CN114914675A - Broadband and gain controllable radio frequency antenna for close-range accurate detection - Google Patents
Broadband and gain controllable radio frequency antenna for close-range accurate detection Download PDFInfo
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Abstract
The invention provides a broadband and gain controllable radio frequency antenna for close-range accurate detection, which has the functions of broadband and gain control and relates to the technical field of antenna application design, and the invention comprises a radio frequency signal radiation patch and a microstrip line which are designed on a dielectric substrate of the antenna; the antenna dielectric substrate comprises a top layer design plane and a bottom layer design plane which are parallel to each other, and the cross section of the antenna dielectric substrate is rectangular; the top layer of the dielectric substrate is provided with a radio frequency signal radiation patch, and the bottom layer of the dielectric substrate is provided with a microstrip line. The radio frequency signal radiation patch is designed to take the center line of the short side of the rectangular section of the dielectric substrate as a reference, and two symmetrical index curves extend to the short side of the rectangular section along the radio frequency signal radiation direction to form an index curve radiation opening; a plurality of parallel rectangular open slots are symmetrically distributed on two sides of the radio-frequency signal radiation patch, so that the technical problem that radio-frequency signal radiation energy generated by eddy current on the surface of the radio-frequency signal radiation patch is not concentrated is solved.
Description
Technical Field
The invention relates to the technical field of antenna design, in particular to a broadband and gain controllable radio frequency antenna for close-range accurate detection.
Background
With the continuous development of the application of microwave detection technology, the bandwidth of the required radio frequency signal is continuously widened. The performance of the antenna as a radio frequency signal transmission and echo signal reception is crucial to the detection accuracy and sensitivity. Radio frequency probe antenna designs, including effective bandwidth, antenna gain, power loss, radiation lobes, to accommodate practical application requirements are of interest to researchers.
After the radio frequency antenna based on the traditional Vivaldi antenna structure is fed, the current eddy current phenomenon is generated at the edges of two sides of the antenna, so that the radiation energy is dissipated, the return loss is increased, the antenna gain is reduced, and the radiation lobe is changed in a disorientation manner. Therefore, how to weaken the eddy current phenomenon of the antenna patch surface current and concentrate the radiation energy of the radio frequency signal at the opening of the antenna is an urgent problem to be solved.
Disclosure of Invention
The invention aims to provide a broadband and gain-controllable radio frequency antenna for close-range accurate detection, so as to solve the technical problems of surface current eddy current and radiation energy dissipation of an antenna patch.
In a first aspect, an embodiment of the present invention provides a broadband and gain-controllable radio-frequency antenna for close-range accurate detection, including a radio-frequency signal radiation patch and a microstrip line designed on a dielectric substrate; the antenna dielectric substrate comprises a top layer design product plane and a bottom layer design plane which are parallel to each other, and the cross section of the antenna dielectric substrate is rectangular; the top layer of the dielectric substrate is provided with a radio frequency signal radiation patch, and the bottom layer of the dielectric substrate is provided with a microstrip line; the radio frequency signal radiation patch is designed to take the center line of the short side of the rectangular section of the dielectric substrate as a reference, and two symmetrical index curves extend to the short side of the rectangular section along the radio frequency signal radiation direction to form an index curve radiation opening; a plurality of parallel rectangular open slots are symmetrically distributed on two sides of the radio frequency signal radiation patch.
With reference to the first aspect, the present invention provides a first possible implementation manner of the first aspect, wherein the rectangular open slot is used to extend a radio frequency signal current path and weaken a current eddy current on a surface of the radiating patch for the radio frequency signal.
With reference to the first aspect, an embodiment of the present invention provides a second possible implementation manner of the first aspect, where two exponential curves of the radio frequency signal radiation patch are symmetric with respect to a center line of a short side of a cross section of the dielectric substrate, and a plurality of parallel rectangular open slots are symmetrically designed on two sides of the two exponential curves of the radio frequency signal radiation patch.
With reference to the first aspect, an embodiment of the present invention provides a third possible implementation manner of the first aspect, where a length of the rectangular open slot is determined by the following formula:
wherein l is the length of the rectangular open slot, epsilon is the dielectric constant of the dielectric substrate, and lambda is the wavelength of the working frequency.
