CN114843776A - A flexible ultra-wideband filter antenna - Google Patents

Abstract

The invention discloses a flexible ultra-wideband filter antenna, which comprises a dielectric substrate, a radiation patch, a feeder line and a ground plate, wherein the dielectric substrate is made of polyimide flexible material, and the radiation patch, the feeder line and the ground plate are arranged on the upper side of the dielectric substrate. The radiation patch is provided with a rectangular patch of a complementary C-shaped groove, the rectangular patch is formed by printing rolled copper on a medium substrate, and the lower end of the rectangular patch adopts a two-semicircle gradient structure. The feeder line is provided with an inverted U-shaped groove and is connected with the lower end of the radiation patch. The grounding plates are in a stepped structure and are positioned on two sides of the feeder line, and meanwhile, symmetrical inverted-L-shaped grooves are formed in the symmetrical grounding plates. The antenna is simulated by HFSS software, the antenna covers an ultra-wideband frequency band with a frequency band of 2-10GHz, and in-band filtering frequency bands of 3.31-3.75GHz, 5.01-6.05GHz and 7.32-8.62GHz respectively correspond to WiMAX, WLAN and satellite X wave bands. The antenna has the characteristics of small size, low loss, in-band filtering, flexibility, wearability and the like, is suitable for the fields of body area networks, short-distance communication, wearable equipment and the like, and has a good application scene.

Description

A flexible ultra-wideband filter antenna

technical field

The invention relates to the fields of flexible antennas, filter antennas and ultra-wideband antennas, and is mainly applied to the fields of short-distance wireless communication and body area network communication.

Background technique

With the rapid development of science and technology, there are more and more human-centered interaction scenarios, such as medical and health monitoring, smart home, smart car system and so on. Communication problems such as higher communication speed, smaller power consumption, and wider bandwidth followed. Since the FCC released the 3.1-106GHz frequency band for ultra-broadband wireless communication in 2002, short-distance wireless communication appeared at this time. a better solution.

The advantages brought by UWB lie in the characteristics of wide bandwidth, low latency, and low power consumption. There are also many challenges faced by UWB, and the most prominent problem is in-band interference. Because the bandwidth occupied by ultra-wideband communication covers the existing narrowband communication frequency band, the narrowband communication is very developed today, and the channel congestion is serious, which means that the in-band interference problem of ultra-wideband communication is more serious. The invention makes changes on the ultra-wideband antenna to make it have better in-band filtering function, and realizes the anti-narrowband communication interference ability to reach the ultra-wideband with the minimum cost.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the existing technology and realize the characteristics of flexibility, in-band filtering capability and miniaturization of the ultra-wideband antenna. The present invention provides a flexible antenna using polyimide as a substrate material. The simulation results show that the working frequency band of the antenna of the invention is 2-10GHz, the in-band filtering frequency band is 3.31-3.75GHz, 5.01-6.05GHz and 7.32-8.62GHz; the return loss in the non-notch frequency band is less than -10dB, and the voltage standing wave ratio is less than -10dB. Less than 2; the return loss in the notch frequency band is greater than -10dB, and the voltage standing wave ratio is greater than 2; at the same time, the antenna has the ability of omnidirectional radiation, and the antenna has the advantages of flexibility, in-band suppression, wide bandwidth, low loss and low profile.

Technical scheme of the present invention:

A flexible filter antenna includes a dielectric substrate 1, a radiation patch 2, a feed line 3 and a grounding plate 4; the dielectric substrate 1 is made of polyimide flexible material, on which is provided a radiation patch 2, a feed line 3 and a ground plate 4; Ground plate 4; Radiation patch 2 is a semi-circular patch with a complementary C-shaped slot in the center; Feeder 3 is connected to the lower end of Radiation Patch 2; Feeder 3 has an inverted U-shaped slot; On both sides of the wire, at the same time, the symmetrical ground plate 4 has a symmetrical inverted L-shaped slot.

Further, the thickness of the dielectric substrate 1 is 0.2 mm, the length is 30 mm, and the width is 35 mm.

Further, the dielectric substrate 1 is made of polyimide flexible material, the dielectric constant thereof is 3.4, and the loss tangent value is 0.008.

Further, the radiation patch 2 has a complementary C-shaped groove in the center, the lower two corners of which are semicircular structures; the dimensions of the two C-shaped grooves are inner diameters R1=2.4mm, R2=5.4mm; Slot width d1=0.1mm, d2=0.7mm; semi-circular structure size is R=13.5mm; two complementary C-shaped grooves are nested, and the opening directions are opposite. The large-sized C-shaped groove opens downward, and its opening faces the semicircular bottom surface of the radiation patch. The two C-shaped grooves share a center point, and the gap angle θ of the two C-shaped grooves is 22°.

Further, the feeder 3 has an inverted U-shaped slot, the size of the U-shaped slot is length d3=9mm, width d4=1.2mm, the slot size is s1=0.1mm, and the size of the feeder is: length lf=10.2mm , width wf=1.6mm.

