Absorption type filtering antenna with low reflection characteristic in wide frequency band

Abstract

The utility model provides an absorption type filtering antenna with a low reflection characteristic in a wide frequency band. The absorption type filtering antenna comprises a rectangular metal block, a first dielectric plate, a second dielectric plate and a coaxial cable, the first dielectric plate is stacked above the second dielectric plate; a coaxial cable connector, an input port connector, a metal stub line, a feed network, a first L-shaped open-circuit microstrip line and a second L-shaped open-circuit microstrip line are printed on the upper surface of the first dielectric plate; the rectangular metal block is supported above the first dielectric plate in a suspended manner through nylon columns, and the rectangular metal block and the structure on the first dielectric plate jointly form a reflection type filtering antenna; and a band elimination filter is printed on the lower surface of the second dielectric plate. According to the utility model, the reflection-type filtering antenna and the band elimination filter are combined, so that the absorption-type filtering antenna with low reflection characteristic in a wide frequency band is realized, and the absorption-type filtering antenna has the characteristics of high gain, wide bandwidth and high roll-off rate.

Description

TECHNICAL FIELD

[0001] The utility model relates to a communication antenna field, concretely relates to an absorption type filter antenna with low reflection characteristic in wide frequency band. BACKGROUND

[0002] As a key component of wireless communication system, the performance of antenna directly affects the quality and efficiency of the whole communication system. With the continuous development of wireless communication technology, the performance requirement of antenna is also higher and higher. These problems promote the research and development of filter antenna technology, but there are still many deficiencies in filter antenna technology.

[0003] The reflection type filter in the traditional filter antenna is prone to resonance, which may have adverse effects on signal transmission, such as causing signal distortion or increased interference. At the same time, the signal filtering effect of the traditional filter antenna for a relatively wide frequency band may not be ideal, and the frequency selectivity is relatively poor. In addition, the filtering edge of the traditional filter antenna may be relatively flat, resulting in unsatisfactory suppression effect on out-of-band signals.

[0004] Therefore, the filter antenna of the prior art has deficiencies in wideband performance, frequency selectivity and out-of-band signal suppression, and needs to be improved and perfected. SUMMARY

[0005] The utility model discloses a kind of absorption type filter antennas with low reflection characteristic in wide frequency band, to solve the problems of the prior art, provide a kind of absorption type filter antenna with low reflection characteristic in wide frequency band.

[0006] To achieve the above object, the utility model adopts the following technical scheme:

[0007] A kind of absorption type filter antenna with low reflection characteristic in wide frequency band, including rectangular metal block, first dielectric plate, second dielectric plate and coaxial cable;

[0008] The first dielectric plate is stacked and arranged above the second dielectric plate, and a metal reflector plate is printed on the lower surface of the first dielectric plate or the upper surface of the second dielectric plate;A coaxial cable connector, an input port connector, a metal stub, a feed network, a first L-shaped open microstrip line and a second L-shaped open microstrip line are printed on the upper surface of the first dielectric plate;

[0009] The coaxial cable connector is arranged in the middle of one side edge of the first dielectric plate, and the coaxial cable connector is connected to the metal reflector plate by a plurality of metal short-circuit columns penetrating the first dielectric plate;The outer conductor of the coaxial cable is connected to the metal reflector plate through the coaxial cable connector, and the inner conductor of the coaxial cable is connected to the input port connector;The metal stub is arranged parallel to the Y-axis direction, one end of the metal stub is connected to the input port connector, and the other end of the metal stub extends towards the middle of the first dielectric plate;

[0010] The feeding network has one input end and two output ends, the input end of the feeding network is connected with the input port connector, and the first L-shaped open microstrip line and the second L-shaped open microstrip line are respectively connected to the two output ends of the feeding network; the feeding network is symmetrical about the metal stub, and the first L-shaped open microstrip line and the second L-shaped open microstrip line are symmetrically distributed on both sides of the metal stub;

[0011] The rectangular metal block is suspended and supported by the nylon column and arranged above the first dielectric plate, and the rectangular metal block and the structure on the first dielectric plate jointly constitute a reflective filtering antenna;

[0012] The lower surface of the second dielectric plate is printed with a band elimination filter, an input end of the band elimination filter is connected with the input port connector through a metal short pin, the metal short pin penetrates the first dielectric plate and the second dielectric plate along the Z-axis direction, and both ends of the metal short pin are respectively connected with the band elimination filter and the input port connector.

