CN1672289A

CN1672289A - Thin patch antenna

Info

Publication number: CN1672289A
Application number: CN 03817958
Authority: CN
Inventors: 罗兰·樊尚; 阿尤布·安娜比; 达尼埃尔·勒克莱克
Original assignee: Amphenol Socapex SA
Current assignee: Amphenol Socapex SA
Priority date: 2002-07-26
Filing date: 2003-07-25
Publication date: 2005-09-21
Also published as: EP1525641A2; WO2004012298A2; AU2003269057A8; WO2004012298A3; JP2005534242A; AU2003269057A1; FR2842951A1

Abstract

The invention concerns a thin patch antenna, comprising a radiating element (50), an antenna power supply connected to the radiating element, a conductive surface (66) substantially parallel to said radiating element and spaced away from said element by a distance e, the conductive surface being provided with at least one slot (68) facing said radiating element; and a conductive connection between said conductive surface and said radiating element.

Description

Thin patch antenna

The present invention relates to a kind of plate aerial of little thickness.

When making portable radiotelephone, current use be PIFA type plate aerial or similar antenna.In fact, described antenna be in the shell of portable phone fully and size less relatively.

Fig. 1 is the vertical section that passes the simplification of this antenna.This antenna comprises radiant element 10, and it is used to mate employed wavelength and required impedance, and this impedance typically is 50 Ω.This antenna also has the ground plane 12 that is arranged essentially parallel to radiant element 10.Between radiant element 10 and ground plane, form short circuit 14.At last, come this antenna of feed with coaxial cable 16 usually, the central conductor 16a of coaxial cable is electrically connected to radiant element 10, and its screen 16b is connected to ground plane.Use this antenna, a minimum spacing need be provided eWork in a satisfactory manner to guarantee antenna.Typically, the dielectric between radiant element and ground plane is an air, and when frequency during less than 2GHz, minimum spacing eFor about 7 millimeters (mm) arrive 10mm.

If attempt to reduce the distance between radiant element and the ground plane e, then the work of the antenna that is obtained is restricted, promptly passband has unacceptable restriction.Particularly, less than the distance of 5mm eBe difficult to obtain frequency, promptly be applied in usually in the radio telephone, particularly the frequency range in the gsm system less than 2GHz.

In the development of current portable radiotelephone, it is more and more littler that wireless telephonic gross thickness must become.Therefore the demand that has antenna with same reduction thickness, particularly, distance eBe significantly smaller than 7mm, for example about 2mm is to 3mm.

Should illustrate, in order to save the radio telephone volume inside, metal layer on the printed circuit board (pcb) (metallization) (being screen etc.) constitutes wireless telephonic ground plane, and the assembly that is made of radiant element, short circuit 14 and feeder cable 16 simultaneously is directly installed on the printed circuit.

Therefore, really the antenna that needs is: have the gross thickness that is not more than 5mm, has acceptable condition of work simultaneously, and can operate in a plurality of frequency bands, these frequency bands are applied to radio telephone, computer modulating demodulator corresponding to those tradition, particularly are applied to the frequency band of portable computer, pcmcia card, PDA etc.

Therefore, the purpose of this invention is to provide the plate aerial that a kind of thickness reduces, its passband meets Current Standard.

The objective of the invention is to use that a kind of plate type antenna of little thickness realizes, it is characterized in that this antenna comprises:

-radiant element;

-be connected to the antenna feeder of this radiant element;

-conductive surface, it is arranged essentially parallel to described radiant element and the distance that is positioned at described element is eThe place, described conductive surface has at least one groove, described groove be open wide and towards described radiant element; And

-described conductive surface is connected with conduction between the described radiant element.

Term " groove " is construed as any groove that covers in the conductive surface, and no matter the shape of its profile how.

Although antenna has the thickness of reduction, for example about 3mm, the antenna that meets above qualification still may obtain to be fit to be applied to be usually operated at the passband of the portable radiotelephone or the similar phone (particularly gsm system) of the frequency band that is lower than 2GHz.This result's acquisition is because except the electric field that is mainly produced by radiant element, has also produced magnetic field in the existence of the groove in the conductive surface of radiant element.The field of these two kinds of quadratures has generated electromagnetic wave together, and this electromagnetic wave is equivalent to the ripple used in the antenna of standard thickness (promptly about 7mm is to 10mm).

Term " unlimited groove " is used to cover the groove that opens wide to the periphery of conductive surface.In other words, when groove opened wide, this groove was not exclusively surrounded by conducting element.Because described groove opens wide, therefore avoided from the radiation of groove and improved the operation of antenna.

Be preferably, the shape of the groove that opens wide and the shape of radiant element are basic identical.

In a kind of variant embodiment, the profile of groove (outline) corresponds essentially to the envelope of described radiant element.

In the preferred embodiment of this antenna, conductive surface is made of conductive plate, and this antenna further comprises an insulation mechanical structure, and radiant element, conductive plate and conduction are connected and all are fixed on this insulation mechanical structure.