With reference to the first aspect, an embodiment of the present invention provides a fourth possible implementation manner of the first aspect, where the width of each of the rectangular open slots is the same, and the width of each of the rectangular open slots is determined by the following formula:
and dw is the width of the rectangular open slot, epsilon is the dielectric constant of the dielectric substrate, and lambda is the wavelength of the working frequency.
With reference to the first aspect, an embodiment of the present invention provides a fifth possible implementation manner of the first aspect, where distances between the rectangular open slots are equal, and the distances between the rectangular open slots are determined by the following formula:
dww<0.25*λ
wherein dww is the distance between the rectangular open slots, and λ is the wavelength of the working frequency.
With reference to the first aspect, an embodiment of the present invention provides a sixth possible implementation manner of the first aspect, where a rectangular transition groove is further disposed on the radio frequency signal radiation patch, a long side of the rectangular transition groove is parallel to a central line of a short side of a cross section of the dielectric substrate, and the rectangular transition groove is symmetric with respect to the central line of the short side of the cross section of the dielectric substrate.
With reference to the first aspect, an embodiment of the present invention provides a seventh possible implementation manner of the first aspect, where the exponential curve y is solved by the following formula
y＝a*e b*x +c
b＝(1/L)*ln(W/sw)
Wherein a and c are constant coefficients of the exponential curve, b is the gradient rate of the exponential curve, and (x) 1 ，y 1 )、(x 2 ，y 2 ) Respectively are the initial point coordinate and the end point coordinate of the exponential curve, L is the length of the antenna, W is the width of the antenna, and sw is the width of the rectangular transition groove. With reference to the first aspect, an embodiment of the present invention provides an eighth possible implementation manner of the first aspect, where the setting position of the rectangular transition groove is determined by an abscissa of a starting point of the exponential curve.
With reference to the first aspect, an embodiment of the present invention provides an eighth possible implementation manner of the first aspect, where a length of the exponential curve determines a radio frequency signal current path on a surface of the rectangular transition slot.
The embodiment of the invention provides a broadband and gain controllable radio frequency antenna for close-range accurate detection, which is characterized in that a plurality of symmetrical parallel rectangular open slots and an index curve radio frequency signal radiation port are designed on a radio frequency signal radiation patch, so that a radio frequency signal current path can be prolonged, the surface current eddy current of the radio frequency signal radiation patch is weakened, the radio frequency signal radiation energy is concentrated in the index curve opening, the directivity of the antenna at a low frequency position is improved, a main beam is enhanced, side lobes are reduced, the radiation performance is improved, and the bandwidth and the gain are improved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic front view of a broadband and gain controllable rf antenna for close-range precise detection according to an embodiment of the present invention;
fig. 2 is a schematic rear view of a wideband and gain controllable rf antenna for close-range accurate detection according to an embodiment of the present invention;
FIG. 3 is a graph of the return loss S11 results for the antenna;
FIG. 4 is a graph showing the standing wave ratio VSWR results for an antenna;
FIG. 5 shows a gain diagram of the antenna;
FIG. 6 is a graph showing the radiation efficiency of the antenna;
FIG. 7 is an E-plane pattern for the antenna at frequency 3 GHz;
FIG. 8 is an E-plane pattern of the antenna at frequency 4 GHz;
FIG. 9 is an E-plane pattern of the antenna at frequency 5 GHz;
FIG. 10 is an H-plane pattern of the antenna at frequency 3 GHz;
FIG. 11 is an H-plane pattern of the antenna at frequency 4 GHz;
fig. 12 is an H-plane pattern of the antenna at frequency 5 GHz.
Icon: 1-a dielectric substrate; 2-exponential gradient; 3-exponential open slot; 4-rectangular transition grooves; 5-radiation patch; 6-a rectangular open slot; 7-microstrip line.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
After the existing ultra-wideband radio frequency antenna Vivaldi feeds, the surface current of a radiation patch has a backflow phenomenon, so that the return loss of the antenna can be increased, the directivity is reduced, and the radiation performance is influenced.
Based on this, the broadband and gain-controllable radio frequency antenna for close-range accurate detection provided by the embodiment of the invention can weaken the surface current backflow of the patch and concentrate the radiation energy.
The following is a detailed description by way of example.
Fig. 1 is a schematic front view of a broadband and gain controllable rf antenna for close-range accurate detection according to an embodiment of the present invention.
