Circularly polarized antenna structures and wearable devices
Provided are a circularly polarized antenna structure and a wearable device. The circularly polarized antenna structure is applicable to the wearable device and includes: a mainboard; an annular radiator, having an effective perimeter equal to a wavelength corresponding to a central operating frequency of the antenna structure; a feeding terminal electrically connected to the radiator at one end and connected to a feeding module of the mainboard at the other end; and a grounding terminal electrically connected to the radiator at one end and electrically connected to a grounding module of the mainboard through a first capacitor at the other end. With the antenna structure of the present disclosure, a circularly polarized antenna may be implemented in the wearable device.
1 . An antenna structure, applicable to a wearable device, the antenna structure being circularly polarized and comprising:
a mainboard;
an annular radiator having an effective perimeter equal to a wavelength corresponding to a central operating frequency of the antenna structure;
a feeding terminal electrically connected to the radiator at a first end and connected to a feeding module of the mainboard at a second end; and
a grounding terminal electrically connected to the radiator at a first end and electrically connected to a grounding module of the mainboard through a first capacitor at a second end, wherein a current in the annular radiator is pulled by the first capacitor, such that the annular radiator produces an effective circulating current being rotated, thereby realizing a circularly polarized antenna structure.
2 . The antenna structure according to claim 1 , wherein a first included angle β is formed along a first direction from a first connecting line connected between the feeding terminal and a center point of the radiator, to a second connecting line connected between the grounding terminal and the center point of the radiator;
the first direction is a counterclockwise direction around the radiator; and
β
∈
(
0
,
π
2
)
⋃
(
π
,
3
π
2
)
.
3 . The antenna structure according to claim 2 , wherein the first included angle β is an angle between 10° to 80°.
4 . The antenna structure according to claim 1 , wherein a first included angle β is formed along a first direction from a first connecting line connected between the feeding terminal and a center point of the radiator, to a second connecting line connected between the grounding terminal and the center point of the radiator;
the first direction is a counterclockwise direction around the radiator; and
β
∈
(
π
2
,
π
)
⋃
(
3
π
2
,
2
π
)
.
5 . The antenna structure according to claim 1 , wherein the radiator has an unbroken annular structure.
6 . The antenna structure according to claim 1 , wherein the antenna structure comprises one of:
a satellite positioning antenna, a Bluetooth antenna, a WiFi antenna, or a 4G/5G antenna.
7 . The antenna structure according to claim 1 , wherein
the first capacitor has a capacitance value of 0.2 pF to 1.5 pF.
8 . The antenna structure according to claim 1 , wherein the antenna structure is a right-hand circularly polarized antenna.
9 . The antenna structure according to claim 1 , wherein a gap is formed between the radiator and the mainboard.
10 . The antenna structure according to claim 1 , wherein a circulating current is produced in the radiator such that the antenna structure is in circular polarization.
11 . The antenna structure according to claim 1 , wherein the first capacitor is configured to pull a generated current rotating in a single direction inside the radiator.
12 . A wearable device, comprising the antenna structure according to claim 1 .
13 . The wearable device according to claim 12 , wherein the wearable device comprises a smart watch, the smart watch comprising:
a case in which the mainboard is disposed; and
a metal bezel surrounding an edge of an open end of the case and forming the radiator.
14 . The wearable device according to claim 13 , wherein
the smart watch further comprises a screen assembly assembled to the open end of the case through the metal bezel.
15 . The wearable device according to claim 12 , wherein the wearable device comprises a smart watch, the smart watch comprising a case in which the mainboard is disposed, wherein the case comprises a metal middle frame, and at least part of the metal middle frame forms the radiator.
16 . The wearable device according to claim 12 , wherein the radiator has an unbroken annular structure.
17 . The antenna structure according to claim 1 , wherein the feeding terminal and the grounding terminal are integrally formed with the radiator and connected to the mainboard through elastic members.
18 . The antenna structure according to claim 1 , wherein a physical perimeter of the radiator is less than the wavelength corresponding to the central operating frequency of the antenna structure.
19 . The antenna structure according to claim 1 , wherein the feeding terminal is connected to the radiator directly at the first end and connected to the feeding module of the mainboard directly at the second end.