Slot Mode Antennas
Patent No. US11018432 (titled "Slot Mode Antennas") was filed by Suunto Oy on Feb 6, 2019.
What is this patent about?
’432 is related to the field of antennas for electronic devices, particularly those used in portable or wearable devices like smartwatches. The background acknowledges the increasing use of metal housings in such devices, which can interfere with traditional antenna designs. Slot antennas are presented as a solution, offering omnidirectional radiation patterns suitable for these challenging environments. Prior art solutions often involve specially manufactured slots, creating a need for a more integrated and efficient antenna design.
The underlying idea behind ’432 is to utilize the existing conductive bezel of a wearable device, in conjunction with a conductive rim on the circuit board, to form a slot antenna . This leverages the device's structural components to create a functional antenna, eliminating the need for dedicated antenna elements. The key insight is that the slot, defined by the gap between the bezel and the circuit board's rim, can be tuned to resonate at desired frequencies, such as those used by GNSS systems.
The claims of ’432 focus on an antenna assembly comprising a circuit board, a conductive body (like a bezel) positioned at a distance from the board, and a conductive rim structure on the circuit board's periphery. The conductive rim and the conductive body together define a slot mode antenna. Crucially, the length of the slot antenna is determined by the connection points where the conductive body is electrically connected to the conductive rim. A feed element is positioned between these connection points to couple the electromagnetic signal from the slot antenna to the circuit board.
In practice, the invention can be implemented in a smartwatch where the metal bezel acts as one side of the slot antenna, and a conductive trace on the edge of the printed circuit board acts as the other. The distance between the bezel and the PCB, along with the length of the slot defined by the connection points, determines the antenna's resonant frequency. A feed pin connects the antenna to the device's radio circuitry, allowing it to receive signals from GPS, Glonass, or other satellite navigation systems. The positioning of the feed pin is optimized to achieve an impedance match for the antenna at the GPS resonant frequency.
The invention differentiates itself from prior approaches by integrating the antenna directly into the device's existing structure. Instead of adding dedicated antenna components, it repurposes the bezel and circuit board rim to create the slot. This approach can lead to a more compact and aesthetically pleasing design, while also improving antenna performance in devices with metal housings. The omnidirectional radiation pattern of the slot antenna is particularly advantageous for wearable devices, ensuring reliable signal reception regardless of the device's orientation.
How does this patent fit in bigger picture?
Technical landscape at the time
In the late 2010s when ’432 was filed, antennas in portable electronic devices were commonly implemented using planar radiating elements with a ground plane, connected by a short-circuit conductor to achieve impedance matching. At a time when metal bodies were increasingly desirable for aesthetic reasons, typical antenna solutions struggled due to the RF shielding effect of the metal, favoring slot-type antennas for their omnidirectional properties, especially in devices requiring multi-band operation.
Novelty and Inventive Step
The claims were rejected under 35 U.S.C. 102(a)(1) as being anticipated by Fujisawa. Claims 1-26 were pending in the application. The prosecution record does not describe the technical reasoning or specific claim changes that led to allowance.
Claims
This patent contains 26 claims, with independent claims 1 and 14. Independent claim 1 focuses on an assembly for an antenna operating in a slot mode, while independent claim 14 focuses on an electronic wristwatch-like device with a slot mode antenna. The dependent claims generally elaborate on and refine the features and configurations described in the independent claims, providing more specific details about the antenna assembly and the wristwatch-like device.
Key Claim Terms New
Definitions of key terms used in the patent claims.
Patent Family
File Wrapper
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Date
Description
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US11018432
- Application Number
- US16268545
- Filing Date
- Feb 6, 2019
- Status
- Granted
- Expiry Date
- Feb 6, 2039
- External Links
- Slate, USPTO, Google Patents