US-12627059-B2 - Antenna structure and communication device

US12627059B2US 12627059 B2US12627059 B2US 12627059B2US-12627059-B2

Abstract

An antenna structure includes a first radiation element, a second radiation element, a third radiation element, an inductor, and a dielectric substrate. The first radiation element has a first feeding point. The second radiation element has a second feeding point. The second radiation element is adjacent to the first radiation element. The third radiation element is coupled through the inductor to the second radiation element. The first radiation element, the second radiation element, and the third radiation element are all disposed on the dielectric substrate.

Inventors

Cheng-Geng Jan
Chieh-Sheng Hsu
Tsung-Hsing Tsai

Assignees

WISTRON NEWEB CORP.

Dates

Publication Date: 20260512
Application Date: 20231016
Priority Date: 20221103

Claims (19)

1 . An antenna structure, comprising: a first radiation element, having a first feeding point; a second radiation element, having a second feeding point, wherein the second radiation element is adjacent to the first radiation element; an inductor; a third radiation element, coupled through the inductor to the second radiation element; and a dielectric substrate, wherein the first radiation element, the second radiation element, and the third radiation element are disposed on the dielectric substrate; wherein the first feeding point is coupled to a positive electrode of a signal source, and the second feeding point is coupled to a negative electrode of the signal source; wherein the first radiation element, the second radiation element, and the third radiation element are excited to generate a first frequency band: wherein the first radiation element and the second radiation element are excited to generate a second frequency band and a third frequency band; wherein the second frequency band is higher than the first frequency band, and wherein the third frequency band is higher than the second frequency band.
2 . The antenna structure as claimed in claim 1 , wherein any of the first radiation element, the second radiation element, and the third radiation element substantially has a rectangular shape, a pentagonal shape, or a hexagonal shape.
3 . The antenna structure as claimed in claim 1 , wherein the first frequency band is from 746 MHz to 894 MHz, the second frequency band is from 1710 MHz to 2200 MHz, and the third frequency band is from 3300 MHz to 4200 MHz.
4 . The antenna structure as claimed in claim 1 , wherein the antenna structure provides an almost omnidirectional radiation pattern within the first frequency band, the second frequency band, and the third frequency band.
5 . The antenna structure as claimed in claim 1 , wherein a length of the first radiation element is substantially equal to 0.25 wavelength of the second frequency band.
6 . The antenna structure as claimed in claim 1 , wherein a length of the second radiation element is substantially equal to 0.25 wavelength of the second frequency band.
7 . The antenna structure as claimed in claim 1 , wherein a total length of the second radiation element and the third radiation element is substantially equal to 0.25 wavelength of the first frequency band.
8 . The antenna structure as claimed in claim 1 , wherein the inductor is considered as a short-circuited element within the first frequency band, and wherein the inductor is considered as an open-circuited element within the second frequency band and the third frequency band.
9 . The antenna structure as claimed in claim 1 , wherein an inductance of the inductor is from 4 nH to 6 nH.
10 . The antenna structure as claimed in claim 1 , wherein the inductor is a lumped inductor or a choke line inductor.
11 . The antenna structure as claimed in claim 1 , wherein the dielectric substrate has a first surface and a second surface opposite to each other, and wherein the first radiation element, the second radiation element, and the third radiation element are disposed on the first surface of the dielectric substrate.
12 . An antenna structure, comprising: a first radiation element, having a first feeding point; a second radiation element, having a second feeding point, wherein the second radiation element is adjacent to the first radiation element; an inductor; a third radiation element, coupled through the inductor to the second radiation element; a dielectric substrate, wherein the first radiation element, the second radiation element, and the third radiation element are disposed on the dielectric substrate; a first extension radiation element, coupled to one side of the third radiation element; and a second extension radiation element, coupled to an opposite side of the third radiation element, wherein the second extension radiation element is substantially parallel to the first extension radiation element.
13 . The antenna structure as claimed in claim 12 , wherein the first extension radiation element and the second extension radiation element are substantially perpendicular to the dielectric substrate.
14 . The antenna structure as claimed in claim 11 , further comprising: a fourth radiation element, disposed on the second surface of the dielectric substrate; and one or more conductive via elements, penetrating the dielectric substrate, wherein the fourth radiation element is coupled through the conductive via elements to the third radiation element.
15 . The antenna structure as claimed in claim 14 , wherein a length of the fourth radiation element is longer than that of the third radiation element.
16 . The antenna structure as claimed in claim 14 , wherein a total length of the second radiation element and the fourth radiation element is substantially equal to 0.25 wavelength of the first frequency band.
