CN1855625A - Planar monopole antenna - Google Patents

Abstract

The invention discloses a planar monopole antenna which is suitable for wireless signal transmission in a frequency range and comprises a substrate, a grounding metal, a first sleeve structure, a second sleeve structure and a radiator. The grounding metal is formed on the substrate, and the first and second sleeve structures are electrically connected with the grounding metal and extend from one side of the grounding metal to a first direction. The first and second sleeve structures have a first and second length in the first direction, respectively, and the side has a third length. The radiator is formed on the substrate and located between the first sleeve structure and the second sleeve structure, the radiator is in a long strip shape and has a fourth length in the first direction, and the fourth length is approximately equal to the sum of the first length, the second length and the third length.

Description

planar monopole antenna

technical field

The invention relates to a planar monopole antenna, in particular to a planar monopole antenna with a sleeve structure.

Background technique

With the rapid development of wireless communication and the trend of miniaturization of communication products, some embedded micro-antennas have emerged as the times require. At present, the commonly used micro-antennas include chip antennas (chipantenna) and planar antennas (planar antennas). )etc. Generally speaking, these types of antennas have the characteristics of small size, among which common chip antennas are ceramic chip antennas (ceramic chip antennas) made of co-fired ceramic technology (LTCC), and there are many planar antenna designs, such as micro Strip antenna (microstripe antenna), printed antenna (printed antenna) and planar inverted F antenna (Planar Inverted F Antenna, PIFA), etc., these antennas are widely used in GSM, DCS, UMTS, WLAN and Bluetooth, etc. Wireless terminal equipment, such as mobile phones, wireless LAN cards, etc.

First please refer to FIG. 1 , taking a conventional planar monopole antenna as an example, which is mainly composed of a substrate S, a ground metal G, a radiator R and a cable W. The ground metal G and the radiator R are disposed on the surface S1 of the substrate S, wherein the radiator R is elongated and extends toward the Y-axis direction.

Generally speaking, the aforementioned cable W is a coaxial cable, which has a signal wire W1 and a ground wire W2 wrapped around the periphery of the signal wire W1. As shown in Figure 1, there is a feed-in terminal RF under the radiator R, the above-mentioned feed-in terminal RF is adjacent to one side of the ground metal G, and is connected to the signal line W1 in the center of the cable W, and the ground metal G It is then connected to the ground wire W2 surrounding the periphery of the signal wire W1.

For Digital Video Broadcasting (DVB) generally at about 460-860MHz, the bandwidth coverage of traditional planar monopole antennas is mostly lower than 30%, so the transmission and reception effects of the antennas are not ideal.

In view of this, how to improve the bandwidth of the traditional planar monopole antenna has become an important issue.

Contents of the invention

In view of the above-mentioned shortcomings of the existing planar antenna structure, the present invention proposes a planar monopole antenna, which is suitable for wireless signal transmission within a frequency range, including a substrate, a ground metal, and a first sleeve structure ( sleeve), a second sleeve structure and a radiator. The aforementioned ground metal is formed on the substrate, the first and second sleeve structures are electrically connected to the ground metal, and extend from one side of the ground metal toward a first direction. The first and second sleeve-shaped structures respectively have a first and second length in the first direction, and the aforementioned side has a third length. The aforementioned radiator is formed on the substrate and is located between the first and second sleeve-shaped structures. The radiator is elongated and has a fourth length in the first direction, wherein the fourth length is approximately equal to the first, second, and second sleeve structures. The sum of the third length.

In one of the embodiments, the aforementioned ground metal, the first and second sleeve structures and the radiator are all formed on a surface of the substrate.

In one embodiment, the distance between the radiator and the first sleeve-shaped structure is equal to the distance between the radiator and the second sleeve-shaped structure.

In one embodiment, the aforementioned first and second sleeve structures are perpendicular to the aforementioned side.

In one of the embodiments, the aforementioned fourth length is approximately equal to a quarter of the wavelength of the wireless signal.

In one embodiment, the aforementioned first length is substantially equal to the second length.

In one of the embodiments, the aforementioned substrate is an FR4 substrate (Flame Retardant Type 4), and the aforementioned grounding metal, first and second sleeve-shaped structures and radiators are formed on a surface of the substrate by a printed circuit manufacturing method superior.