This combination can directly be fixed on the printed circuit, and is connected to the conductive traces of printed circuit by rights.

By reading the of the present invention various embodiment that provide as non-limiting example described below, other features of the present invention and advantage will be more obvious.This is described with reference to the accompanying drawings, wherein:

Above-mentioned Figure 1 shows that traditional PiFa type antenna;

Fig. 2 A is the plane graph according to the conductive surface of the antenna of the first embodiment of the present invention;

Fig. 2 B is the plane graph corresponding to the radiant element of Fig. 2 A;

Fig. 2 C is the vertical cross section of antenna that comprises the parts of Fig. 2 A and Fig. 2 B;

Figure 3 shows that two curves to the antenna of Fig. 2 C corresponding to reference antenna and Fig. 2 A;

Fig. 4 is the vertical section that passes the antenna of first variant embodiment;

Fig. 5 is the vertical section that passes the antenna of second variant embodiment; And

Fig. 6 is the further perspective view of the antenna of another variant embodiment.

To 2C, first embodiment according to antenna of the present invention is described below with reference to Fig. 2 A.

Shown in Fig. 2 B, in this embodiment, radiant element 50 comprises two parallel main parts 52 and 54, and they are at one end combined by annular section (loop) 56, and extend to branch 58 in the opposite end of straight line portion 52.The shape of radiant element is determined by the operating frequency (or a plurality of operating frequency) of antenna and by required impedance.Branch 58 extends to two braces 60 and 62, is respectively applied for antenna and short circuit, and these two braces are fixed to dual link element 64.

Fig. 2 A is depicted as conductive surface 66, and the profile of the groove 68 of this conductive surface approaches the profile of radiant element 50, but does not need identical with it.This groove by slot part 52 ', 54 ', 56 ' and 58 ' form.The branch 58 of groove ' extend to part 70, this part is opened wide to the peripheral 66a of conductive surface 66, thus the groove that opens wide on the definition meaning that obtains to provide more than.Slot part 70 is between bonding pad 72 and 74, and bonding pad 72 and 74 is correspondingly set up the electrical short between radiant element and the conductive surface 66 respectively, and this antenna of feed.Dual link 64 has also constituted and mechanically radiant element has been fixed to the device of conductive surface, thus be parallel to conductive surface be about 2mm apart from the fixing described radiant element in e1 place, and under any circumstance described distance is all less than 5mm.

Conductive surface 66 can constitute by the conductive plate on the dielectric substrate or by metal layer.

Fig. 3 shows the first curve I of the reference antenna standing-wave ratio (SWR) that changes with frequency F, and with Fig. 2 A of frequency change second curve II to the voltage standing wave ratio (VSWR) of the antenna of 2C.Corresponding to the reference antenna of curve I be with Fig. 2 A to antenna identical shown in the 2C, except its conductive surface 66 that forms ground plane does not have groove 68.

Fig. 3 has clearly illustrated that the passband corresponding to the reference antenna of curve I reduces greatly, and its magnification ratio (amplification) is much smaller than the antenna corresponding to the formation theme of the present invention of curve II.

Fig. 6 has shown another embodiment according to antenna of the present invention.This embodiment approaches the embodiment among Fig. 2 A, 2B and the 2C.

Fig. 6 has shown conductive surface 140, and for example, this conductive surface is to be made of some metal layers that are formed on the dielectric substrate 142.Conductive surface 140 has groove 144, and this groove will be in following detailed description.Fig. 6 has shown radiant element 146 equally, and this radiant element is placed on the plane that is arranged essentially parallel to conductive surface 140.In this embodiment, radiant element 146 comprise first branch 148 corresponding to first frequency band, corresponding to second branch 150 and the substrate 152 of second frequency band.Second branch 150 for example constitutes by the 150a of first that is arranged essentially parallel to first branch 148 with respect to the second portion 150b of the 150a of first withdrawal.Comprise at last two substrates 152 that branch is shared.Radiant element 146 can be formed by the conductive metal sheet cutting of little thickness.In this embodiment, radiant element 146 is installed on the twin connectors 154.Between short circuit connection between this connector formation radiant element and the conductive surface 140 and radiant element and the antenna cable 156 second connects.Distance between radiant element 146 and the conductive surface 140 eEqual 2mm.

The basic complete envelope of the profile 144a of groove 144 corresponding to radiant element 146.In example shown in Figure 6, profile 144a is a rectangle.This groove preferably is facing relation with radiant element basically and places.Groove 144 itself extends to extension 158, and this extension is opened wide to the peripheral 140a of conductive surface 140, with the groove that opens wide on the elocutionary meaning that forms above definition.

As mentioned above, conductive surface can comprise the several grooves relevant with the shape of radiant element.Be preferably, these grooves be open wide or these grooves at least one open wide.