[0013] Further, the rectangular metal block and the first dielectric plate have a profile height of 6 mm.

[0014] Further, the feeding network comprises a first feeding microstrip line and a second feeding microstrip line, and the first feeding microstrip line and the second feeding microstrip line are symmetrically distributed on both sides of the metal stub in the X-axis direction;

[0015] The first feeding microstrip line comprises a first segment microstrip line, a second segment microstrip line, a third segment microstrip line and a fourth segment microstrip line connected in sequence, wherein the first segment microstrip line and the third segment microstrip line are parallel to the X-axis direction, and the second segment microstrip line and the fourth segment microstrip line are parallel to the Y-axis direction; the end of the first segment microstrip line is connected with the input port connector, and the end of the fourth segment microstrip line is connected with the first L-shaped open microstrip line;

[0016] The second feeding microstrip line comprises a fifth segment microstrip line, a sixth segment microstrip line, a seventh segment microstrip line and an eighth segment microstrip line connected in sequence, wherein the fifth segment microstrip line and the seventh segment microstrip line are parallel to the X-axis direction, and the sixth segment microstrip line and the eighth segment microstrip line are parallel to the Y-axis direction; the end of the fifth segment microstrip line is connected with the input port connector, and the end of the eighth segment microstrip line is connected with the second L-shaped open microstrip line.

[0017] Further, the first L-shaped open microstrip line comprises a first open microstrip line and a second open microstrip line connected perpendicularly to each other, wherein the first open microstrip line is parallel to the X-axis direction, the second open microstrip line is parallel to the Y-axis direction and has a length greater than that of the first open microstrip line; one end of the first open microstrip line is connected with the fourth segment microstrip line in the first feeding microstrip line, and the other end of the first open microstrip line is connected with one end of the second open microstrip line;

[0018] The second L-shaped open circuit microstrip line comprises a third open circuit microstrip line and a fourth open circuit microstrip line connected perpendicularly to each other, wherein the third open circuit microstrip line is parallel to the X-axis direction, and the fourth open circuit microstrip line is parallel to the Y-axis direction and has a length greater than that of the third open circuit microstrip line; one end of the third open circuit microstrip line is connected to the eighth segment of the second feeding microstrip line, and the other end of the third open circuit microstrip line is connected to one end of the fourth open circuit microstrip line.

[0019] Further, the band-stop filter comprises a filter input connector, a rectangular microstrip line, a first L-shaped metal stub, a second L-shaped metal stub, a first coupling metal stub, a second coupling metal stub and a 50-ohm absorbing resistor printed on the lower surface of the second dielectric plate.

[0020] The filter input connector and the rectangular microstrip line are arranged below the metal stubs and extend along the Y-axis direction; one end of the filter input connector is connected to the input port connector on the upper surface of the first dielectric plate through a metal short pin, the other end of the filter input connector is connected to one end of the rectangular microstrip line, and the other end of the rectangular microstrip line is connected to the 50-ohm absorbing resistor.

[0021] The first L-shaped metal stub and the second L-shaped metal stub are respectively connected to the two sides of the rectangular microstrip line in the X-axis direction; the first coupling metal stub and the second coupling metal stub are respectively arranged outside the first L-shaped metal stub and the second L-shaped metal stub.

[0022] Further, the first L-shaped metal stub comprises a first stub and a second stub connected perpendicularly to each other, wherein the first stub is parallel to the X-axis direction, and the second stub is parallel to the Y-axis direction and has a length greater than that of the first stub; one end of the first stub is connected to the rectangular microstrip line, the other end of the first stub is connected to one end of the second stub, and the other end of the second stub extends towards the side where the 50-ohm absorbing resistor is located.