Referring to fig. 1, the antenna includes: the antenna comprises a radiation patch 5, a dielectric substrate 1 and a microstrip line 7; the radiation patch 5 is arranged on the top layer of the dielectric substrate 1, and the microstrip line 7 is arranged on the bottom layer of the dielectric substrate 1; the cross section of the dielectric substrate 1 is rectangular; the radiation patch 5 is provided with an index open slot 3, and the index open slot 3 is formed by encircling one side of the rectangular section of the medium substrate 1 and two index gradient lines 2; and a plurality of rectangular open grooves 6 are also symmetrically distributed on the radiation patch 5 by taking the center line of the short side of the section of the dielectric substrate 1 as a reference.
In a preferred embodiment of practical application, by opening the plurality of rectangular open slots 6 and the index open slot 3 on the radiation patch 5, a current path can be extended, surface current backflow of the radiation patch 5 is weakened, radiation energy is concentrated in the index open slot 3, directivity of the antenna at a low frequency is improved, a main beam is enhanced, side lobes are reduced, radiation performance is improved, and gain is improved.
Wherein the rectangular open slot 6 is used to extend the current path and to attenuate surface current return of the radiating patch 5.
It should be noted that, if the rectangular open slot 6 is etched at the tail of the antenna, the current dispersed at the tail of the antenna can be collected on the slot line, so as to reduce the energy lost by backward radiation, increase the energy of forward radiation, and reduce the level of the tail lobe, but considering the requirement of the actual system on performance, the improvement of the performance by this structure cannot compensate the gain reduction; if the rectangular open slots 6 are etched on both sides of the radiation patch 5, not only the return loss can be reduced, but also the loss of radiation energy can be reduced, the direction can be reduced as shown in the sidelobe levels in fig. 7 to 12, and meanwhile, the gain of the antenna can be ensured to be improved to some extent, so that the rectangular open slots 6 are etched on the radiation patches 5 on both sides of the antenna in this embodiment.
In some embodiments, the radiation patch 5 is symmetrical with respect to a center line of a short side of the cross section of the dielectric substrate 1, and a plurality of rectangular open slots 6 are respectively etched on two sides of the center line of the short side of the radiation patch 5. After the position of the rectangular opening groove 6 is designed, the size of the rectangular opening groove 6 needs to be designed. In the present embodiment, the dimensions of the rectangular open grooves 6 include the length of the rectangular open grooves 6, the width of the rectangular open grooves 6, and the pitch of the adjacent rectangular open grooves 6.
In some embodiments, the length of the rectangular open slot 6 is determined by the following formula:
where l is the length of the rectangular open slot 6, epsilon is the dielectric constant of the dielectric substrate 1, and lambda is the wavelength of the current frequency (operating frequency).
As shown in fig. 1, in the present embodiment, the lengths of the rectangular open slots 6 on both sides of the antenna decrease linearly along the opening direction of the exponential gradient line 2, so that the frequency points corresponding to the lengths of the rectangular open slots 6 become larger gradually in design. Through optimization analysis, the length of the highest rectangular open slot 6 at the left side in fig. 1 is determined to be 40mm, and the length of the lowest rectangular open slot 6 at the right side in fig. 1 is determined to be 24 mm.
In some embodiments, the width of each rectangular open slot 6 is the same, and the width of the rectangular open slot 6 is determined by the following formula:
wherein dw is the width of the rectangular open slot 6, epsilon is the dielectric constant of the dielectric substrate 1, and lambda is the wavelength of the current frequency.
In some embodiments, the spacing between each rectangular open slot 6 is equal, and the spacing between the rectangular open slots 6 is determined by the following formula:
dww<0.25*λ
where dww is the spacing between rectangular open slots 6 and λ is the wavelength of the current frequency.
It should be noted that, when the width and the distance of the rectangular open slot 6 are designed, the size of the rectangular open slot 6 can be adjusted according to the application frequency of the current antenna. The lowest frequencies of the antennas are selected for this embodiment. The width value of the rectangular open slot 6 does not influence the resonant frequency too much, but in order to load more rectangular open slots 6, better inhibiting effect is generated on the current backflow inside the exponential gradient line 2, the width of the rectangular open slot 6 is set to be 5mm, and the distance is set to be 2 mm.