Further, the grounding plate 4 is a symmetrical ladder type patch, including three layers of ladders in total. The height L3=4mm, the height of the third step is 1.2mm; the width of the bottom of the step structure is W1=13.95mm; at the same time, the symmetrical ground plate has 4 symmetrical inverted L-shaped grooves, and the L-shaped groove dimensions are d5=5mm, d6=8mm , the gap size is s2=0.1mm;.

Beneficial effects of the present invention:

1. The antenna impedance bandwidth of the present invention covers the ultra-broadband frequency band of 2-10 GHz, suppresses three frequency bands of WiMAX, WLAN and satellite X-band in the band, solves the problem of in-band interference of ultra-broadband communication, and at the same time the antenna meets the communication requirements. , The antenna has the characteristics of small size, wide dynamic range, easy processing, and can be used in wearable devices, and is used in ultra-broadband fields such as short-distance wireless communication.

2. In the non-suppressed frequency band VSWR<2, return loss S11<-10dB; in the in-band suppression frequency band VSWR>2, return loss S11>-10dB, with high speed, low loss, low power It has the characteristics of low power consumption and low delay, and the substrate is made of flexible material polyimide, with a dielectric constant of 3.4, low loss and the flexibility of an antenna.

3. The present invention makes the antenna have in-band suppression of three frequency bands by slotting the radiating patch, feed line and ground plate, so that the antenna has the ability to resist narrow-band signals, specifically: the in-band suppression frequency band of the antenna of the present invention It is 3.31-3.75GHz, 5.01-6.05GHz and 7.32-8.62GHz, respectively: a rectangular patch with a complementary C-shaped groove in the center of the radiation patch can suppress the frequency band of 3.31-3.75GHz, and the lower two corners are semicircle The feeder has an inverted U-shaped slot to suppress the 5.01-6.05GHz frequency band. The grounding plate is located on both sides of the feeder with a stepped structure. The purpose of the stepped structure is to increase the antenna bandwidth. Symmetrical inverted L-shaped groove achieves suppression of the 7.32-8.62GHz frequency band.

Description of drawings

Fig. 1 is the structure schematic diagram and concrete structure diagram of the present invention

Figure 2 is a structural dimension drawing

Fig. 3 is the return loss simulation result diagram of the antenna of the present invention

Fig. 4 is the simulation diagram of the voltage standing wave ratio of the antenna of the present invention

Figure 5 is a simulation diagram of the radiation direction of the antenna at the center frequency

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to FIG. 1 , the present invention designs a flexible ultra-wideband filter antenna, which includes a dielectric substrate 1 , a radiation patch 2 , a feed line 3 and a ground plate 4 . The dielectric substrate 1 is made of polyimide flexible material, the dielectric constant is 3.4, and the loss tangent value is 0.008. The substrate thickness is 0.2mm.

The dielectric substrate 1 is provided with a radiation patch 2, a feed line 3 and a grounding plate 4; the radiation patch 2 is a rectangular patch with a complementary C-shaped groove in the center, and the lower two corners are semicircular structures; the feed line 3 and the The lower ends of the radiating patches 2 are connected; the feeder 3 has an inverted U-shaped slot; the grounding plate 4 is located on both sides of the feeder in a stepped structure, and the symmetrical grounding plate 4 has a symmetrically inverted L-shaped slot. The feeding method adopts a coplanar waveguide structure, the input impedance is 50Ω, and the materials of the radiation patch, feeding line and grounding plate are all copper.

In Figure 1, the specific dimensions of the antenna after the optimized design are shown in Figure 2: W=30mm, L=35mm, W1=13.95mm, R=13.5mm, L1=9.2mm, L2=L3=4mm, Wf=1.6mm, R1=2.4mm, R2=5.4mm, d1=0.1mm, d2=0.7mm, d3=9mm, d4=1.2mm, s1=0.1mm, d5=5mm, d6=8mm, s2=0.1 mm.

As a branch of wireless communication, UWB communication covers a wider bandwidth, and the disadvantage brought by the wider bandwidth is that the in-band interference is more serious, so this implementation has the feature of in-band suppression. In order to verify the performance of the antenna, the HFSS electromagnetic simulation software is used to conduct simulation experiments:

First, the performance indicators of the antenna are proposed: the bandwidth coverage of the antenna is 2-10GHz, and the in-band suppression frequency bands of the antenna are 3.31-3.75GHz, 5.01-6.05GHz, and 7.32-8.62GHz; Wave loss S11 <-10dB; VSWR>2 in the in-band suppression frequency band, return loss S11>-10dB; the antenna model of the structure as shown in Figure 1, the antenna adopts a coplanar waveguide feed structure, and is complementary in the center of the radiation sticker The rectangular patch of the C-shaped slot can suppress the frequency band of 3.31-3.75GHz, and the lower two corners adopt a semi-circular structure to increase the bandwidth of the antenna. Suppression, the ground plate adopts a stepped structure on both sides of the feeder. The purpose of the stepped structure is to increase the bandwidth of the antenna. It is said that the ground plate has four symmetrical inverted L-shaped slots to suppress the frequency band of 7.32-8.62 GHz.