In one of the embodiments, the above-mentioned planar monopole antenna further includes a cable, the above-mentioned cable has a signal line and a ground line, and the radiator has a feed-in end, and the above-mentioned feed-in end is adjacent to the aforementioned side, Wherein the ground metal is connected to the ground wire, and the feed-in end is connected to the signal wire.

As in the aforementioned planar monopole antenna, the above-mentioned cable is a coaxial cable, wherein the ground wire is wrapped around the periphery of the signal wire.

The invention proposes a planar monopole antenna suitable for wireless signal transmission within a range, which includes a substrate, a ground metal, a first sleeve structure, a second sleeve structure and a radiator. The ground metal is formed on the substrate, the first and second sleeve structures are electrically connected to the ground metal, and extend from one side of the ground metal toward a first direction. The first and second sleeve-shaped structures respectively have a first and second length in the first direction, and the aforementioned side has a third length. The aforementioned radiator is formed on the substrate and is located between the first and second sleeve-shaped structures, and the radiator has a main radiation part and two symmetrical bent parts. The bent parts are generally L-shaped and connected to the main One end of the radiating portion generally extends opposite to the first direction. In particular, the sum of the lengths of one of the radiator and the bending portion is approximately equal to the sum of the lengths of the first, second, and third.

In one of the embodiments, the aforementioned bent portion has a tooth-like structure.

In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, the detailed embodiments are described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of an existing planar monopole antenna;

Fig. 2 is a schematic diagram of a planar monopole antenna of the present invention;

3 is a schematic diagram of the voltage standing wave ratio (VSWR) presented by the traditional planar monopole antenna and the planar monopole antenna of the present invention in the frequency range of 400-900 MHz;

4 is a schematic diagram of another embodiment of the planar monopole antenna of the present invention; and

FIG. 5 is a schematic diagram of a tooth-shaped bending portion in the planar monopole antenna of the present invention.

Detailed ways

Please refer to FIG. 2 , which shows a schematic diagram of a planar monopole antenna of the present invention. As shown in the figure, the planar monopole antenna of the present invention can transmit wireless signals within a specific frequency range, and mainly includes a substrate S, a ground metal G, a first sleeve G1, a first Two sleeve-shaped structures G2, a radiator R and a cable W, the ground metal G and the radiator R are formed on the surface S1 of the substrate S, wherein the radiator R is elongated and faces a first direction (Y-axis direction ) extension, and a feed-in terminal RF located below the radiator R is adjacent to one side G′ of the ground metal G. In this embodiment, the above-mentioned cable W is a coaxial cable, including a signal wire W1 and a ground wire W2, the above-mentioned ground wire W2 is wrapped around the periphery of the signal wire W1, wherein the signal wire W1 is connected to the bottom of the radiator R. The feed-in terminal RF, and the ground wire W2 is connected to the ground metal G.

As shown in Figure 2, the aforementioned first and second sleeve-shaped structures G1 and G2 are arranged in parallel on the surface S1, and respectively extend from the two ends of the side G' toward the first direction (Y-axis direction), wherein the first sleeve The sleeve-shaped structure G1 has a first length L1 in the direction of the Y-axis, and the second sleeve-shaped structure G2 has a second length L2 in the direction of the Y-axis. The lengths of the first and second sleeve-shaped structures G1 and G2 are approximately equal , that is, the first length L1 is approximately equal to the second length L2. In particular, the aforementioned substrate S can be an FR4 substrate (Flame Retardant Type 4). In addition, the aforementioned first and second sleeve structures G1 and G2 are made of metal and integrally formed with the grounding metal G, which can be passed through a printed circuit ( Printed Circuit) is formed on the aforementioned substrate S surface S1.

In FIG. 2, the aforementioned side G' is perpendicular to the Y-axis direction and has a third length L3 (that is, the distance between the first and second sleeve structures G1 and G2). In addition, the radiator R and the first sleeve structure The distance d between G1 is equal to the distance d between the radiator R and the second sleeve structure G2. In particular, the aforementioned radiator R has a fourth length L4 in the Y-axis direction, which is approximately equal to a quarter of the wavelength of the wireless signal, and approximately equal to the sum of the first, second, and third lengths L1, L2, and L3. , that is, L4=L1+L2+L3. In this way, the present invention can generate capacitive interaction between the radiator R and the sleeve structures G1 and G2 , thereby having a larger bandwidth than the traditional planar monopole antenna.

