Multi-band Loop Antenna with Slotted Opening for Compact Wireless Devices
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Solution Overview
Problem
Designing antennas for mobile wireless communications devices that provide desired operating characteristics within the limited space available while supporting multi-band performance and minimizing interference between different frequency bands.
Innovation Solution
A dual-band antenna design featuring first and second feed legs extending from a printed circuit board, a loop conductor with gaps, and conductor arms that define slotted openings into the loop conductor, allowing for increased multi-band performance and reduced interference, operating in both common and differential modes to cover GPS and WLAN frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna structure is made compact to fit limited device space, then the device size is reduced, but the antenna's operating characteristics and multi-band performance deteriorate
Solution Approach 1:
The antenna is divided into multiple conductor arms (first conductor arm, second conductor arm, third conductor arm) with different lengths and orientations. Each arm segment resonates at different frequency bands, enabling multi-band operation within a compact overall structure that fits limited device space while maintaining desired operating characteristics.
Solution Approach 2:
The antenna structure extends in multiple spatial dimensions with conductor arms arranged at different orientations and lengths. The first conductor arm extends in a first direction, the second conductor arm extends in a second direction, and the third conductor arm extends in a third direction, creating a three-dimensional configuration that achieves multi-band performance in a compact footprint.
2Adaptability or versatility
If multiple frequency bands are supported in a compact antenna, then multi-band performance is improved, but interference between different frequency bands increases
Solution Approach 1:
The conductor arms are designed with asymmetric lengths and orientations to support different frequency bands. The first conductor arm has a first length, the second conductor arm has a second length, and the third conductor arm has a third length, with each arm optimized for specific frequency ranges. This asymmetric design enables multi-band operation while minimizing mutual interference between bands through directional isolation.
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
The antenna achieves high efficiency, approximately 45% in the WLAN frequency band, and improved performance at lower frequencies, such as GPS, with reduced impact from the ground plane, while being adaptable to fit various housing sizes and shapes.
Implementation Method 1
a first conductor arm spaced above the PCB and extending between the first feed leg and the first end of the loop conductor, a second conductor arm spaced above the PCB and having a proximal portion extending between the second feed leg and the second end of the loop conductor
Implementation Method 2
The antenna may provide increased multi-band performance... operating in both common and differential modes to cover GPS and WLAN frequency bands
Data Source
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AI summary
A mobile wireless communications device may include a housing, a printed circuit board (PCB) (32) carried by the housing. The device may also include an antenna (35) coupled to wireless transceiver circuitry carried by the PCB. The antenna may include first and second feed legs (41), (42), extending upwardly from the PCB, a loop conductor (36) spaced above the PCB and having a gap (37) therein defining first and second ends, and a first conductor arm (45) spaced above the PCB and extending between the first feed leg and the first end. The antenna may further include a second conductor arm (46) spaced above the PCB and having a proximal portion (48) between the second feed leg and the second end, and having a distal portion (47) extending outwardly from the second feed leg. The first conductor arm and the proximal portion may define a slotted opening (51) into an interior of the loop conductor.