CN104953295B

CN104953295B - Miniaturized directional slot antenna

Info

Publication number: CN104953295B
Application number: CN201510334836.XA
Authority: CN
Inventors: 陈付昌; 胡豪涛; 褚庆昕; 涂治红
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2015-06-16
Filing date: 2015-06-16
Publication date: 2020-04-28
Anticipated expiration: 2035-06-16
Also published as: CN104953295A

Abstract

The invention discloses a miniaturized directional slot antenna, which comprises a metal foil feed structure and a slot structure, wherein the metal foil feed structure is positioned on the upper surface of a plate-shaped dielectric substrate and comprises a first feed substructure, a second feed substructure and a third feed substructure; the first feed substructure is connected with the second feed substructure, and the connection point of the first feed substructure and the second feed substructure divides the second feed substructure into two parts, wherein the lengths of the two parts are different by a quarter waveguide wavelength; the third feed structure comprises two feed metal sheets with the same structure, and the two feed metal sheets are respectively connected with two ends of the second feed substructure; the gap structure is positioned on the grounding plate and comprises a first gap radiation unit, a second gap radiation unit and an isolation gap. The miniaturized directional slot antenna has the advantages of compact structure, small size, low cost and easy integration, and is suitable for being applied to the existing small wireless terminal.

Description

Miniaturized directional slot antenna

Technical Field

The invention relates to the technical field of wireless communication, in particular to a miniaturized directional slot antenna.

Technical Field

In recent years, wireless communication devices have been rapidly developed towards multifunction and miniaturization, and many wireless terminals, including mobile devices and fixed devices, are designed to have an antenna with certain directivity, so as to receive signals better and avoid interference of different communication systems. There are also many requirements on the antenna in certain specific applications. For the current wireless terminal, the antenna is required to be compact in structure, light in weight, wide in frequency band, high in front-to-back ratio and the like.

Slot antennas, which are more commonly microstrip slot antennas, are often used in mobile terminals due to their good properties of coplanar structure, small size, light weight, and easy integration with other components. However, in the existing directional slot antenna structures, although all have a high front-to-back ratio, these structures have a relatively narrow bandwidth instead of a relatively large size of the antenna, and are difficult to meet the current requirements for the directional slot antenna. Therefore, it is one of the research hotspots of today to design a wide-band, miniaturized, high-front-to-back ratio directional slot antenna.

In 2011, Chien-Jen Wang et al published an article entitled "Enhancement of pattern directivity for the open slot antenna by Microwave and optical technology drivers", which employed two slot array elements that differed by half a wavelength distance and fed equally by 180 degrees. Meanwhile, eight metal strips are added in front of the gap in order to increase the front-to-back ratio. Although the structure can obtain high front-to-back ratio, on one hand, the structure is complex in design, occupies larger size and is not beneficial to the miniaturization of the antenna; on the other hand, it basically operates at dot frequency and has narrow frequency band. Therefore, the antenna has limited practical application value.

In the same year, Te-Ling Sun et al published an article entitled "Design of a microstrip monopole slot antenna with unidirectional characterization" on "IEEE transactions on Antennas and protocols". On one hand, the article adopts a step impedance slot as a radiation unit, which effectively increases the working bandwidth of the antenna; on the other hand, the article adopts two gaps to be arranged at the back of the radiation unit, the main purpose is to cut off the backward current of the radiation unit, and the front-to-back ratio is improved to a certain extent. The disadvantage is also evident, however, and the structure still faces problems of large size, etc.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides an antenna applied to the field of wireless communication, in particular to a planar printing directional slot antenna. The antenna structure has small size, light weight and easy processing and manufacturing, and is suitable for being used in small-sized wireless terminals.

The purpose of the invention is realized by the following technical scheme:

a miniaturized directional slot antenna comprises a plate-shaped dielectric substrate, a grounding plate, a metal foil feed structure and a slot structure, wherein,

the metal foil feed structure is positioned on the upper surface of the plate-shaped dielectric substrate and comprises three feed sub-structures, the first feed sub-structure is connected with the second feed sub-structure, the connecting point of the first feed sub-structure and the second feed sub-structure divides the second feed sub-structure into two parts, and the lengths of the two parts are different by a quarter of waveguide wavelength; the third feed structure comprises two feed metal sheets with the same structure, and the two feed metal sheets are respectively connected with two ends of the second feed substructure;

the gap structure is located on the grounding plate and comprises a first gap radiation unit, a second gap radiation unit and an isolation gap located between the first gap radiation unit and the second gap radiation unit.

Specifically, the first slot radiation unit and the second slot radiation unit have the same structure and are both open-circuit slots, the length of each open-circuit slot is a quarter wavelength, and the center distance between the first slot radiation unit and the second slot radiation unit is a quarter space wavelength.

Specifically, the first feed substructure is sharpened at the position where the first feed substructure is connected with the second feed substructure.

Specifically, the lengths of the two feeding metal sheets of the third feeding structure are both quarter waveguide wavelengths, and the two feeding metal sheets are respectively located above the first slot radiation unit and the second slot radiation unit.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the miniaturized directional slot antenna realizes good directivity under the condition of not introducing any reflector and director.

