CN103380541A - A meander line antenna - Google Patents

Abstract

The invention discloses a meander line antenna, comprising: a first meander line part (11) printed on a first surface of a dielectric substrate; a second meander line part printed on a second surface of the medium substrate (12); wherein, the first bending line portion (11) is a bent metal strip, and the first bending line portion (11) and the second bending line portion (12) have a shape with respect to the dielectric substrate mirror image symmetry; the microstrip feeder (13) printed on the first surface of the dielectric substrate is connected to the bottom of the first bend line part (11), wherein the microstrip feeder (13) The connection point with the first bend line portion (11) is a feed point; and at least one short-circuit probe (14) at the feed point is used to connect the first bend line portion (11) and The second bend line portion (12). The double-layer meander-line antenna provided by the present invention can effectively reduce the quality factor of the meander-line antenna and increase the impedance bandwidth of the meander-line antenna.

Description

A meander wire antenna

technical field

The invention relates to the technical field of antennas, in particular to a meander line antenna (MLA, Meander Line Antenna).

Background technique

At present, modern wireless communication systems have higher and higher demands on the miniaturization of antennas. Especially in the application scenarios that need to meet omnidirectional radiation, broadband operation and relatively high gain requirements at the same time, this demand for antenna miniaturization will challenge the work of antenna engineers.

MLA is a small antenna constructed by bending a monopole antenna (Monopole) back and forth, and its structure is shown in Figure 1. W in FIG. 1 represents the width of the bending line, N represents the number of times the bending line is bent, and S represents the distance between the bending lines. MLA can provide omnidirectional radiation with high radiation efficiency and low cross polarization. However, the impedance bandwidth of this traditional MLA is relatively narrow, and its input impedance is related to the thickness (or width) and spacing of its bent line, and the input impedance easily presents a strong inductive reactance and a large real part of the input impedance. This brings difficulty in impedance matching of the antenna.

Contents of the invention

In order to solve the above problems, embodiments of the present invention provide an MLA with a wider impedance bandwidth.

A meander line antenna provided according to an embodiment of the present invention includes:

a first bend line portion 11 printed on the first surface of the dielectric substrate;

A second bending line portion 12 printed on the second surface of the dielectric substrate; wherein, the first bending line portion 11 is a bent metal strip, and the first bending line portion 11 and the first bending line portion 11 are The two bending line parts 12 are mirror-symmetrical with respect to the dielectric substrate;

The microstrip feeder 13 printed on the first surface of the dielectric substrate is connected to the bottom of the first bend line part 11, wherein the microstrip feeder 13 is connected to the bottom of the first bend line part 11 the connection point is the feed point; and

At least one short-circuit probe 14 at the feed point is used to connect the first bend line portion 11 and the second bend line portion 12 .

The above meander line antenna further includes: a ground layer 15 printed under the second meander line portion 12 .

The above-mentioned meander line antenna further includes: sleeves located above the formation 15 and beside the bottom sides of the second meander line portion 12 .

The meander line antenna provided by another embodiment of the present invention has a wider impedance bandwidth and can better match a 50-ohm feeder, including:

a first bend line portion 11 printed on the first surface of the dielectric substrate;

A second bending line portion 12 printed on the second surface of the dielectric substrate; wherein, the first bending line portion 11 is a bent metal strip, and the first bending line portion 11 and the first bending line portion 11 are The two bending line parts 12 are mirror-symmetrical with respect to the dielectric substrate;

A first capacitive strip 21 printed on the first surface of the dielectric substrate, the first end of which is connected to the bottom of the first bend line portion 11;

A second capacitive strip 22 printed on the second surface of the dielectric substrate, the first end of which is connected to the bottom of the second bend line portion 12;

The microstrip feeder 23 printed on the first surface of the dielectric substrate is connected to the second end of the first capacitive strip 21, wherein the microstrip feeder 23 is connected to the first capacitive strip The connection point of 21 is the feeding point; and

At least one short-circuit probe 24 at the feed point for connecting the first capacitive strip 21 and the second capacitive strip 22 .

Both the first capacitive strip 21 and the second capacitive strip 22 are rectangular.

Both the first bending line portion 11 and the second bending line portion 12 are tapered or trapezoidal.