With reference to figure 4, another variant embodiment according to antenna of the present invention is described.In this modification, the structure of antenna itself is identical with the above, but has increased a mechanical structure thereon to form the modularization antenna.This mechanical structure is made by insulating material, is preferably a kind of plastic plastic material, and is given total with reference to numeral 80 to this mechanical structure, and its overall shape is to have upper wall 82 and four sidewalls as 84 lid.Being shown as 86 radiant element with simplified way is preferably and is embedded in the plastic material that constitutes upper wall 82.This radiant element can have the shape shown in Fig. 2 B.Towards the part 86a of radiant element, upper wall 82 has the

groove

88 and 90 of connection.In addition, mechanical structure 80 forms a housing 92, can any other mode that is fit to clamp or install dual connection member 94 in this housing.Member 94 is used to provide antenna to connect and is connected with short circuit.For this reason, connecting elements 94 has two top connections 96 penetrating in

groove

88 and 90 and 98 and two

lower contacts

100 and 102.

The bottom of the sidewall 84 of lid 80 has the edge 104 that thickness increases, and is used for fixing the periphery of the conductive plate 106 that constitutes conductive surface.The groove (a plurality of groove) 108 that opens wide that is formed in the plate 106 shows in a simplified manner.In addition, plate 106 has flexible joint 110, and this joint penetrates in the housing 92 providing and being electrically connected of short circuit terminals 102, thereby and provides and being connected of radiant element.

Fig. 4 has also shown the part of the printed circuit 112 with conductive traces 114, and this track has at first constituted electrical grounding, and next has constituted antenna conductor.These conductive traces 114 are connected to the

electric connection

100 and 102 of connecting elements 94.

Be appreciated that surface that the assembly that is made of the lid 80 with connecting elements 94 can directly be fixed to printed circuit 112 setting up above-mentioned electrical connection, thereby and lid be mechanically fixed on the printed circuit.Certainly, in this embodiment, between radiant element 86 and the conductive plate 106 apart from e ₁Be about 2mm.

Fig. 5 has shown second variant embodiment according to antenna of the present invention.This antenna quilt is as printed circuit 120.In the figure, can see the thickness e of the dielectric substrate 122 of printed circuit ₂Be about 2mm.On first 122a of dielectric substrate 122, have first metal layer 124 of definite radiant element, this radiant element can be Fig. 2 B or shape shown in Figure 6.Second metal layer 126 is formed on second 122b of dielectric substrate 122, to constitute the conductive surface of antenna.This conductive surface has towards radiant element 124 naturally and its profile is basic identical with the profile of radiant element or the one or more unlimited groove 128 corresponding with the envelope of radiant element.Set up short circuit through first plated-through-hole 130, this plated-through-hole is passed dielectric substrate 122 and is connected to metal layer 126.The face 122b that another metal layer 132 is formed on dielectric substrate 122 goes up to constitute antenna conductor.Antenna conductor 132 is connected to radiant element 124 by second plated-through-hole 134.

Dielectric between radiant element 124 and conductive surface 126 no longer is the air, and this embodiment provides an antenna that has with the identical characteristic of the foregoing description.But the material of the dielectric substrate 122 of formation printed circuit is slightly different.

Claims

1. the plate aerial of a little thickness is characterized in that this antenna comprises:

-radiant element;

-be connected to the antenna feeder of this radiant element;

-conductive surface, it is arranged essentially parallel to described radiant element and the distance that is positioned at described element is the e place, described conductive surface has at least one groove, described groove be open wide and basically towards described radiant element; And

2. antenna according to claim 1 is characterized in that described radiant element has specific shape, and described groove or described a plurality of groove have the essentially identical shape of described given shape with this radiant element.

3. antenna according to claim 1 is characterized in that the envelope of the profile of described groove corresponding to described radiant element.

4. according to the described antenna of arbitrary claim in the claim 1 to 3, it is characterized in that described conductive surface is made of conductive plate.

5. antenna according to claim 4 is characterized in that this antenna further comprises insulation mechanical structure, and described radiant element, described conductive plate and described conduction are connected and all are fixed on this insulation mechanical structure.

6. antenna according to claim 5 is characterized in that described mechanical structure made by plastic material, and described structure has a top, and described radiant element is embedded in this top.

7. according to claim 5 or 6 described antennas, it is characterized in that this antenna further comprises the connector component that is installed on the described mechanical structure, be used for described radiant element is electrically connected to described antenna feeder, and be used between described radiant element and ground, forming short circuit.

8. antenna according to claim 7 is characterized in that described mechanical structure comprises at least two sidewalls, and described conductive plate fixed thereon is parallel to described radiant element.

9. according to the described antenna of arbitrary claim in the claim 1 to 4, it is characterized in that this antenna comprises the dielectric substrate of printed circuit; First metal layer, its first of being formed on described substrate goes up to form described radiant element; Second metal layer, its second of being formed on described dielectric substrate goes up to form described conductive surface; And two current source roads, it passes described substrate to set up described electrical connection and described antenna feeder.

10. according to the described antenna of arbitrary claim in the claim 1 to 9, the operating frequency that it is characterized in that described antenna is less than 2GHz.