CN1677748A - Micro-transmission line antenna structure - Google Patents

Abstract

A flat printing segment and a coaxial cable are setup at printing circuit board (PCB). The said flat printing segment is etched on one side of PCB, where there are a printed metal line and a ground line. The ground line is located on edge at one side of PCB. One end of the ground line connected to one end of the printed metal line forms a short circuit end; the other end of the ground line connected to the other r end of the printed metal line forms an open circuit end. A feeding point is setup at the ground line. A connection line between short circuit end and open circuit end connects the printed metal line to the feeding point. Central wire of the coaxial cable connects the open circuit end to the printed metal line; and braided shield of the coaxial cable connects the open circuit end to the ground line.

Description

Microminiaturized transmission-line aerial structure

Technical field

The present invention relates to a kind of structure-improved of transmission-line aerial, refer to a kind of designed minimization transmission-line aerial (small transmissionline antenna) that goes out of composite construction (composite structure) that utilizes especially.

Background technology

The basic functional principle of general transmission-line aerial (transmission line antenna), basic framework that can be as shown in Figure 1, its hypothesis is a short-circuit end (short) at " a " some place, the place is an open end (open) at " b " point, and the characteristic impedance value of whole transmission line (characteristic impedance) is " Z _o", relative characteristic admittance is " Y _o=1/Z _o", and to locate in " 0 " be a signal input end.

Modern hypothesis, S＜＜the λ wavelength (wavelength=velocity of wave/frequency) on the λ transmission line (transmission line) wherein, please refer to Smith chart shown in Figure 2 (smith chart), this short-circuit end " a " and its admittance of this open end " b " (admittance) difference right side, left two-end-point thereon, so, through a segment distance " L _s" after, the admittance of the short-circuit end of seeing in " O " place is " Y _Short" and on the other hand, " b " locates to be " L to the distance that " O " locates _R", the admittance of the open end of being seen is " Y _Open", if " L _s" and " L _o" distance walked is " L _s+ L _o=λ/4 ", " Y then _Open+ Y _Short=0 ", under this resonance situation, the input impedance " Z that antenna is located at " O " _In" can be by the resistance decision of the feed-in line of " S " section, if design proper, " Z _In=R _In" become a pure resistance value (for example: 50 ohm), can reach the purpose of coupling (match) with system.

Promptly be the basic functional principle of transmission-line aerial below, but it is noted that " L _s+ L _o" need altogether " λ/4 " length, the antenna of still non-genus miniaturization (small antenna), but because of the change of structure, it then belongs to the antenna of one " low clearance " (low profile).

Please refer to the basic framework of the transmission-line aerial of Fig. 3,, but still, then can derive again at " O " and locate to locate and equivalence to see a radiation resistance R to " a " according to transmission line theory much smaller than λ if S is long slightly _Rs(radiationresistance):

$R_{\mathrm{rs}}=\frac{30{\left(\mathrm{\βS}\right)}^2}{{\cos }^2\mathrm{\β}{L}_s}\·\{1-\frac{\mathrm{Sin}2\mathrm{\β}{L}_S}{2\mathrm{\β}{L}_s}\}...\left(1\right)$

On the other hand, see also shown in Figure 4ly, locate, another equivalent radiation resistance R is then arranged from " O " past " b " _Ro(radiation resistance):

$R_{\mathrm{ro}}=\frac{30{\left(\mathrm{\βS}\right)}^2}{{\mathrm{Sin}}^2\mathrm{\β}{L}_o}\·\{1-\frac{\mathrm{Sin}2\mathrm{\β}{L}_o}{2\mathrm{\β}{L}_o}\}...\left(2\right)$

Wherein " β " is the propagation constant (propagation constant) of transmission line, and therefore, the effective radiation resistance that obtains in signal transmitting terminal " O " place is

R _r＝R _rs∥R _ro；

So " R _In" as remaining unchanged, " R then _r" be to be the bigger the better high efficiency is just arranged;

Because " L _o+ L _s" level off to λ/4; if be the antenna that belongs to low frequency; though this class antenna belongs to low clearance; total length is still very long; be difficult to be applied on the small-sized receiving system of present mobile radio communication; please refer to shown in Figure 5, be the design of a planar transmission wire antenna, if modern considering will be adopted this class antenna the design of planographic type, use and the circuit system intercropping is integrated, will account for great area and unrealistic of antenna, for instance, as operating frequency is 100MHz, λ=300cm, if λ/4=75cm is employed again printed circuit board (PCB) (Printed Circuit Board, abbreviation PCB) dielectric constant (dielectricconstant) is ε r=4, then shortens to again $75/\left(\sqrt{4}\right)=37.5\mathrm{cm},$ Be still very long.

