable a single antenna structure to perform multiple functions by tuning to different resonant frequencies, reducing the need for separate antennas for each function.
Solution Approach 2:
The patent combines multiple antenna functions into a single integrated antenna structure with shared components. The first, second, and third radiators along with common parasitic elements form a unified antenna system that supports multiple frequency bands and functions, thereby reducing overall device complexity compared to using separate antennas for each function.
4Adaptability or versatility
If multiple antennas are installed to support multi-functional devices, then functionality is improved, but device miniaturization becomes more difficult
Solution Approach 1:
The patent designs a multiband antenna system where multiple radiators can operate across different frequency bands (GSM 850, GSM 1900, PCS 1900, etc.). The switchable parasitic elements enable a single antenna structure to perform multiple functions by tuning to different resonant frequencies, reducing the need for separate antennas for each function.
Solution Approach 2:
The patent combines multiple antenna functions into a single integrated antenna structure with shared components. The first, second, and third radiators along with common parasitic elements form a unified antenna system that supports multiple frequency bands and functions, thereby reducing overall device complexity compared to using separate antennas for each function.
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 enhances antenna performance, reduces SAR and HAC issues, and allows for a smaller device form factor by independently controlling low and high band frequencies, thus addressing the challenges of miniaturization and interference in cellular devices.
Implementation Method 1
a first radiator comprising a radiator element and a parasitic element adjacent thereto, the parasitic element being selectively switchable between floating and grounded states
Implementation Method 2
multiple-band antenna design featuring a first radiator with a parasitic element that can be switched between floating and grounded states
Implementation Method 3
supported by a non-planar dielectric substrate, allowing independent tuning of low and high band frequencies
Data Source
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AI summary
A mobile wireless communications device (30) may include a housing (96), a wireless transceiver (31) carried by the housing, and a multiple-band antenna (32) carried by the housing and coupled to the wireless transceiver. The multiple-band antenna may include a first radiator (33) comprising a radiator element (36) and a parasitic element (35) adjacent to the radiator element. The parasitic element may be selectively switchable between floating and grounded states. The multiple-band antenna may include a second radiator (34) insulated from the first radiator.