Further, the number of slots for each patch in this embodiment can be specified. The different number of the slots is equivalent to loading a plurality of resistors with different resistance values on the surface of the antenna, and the return loss, gain, directivity and the like of the antenna at different frequency points can be improved. In combination with the width and the slot pitch of the rectangular open slots 6, in this embodiment, a plurality of rectangular open slots 6 are etched on each side of the antenna, and preferably, 9 rectangular open slots 6 arranged on each side may be surrounded. The circuit path on the surface of the antenna radiation patch 5 after the rectangular open slot 6 is etched is prolonged, and the antenna performance influence caused by current backflow and size change is avoided.
In some embodiments, the radiation patch 5 is further provided with a rectangular transition groove 4, the long side of the rectangular transition groove 4 is parallel to the middle line of the short side, and the rectangular transition groove 4 is symmetrical about the middle line of the short side.
Illustratively, the dielectric substrate 1 may be understood as a rectangular parallelepiped, wherein the cross section of the top layer of the dielectric substrate 1 is rectangular, the long side of the rectangular transition slot 4 is parallel to the center line of the short side of the cross section, and the rectangular transition slot 4 is symmetrical about the center line of the short side, i.e. the width of the short side of the rectangular transition slot 4 is bisected by taking the center line of the short side as an axis. In the foregoing embodiment, the center line of the short side is a straight line y equal to 0.5 × W, where W is the width of the short side of the cross section of the dielectric substrate 1/the width of the ultra-wideband rf antenna.
FR4 can be selected as the material of the dielectric substrate 1, so that the aim of saving cost is fulfilled.
In some embodiments, the exponential taper (exponential curve) y is represented by the formula:
y＝a*e b*x +c
b＝(1/L)*ln(W/sw)
wherein a and c are constant coefficients of exponential gradient 2, b is gradient rate of exponential gradient 2, (x) 1 ，y 1 )、(x 2 ，y 2 ) Respectively, a start point coordinate and an end point coordinate of the exponential gradient 2, wherein L is the length of the antenna, W is the width of the antenna, and sw is the width of the rectangular transition groove 4.
The gradient rate b determines the degree of inclination of the exponential gradient 2.
In some embodiments, the length of the exponential ramp 2 determines the propagation path of the current after passing through the rectangular transition slot 4.
Since the current will continue to flow to the antenna opening along the edge of the exponential open slot 3 after flowing through the rectangular transition slot 4 on the surface of the radiating patch 5, the length of the exponential gradient 2 determines the propagation path of the current after passing through the rectangular transition slot 4.
And the abscissa of the end point of the exponential gradient 2 can be determined according to the size of the dielectric substrate 1, x 2 The value is 10mm of the length of the substrate, so that the propagation path of the current on the index patch is mainly limited by the abscissa x of the starting point of the exponential gradient 2 1 And (6) determining. In the present embodiment, the abscissa of the starting point of the exponential taper line 2 can be preferably x after optimization analysis 1 Is 13 mm. The ordinate of the end point of the exponential ramp 2 determines the opening width of the exponential patch. The index patch has an excessively large opening, which affects current propagation and increases the difficulty of current collection at the opening. Too small an opening width may affect the main beam radiated by the antenna. Through optimization analysis, the end point ordinate of the exponential gradient 2 can be preferably y 2 82mm, the width of the opening of the index patch can be calculated as 68mm according to the principle of symmetry of the figure. Designed by the rectangular transition groove 4, the ordinate of the initial point of the exponential gradient 2 is y 1 Is 48.25 mm. By substituting the foregoing formula based on the coordinates of the start point and the end point of exponential decay line 2, constant coefficient a can be determined to be 0.14 and c to be 47.98. Then, according to the parameters a, b and c, the exponential-gradient 2 equation is determined as y being 0.14 x exp (0.05 x) +47.98 (x) 1 X is less than or equal to L), two exponential radiating patches 5 can be designed in combination with the symmetry property, as shown in fig. 1.
In some embodiments, the rectangular transition slot 4 may be designed according to the starting points of the two exponential graduations 2 and the relevant parameters of the rectangular transition slot 4. The setting position of the rectangular transition groove 4 is determined by the abscissa of the starting point of the exponential gradient line 2. One end of the rectangular transition groove 4 is tightly connected with the starting point of the gradual change exponential line. The width of the rectangular transition groove 4 is equal to the distance between the starting points of the two exponential gradient lines 2.