[0023] The second L-shaped metal stub comprises a third stub and a fourth stub connected perpendicularly to each other, wherein the third stub is parallel to the X-axis direction, and the fourth stub is parallel to the Y-axis direction and has a length greater than that of the third stub; one end of the third stub is connected to the rectangular microstrip line, the other end of the third stub is connected to one end of the fourth stub, and the other end of the fourth stub extends towards the side where the 50-ohm absorbing resistor is located.

[0024] The first coupling metal stub and the second coupling metal stub are both parallel to the Y-axis direction; the first coupling metal stub is arranged parallel to the outside of the second stub, and the second coupling metal stub is arranged parallel to the outside of the fourth stub.

[0025] Further, the first stub line and the third stub line are connected to different positions in the Y-axis direction of the rectangular microstrip line respectively, so that the second stub line and the fourth stub line are staggered with each other in the Y-axis direction.

[0026] Further, a rectangular groove is excavated at the lower surface edge of one side of the second dielectric plate, and the 50-ohm absorbing resistor is arranged in the rectangular groove.

[0027] The utility model discloses a reflection type filter antenna and band elimination filter are combined, realize an absorbing type filter antenna with low reflection characteristic in wide frequency band, and its out-of-band suppression level exceeds 19.3dB, has the characteristics of high gain, wide bandwidth and high roll-off rate, simultaneously, the antenna structure of the utility model is simple and easy to process, and the production manufacturing cost of antenna is saved greatly. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the whole structure schematic diagram of the absorbing type filter antenna with low reflection characteristic in wide frequency band provided by the utility model embodiment.

[0029] Figure 2 It is the top structure schematic diagram of the rectangular metal block in the utility model embodiment.

[0030] Figure 3 It is the top structure schematic diagram of the first dielectric plate in the utility model embodiment.

[0031] Figure 4 It is the bottom structure schematic diagram of the second dielectric plate in the utility model embodiment.

[0032] Figure 5 It is the S parameter curve diagram of the utility model embodiment.

[0033] Figure 6 It is the gain curve diagram of the utility model embodiment.

[0034] Figure 7 It is the radiation pattern of the utility model embodiment. DETAILED DESCRIPTION

[0035] The technical scheme of the utility model will be explained in detail below in combination with the drawings and specific embodiments.

[0036] As Figures 1 to 4 The utility model embodiment provides an absorbing type filter antenna with low reflection characteristic in wide frequency band, and it includes rectangular metal block 1, first dielectric plate 2, second dielectric plate 3 and coaxial cable 4.The first dielectric plate 2 is arranged on the top of the second dielectric plate 3, and the lower surface of the first dielectric plate 2 or the upper surface of the second dielectric plate 3 is printed with a metal reflection plate.

[0037] AsFigure 3 As shown, the upper surface of the first dielectric plate 2 is printed with a coaxial cable connector 201, an input port connector 202, a metal stub 203, a feed network 204, a first L-shaped open microstrip line 205 and a second L-shaped open microstrip line 206.

[0038] The coaxial cable connector 201 is arranged at the middle of one side edge of the first dielectric plate 2, and is connected to the metal reflection plate through a plurality of metal shorting posts 41 penetrating the first dielectric plate 2; the outer conductor of the coaxial cable 4 is connected to the metal reflection plate through the coaxial cable connector 201, and the inner conductor of the coaxial cable 4 is connected to the input port connector 202; the metal stub 203 is arranged parallel to the Y-axis direction, one end of the metal stub 203 is connected to the input port connector 202, and the other end of the metal stub 203 extends towards the middle of the first dielectric plate 2.

[0039] The feed network 204 has one input end and two output ends, the input end of the feed network 204 is connected to the input port connector 202, and the first L-shaped open microstrip line 205 and the second L-shaped open microstrip line 206 are respectively connected to the two output ends of the feed network 204; the shape of the feed network 204 is symmetrical about the metal stub 203, and the first L-shaped open microstrip line 205 and the second L-shaped open microstrip line 206 are symmetrically distributed on both sides of the metal stub 203.