Since wireless telecommunications electronic industry now towards light, thin, short, little for it develops main shaft, so as if can not be with the transmission-line aerial minimization, this miniature trend for the wireless telecommunications electronics will cause greatest obstruction.Therefore, how developing a kind of transmission-line aerial of minimization, use to cooperate being installed in the wireless telecommunications electronics (as: Digital Audio Broadcasting DAB receiver), is the very urgent important topic that needs to be resolved hurrily of present industry in fact.

Because aforesaid many disappearances, the inventor is through the permanent research and experiment of making great efforts, and according to being engaged in the technical experience that antenna is made for many years, development and Design goes out the transmission-line aerial structure of a kind of microminiaturization of the present invention finally, in the hope of by clever thought of the present invention, can contribution be proposed to society.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of transmission antenna structure of microminiaturization, refers in particular to a kind ofly can significantly reduce volume, but still possesses the transmission-line aerial (smalltransmission line antenna) of the good radiation characteristic of antenna.

Another technical problem that the present invention will solve provides a kind of transmission antenna structure of microminiaturization, release by microminiaturized transmission-line aerial, when making it be installed in the wireless telecommunications electronics, only take minimum installing space, and then make and the volume of wireless telecommunications electronics be able to do the design or the improvement of microminiaturization towards lighter, thin, short, little developing direction.

For this reason, the invention provides a kind of transmission-line aerial structure of microminiaturization, it is provided with in a printed circuit board (PCB):

One planographic section, this planographic section is located on the one side of this printed circuit board (PCB), be provided with a type metal line and an earth connection, this earth connection is along being located on this printed circuit board (PCB) one lateral edges, the one end is connected with an end of this type metal line and forms a short-circuit end, and the other end of its other end and this type metal line keeps suitable distance and form an open end;

One load point, this load point passes this earth connection;

One connecting line, this connecting line are between this open end and this short-circuit end, and this type metal line is connected on this load point certainly;

One coaxial cable line, its center line of an end of this coaxial wire is to be arranged on this type metal line from this open end, its separator then is arranged on this earth connection.

Aforesaid antenna structure, this coaxial wire can be a kind of elongated and fine cable that can curl.

Aforesaid antenna structure, this fine cable can be contained on arbitrary that depends on this printed circuit board (PCB).

Aforesaid antenna structure, this center line can adopt the mode of spot welding to be arranged on this type metal line.

Aforesaid antenna structure, this center line can adopt the mode of a glue to be arranged on this type metal line.

Antenna structure as described, this shielding wire can adopt the mode of spot welding to be arranged on this earth connection.

Aforesaid antenna structure, this shielding wire can adopt the mode of a glue to be arranged on this earth connection.

Can draw according to above-mentioned structure, the transmission-line aerial structure of microminiaturization of the present invention when making it be installed in the receiver, only takies minimum installing space, and then makes this receiver can reach the design requirement of a miniaturization.

Description of drawings

Fig. 1 is one of schematic diagram of known technology.

Fig. 2 be known technology schematic diagram two.

Fig. 3 be known technology schematic diagram three.

Fig. 4 be known technology schematic diagram four.

Fig. 5 is the stereogram of known technology.

Fig. 6 is a stereogram of the present invention.

Fig. 7 is the embodiments of the invention schematic diagram.