The above-mentioned meander line antenna further includes: a ground layer 16 printed under the second capacitive strip 22 .

The above-mentioned meander line antenna further includes: a sleeve 17 located above the formation 16 and beside the bottom of the second capacitive strip 22 .

The above-mentioned short-circuit probe 24 is used to connect the first capacitive strip 21 and the second capacitive strip 22 at the feeding point via a metal probe.

The above-mentioned short-circuit probe 24 is used to connect the second end of the first capacitive strip 21 and the second end of the second capacitive strip 22 at the feed point.

The improved meander line antenna provided by the embodiment of the present invention adopts a double-layer meander line part, so that the reactance part of the input impedance of the meander line antenna at the feeding point is halved while the resistance part remains unchanged, so that the meander line antenna can be effectively reduced. The quality factor of the antenna increases the impedance bandwidth of the meander line antenna.

Description of drawings

Fig. 1 is the structural representation of traditional MLA;

Figure 2a is a schematic structural view of the MLA described in Example 1 of the present invention;

Figure 2b is a schematic structural diagram of the MLA described in Example 1 of the present invention;

Figure 3a is a schematic structural diagram of the MLA described in Example 2 of the present invention;

Figure 3b is a schematic structural diagram of the MLA described in Example 2 of the present invention;

Figure 4a shows a schematic view of the structure of an MLA when the first bending line part is set into a tapered shape;

Figure 4b shows an MLA structure when the second bend line portion is tapered; and

FIG. 5 shows voltage standing wave ratio (VSWR) versus frequency for an MLA with tapered bend line portions on both sides of the dielectric substrate and with a tapered bend line portion on one face of the dielectric substrate.

Detailed ways

In order to solve the problems existing in the traditional MLA, the present invention improves the traditional MLA. Specific embodiments according to the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

In order to solve the problem of narrow impedance bandwidth of traditional MLA, an embodiment of the present invention provides an improved MLA, which has a double-layer bending line part, which is printed on two sides of a dielectric substrate (Dielectric Substrate) in a planar form. face. Figures 2a and 2b show the structure of the MLA in this embodiment, wherein Figure 2a shows the first side of the dielectric substrate; Figure 2b shows the second side of the dielectric substrate. As shown in Figures 2a and 2b, the MLA described in this embodiment mainly includes the following components:

A first bending line part (Meandering Section) 11 printed on the first side of the dielectric substrate;

The second bending line part 12 printed on the second surface of the medium substrate; wherein, the first bending line part 11 is a bent metal strip, and the first bending line part 11 and the second bending line part 12 There is a mirror image symmetrical relationship with respect to the dielectric substrate;

A microstrip feedline (Microstrip Feedline) 13 printed on the first surface of the dielectric substrate is connected to the bottom of the first bend line part 11, wherein the connection point between the microstrip feedline 13 and the first bend line part 11 is the feed point; and

At least one shorting pin (Shorting Pin) 14 at the feed point is used to connect the first bend line portion 11 and the second bend line portion 12 .

In this embodiment, the at least one short-circuit probe 14 may be connected to the first bend line portion 11 and the second bend line portion 12 through at least one metal pin (Metal Pin).

The above MLA may further include: a ground layer 15 printed on the second surface of the dielectric substrate under the second bending line portion 12 .

As described above, the present embodiment of the present invention provides an improved MLA using double-layered bend line portions printed on both sides of a dielectric substrate. It can be seen from the double-layer structure that the current at the feeding point (that is, the position of the short-circuit probe) is divided into two parts, and the current of each part enters the bending line part on one surface of the dielectric substrate. Since the two meander line parts resonate at the same frequency, from the viewpoint of equivalent circuits, the meander line parts on each side of the dielectric substrate can be equivalent to a resonant circuit, and they pass through one or more short-circuit probes , so that the inductance and self-capacitance mainly generated by the meander line part are nearly halved, while the mutual capacitance between the meander line parts from the double layer is increased, and the conductor loss is doubled at the same time (the conductor loss can be reduced at low frequencies. negligible) while the dielectric loss remains unchanged. That is, the reactive part of the input impedance at the feed point is nearly halved while the resistive part (corresponding to losses) is almost unchanged, which reduces the quality factor of the MLA and further increases the impedance bandwidth of the MLA.