In the practical application process, the length value of the rectangular transition slot 4 influences the return loss characteristic of the antenna. The symmetrical nature of the rectangular transition slot 4 facilitates uniform current flow across the surface of the radiating patch 5. Through optimization analysis, the width of the short side of the rectangular transition groove 4 can be preferably 0.5mm, and the length of the long side can be preferably 9 mm.
Illustratively, the rectangular transition slot 4 is also used for coupling feeding with the microstrip line 7. The microstrip line 7 is arranged as shown in fig. 2, so that good return loss and uniform current distribution at two sides of the radiating patch 5 can be ensured when the antenna works.
According to the antenna provided by the embodiment of the invention, the current backflow phenomenon is effectively weakened by etching a plurality of rectangular open slots with gradually changed lengths, equal widths and equal intervals on the radiation patches at the two wings of the antenna, the low-frequency working range of the antenna is widened, and the position of a working frequency resonant point is reduced; the rectangular open slots etched by the radiation patches on the two wings of the antenna effectively concentrate energy, concentrate radiation energy on the exponential open slots, improve the directivity of the antenna at a low frequency, enhance a main beam, reduce side lobes, improve radiation performance and improve gain.
In some embodiments, the performance test result may be obtained by performing analog simulation on the antenna:
1. return loss S11
Fig. 3 is a graph showing the return loss S11 result of the antenna. S11 reflects the transmission performance of the antenna. The result shows that the S11 value of the antenna in the frequency band of 2.5-8.2GHz is lower than-10 dB. The return loss in the frequency band is small, and more energy is not received by the transmitting antenna after being radiated from the antenna radiation opening, which shows that the transmitting performance of the antenna in the frequency band is good. The resonance point of the antenna is located at 3.5GHz, the resonance point frequency is low, and the S11 curve near the resonance point is relatively smooth. Generally speaking, the slotted structure prolongs the current propagation path, so that the current backflow phenomenon on the surface of the antenna patch is weakened, the current can stably flow to the opening along an exponential line, and the return loss of the antenna is low and stable. The low loss characteristic makes the antenna suitable for ultra-wideband radar.
2. Standing wave ratio VSWR
Figure 4 is a graph showing the standing wave ratio VSWR results for the antenna. The VSWR reflects the impedance matching of the antenna feed and the antenna. It can be seen from the results that the VSWR value of the antenna in the frequency band of 2.5-8.2GHz is lower than 2, and the curve is relatively stable. Most energy in the frequency band can be radiated from the antenna, the matching condition of the antenna feeder line and the antenna is good, and the performance of the ultra-wideband radar can be improved.
3. Antenna gain
Fig. 5 shows a gain diagram of the antenna. The gain of an antenna describes the degree to which an antenna concentrates input and output power for use in measuring the ability of the antenna to transmit and receive signals in a particular direction. It can be seen from the results that the antenna has a higher gain in 2.5-8.2GHz, where the gain can reach 9dBi at 4 GHz. In the frequency band, the fluctuation of a gain change curve is small, and the antenna has stable gain. Generally, rectangular open slots etched on two sides of the antenna are subjected to current backflow through a current control device, so that energy on the surface of the patch is concentrated, the antenna has high and stable gain, the signal distortion degree can be guaranteed to be small in application of the ultra-wideband radar, and the efficiency is improved.
4. Radiation efficiency
Fig. 6 shows a radiation efficiency diagram of the antenna. The radiation efficiency of the antenna visually reflects the radiation capability of the antenna. From the results, the radiation efficiency of the antenna in the frequency band of 2.5GHz-8.2GHz is higher than 50%, especially in the frequency range of 2.5GHz-5GHz, the radiation efficiency of the antenna can reach more than 70%, and the radiation efficiency at 3GHz is close to 80%. Although the radiation efficiency curve shows the trend of ascending first and then descending, in general, rectangular open slots are etched on the two sides of the antenna, so that the radiation efficiency of the antenna is better and stable, and the working performance of a system is favorably ensured.
5. Direction of radiation
Fig. 7 to 9 show the E-plane pattern of the antenna, and fig. 10 to 12 show the H-plane pattern of the antenna. The directional pattern reflects the directivity of the antenna. The results show that the antenna has large main lobe proportion, small side lobe proportion and concentrated beam width in the direction diagram of 3-5 GHz. In the frequency band, as the frequency rises, the main lobe level rises first and then falls, the main lobe level at 4GHz is the highest, and both the E surface and the H surface can reach 10.3 dB. The E-plane and H-plane directional pattern side lobes of the antenna at 3GHz are low, which shows that the directivity of the antenna is good at low frequency. Generally, rectangular open slots etched on two sides of the antenna effectively concentrate surface currents of the patch, so that energy can be concentrated at an index opening when the antenna radiates, the strength of a main beam is enhanced, and the directional radiation performance of the antenna is improved.