Next, please refer to FIG. 3 , which shows a schematic diagram of the voltage standing wave ratio (Voltage Standing Wave Ratio, VSWR) presented by the traditional planar monopole antenna and the planar monopole antenna of the present invention in the frequency range of 400-900 MHz. As shown in the figure, curve 31 represents the variation of the voltage standing wave ratio (VSWR) presented by the planar monopole antenna shown in FIG. The antenna does not have a sleeve structure; in addition, the curve 32 represents the variation of the voltage standing wave ratio (VSWR) presented by the planar monopole antenna of the present invention (as shown in FIG. 2 ) in the frequency range of 400-900 MHz, wherein L1=L2=65mm, L3=12mm, L4=140mm.

Generally speaking, in the existing standard specifications in the industry, the voltage standing wave ratio (VSWR) of the planar monopole antenna must be less than 3 to meet the performance requirements, so it can be found from the test results shown in Figure 3 that the present invention The planar monopole antenna can greatly increase the bandwidth (that is, the ratio of the frequency band with a VSWR lower than 3 to the overall frequency band of 400-900 MHz) from about 25% to about 90%.

Next, please refer to FIG. 4 , which shows a schematic diagram of another embodiment of the present invention. In this embodiment, the radiator R' mainly achieves the purpose of reducing the size by changing the geometric shape. As shown in the figure, the radiator R' mainly includes a main radiation portion R1 and two symmetrical bent portions R2, R3, wherein the bent portions R2, R3 are roughly L-shaped. In particular, the total length of the main radiation portion R1 plus any bending portion R2 (or bending portion R3) is approximately equal to the sum of the aforementioned first, second, and third lengths L1, L2, and L3, and is approximately equal to the wireless signal A quarter of the wavelength generates capacitive interaction between the radiator R' and the sleeve structures G1 and G2, so the bandwidth of the antenna can be effectively increased.

In this embodiment, since the above-mentioned bending parts R2 and R3 are bent outward from the end of the main radiation part R1, and extend in the opposite direction of the first direction (Y-axis direction), so when the first, second, When the total length of the third lengths L1, L2, and L3 remains unchanged, the radiator R' can have a smaller length L4' in the Y-axis direction to achieve the purpose of reducing the size, wherein the length L4' in FIG. 4 is less than The fourth length L4 in FIG. 2 .

As shown in Figure 5, in order to more effectively utilize the space on the surface S1 of the substrate S, the above-mentioned bending parts R2 and R3 have a tooth-like structure, and the length of the bending parts R2 and R3 can be increased to form the tooth-like structure, and then can Reduce the required length of the radiator R' in the Y-axis direction. As mentioned above, the total length of the main radiation portion R1 plus any bending portion R2 (or bending portion R3) must be approximately equal to the sum of the aforementioned first, second, and third lengths L1, L2, and L3, and approximately It is equal to a quarter of the wavelength of the wireless signal. Since the capacitive interaction can be generated between the radiator R' and the sleeve structures G1 and G2, the bandwidth of the antenna can be effectively increased. From the comparison of Figure 2, Figure 4, and Figure 5, it can be seen that when the total length of the first, second, and third lengths L1, L2, and L3 remains unchanged, the length of the radiator in the Y-axis direction can be seen Bending is required to reduce the size, where L4"<L4'<L4.

In summary, the present invention mainly forms two symmetrical sleeve-shaped structures on the planar monopole antenna, and can generate capacitive interaction between the radiator and the sleeve-shaped structures through the manufacturing method of the printed circuit. It is used to achieve the effect of increasing the bandwidth. In addition, the geometric shape of the radiator can be changed as required to reduce the size. Since the present invention can effectively increase the bandwidth compared with the traditional planar antenna, it can be widely used in various digital video broadcasting (DVB) devices (such as digital TV).

Although the present invention has been disclosed with detailed embodiments, it is not intended to limit the scope of the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore The scope of protection of the present invention should be defined by the claims.