It should be noted that, on the basis of the above-mentioned double-layer structure, in order to further increase the impedance bandwidth of the MLA, one of the following three methods or any combination thereof can be further adopted:

Method 1) Setting the above-mentioned first bending line part 11 and second bending line part 12 into a tapered or trapezoidal shape with a wide top and a narrow bottom;

Method 2) increasing the width of the first bending line portion 11 and the second bending line portion 12;

Method 3) A sleeve (Sleeve) is added beside the two sides of the bottom of the second bending line part 12 and above the formation 15 . Wherein, the sleeve is printed on the second surface of the dielectric substrate.

Example 2

In order to further solve the problem of difficult impedance matching of traditional MLA, this embodiment provides another improved MLA. Compared with the MLA shown in Figs. 2a and 2b, this MLA adds a capacitive metal strip on each side of the dielectric substrate. Figures 3a and 3b show the structure of the MLA in this embodiment, wherein Figure 3a shows the first surface of the dielectric substrate; Figure 3b shows the second surface of the dielectric substrate. As shown in Figures 3a and 3b, the MLA described in this embodiment mainly includes the following components:

a first bend line portion 11 printed on the first surface of the dielectric substrate;

The second bending line part 12 printed on the second surface of the medium substrate; wherein, the first bending line part 11 is a bent metal strip, and the first bending line part 11 and the second bending line part 12 There is a mirror image symmetrical relationship with respect to the dielectric substrate;

A first capacitive band 21 printed on the first side of the dielectric substrate, the first end of which is connected to the bottom of the first bend line portion 11;

A second capacitive strip 22 printed on the second side of the dielectric substrate, the first end of which is connected to the bottom of the second bend line portion 12;

The microstrip feeder 23 printed on the first surface of the dielectric substrate is connected to the second end of the first capacitive band 21, wherein the connection point between the microstrip feeder 13 and the first capacitive band 21 is the feeder electric point; and

At least one short-circuit probe 24 at said feed point for connecting the first capacitive strip 21 and the second capacitive strip 22 .

In this embodiment, the at least one short-circuit probe 24 may connect the second end of the first capacitive strip 21 and the second end of the second capacitive strip 22 through at least one metal probe.

Wherein, the above-mentioned first capacitive strip 21 and the second capacitive strip 22 are both rectangular.

In addition, the above MLA may further include: a formation layer 16 printed on the second surface of the dielectric substrate under the second capacitive strip 22 .

As mentioned above, the MLA described in this embodiment can greatly increase the impedance bandwidth of the MLA due to the use of double-layer bent line parts.

Since the traditional MLA is a self-resonant structure, its equivalent inductance and capacitance parts can be changed by changing the characteristics of the bent line part. In order to achieve impedance matching, the equivalent inductance of the MLA can cancel the equivalent capacitance, which usually requires small spacing between the bending lines and high processing accuracy. In this embodiment, by adding capacitive metal strips on each surface of the dielectric substrate, the equivalent capacitance of the MLA can be significantly increased, and the capacitance value of the capacitive metal strips can be adjusted by adjusting the size of the capacitive strips. To effectively offset the inductance of the MLA. In this embodiment, the impedance matching between the MLA and the 50 ohm feeder can be realized without an external impedance matching network or a tuning stub (Tuning Stub), thereby solving the problem of difficult impedance matching of the traditional MLA.

The MLA described in this embodiment has a wider impedance bandwidth and can better match a 50 ohm feeder.

As mentioned above, in order to further increase the impedance bandwidth of the MLA, on the basis of the above-mentioned double-layer structure, one of the following three methods or any combination thereof can be further used:

Method 1) Setting the above-mentioned first bending line part 11 and second bending line part 12 into a tapered or trapezoidal shape with a wide top and a narrow bottom;

Method 2) increasing the width of the first bending line portion 11 and the second bending line portion 12;

Method 3) Add sleeves 17 on both sides of the bottom of the capacitive belt 22 and above the formation 16 . Wherein, the sleeve is printed on the second surface of the dielectric substrate.

Figures 4a and 4b show a schematic view of the structure of an MLA when the first bend line part 11 and the second bend line part 12 are set into a tapered shape, wherein Figure 4a shows the first surface of the dielectric substrate, and Figure 4b shows the medium the second side of the substrate. The sleeve 17 is also shown in Figure 4b.