[0040] The rectangular metal block 1 is suspended and supported by the nylon column 10 above the first dielectric plate 2, and the rectangular metal block 1 and the structure on the first dielectric plate 2 together constitute a reflective filtering antenna. Among them, the cross-sectional height between the rectangular metal block 1 and the first dielectric plate 2 is 6mm.

[0041] Specifically, the feed network 204 includes a first feed microstrip line and a second feed microstrip line, and the first feed microstrip line and the second feed microstrip line are symmetrically distributed on both sides of the metal stub 203 in the X-axis direction.

[0042] The first feed microstrip line includes a first segment microstrip line, a second segment microstrip line, a third segment microstrip line and a fourth segment microstrip line connected end to end in sequence, wherein the first segment microstrip line and the third segment microstrip line are parallel to the X-axis direction, and the second segment microstrip line and the fourth segment microstrip line are parallel to the Y-axis direction; the end of the first segment microstrip line is connected to the input port connector 202, and the end of the fourth segment microstrip line is connected to the first L-shaped open microstrip line 205.

[0043] The second feeding microstrip line comprises a fifth segment microstrip line, a sixth segment microstrip line, a seventh segment microstrip line and an eighth segment microstrip line connected in sequence, wherein the fifth segment microstrip line and the seventh segment microstrip line are parallel to the X-axis direction, and the sixth segment microstrip line and the eighth segment microstrip line are parallel to the Y-axis direction; the end of the fifth segment microstrip line is connected with the input port connector 202, and the end of the eighth segment microstrip line is connected with the second L-shaped open microstrip line 206.

[0044] Further, the first L-shaped open microstrip line 205 comprises a first open microstrip line and a second open microstrip line connected perpendicularly to each other, wherein the first open microstrip line is parallel to the X-axis direction, and the second open microstrip line is parallel to the Y-axis direction and has a length greater than that of the first open microstrip line; one end of the first open microstrip line is connected with the fourth segment microstrip line in the first feeding microstrip line, and the other end of the first open microstrip line is connected with one end of the second open microstrip line.

[0045] The second L-shaped open microstrip line 206 comprises a third open microstrip line and a fourth open microstrip line connected perpendicularly to each other, wherein the third open microstrip line is parallel to the X-axis direction, and the fourth open microstrip line is parallel to the Y-axis direction and has a length greater than that of the third open microstrip line; one end of the third open microstrip line is connected with the eighth segment microstrip line in the second feeding microstrip line, and the other end of the third open microstrip line is connected with one end of the fourth open microstrip line.

[0046] As shown in Figure 4 The lower surface of the second dielectric plate 3 is printed with a band-stop filter, the input end of the band-stop filter is connected with the input port connector 202 through a metal shorting pin 42, the metal shorting pin 42 penetrates the first dielectric plate 2 and the second dielectric plate 3 along the Z-axis direction, and the two ends of the metal shorting pin 42 are respectively connected with the band-stop filter and the input port connector 202.

[0047] Specifically, the band-stop filter comprises a filter input end connector 301 printed on the lower surface of the second dielectric plate 3, a rectangular microstrip line 302, a first L-shaped metal stub 304, a second L-shaped metal stub 305, a first coupling metal stub 306, a second coupling metal stub 307 and a 50-ohm absorbing resistor 303.

[0048] The filter input end connector 301 and the rectangular microstrip line 302 are arranged below the metal stub 203 and extend along the Y-axis direction, one end of the filter input end connector 301 is connected with the input port connector 202 on the upper surface of the first dielectric plate 2 through the metal shorting pin 42, the other end of the filter input end connector 301 is connected with one end of the rectangular microstrip line 302, and the other end of the rectangular microstrip line 302 is connected with the 50-ohm absorbing resistor 303.

[0049] The first L-shaped metal stub 304 and the second L-shaped metal stub 305 are connected to the two sides of the rectangular microstrip line 302 in the X-axis direction respectively; the first coupling metal stub 306 and the second coupling metal stub 307 are arranged outside the first L-shaped metal stub 304 and the second L-shaped metal stub 305 respectively.