The drawing reference numeral explanation:

1, printed circuit board (PCB) 11, planographic section 111, type metal line

112, earth connection 12, coaxial wire 121, center line

122, shielding wire A, short-circuit end B, open end

C, connecting line D, load point

Embodiment

Can be for just your auditor to the object, the technical characteristics and the effect of the present invention, do further understanding and understand, for the embodiment conjunction with figs., be described in detail as follows now:

The transmission-line aerial structure of a kind of microminiaturization that the present invention proposes, see also shown in Figure 6, be provided with a planographic section 11 and a coaxial cable line 12 in a printed circuit board (PCB) (PCB) 1, wherein this planographic section 11 is etched on the one side of this printed circuit board (PCB) 1, comprise a type metal line 111 (printed mentalline) and an earth connection 112 (ground line), this earth connection 112 is along being located on this printed circuit board (PCB) 1 one lateral edges, the one end is connected with this type metal line 111 and forms a short-circuit end A (short), its other end then keeps suitable distance and forms an open end B (open) with this type metal line 111, in addition, be provided with a load point D (feeding point) in this earth connection 112, and between this open end B and this short-circuit end A, be provided with a connecting line C, this connecting line C is connected on this load point D from this type metal line 111, again, these coaxial wire 12 its center lines 121 (central wire) this open end B certainly are arranged on this type metal line 111, and these coaxial wire 12 its shielding wires 122 (braided shield) then are arranged on this earth connection 112 (ground line).

By above perfect structural design, see also shown in Figure 6 again, this coaxial wire 12 (Micro-cable) can continue to reach the resonance functional of transmission line, and since the characteristic impedance of this coaxial wire 12 can with these planographic section 11 inequalities, therefore, though this coaxial wire 12 still is about λ/4 wavelength with the total length of this type metal line 111, but because of the coaxial wire 12 that uses can be a kind of elongated and fine cable (micro-cable) that can curl, (front or reverse side all can so arbitrary of this fine cable can be depended on this printed circuit board (PCB) 1 after curling goes up, see also shown in Figure 7), so, when making it be installed in the receiver (not shown), only take minimum installing space, and then make this receiver can reach the design requirement of a miniaturization.

In the present invention, see also shown in Figure 6ly again, these coaxial wire 12 its center lines 121 connect the mode that is located on this type metal line 111, and this shielding wire 122 is arranged in this earth connection 112 upper types, all can adopt the mode of a glue or spot welding.

In sum, by clever thought of the present invention, can make transmit antenna be able to microminiaturization, without doubt, the present invention is for vast consumption is popular, be a great contribution and invention in fact, and for the manufacturer of mobile electronic equipment, also be big sharp weapon of in selling market with keen competition, showing one's talent, only, described herein, only be one of best specific embodiment of the present invention, technical characterictic in fact of the present invention is not limited thereto, and anyly is familiar with this skill person in field of the present invention, can think easily and variation or modification, all can be encompassed in claims scope of the present invention.

Claims (7)

1, a kind of transmission-line aerial structure of microminiaturization, it is provided with in a printed circuit board (PCB):

One planographic section, this planographic section is located on the one side of this printed circuit board (PCB), be provided with a type metal line and an earth connection, this earth connection is along being located on this printed circuit board (PCB) one lateral edges, the one end is connected with an end of this type metal line and forms a short-circuit end, and the other end of its other end and this type metal line keeps suitable distance and form an open end;

One load point, this load point passes this earth connection;

One connecting line, this connecting line are between this open end and this short-circuit end, and this type metal line is connected on this load point certainly;

One coaxial cable line, its center line of an end of this coaxial wire is to be arranged on this type metal line from this open end, its separator then is arranged on this earth connection.

2, antenna structure as claimed in claim 1 is characterized in that: this coaxial wire can be a kind of elongated and fine cable that can curl.

3, antenna structure as claimed in claim 2 is characterized in that: this fine cable can be contained on arbitrary that depends on this printed circuit board (PCB).

4, antenna structure as claimed in claim 2 is characterized in that: this center line can adopt the mode of spot welding to be arranged on this type metal line.

5, antenna structure as claimed in claim 2 is characterized in that: this center line can adopt the mode of a glue to be arranged on this type metal line.

6, antenna structure as claimed in claim 2 is characterized in that: this shielding wire can adopt the mode of spot welding to be arranged on this earth connection.

7, antenna structure as claimed in claim 2 is characterized in that: this shielding wire can adopt the mode of a glue to be arranged on this earth connection.

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