2. The miniaturized directional slot antenna does not introduce any reflector and director, so that the antenna is compact in structure and small in size.

3. The miniaturized directional slot antenna has the advantages of simple design, small volume, low cost and easy integration of a planar structure, and can be applied to various wireless communication terminals.

Drawings

Fig. 1 is a vertical cross-sectional view of a miniaturized directional slot antenna according to the present invention;

fig. 2 is a schematic structural diagram of the slot antenna shown in fig. 1;

fig. 3 is a simulation result of scattering parameters of the miniaturized directional slot antenna in the embodiment.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

The vertical cross-sectional view of the miniaturized directional slot antenna of the present invention is shown in fig. 1, and mainly includes a plate-shaped dielectric substrate 10, a feeding structure 11 formed by a metal foil on the upper surface of the substrate 10, a ground plate 12 formed by a metal foil on the lower surface of the substrate 10, and a slot structure 13 formed by digging a groove in the ground plate 12.

Fig. 2 shows a schematic structural diagram of a miniaturized directional slot antenna according to the present invention, where a feed structure 11 includes: a first feed sub-structure 110, with a 50 ohm impedance match at the port of feed sub-structure 110; the junction of the second feed sub-structure 111 and the first feed sub-structure 110 divides the second feed sub-structure 111 into two

parts

112 and 114, where the lengths of 112 and 114 differ by a quarter of the waveguide wavelength;

third feed sub-structure

113, 115, wherein

feed sub-structures

113 and 115 are identical,

feed sub-structures

113 and 115 are each a quarter waveguide wavelength. For better impedance matching, the first feed sub-structure 110 is sharpened where it connects to the second feed sub-structure 111. The slot structure 13 includes

slot radiating elements

131 and 132 and an isolation slot 133. The

slot radiating elements

131 and 132 are identical, are a quarter wavelength long and are separated by a quarter spatial wavelength in their centers. The whole antenna works in such a way that electromagnetic signals are input from the port of the feed unit 110, coupled to the antenna unit formed by the two slots and radiated, and the receiving mode of the signals is opposite.

The miniaturized directional slot antenna is manufactured on a polytetrafluoroethylene double-sided copper-clad microstrip plate with the dielectric constant of 4.2 and the thickness of 1.5mm in a printed circuit board mode, and can be easily manufactured by using the technologies of mechanical engraving, laser engraving, circuit board corrosion and the like.

Fig. 3 shows the simulation result of the scattering parameter of the miniaturized directional slot antenna in this embodiment, in which the horizontal axis represents the signal frequency of the miniaturized directional slot antenna in this embodiment, and the vertical axis represents the amplitude of the return loss (S11). In the signal transmission process of the miniaturized directional slot antenna of the embodiment, part of the power of the signal is reflected back to the signal source, and the reflected power becomes the reflected power. S11 represents the relationship between the input power of the signal and the reflected power of the signal passing through the miniaturized directional slot antenna in this embodiment, and its corresponding mathematical function is as follows: reflected/incident power 20 log S11.

As shown in FIG. 3, the slot antenna of the present invention has 15dB reflection loss range from 5.0GHz to 6.1GHz, relative bandwidth up to 20%, and covers WLAN (5.15-5.825GHz), WiMAX (5.250-5.850GHz) and other frequency bands. The front-to-back ratio reaches 15dB at the center frequency of 5.5 GHz. The overall antenna size is 38mm x 29mm, i.e. 1.25 x 0.95 x g, which is the waveguide wavelength at a center frequency of 5.5 GHz.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A miniaturized directional slot antenna comprises a plate-shaped dielectric substrate and a grounding plate, and is characterized by further comprising a metal foil feed structure and a slot structure, wherein,

the metal foil feed structure is positioned on the upper surface of the plate-shaped dielectric substrate and comprises a first feed substructure, a second feed substructure and a third feed substructure, the first feed substructure is connected with the second feed substructure, and the connecting point of the first feed substructure and the second feed substructure divides the second feed substructure into two parts, and the lengths of the two parts are different by a quarter waveguide wavelength; the third feed structure comprises two feed metal sheets with the same structure, and the two feed metal sheets are respectively connected with two ends of the second feed substructure; the grounding plate is positioned on the lower surface of the dielectric substrate;

the gap structure is positioned on the grounding plate and comprises a first gap radiation unit, a second gap radiation unit and an isolation gap positioned between the first gap radiation unit and the second gap radiation unit;

the first gap radiation unit and the second gap radiation unit have the same structure and are both open-circuit gaps, the length of each open-circuit gap is one quarter of the wavelength, and the center distance between the first gap radiation unit and the second gap radiation unit is one quarter of the space wavelength;

the first feed substructure is connected with the second feed substructure and is sharpened;

the lengths of the two feeding metal sheets of the third feeding structure are both quarter waveguide wavelengths, and the two feeding metal sheets are respectively positioned above the first slot radiation unit and the second slot radiation unit.