KR102050347B1 - Uhf wideband antenna with a metamaterial open ended stub-shaped compact notch filter - Google Patents

Abstract

The present invention relates to a UHF wideband antenna coupled to a small band stop filter of a metamaterial open-ended stub structure, and more particularly, a radiator is formed in the shape of a wine glass, and at a position spaced a predetermined distance from both sides of the radiator. It relates to an antenna including a first parasitic element, and a second parasitic element at a position spaced a predetermined distance from the upper surface or the lower surface of the radiator. The present invention also relates to an antenna further including a small band reject filter having a metamaterial open-ended stub structure in a feeding part.
According to at least one of the embodiments of the present invention, having a wide bandwidth of 700 MHz to 1.3 GHz, there is an effect that noise can be removed while minimizing antenna performance degradation.

Description

UHF WIDEBAND ANTENNA WITH A METAMATERIAL OPEN ENDED STUB-SHAPED COMPACT NOTCH FILTER}

The present invention relates to a UHF broadband small antenna, and more particularly, to form a parasitic element on both sides of the radiator and the back of the radiator to expand the bandwidth, and of the ultra-small meta-material band stop stub structure that can be attached like a stub (STUB) The present invention relates to a UHF wideband antenna capable of blocking a specific frequency region through a band stop filter.

An antenna is a key component of a wireless communication system. Wideband antennas are used in a variety of mobile applications using different frequency ranges. UHF Well-known wideband antennas are ultra wideband (UWB) modified monopole antennas operating between 3.2 GHz and 10.8 GHz. Wideband modulated monopole antennas range from 3.2 GHz to 10.8 GHz in broadband. It is used in various applications such as radar and Z-wave communication.

As a drawback of broadband antennas, the use of many wireless applications can degrade the quality of a wireless system in operation due to unwanted band effects. Thus, unwanted band interference for the system can be avoided by the use of notch filters (bandstop filters), but various methods can be used to block unwanted frequencies in a wireless system. For example, a preferred method is to make U-slits or double Y-slits in two-dimensional (2D) or three-dimensional monopoles, radiating element elements, stepped impedance resonators folded parallel to the feed and radiator : SIR) -Metal wire is used.

It is an object of the present invention to have a wineglass-like structure for use in the UHF band of 700 MHz to 1.3 GHz, which is much lower than the UWB band of 3.2 GHz to 10.8 GHz, and has both side edges and top or bottom of the radiator. To provide a UHF broadband antenna having a parasitic element formed at a predetermined distance apart from the.

It is still another object of the present invention to attach a miniature band stop filter having a metamaterial open terminated stub structure without modifying the radiator or attaching a quarter wave stub structure to the feeder to remove noise of the antenna. The present invention provides a UHF wideband antenna that removes noise without degrading antenna operation.

According to an aspect of the present invention to achieve the above or another object, a radiator having a structure that is gradually tapered from one end to the other end; And a feeder connected below one end of the radiator, wherein the shape of the radiator is a wine glass, and provides a UHF broadband antenna coupled with a small band stop filter of a metamaterial open-ended stub structure. .

Here, the parasitic elements may further include first parasitic elements formed on both sides of the radiator to be coupled to reinforce the insufficient capacitance due to the thin film substrate, which is necessary at a low frequency and is spaced apart from the edge of the radiator.

And a second parasitic element formed at a low frequency formed at a position corresponding to the radiator spaced apart from a top surface or a bottom surface of the radiator to reinforce insufficient capacitance by a thin film substrate. The second parasitic element may further include a uniform width at positions corresponding to both side edges of the radiator.

In addition, the power supply may further include a band reject filter having a stub structure.

Referring to the effect of the UHF broadband antenna according to the present invention.

According to at least one of the embodiments of the present invention, there is an effect that has a wide bandwidth of 700 MHz to 1.3 GHz.