[0050] Specifically, the first L-shaped metal stub 304 includes a first stub and a second stub connected perpendicularly to each other, wherein the first stub is parallel to the X-axis direction, and the second stub is parallel to the Y-axis direction and has a length greater than that of the first stub; one end of the first stub is connected to the rectangular microstrip line 302, the other end of the first stub is connected to one end of the second stub, and the other end of the second stub extends towards the side where the 50-ohm absorbing resistor 303 is located;

[0051] The second L-shaped metal stub 305 includes a third stub and a fourth stub connected perpendicularly to each other, wherein the third stub is parallel to the X-axis direction, and the fourth stub is parallel to the Y-axis direction and has a length greater than that of the third stub; one end of the third stub is connected to the rectangular microstrip line 302, the other end of the third stub is connected to one end of the fourth stub, and the other end of the fourth stub extends towards the side where the 50-ohm absorbing resistor 303 is located;

[0052] The first coupling metal stub 306 and the second coupling metal stub 307 are both parallel to the Y-axis direction; the first coupling metal stub 306 is arranged in parallel outside the second stub, and the second coupling metal stub 307 is arranged in parallel outside the fourth stub.

[0053] Further, the first stub and the third stub are connected to different positions of the rectangular microstrip line 302 in the Y-axis direction respectively, so that the second stub and the fourth stub are staggered with each other in the Y-axis direction.

[0054] Further, a rectangular groove 30 is excavated at the lower surface edge of one side of the second dielectric plate 3, and the 50-ohm absorbing resistor 303 is arranged in the rectangular groove 30.

[0055] During operation of the embodiment, the feeding structures above the first dielectric plate 2 cancel each other out by using current, and can independently generate four zero points, thereby playing a filtering role, i.e., forming a reflection-type filtering antenna. Specifically, the structure of the feeding network 204 itself generates a first zero point at f=2.44 GHz, and the current at this frequency is concentrated on the feeder of the feeding network 204, and since the current on the feeder presents an equal-amplitude and opposite-phase trend, the far field radiated at f=2.44 GHz cancels each other out, thereby introducing the first zero point.

[0056] After adding two L-shaped open circuit microstrip lines, a new low-frequency radiation zero point, i.e., a second zero point, can be generated near f=1.49GHz, and a new high-frequency radiation zero point, i.e., a third zero point, can be generated near f=5.24GHz. Specifically, after adding two L-shaped open circuit microstrip lines, the current at the frequency f=1.49GHz is mainly concentrated in the feeding network 204 and the two L-shaped open circuit microstrip lines, and these currents all present an equal-amplitude anti-phase flow state, so the far-field radiation generated at this frequency point cancels out each other to generate the second zero point. At the same time, due to the introduction of the two L-shaped open circuit microstrip lines, the original first zero point near the frequency f=2.44GHz moves to the frequency f=2.61GHz, so that the low-frequency roll-off rate of the gain curve is better. In addition, the frequency of the third zero point appearing at the high frequency is almost twice that of 2.61GHz, so it can be considered that the third zero point near the frequency f=5.24GHz is a frequency-doubled radiation zero point generated after the first zero point moves to the frequency f=2.61GHz.

[0057] After introducing the metal stub 203, part of the current is concentrated on the metal stub 203, and this part of the current is equal in amplitude and opposite in phase to the current on the feeding network 204 before, so that the metal stub 203 introduces a new radiation zero point, i.e., a fourth zero point, near the frequency f=4.62GHz, further enhancing the roll-off rate of the antenna in the high-frequency filtering part.

[0058] The utility model embodiment further sets the band elimination filter on the lower surface of the second dielectric plate 3, can realize the characteristic of no reflection out of band, help to improve the final bandwidth of the antenna, and further improve the roll-off rate of the antenna. On the output end of the band elimination filter, the 50 ohm absorbing resistance 303 is placed in the way of digging a groove under the second dielectric plate 3, which can avoid introducing additional structures, so that the simulation design of the antenna becomes simpler.

[0059] The input end of the band elimination filter and the reflective filter antenna in the utility model form a parallel structure through the metal short pin 42, and at the same time, the band elimination filter and the reflective filter antenna share the same metal reflector plate, which reduces the profile of the antenna, simplifies the antenna structure, and makes the overall size of the antenna only 0.7λ*λ*0.12λ (λ is the wavelength at the center frequency of the antenna).