Claims (20)

1. a planar monopole antenna is applicable to transmission one wireless signal, comprising:

One substrate:

One grounded metal;

One first sleeve shape structure (sleeve) is formed on this substrate and is electrically connected this grounded metal, and wherein this first sleeve shape structure is that a side by this grounded metal extends towards a first direction, and has one first length on this first direction;

One second sleeve shape structure is formed on this substrate and is electrically connected this grounded metal, and wherein this second sleeve shape structure is to be extended towards this first direction by the two ends of this side, and has one second length on this first direction, and this side has one the 3rd length in addition; One radiant body is formed on this substrate and this first, second and tucks inside the sleeve between the shape structure, and this radiant body is strip, and has one the 4th length on this first direction, and wherein the 4th length is substantially equal to the summation of this first, second, third length; And

One cable couples this radiant body, uses this wireless signal of conduction.

2. planar monopole antenna as claimed in claim 1, wherein this grounded metal, this first, second sleeve shape structure and this radiant body all are formed on the surface of this substrate.

3. planar monopole antenna as claimed in claim 1, wherein between this radiant body and this first sleeve shape structure apart from equaling this radiant body and this second spacing of tucking inside the sleeve the shape structure.

4. planar monopole antenna as claimed in claim 1, wherein first, second sleeve shape structure is perpendicular to this side.

5. planar monopole antenna as claimed in claim 1, wherein the 4th length is substantially equal to 1/4th of this wireless signal wavelength.

6. planar monopole antenna as claimed in claim 1, wherein this first length is substantially equal to this second length.

7. planar monopole antenna as claimed in claim 1, wherein this substrate is a FR4 substrate (Flame Retardant Type 4).

8. planar monopole antenna as claimed in claim 1, wherein this grounded metal, this first, second sleeve shape structure and this radiant body are that production method with printed circuit is formed on the surface of this substrate.

9. planar monopole antenna as claimed in claim 1, wherein this cable also has a holding wire and an earth connection, and this radiant body has a feed side, contiguous this side in this feed side, wherein this grounded metal connects this earth connection, and this feed side connects this holding wire.

10. planar monopole antenna as claimed in claim 8, wherein this cable is a coaxial cable, and this earth connection is coated on this holding wire periphery.

11. a planar monopole antenna is applicable to transmission one wireless signal, comprising:

One substrate:

One grounded metal;

One first sleeve shape structure (sleeve) is formed on this substrate and is electrically connected this grounded metal, and wherein this first sleeve shape structure is that a side by this grounded metal extends towards a first direction, and has one first length on this first direction;

One second sleeve shape structure is formed on this substrate and is electrically connected this grounded metal, and wherein this second sleeve shape structure is to be extended towards this first direction by the two ends of this side, and has one second length on this first direction, and this side has one the 3rd length in addition;

One radiant body, be formed on this substrate and and tuck inside the sleeve between the shape structure this first, second, this radiant body has the kink of a primary radiation portion and two symmetries, this each kink is L-shaped substantially, an end that is connected in primary radiation portion is also roughly towards the reverse extension of this first direction, and wherein this radiant body and this each one of them person's of kink length sum total is substantially equal to this length summation of first, second, third; And

One cable couples this radiant body, in order to conduct this wireless signal.

12. planar monopole antenna as claimed in claim 11, wherein this kink has dentalation.

13. planar monopole antenna as claimed in claim 11, wherein this grounded metal, this first, second sleeve shape structure and this radiant body all are formed on the surface of this substrate.

14. planar monopole antenna as claimed in claim 11, wherein the spacing of this radiant body and this first sleeve shape structure equals the spacing of this radiant body and this second sleeve shape structure.

15. planar monopole antenna as claimed in claim 11, wherein first, second sleeve shape structure is perpendicular to this side.

16. planar monopole antenna as claimed in claim 11, wherein the 4th length is substantially equal to 1/4th of this wireless signal wavelength.

17. planar monopole antenna as claimed in claim 11, wherein this first length is substantially equal to this second length.

18. planar monopole antenna as claimed in claim 11, wherein this substrate is a FR4 substrate (Flame Retardant Type 4).

19. planar monopole antenna as claimed in claim 18, wherein this grounded metal, this first, second sleeve shape structure and this radiant body are that production method with printed circuit is formed on the surface of this substrate.

20. planar monopole antenna as claimed in claim 11, wherein this cable also has a holding wire and an earth connection, and this radiant body has a feed side, contiguous this side in this feed side, wherein this grounded metal connects this earth connection, and this feed side connects this holding wire.

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