In addition, according to at least one of the embodiments of the present invention, there is an effect that noise can be removed while minimizing antenna performance degradation.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a diagram illustrating a UHF wideband antenna combined with a small band reject filter of a metamaterial open-ended stub structure according to an embodiment of the present invention.
2 is a view showing another embodiment of the present invention.
3 is a view showing another embodiment of the present invention.
4 is an embodiment of the present invention, the first parasitic element and the second parasitic element for the purpose of the coupling role to reinforce the insufficient capacitance caused by the thin film substrate with the radiator of the antenna made in real life Is a diagram illustrating an antenna on which is formed.
5 is a view showing a specific shape of the radiator structure shown in FIGS.
FIG. 6 is a graph illustrating simulation results of the return loss and the bandwidth of each embodiment of the antenna according to the present invention.
FIG. 7 is a graph illustrating characteristics of the antenna of FIG. 4.
FIG. 8 is a graph illustrating an antenna coupled to a band rejection filter having a conventional quarter-wavelength open-ended stub structure and characteristics of the antenna (case 1).
FIG. 9 is a graph illustrating an antenna having a slot formed in a radiator and a characteristic thereof for generating a notch at 900 MHz according to a conventional method (case 2).
FIG. 10 is a diagram illustrating a proposed CRLH phase shifter and a schematic diagram of characteristics of a band reject filter and CRLH.
11 illustrates a physical implementation of a CRLH notch filter circuit in a full wave simulator.
FIG. 12 is a diagram illustrating an antenna and return loss of an actual manufactured case3.
FIG. 13 is a graph illustrating a far-field pattern characteristic of the antenna shown in FIG. 12 (a).
FIG. 14 is a graph illustrating available bandwidths in case 1 to case 3. FIG.
FIG. 15 is a graph illustrating comparison of simulated simulated gains for frequency bands in cases 1 to 3 including the antenna and the filter of FIG. 3 without the filter.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar components are denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. The suffix "part" for components used in the following description is given or mixed in consideration of ease of specification, and does not have meanings or roles that are distinguished from each other. In addition, in describing the embodiments disclosed herein, when it is determined that the detailed description of the related known technology may obscure the gist of the embodiments disclosed herein, the detailed description thereof will be omitted. In addition, the accompanying drawings are intended to facilitate understanding of the embodiments disclosed herein, but are not limited to the technical spirit disclosed herein by the accompanying drawings, all changes included in the spirit and scope of the present invention. It should be understood to include equivalents and substitutes.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

1 illustrates a UHF broadband antenna according to an embodiment of the present invention.

According to an embodiment of the present invention,

It includes a radiator 100 having a structure that is gradually tapered from one end to the other end and a feeder 150 connected to one end of the radiator 100, the shape of the radiator 100 A UHF wideband antenna coupled with a small band reject filter of a metamaterial open-ended stub structure is characterized in that it is in the form of a wine glass.

1A illustrates a radiator 100 having a structure in which a width is gradually tapered from one end connected to the feeder 150 to the other end, and a feeder connected to one end of the radiator 100. 150, the radiator 100 may have a polygonal structure in the shape of a wine glass.

FIG. 1B illustrates a partial ground 160 formed at a position corresponding to the power supply unit 150 by a predetermined distance from an upper surface or a lower surface where the radiator 100 and the power supply unit 150 are formed. ).

In more detail, the radiator 100 has a structure in which the width of the radiator 100 gradually increases from one end connected to the feeding part 150 to the other end, and the width of the radiator 100 is increased. This widening degree may have a structure that increases and decreases again. In other words, the radiator 100, which is connected to the feeder 150, may have a structure similar to that of a wineglass. Such a structure has an effect of minimizing the influence of sudden impedance change at the input part, and has an effect of improving the characteristics of the antenna by widening the bandwidth of the radiator.

5 illustrates a specific shape of the structure of the radiator 100 illustrated in FIGS. 1 to 3.

As shown in FIG. 5, the radiator 100 has a left-right symmetrical structure and is connected to the feeding part 150 to form a first symmetrical axis and a first inclination angle θ1; A second edge 120 connected to the first edge 110 to form a left and right symmetry axis and a second inclination angle θ2; A third edge 130 connected to the second edge 120 to form a left and right symmetry axis and a third inclination angle θ3; And a fourth edge 140 connected to the third edge 130 to be parallel to the left and right symmetry axes, wherein the second inclination angle θ2 is greater than the first inclination angle θ1 and the third inclination angle θ3. Has a value.

Referring to the structure of the radiator 100 in more detail by quantifying the structure, as shown in FIG. 5, the radiator 100 has a left-right symmetry structure, and based on the left-right symmetry axis, the first edge 110. The first inclination angle θ1 formed by) may be between 38 degrees and 48 degrees, and the second inclination angle θ2 formed by the second edge 120 may be between 58.5 degrees and 68.5 degrees, and the third edge 130 may be formed by the first inclination angle θ1. The three inclination angles θ3 may be 23.5 degrees to 33.5 degrees.