[0060] Figure 5 、 Figure 6 、 Figure 7The S parameter curve diagram, the gain curve diagram and the radiation direction diagram of the embodiment of the utility model respectively, from the diagram, the utility model's working frequency band is 3.08GHz~3.98GHz, its working bandwidth is 14% (3.3GHz~3.8GHz), the highest gain in band is 8.2dBi, solved the problem of traditional filtering antenna bandwidth narrow, further, the utility model adopts the design of band-stop filter and reflection type filtering antenna combination, makes the out-of-band rejection level to exceed 19.3dB, solved the problem of traditional filtering antenna to the out-of-band signal suppression insufficient, in addition, the utility model's structure is simple, adopts the method of grooving to place output end resistance, easy to process, thereby saved the cost, solved the problem of traditional filtering antenna structure complex, high cost.

[0061] In conclusion, the utility model combines the reflection type filtering antenna and the band-stop filter, realizes a kind of absorption type filtering antenna with low reflection characteristic in wide frequency band, and the out-of-band rejection level exceeds 19.3dB, with the characteristics of high gain, wide bandwidth and high roll-off rate, simultaneously, the antenna structure of the utility model is simple and easy to process, greatly saves the production manufacturing cost of antenna.

[0062] The above-described embodiments only express several implementation manners of the utility model, and the description is more specific and detailed, but it should not be understood as the limitation of the utility model patent scope. It should be pointed out that, for ordinary skilled person in the art, without departing from the concept of the utility model, a number of variations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. An absorptive filter antenna having low reflection characteristics over a wide frequency band, characterized by comprising: The rectangular metal block, the first dielectric plate, the second dielectric plate and the coaxial cable are included. The first dielectric plate is arranged above the second dielectric plate, and the lower surface of the first dielectric plate or the upper surface of the second dielectric plate is printed with a metal reflection plate; the upper surface of the first dielectric plate is printed with a coaxial cable connector, an input port connector, a metal stub, a feed network, a first L-shaped open microstrip line and a second L-shaped open microstrip line. The coaxial cable connector is arranged in the middle of one side edge of the first dielectric plate, and the coaxial cable connector is connected to the metal reflection plate through a plurality of metal shorting posts penetrating the first dielectric plate; the outer conductor of the coaxial cable is connected to the metal reflection plate through the coaxial cable connector, and the inner conductor of the coaxial cable is connected to the input port connector; the metal stub is arranged parallel to the Y-axis direction, one end of the metal stub is connected to the input port connector, and the other end of the metal stub extends towards the middle of the first dielectric plate. The feed network has one input end and two output ends, the input end of the feed network is connected to the input port connector, and the first L-shaped open microstrip line and the second L-shaped open microstrip line are respectively connected to the two output ends of the feed network; the shape of the feed network is symmetrical about the metal stub, and the first L-shaped open microstrip line and the second L-shaped open microstrip line are symmetrically distributed on both sides of the metal stub. The rectangular metal block is suspended and supported by a nylon column above the first dielectric plate, and the rectangular metal block and the structure on the first dielectric plate together constitute a reflective filtering antenna. The lower surface of the second dielectric plate is printed with a band-stop filter, the input end of the band-stop filter is connected to the input port connector through a metal shorting pin, the metal shorting pin penetrates the first dielectric plate and the second dielectric plate along the Z-axis direction, and the two ends of the metal shorting pin are respectively connected to the band-stop filter and the input port connector.

2. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 1, characterized by, The rectangular metal block and the first dielectric plate have a cross-sectional height of 6mm.

3. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 1, characterized by, The feed network includes a first feed microstrip line and a second feed microstrip line, and the first feed microstrip line and the second feed microstrip line are symmetrically distributed on both sides of the metal stub in the X-axis direction; The first feed microstrip line includes a first segment microstrip line, a second segment microstrip line, a third segment microstrip line and a fourth segment microstrip line connected end to end, wherein the first segment microstrip line and the third segment microstrip line are parallel to the X-axis direction, and the second segment microstrip line and the fourth segment microstrip line are parallel to the Y-axis direction; the end of the first segment microstrip line is connected to the input port connector, and the end of the fourth segment microstrip line is connected to the first L-shaped open microstrip line; The second feed microstrip line includes a fifth segment microstrip line, a sixth segment microstrip line, a seventh segment microstrip line and an eighth segment microstrip line connected end to end, wherein the fifth segment microstrip line and the seventh segment microstrip line are parallel to the X-axis direction, and the sixth segment microstrip line and the eighth segment microstrip line are parallel to the Y-axis direction; the end of the fifth segment microstrip line is connected to the input port connector, and the end of the eighth segment microstrip line is connected to the second L-shaped open microstrip line.

4. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 3, characterized by, The first L-shaped open microstrip line comprises a first open microstrip line and a second open microstrip line connected perpendicularly to each other, wherein the first open microstrip line is parallel to the X-axis direction, and the second open microstrip line is parallel to the Y-axis direction and has a length greater than that of the first open microstrip line; one end of the first open microstrip line is connected to the fourth segment of the first feeding microstrip line, and the other end of the first open microstrip line is connected to one end of the second open microstrip line; The second L-shaped open microstrip line comprises a third open microstrip line and a fourth open microstrip line connected perpendicularly to each other, wherein the third open microstrip line is parallel to the X-axis direction, and the fourth open microstrip line is parallel to the Y-axis direction and has a length greater than that of the third open microstrip line; one end of the third open microstrip line is connected to the eighth segment of the second feeding microstrip line, and the other end of the third open microstrip line is connected to one end of the fourth open microstrip line.

5. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 1, wherein, The band-stop filter comprises a filter input connector, a rectangular microstrip line, a first L-shaped metal stub, a second L-shaped metal stub, a first coupling metal stub, a second coupling metal stub and a 50-ohm absorbing resistor, which are printed on the lower surface of the second dielectric plate. The filter input connector and the rectangular microstrip line are arranged below the metal stubs and extend along the Y-axis direction; one end of the filter input connector is connected to the input port connector on the upper surface of the first dielectric plate through a metal short pin, the other end of the filter input connector is connected to one end of the rectangular microstrip line, and the other end of the rectangular microstrip line is connected to the 50-ohm absorbing resistor. The first L-shaped metal stub and the second L-shaped metal stub are respectively connected to the two sides of the rectangular microstrip line in the X-axis direction; the first coupling metal stub and the second coupling metal stub are respectively arranged outside the first L-shaped metal stub and the second L-shaped metal stub.

6. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 5, wherein The first L-shaped metal stub comprises a first stub and a second stub connected perpendicularly to each other, wherein the first stub is parallel to the X-axis direction, and the second stub is parallel to the Y-axis direction and has a length greater than that of the first stub; one end of the first stub is connected to the rectangular microstrip line, the other end of the first stub is connected to one end of the second stub, and the other end of the second stub extends towards the side where the 50-ohm absorbing resistor is located; The second L-shaped metal stub comprises a third stub and a fourth stub connected perpendicularly to each other, wherein the third stub is parallel to the X-axis direction, and the fourth stub is parallel to the Y-axis direction and has a length greater than that of the third stub; one end of the third stub is connected to the rectangular microstrip line, the other end of the third stub is connected to one end of the fourth stub, and the other end of the fourth stub extends towards the side where the 50-ohm absorbing resistor is located; The first coupling metal stub and the second coupling metal stub are both parallel to the Y-axis direction; the first coupling metal stub is arranged parallel to the outside of the second stub, and the second coupling metal stub is arranged parallel to the outside of the fourth stub.

7. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 6, characterized by, The first stub and the third stub are respectively connected to different positions of the rectangular microstrip line in the Y-axis direction, so that the second stub and the fourth stub are staggered with each other in the Y-axis direction.

8. The absorptive filter antenna having low reflection characteristics in a wide frequency band according to claim 5, wherein, The second medium plate is provided with a rectangular groove at the lower surface edge of one side, and the 50-ohm absorbing resistor is arranged in the rectangular groove.

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