17 . A communication device, comprising: a motherboard; a cooling fin, coupled to the motherboard; and an antenna system, comprising a plurality of antenna structures, wherein the motherboard and the cooling fin are substantially surrounded by the antenna structures, and wherein each of the antenna structures comprises: a first radiation element, having a first feeding point; a second radiation element, having a second feeding point, wherein the second radiation element is adjacent to the first radiation element; an inductor; a third radiation element, coupled through the inductor to the second radiation element; and a dielectric substrate, wherein the first radiation element, the second radiation element, and the third radiation element are disposed on the dielectric substrate.
18 . The communication device as claimed in claim 17 , wherein the communication device is implemented with a wireless access point or a small base station.
19 . The communication device as claimed in claim 17 , wherein disposition heights of the first radiation element and the second radiation element of each of the antenna structures are higher than maximum heights of the motherboard and the cooling fin.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority of Taiwan Patent Application No. 111141939 filed on Nov. 3, 2022, the entirety of which is incorporated by reference herein. BACKGROUND OF THE INVENTION Field of the Invention The disclosure generally relates to an antenna structure, and more particularly, to a wideband antenna structure. Description of the Related Art With the advancements being made in mobile communication technology, mobile devices such as portable computers, mobile phones, multimedia players, and other hybrid functional portable electronic devices have become more common. To satisfy consumer demand, mobile devices can usually perform wireless communication functions. Some devices cover a large wireless communication area; these include mobile phones using 2G, 3G, and LTE (Long Term Evolution) systems and using frequency bands of 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2500 MHz. Some devices cover a small wireless communication area; these include mobile phones using Wi-Fi systems and using frequency bands of 2.4 GHz, 5.2 GHz, and 5.8 GHz. Antennas are indispensable elements for wireless communication. If an antenna used for signal reception and transmission has insufficient bandwidth, it will negatively affect the communication quality of the mobile device in which it is installed. Accordingly, it has become a critical challenge for designers to design a wideband antenna structure that is small in size. BRIEF SUMMARY OF THE INVENTION In an exemplary embodiment, the invention is directed to an antenna structure that includes a first radiation element, a second radiation element, a third radiation element, an inductor, and a dielectric substrate. The first radiation element has a first feeding point. The second radiation element has a second feeding point. The second radiation element is adjacent to the first radiation element. The third radiation element is coupled through the inductor to the second radiation element. The first radiation element, the second radiation element, and the third radiation element are all disposed on the dielectric substrate. In another exemplary embodiment, the invention is directed to a communication device that includes a motherboard, a cooling fin, and an antenna system. The cooling fin is coupled to the motherboard. The antenna system includes a plurality of antenna structures. The motherboard and the cooling fin are substantially surrounded by the antenna structures. Each of the antenna structures includes a first radiation element, a second radiation element, a third radiation element, an inductor, and a dielectric substrate. The first radiation element has a first feeding point. The second radiation element has a second feeding point. The second radiation element is adjacent to the first radiation element. The third radiation element is coupled through the inductor to the second radiation element. The first radiation element, the second radiation element, and the third radiation element are all disposed on the dielectric substrate. BRIEF DESCRIPTION OF DRAWINGS The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: FIG. 1A is a perspective view of an antenna structure according to an embodiment of the invention; FIG. 1B is a side view of an antenna structure according to an embodiment of the invention; FIG. 2 is a diagram of return loss of an antenna structure according to an embodiment of the invention; FIG. 3A is a radiation pattern of an antenna structure operating in a first frequency band according to an embodiment of the invention; FIG. 3B is a radiation pattern of an antenna structure operating in a second frequency band according to an embodiment of the invention; FIG. 3C is a radiation pattern of an antenna structure operating in a third frequency band according to an embodiment of the invention; FIG. 4 is a perspective view of an inductor according to an embodiment of the invention; FIG. 5 is a perspective view of an antenna structure according to an embodiment of the invention; FIG. 6 is a perspective view of an antenna structure according to an embodiment of the invention; FIG. 7A is a perspective view of an antenna structure according to an embodiment of the invention; FIG. 7B is a side view of an antenna structure according to an embodiment of the invention; and FIG. 8 is a perspective view of a communication device according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION In order to illustrate the purposes, features and advantages of the invention, the embodiments and figures of the invention are shown in detail as follows. Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not inte