As shown in FIG. 1A, the length L _t1 of the first edge 110 of the radiator 100 may be 19 mm to 21 mm, and the length L _t2 of the second edge 120. May be 21 mm to 23 mm, the length L _t3 of the third edge 130 may be 14 mm to 16 mm, and the length L _t4 of the fourth edge 140 may be 21 mm to 23 mm.

Due to the structure of the radiator 100 having a polygonal structure of the wineglass as described above, the antenna has an effect that the bandwidth has a bandwidth that can cover up to 700MHz band.

2 shows another embodiment according to the present invention.

According to the present invention, the antenna further includes first parasitic elements 200a and 200b formed at both sides of the radiator 100 to be spaced apart from the edge of the radiator 100 by a predetermined distance.

 2 (a) is formed at a predetermined distance from the edge of the radiator 100 on both sides of the feeder 150 and the radiator 100 connected to the radiator 100 and one end of the radiator 100 The first parasitic elements 200a and 200b are shown.

FIG. 2B has the same structure as that of FIG. 1A.

In more detail, the first parasitic elements 200a and 200b may be formed on both sides of the radiator 100 in FIG. 2 (a) to be spaced apart from the edge of the radiator 100 by a predetermined distance. By the structures of the first parasitic elements 200a and 200b, the first parasitic elements 200a and 200b may serve as capacitive elements in the radiator 100. In conventional dielectric substrates, since the dielectric substrate has a thin film structure, capacitances that can be obtained from the dielectric substrate are limited. Additional capacitance can be obtained by the first parasitic elements 200a and 200b having the above structure, and insufficient capacitance can be obtained. It can be reinforced, thereby obtaining the effect of widening the band of the antenna.

In addition, an interval between the edge of the radiator 100 and the first parasitic elements 200a and 200b may be 4 mm to 6 mm, preferably 5 mm.

The first parasitic elements 200a and 200b may have a width of 3 mm.

This value is a value that can represent the optimal capacitance with the radiator 100, and is a numerical range obtained experimentally.

Figure 3 shows another embodiment according to the present invention.

As shown in FIG. 3, further comprising second parasitic elements 300a and 300b spaced apart from the upper or lower surface of the radiator 100 by a predetermined distance and formed at positions corresponding to the radiator 100. The second parasitic elements 300a and 300b may be formed to have a uniform width at positions corresponding to both side edges of the radiator 100.

The second parasitic element is formed to be spaced apart from the radiator 100 at regular intervals, and serves to form capacitance by interacting with the radiator 100. Since the electromagnetic wave in the radiator 100 is mostly formed along both side edges of the radiator 100, the position corresponding to the center portion of the radiator 100 does not substantially contribute to the capacitance function. Therefore, the second parasitic elements 300a and 300b may be separated into two at positions corresponding to both side edges of the radiator 100.

The second parasitic elements 300a and 300b interact with the radiator 100 to form a coffee capacitance. This is another capacitance formed independently of the first parasitic elements 200a and 200b.

In addition, the second parasitic elements 300a and 300b may be formed to have a width of 1 mm to 3 mm and preferably 2 mm in order to have sufficient capacitance to interact with the radiator 100.

The bandwidth of the small antenna can be changed by the structure, and in the case of the broadband antenna, it is easy to expand the bandwidth in the region above 1 GHz due to the modification of the structure, but it is difficult to extend the bandwidth of the antenna in the region below 1 GHz. In addition, extending the bandwidth of the antenna in the region below 1 GHz is a major concern in the design of a wide band antenna, and is a problem directly related to the performance of the antenna.

As described above, the radiator 100 is designed in a wineglass polygon structure, and the first parasitic elements 200a and 200b and the second parasitic elements 300a and 300b are formed. Compared to the radiator having a simple inverted triangular shape, the antenna has an effect of designing an antenna having a wide bandwidth up to the 700 MHz region even in a region less than 1 GHz. In addition, the effects of the bandwidth gain by the first and second parasitic elements 200a, 200b, 300a, and 300b will be described with the experimental data of FIGS. 6 to 9 below.

4 illustrates an antenna in which the radiator 100, the first parasitic elements 200a and 200b, and the second parasitic elements 300a and 300b of the antenna manufactured in real life are formed. Shows.