In order to better illustrate the performance of the MLA provided by this embodiment, the MLA with tapered bend line portions on both surfaces of the dielectric substrate and the MLA with tapered bend line portions on one surface of the dielectric substrate were measured respectively. , to obtain the voltage standing wave ratio (VSWR, Voltage Standing Wave Ratio) of the two MLAs as a function of frequency, as shown in Figure 5. Among them, the curve with dots represents the VSWR curve of MLA with a tapered bend line on one side of the dielectric substrate as a function of frequency; the curve with squares represents the tapered bend line on both sides of the dielectric substrate Part of the VSWR curve of the MLA as a function of frequency. It can be seen from Fig. 5 that the fractional bandwidth of MLA is widened from 8% to 12%, which confirms that the impedance bandwidth of MLA can be effectively improved through this double-layer structure. Also, it is worth pointing out that the two MLAs exhibit roughly the same antenna gain (1.8dB), the same 3D radiation pattern, and the same cross-polarization levels. This also shows that this kind of MLA can realize omnidirectional radiation, and has high antenna gain, low cross polarization and wide impedance bandwidth at the same time.

Claims (11)

1. A meander line antenna, said meander line antenna comprising: a first bend line portion (11) printed on the first side of the dielectric substrate; A second bending line portion (12) printed on the second surface of the dielectric substrate; wherein, the first bending line portion (11) is a bent metal strip, and the first bending line portion ( 11) and the second bending line portion (12) are mirror-symmetrical with respect to the dielectric substrate; The microstrip feeder (13) printed on the first surface of the dielectric substrate is connected to the bottom of the first bending line part (11), wherein the microstrip feeder (13) is connected to the first bending line part (11). the connection point of a meander line portion (11) is the feed point; and At least one short-circuit probe (14) at the feeding point is used to connect the first bend line portion (11) and the second bend line portion (12). 2. The meander line antenna according to claim 1, further comprising: a ground layer (15) printed under the second meander line portion (12). 3. The meander line antenna according to claim 2, further comprising: a sleeve located above the formation (15) and beside the bottom sides of the second meander line portion (12). 4. The meander antenna according to any one of claims 1 to 3, wherein the short-circuit probe (14) is used to connect the first meander line portion through a metal probe at the feeding point (11) and the second bend line portion (12). 5. A meander line antenna, said meander line antenna comprising: a first bend line portion (11) printed on the first side of the dielectric substrate; A second bending line portion (12) printed on the second surface of the dielectric substrate; wherein, the first bending line portion (11) is a bent metal strip, and the first bending line portion ( 11) and the second bending line portion (12) are mirror-symmetrical with respect to the dielectric substrate; a first capacitive strip (21) printed on the first surface of the dielectric substrate, the first end of which is connected to the bottom of the first bend line portion (11); a second capacitive strip (22) printed on the second side of the dielectric substrate, the first end of which is connected to the bottom of the second bend line portion (12); The microstrip feeder (23) printed on the first surface of the dielectric substrate is connected to the second end of the first capacitive strip (21), wherein the microstrip feeder (23) is connected to the The point of connection of said first capacitive strip (21) is the feed point; and At least one short-circuit probe (24) at the feed point for connecting the first capacitive strip (21) and the second capacitive strip (22). 6. The meander line antenna according to claim 5, further comprising: a ground layer (16) printed under the second capacitive strip (22). 7. The meander line antenna according to claim 5 or 6, wherein both the first capacitive strip (21) and the second capacitive strip (22) are rectangular. 8. The meander line antenna according to claim 6, said meander line antenna further comprising: a sleeve ( 17). 9. The meander line antenna according to any one of claims 5 to 8, wherein the shorting probe (24) is used to connect the first capacitive strip at the feeding point via a metal probe (21) and the second capacitive strap (22). 10. The meander line antenna according to any one of claims 5 to 9, the short-circuit probe (14) is used to connect the second end of the first capacitive strip (21) and the second capacitive The second end of the sex belt (12). 11. The meander line antenna according to any one of claims 1 to 10, wherein the first meander line portion (11) and the second meander line portion (12) are both tapered or trapezoidal.

Images