Figure 3 shows that the bandwidth of the antenna is 2-10GHz, and the in-band suppression bandwidth is 3.31-3.75GHz, 5.01-6.05GHz and 7.32-8.62GHz. The bandwidth of the entire antenna frequency band includes the entire ultra-wideband communication bandwidth.

Figure 4 shows that the voltage standing wave ratio of the antenna in the frequency bands of 3.31-3.75GHz, 5.01-6.05GHz and 7.32-8.62GHz is much greater than 2. At this time, the antenna cannot work normally in the standing wave state, so it achieves the effect of in-band filtering; In other frequency bands, the VSWR of the antenna is less than 2, and the antenna can work normally.

Figure 5 shows the shape of the E and H surfaces of the antenna. The E surface direction is similar to the "8" shape, and the H surface is circular. At this time, the antenna has the characteristics of omnidirectional radiation.

To sum up, the performance of the flexible ultra-wideband filter antenna proposed by the present invention satisfies the frequency band of 2-10 GHz, suppresses three frequency bands of WiMAX, WLAN and satellite X-band in the band, and solves the in-band interference of ultra-wideband communication. problem, while the antenna meets the communication needs. The antenna has the characteristics of small size, wide dynamic range, easy processing, and can be used in wearable devices, and is used in ultra-broadband fields such as short-distance wireless communication.

The series of detailed descriptions listed above are only specific descriptions for the feasible embodiments of the present invention, and they are not used to limit the protection scope of the present invention. All should be included within the protection scope of the present invention.

Claims (9)

1. A flexible ultra-wideband filter antenna, characterized in that it comprises a dielectric substrate (1), a radiation patch (2), a feed line (3) and a ground plate (4); the radiation patch (2), the feeder The electric wire (3) and the grounding plate (4) are both arranged on the dielectric substrate; the radiation patch (2) is a semicircular patch with a complementary C-shaped groove in the center, and the lower two corners adopt a semicircular structure; The feed line (3) is connected to the lower end of the radiation patch (3), and the feed line (3) has an inverted U-shaped slot; the grounding plate (4) is located on both sides of the feed line (3). 2 . The flexible ultra-wideband filter antenna according to claim 1 , wherein the dielectric substrate ( 1 ) has a thickness of 0.2 mm, a length L=30 mm, and a width W=35 mm. 3 . 3 . The flexible ultra-wideband filter antenna according to claim 1 , wherein the dielectric substrate ( 1 ) is made of polyimide flexible material, the dielectric constant thereof is 3.4, and the loss tangent value is 0.008. 4 . 4. a kind of flexible ultra-wideband filter antenna according to claim 1, is characterized in that, described radiating patch (2) center is opened with 2 complementary C-shaped grooves, and its lower two corners adopt semicircular structure, The width of the radiation patch is W0=24mm; the size of the two C-shaped grooves is the inner diameter R1=2.4mm, R2=5.4mm; the gap width of the two rings is d1=0.1mm, d2=0.7mm from the inside to the outside; The semicircular structure has a radius of R=13.5mm; the two complementary C-shaped grooves are nested and placed in opposite directions. The opening faces the semicircular bottom surface of the radiation patch, the two C-shaped grooves share a center point, and the notch angle of the two C-shaped grooves=22. 5. A flexible ultra-wideband filter antenna according to claim 1, characterized in that, the feeder (3) is a rectangle, with a length of lf=10.2mm, a width of _wf =1.6mm, and a radiating patch The bottom of the semi-circle is connected perpendicularly, and the right-angle U-shaped groove is opened on the top of the feeder, and the opening of the U-shaped groove is downward. Both sides of the U-shaped slot are equally spaced from both sides of the feeder, and the bottom is aligned with the bottom of the feeder. 6 . The flexible ultra-wideband filter antenna according to claim 1 , wherein the grounding plate ( 4 ) is a patch distributed on both sides of the feeder line as the axis of symmetry, and both sides are stepped. 7 . 7 . The flexible ultra-wideband filter antenna according to claim 6 , wherein the stepped shape on both sides is a three-layer stepped structure. 8 . 8 . The flexible ultra-wideband filter antenna according to claim 7 , wherein the total height L1 = 9.2 mm of the stepped structure on each side, the height L2 = 4 mm of the first layer of steps from top to bottom, and the The height of the second layer of stairs is L3=4mm, the height of the third layer of stairs is 1.2mm, and the width of the bottom of the step structure is W1=13.95mm. 9. A kind of flexible ultra-wideband filter antenna according to claim 7 or 8, characterized in that, the two sides of the ground plate 4 are provided with symmetrical inverted L-shaped grooves, and the L-shaped groove dimensions are: width d5=5mm, height d6=8mm, and the slit width dimension of the L slot is s2=0.1mm.

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