The antenna shown in FIG. 4 is a feeder 150 having a length of Lf = 85 mm and a width of Wf = 3 mm in the antenna shown in FIG. 3. The first inclination angle θ1 is 42 degrees and the second inclination angle ( θ2) is 63.4 degrees and the third inclination angle θ3 is 18.5 degrees, the length of the first edge 110 is 20.18mm, the length of the second edge 120 is 22.36mm, and the length of the third edge 130 is The length of the 15.18mm and the fourth edge 140 is 10mm, the width of one end is 3mm, the width of the other end is 80mm is connected to the radiator 100. In addition, first parasitic elements 200a and 200b are formed on both side edges of the radiator 100 so as to have a width of 3 mm at intervals of 5 mm. The radiator 100 and the first parasitic elements 200a and 200b have a relative dielectric constant of 4.3, a relative permeability of 1, a width (Ws) of 100 mm, a length (Ls) of 150 mm, and a thickness (Hs) of 1.2. It is formed on one side of the FR4 substrate which is mm. The overall size of the antenna is 150mm (Ls) x 100mm (Ws) x 1.2mm (Hs), which is relatively small among the broadband antennas in the UHF range. On the other side of the substrate, a partial ground 160 having a size of Lg = 85 mm and Wg = 100 mm is formed at a position corresponding to the feed part 150 formed on one surface of the substrate, Second parasitic elements 300a and 300b having a width of Wp2 = 2 mm are formed at positions corresponding to both side edges of the radiator 100 formed on one surface thereof. The second parasitic elements 300a and 300b have the same shape as that of the side edge of the radiator 100, and include the first inclination angle θ1 to the third inclination angle and the first edge 110 to the radiator 100. Has the same angle and length as the length of the fourth edge 140, and is formed spaced apart from the partial ground 160, the second parasitic elements (300a, 300b) are formed by separating the left and right elements, respectively have.

FIG. 6 shows simulation results of simulated return loss and bandwidth of each embodiment of the antenna according to the present invention.

FIG. 6 (a) is a simulation test result of the return loss and the bandwidth of the antenna shown in FIG. 1 according to an embodiment of the present invention.

FIG. 6 (b) is a simulation test result of the return loss and the bandwidth of the antenna shown in FIG. 2 according to an embodiment of the present invention.

FIG. 6 (c) shows simulation results of simulated reflection loss and bandwidth of the antenna shown in FIGS. 1, 2, and 3 according to one embodiment of the present invention.

As shown in FIG. 6 (a), the antenna 100 has a characteristic of having a very wide bandwidth in the region of about 0.67 GHz to 1.08 GHz by the radiator 100 having a wineglass polygonal structure. see.

As shown in FIG. 6 (b), by adding the first parasitic elements 200a and 200b to the radiator 100, the bandwidth of the antenna is about 0.7 GHz to 1.34 GHz, and FIG. 6 (a Wider than the bandwidth shown in

As shown in FIG. 6 (c), the first parasitic elements 200a and 200b and the second parasitic elements 300a and 300b are formed on the radiator 100 to thereby form an antenna with a bandwidth of 0.67 GHz. To 1.35 GHz. The results show that the bandwidth of the antenna can be improved by about 250 MHz by further forming the first parasitic elements 200a and 200b and the second parasitic elements 300a and 300b in the radial antenna.

7 illustrates the characteristics of the antenna of FIG. 4.

FIG. 7 (a) shows the simulated simulated return loss and bandwidth of the antenna of FIG. 4 and the actual measured and measured return loss and bandwidth characteristics.

FIG. 7B shows a far-field pattern of an antenna measured at each frequency (780 MHz, 932 MHz, and 1.12 GHz) in the xy-plane (or horizontal plane).

FIG. 7C shows the far-field pattern of the antenna measured at each frequency (780 MHz, 932 MHz, and 1.12 GHz) in the yz-plane (or vertical plane).

FIG. 7 (d) shows simulated beam-pattern and measured beam-pattern simulated at frequency points M ₁ , S ₁ marked in FIG. 7 (a) in the vertical plane. ) Is shown in comparison.

FIG. 7 shows an experimental measurement of the actually manufactured antenna shown in FIG. 4 using an Agilent vector network analyzer. FIG. 7 (a) shows simulated simulated and measured loss losses, showing good results of -10 dB in the range of about 0.7 GHz to 1.3 GHz. The far-field pattern of the proposed antenna is measured in an anechoic chamber environment. 7 (b)-(d) show a comparison between simulated simulated far patterns and measured far patterns of the antenna shown in FIG. 4 at various frequencies ranging from 700 MHz to 1.3 GHz. The beam pattern in the horizontal plane with respect to the sample frequency is almost the same despite the different gains. Also, in the vertical plane plot, FIG. 4C has a similar far-field pattern at the sample frequency. As the marker frequency of FIG. 7 (a), as shown in FIG. 7 (d) in S ₁ and M ₁ , the simulated simulated far-field pattern and the measured far-field pattern have a high correlation.

According to another embodiment of the present invention,

The power supply unit 150 may further include a band stop filter having a stub structure.

In order to prevent communication interference in the antenna operating band, a band notch filter should be designed to block a specific frequency band.

Conventionally, in order to design a band stop filter, a quarter wave terminated stub is typically used as shown in FIG. 8, or a slot is formed in the radiator as shown in FIG. 9. However, both methods destabilize the overall operating band gain of the antenna or reduce the operating bandwidth.

Accordingly, the present invention proposes an antenna combined with a small band reject filter having a metamaterial open-ended stub structure that maintains the overall operating band gain of the antenna and has a low bandwidth loss.

FIG. 8 shows an antenna coupled to a band reject filter having a conventional quarter-wavelength open-ended stub structure and characteristics of the antenna (case 1).

FIG. 8 (a) shows the return loss and the bandwidth when the antenna is simulated, when the antenna is actually manufactured and measured, and when the band rejection filter is excluded from the antenna.

Figure 8 (b) shows the far-field pattern measured in the xy-plane of the antenna combined with the band stop filter with the quarter-wavelength open terminated stub structure.

FIG. 8 (c) shows the far-field pattern measured in the yz-plane of the antenna combined with the band stop filter with the quarter-wavelength open terminated stub structure.

The quarter-wavelength open-ended bandstop filter acts as a filter to block the desired frequency. To operate as a band-stop filter at 900 MHz, the stub must be less than 45 mm long. Placing the stub on the antenna feed section creates a notch at 900 MHz. As shown in FIG. 8 (a), the performance of the broadband antenna is degraded due to the filter having the quarter-wavelength open terminated stub structure attached to the feed section. In Fig. 8 (a), although notches are produced at 900 MHz, the overall operating bandwidth of the antenna is disturbed, which is an undesirable result. The operating bandwidth of the antenna divided into two regions by the band-stop filter is expressed as BW _L and BW _H. Apart from this, the far-field patterns of some sample frequencies (780 MHz, 932 MHz, 1.12 GHz and 1.34 GHz) are plotted in FIGS. 8B and 8C. The patterns shown in Figures 8 (b) and (c) are similar to Figures 7 (b) and (c) except 900MHz, which has the lowest gain around -25dB due to the notch.

FIG. 9 illustrates an antenna in which a slot is formed in a radiator for generating notches at 900 MHz, which is a conventional method, and characteristics thereof (case 2).

9 (a) shows the return loss and the bandwidth when the antenna is simulated, when the antenna is actually manufactured and measured, and when the slot is excluded from the antenna.

Figure 9 (b) shows a far-field pattern measured in the xy-plane of the antenna slotted in the radiator.

9 (c) shows a far-field pattern measured in the yz-plane of the antenna in which the slot is formed in the radiator.

The notch effect of a wideband antenna can be realized by forming one or more slots in the main radiator of the system. 9 illustrates the operation of a wideband antenna when a modified V-shaped slot having a width W _slot of 2 mm is formed along the lower rim of the radiator.

As shown in Figure 9 (a), the simulated simulated return loss and bandwidth characteristics are in good agreement with the measured return loss and bandwidth characteristics. Notch formation at 900 MHz splits the original broadband-band into BW _L and BW _H , which means that the available bandwidth is less affected than case 1. 9 (b) and 9 (c) show far-field patterns for various frequencies (780 MHz, 932 MHz, 1.12 GHz and 1.34 GHz) in the xy and yz planes to observe the influence of the notch. 9 (b) and (c) show the weakest radiation associated with the notch frequency found in case 1.

10 shows a schematic of the proposed CRLH phase shifter and the characteristics of the band reject filter and CRLH.

10 (a) shows a CRLH phase shifter band-stop filter circuit diagram,

10 (b) shows the band stop filter dispersion diagram for a CRLH phase shifter.

FIG. 10 shows a new small band reject filter designed based on a Composite Right / Left Handed-Transmission Line (CRLH-TL) phase shifter, which carries a 90 degree phase shift at 900 MHz. It is built into an open-ended stub to make a notch.

Referring to FIG. 10 (a), the small band reject filter of the metamaterial open-ended stub structure may include a first lumped element C _L1 and a first TL in which a left hand rule is applied to a feeder. Line), the second capacitive lumped element (C _L2 ) to which the left-hand rule is applied, the second TL, the third capacitive lumped element (C _L3 ) to which the left-hand rule is applied, and the third TL may be connected in series, and the left hand is One end of the first inductive concentrator L _L1 to which the law is applied is connected between the first TL and the second capacitive concentrator C _L2 , and the other end is connected to the ground. One end of the applied second inductive concentrator L _L2 may be connected between the second TL and the third capacitive concentrator C _L3 , and the other end may have a structure connected to the ground. .

 Comparing the filter (case 3) with a 1/4 wavelength open-ended filter (case 1), the 1/4 wavelength open-ended filter (case 1) is 42 mm corresponding to a length of 0.25 wavelength to block the 900 MHz band. On the other hand, the filter case 3 requires only 12 mm corresponding to a length of 0.07 wavelength. This is a very advantageous advantage for miniaturization in filter fabrication.

Fig. 10 (a) shows a schematic diagram of the proposed phase shifter applied to the notch filter of the antenna feeder, and Fig. 10 (b) shows the right hand showing L _R = 0.02 nH / m and C _R = 14.4 nF / m. Right Handed Region (ω> ω0) shows a scatter diagram of the circuit using initial values L _L = 14.39 nH, C _L = 0.88 pF and d = 12 mm as the TL segment.

In Fig. 10 (b) a typical nonlinear dispersion curve in the CRLH structure is shown, where L _L and C _L act on the Left Handed Region (ω <ω 0), and the TL segment d is the Right Handed. Region) (ω> ω0).

11 shows the physical implementation of a CRLH notch filter circuit in a full wave simulator.

11 (a) shows the geometry,

Figure 11 (b) shows the simulated simulated results.

11 (a) is implemented as follows in the simulator. The implemented structure is a microstrip with a width (w _t ) of 3.2 mm and a length (l _t ) of 20 mm designed for a characteristic impedance of 50 Ω, taking into account a FR4 substrate with a dielectric constant ( _r ) of 4.3 and a height of 1.2 mm. line). The length l _s and width w _s of the substrate are 20 mm. The lumped elements are C ₁ = 2.2 pF, C ₂ = C ₃ = 1.49 pF, L ₁ = 4.34 nH and L ₂ = 3.98 nH. Here vias are used with a radius r of 0.2 mm and a height h of 1.2 mm. The gap between the microstrip line segments is g = 0.5 mm and the length of the segments is l ₂ = l ₃ = 3.5 mm and l ₁ = l ₄ = 0.2 mm. C ₁ , C ₂ , C ₃ , L _1, and L ₂ of FIG. 11 (a) correspond to C _L1 , C _L2 , C _L3 , L _L1, and L _L2 of FIG. 10 (a), respectively.

The results shown in Figure 11 (b) show that the proposed design method is valid. In the S ₂₁ graph shown in Fig. 11 (b), this notch is shown with an insertion loss of about -20 dB at 900 MHz.

12 shows the antenna and return loss of case3 actually fabricated.

FIG. 12 (a) shows the actual fabricated form of the antenna of case3 in which the antenna shown in FIG. 3 and the small band-stop filter of the metamaterial terminated stub structure are combined.

FIG. 12 (b) shows simulated return loss and bandwidth of the simulated case3 antenna of the case3 antenna, measured return loss and bandwidth of the actually produced case3 antenna, and measured reflection of the antenna of the manufactured FIG. The loss and bandwidth are shown.

The notch filter illustrated in FIG. 12 (a) was attached to a portion 53.5 mm away from the input port at the bottom of the antenna feeder 150.

Looking at the return loss and bandwidth graphs shown in FIG. 12 (b), the notch frequency in the simulated simulated return loss graph of the antenna including the CRLH notch filter is 900 MHz (S ₁ ), but notch in the measured return loss graph. The frequency has a value above 950 MHz. This result is due to the change of substrate and the manual soldering of lumped elements. Comparing the return loss and the bandwidth of the antenna with the band stop filter in FIG. 12 (b) with the return loss and bandwidth of the antenna of FIG. 4 without the band stop filter, the existing bandwidth is divided by the band stop filter, but the 900 MHz Blocking frequencies minimizes the negative impact on other bandwidths.

FIG. 13 shows a far-field pattern characteristic of the antenna shown in FIG. 12 (a).

FIG. 13A shows a far-field pattern of an antenna measured at each frequency (712 MHz, 932 MHz, 1.12 GHz, and 1.39 GHz) in the xy-plane (or horizontal plane).

Figure 13 (b) shows the far-field pattern of the antenna measured for each frequency (712 MHz, 932 MHz, 1.12 GHz and 1.39 GHz) in the yz-plane (or vertical plane).

FIG. 13 (c) shows simulated beam-pattern and measured beam-pattern simulated at the frequency points M ₁ , S ₁ indicated in FIG. 12 (b) in the vertical plane. The comparison is shown.

The graph of FIG. 13 (a) has a similar omnidirectional distribution except for the smallest gain at the notch frequency. In addition, as in FIG. 10 (b), the antenna gain at the notch frequency is about 10 dB lower than the other curves. Finally, simulated simulated far patterns and measured far patterns of the marker frequencies S ₁ and M ₁ shown in FIG. 10 (c) are shown, and they behave similarly.

FIG. 14 shows a comparison of available bandwidths in case 1 to case 3. FIG.

Table 1 below shows the comparison of the BW _L and BW _H obtained in the case of case 1 to case 3 of FIG.

BW _L (MHz) BW _H (MHz) Case 1 20 100 Case 2 60 30 Case 3 100 250

As shown in Table 1, in case 3, BW _L and BW _H show relatively wide available bandwidths of 100 MHz and 250 MHz, respectively, but in case 1, much narrower available bandwidth such as 20 MHz and 100 MHz, and case 2 in 60 MHz and 30 MHz, respectively. Have

FIG. 15 shows a comparison of simulated simulated gains of frequency band gains in cases 1 to 3 including the antenna and the filter of FIG. 3 without the filter.

FIG. 15 shows that, among all the tested cases, the available bandwidth in case 3 was least affected by the band reject filter compared to case 1 and case 2. FIG. This is a result of the increase in the Q factor (quality factor) of the notch due to the space concentration, because the band-stop filter in case 3 occupies the smallest space compared to case 1 and case 2. Thus, in contrast to cases 1 and 2 with good gain suppression but poor return loss, the CRLH-TL notch filter applied in case 3 suppresses the gain of the antenna at the notch frequency without affecting the overall return loss of the antenna. Has an effect.

100: radiator
110: first edge
120: second edge
130: third edge
140: fourth edge
150: feeder
160: partial ground
200a, 200b: first parasitic element
300a and 300b: second parasitic elements

Claims (17)

A radiator having a structure in which a width is gradually tapered from one end to the other end;
A feeder connected to one end of the radiator; And
And a band stop filter having a stub structure in the feed section.
And the bandstop filter is a phase shifter of metamaterials. A UHF wideband antenna combined with a small bandstop filter of a metamaterial open-ended stub structure.
The method of claim 1,
The radiator has a symmetrical structure,
A first edge connected to one end of the radiator to form a first inclination angle with a left and right symmetry axis;
A second edge connected to the first edge to form a second inclination angle with the left and right symmetry axes;
A third edge connected to the second edge to form a third inclination angle with the left and right symmetry axes; And
A fourth edge connected to the third edge and formed in parallel with the left and right symmetry axes, wherein the second inclination angle has a value greater than the first inclination angle and the third inclination angle. UHF wideband antenna combined with a small band reject filter.
The method of claim 2,
The first inclination angle is 38 degrees to 48 degrees, the second inclination angle is 58.5 degrees to 68.5 degrees, and the third inclination angle is 23.5 degrees to 33.5 degrees,
The length of the first edge is 19mm to 21mm, the length of the second edge is 21mm to 23mm, the length of the third edge is 14mm to 16mm, the length of the fourth edge is 21mm to 23mm UHF wideband antenna combined with a small band-stop filter with open-ended stubs.
The method according to any one of claims 1 to 3,
The radiator has a left-right symmetrical structure, UHF wideband antenna combined with a small band-stop filter of the metamaterial open-ended stub structure characterized in that it consists of only one of the left structure or the right structure.
The method according to any one of claims 1 to 3,
UHF broadband antenna coupled to the small band-stop filter of the meta-material open-ended stub structure further comprises a first parasitic element formed on both sides of the radiator spaced apart from the edge of the radiator by a predetermined distance.
The method of claim 5,
UHF broadband antenna coupled to the small band-stop filter of the metamaterial open-ended stub structure characterized in that the spacing between the edge of the radiator and the first parasitic element is 5mm.
The method of claim 6,
UHF wideband antenna coupled to the small band-stop filter of the metamaterial open-ended stub structure characterized in that the width of the first parasitic element is 3mm.
The method of claim 5,
The radiator and the first parasitic element is a left-right symmetric structure, UHF broadband antenna combined with a small band stop filter of the meta-material open-ended stub structure, characterized in that consisting of only one of the left or right structure.
The method of claim 5,
And further comprising a second parasitic element spaced apart from the upper surface or the lower surface of the radiator at a position corresponding to the radiator,
The second parasitic element is UHF broadband antenna coupled to the small band-stop filter of the metamaterial open-ended stub structure is formed in a uniform width at a position corresponding to both side edges of the radiator.
The method of claim 9,
And the second parasitic element has a width of 2 mm and a UHF wideband antenna coupled with a small band reject filter of a metamaterial open-ended stub structure.
The method of claim 9,
The second parasitic element has the same shape as that of the side edge of the radiator, and has the same angle and length as the length of the first to third inclination angles and the length of the first to fourth edges of the radiator, and the feed part is formed. It is formed to be spaced apart from the surface and the partial ground formed at a position corresponding to the power supply portion, and the second parasitic element is separated into left and right elements, respectively, characterized in that the meta-material opening UHF wideband antenna combined with a small band-stop filter with an end stub structure.
The method of claim 9,
The radiator, the first parasitic element and the second parasitic element are left and right symmetrical structure, combined with a small band stop filter of the metamaterial open-ended stub structure, characterized in that only one of the left structure or the right structure. UHF broadband antenna.
delete The method according to any one of claims 1 to 3,
UHF broadband antenna coupled to the small band stop filter of the meta-material open-ended stub structure characterized in that the plurality of band stop filter is formed in the feed.
delete The method according to any one of claims 1 to 3,
The band reject filter
The first capacitive lumped elements C _L1 to which the left hand rule is applied, the first TL (Transmission Line), the second capacitive lumped element C _L2 to which the left hand rule is applied, and a second portion TL, the third capacitive lumped element C _L3 to which the left-hand rule is applied, and the third TL are connected in series,
One end of the first inductive concentrated element element L _L1 to which the left-hand rule is applied is connected between the first TL and the second capacitive concentrated element element C _L2 , and the other end is connected to ground. ,
One end of the second inductive concentrated element element L _L2 to which the left hand law is applied is connected between the second TL and the third capacitive concentrated element element C _L3 , and the other end is connected to ground. UHF wideband antenna combined with a small band-stop filter of the metamaterial open-ended stub structure, characterized in that formed.
The method of claim 16,
The band reject filter
Designed on a FR4 substrate with a dielectric constant of 4.3 and a height of 1.2 mm with a microstrip line 3.2 mm wide and 20 mm long, designed to have a characteristic impedance of 50 ohms.
The first capacitive lumped element is 2.2pF, the second capacitive lumped element and the third capacitive lumped element are 1.49pF, the first inductive lumped element is 4.34nH, and the second inductive. Lumped element is 3.98nH,
The length of the microstrip line segment between the feed section and the first capacitive lumped element is 0.2 mm,
The length of the microstrip line segment between the first capacitive lumped element and the second capacitive lumped element is 3.5 mm,
The length of the microstrip line segment between the second capacitive lumped element and the third capacitive lumped element is 3.5 mm,
The length of the microstrip line segment that is open in connection with the third capacitive lumped element is 0.2 mm,
And a gap (g) between the microstrip line segments is 0.5 mm, combined with a small band reject filter of a metamaterial open-ended stub structure.

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