In the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein.
Claims (10)
1. A broadband and gain controllable radio frequency antenna for close-range accurate detection is characterized in that a dielectric substrate of the antenna comprises: a radio frequency signal radiation patch and a microstrip line; the cross section of the medium substrate is rectangular and is divided into a top medium and a bottom medium which are parallel to each other; the radio frequency signal radiation patch is arranged on the top layer of the dielectric substrate, and the microstrip line is arranged on the bottom layer of the dielectric substrate; the radio-frequency signal radiation patch is designed to take the center line of the short side of the rectangular section of the dielectric substrate as a symmetrical reference, and two symmetrical index curves extend to the short side of the rectangular section along the radio-frequency signal radiation direction to form an index curve radiation opening; a plurality of parallel rectangular open slots are symmetrically distributed on two sides of the radio frequency signal radiation patch.
2. The broadband and gain-controllable radio-frequency antenna for close-range precise detection according to claim 1, wherein a plurality of parallel rectangular open slots are symmetrically distributed on two sides of the radio-frequency signal radiation patch for extending a radio-frequency signal current path so as to eliminate an eddy current phenomenon formed by surface current backflow of the radio-frequency signal radiation patch.
3. The broadband and gain-controllable radio-frequency antenna for close-range precise detection according to claim 1 or 2, wherein two exponential curves of the radio-frequency signal radiation patch are symmetrical with reference to a center line of a short side of the cross section of the dielectric substrate, and a plurality of parallel rectangular open slots are symmetrically designed on two sides of the two exponential curves of the radio-frequency signal radiation patch.
4. A wideband and gain controllable radio frequency antenna for close range accurate detection according to claim 3, wherein the length of the rectangular open slot is calculated by the following formula:
wherein l is the length of the rectangular open slot, epsilon is the dielectric constant of the dielectric substrate, and lambda is the wavelength of the working frequency.
5. A broadband and gain-controllable radio frequency antenna for close-range accurate detection according to claim 3, wherein the width of each of the rectangular open slots is the same, and the width of the rectangular open slot is determined by the following formula:
and dw is the width of the rectangular open slot, epsilon is the dielectric constant of the dielectric substrate, and lambda is the wavelength of the working frequency.
6. A wideband and gain controllable radio frequency antenna for close range accurate detection as claimed in claim 3, wherein the spacing between the rectangular open slots is equal, and the spacing between the rectangular open slots is determined by the following formula:
dww<0.25*λ
wherein dww is the distance between the rectangular open slots, and λ is the wavelength of the operating frequency.
7. The broadband and gain-controllable radio-frequency antenna for close-range accurate detection according to claim 1 or 2, wherein a rectangular transition groove is further disposed on the radio-frequency signal radiation patch, a long side of the rectangular transition groove is parallel to a central line of a short side of the cross section of the dielectric substrate, and the rectangular transition groove is symmetrical with respect to the central line of the short side of the cross section of the dielectric substrate.
8. The broadband and gain controllable radio frequency antenna for close range accurate detection according to claim 7, wherein the exponential curve y is solved by the following formula:
y＝a*e b*x +c
b＝(1/L)*ln(W/sw)
wherein a and c are constant coefficients of the exponential curve, b is the gradient rate of the exponential curve, and (x) 1 ，y 1 )、(x 2 ，y 2 ) Respectively are the initial point coordinate and the end point coordinate of the exponential curve, L is the length of the antenna, W is the width of the antenna, and sw is the width of the rectangular transition groove.
9. The broadband and gain controllable radio frequency antenna for close range accurate detection according to claim 7, wherein the setting position of the rectangular transition slot is determined by the abscissa of the starting point of the exponential curve.
10. The broadband and gain controllable rf antenna for close range accurate detection according to claim 9, wherein the length of the exponential curve determines the rectangular transition slot surface rf signal current path.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114824773A (en) * | 2022-05-07 | 2022-07-29 | 山东师范大学 | Vivaldi antenna for ultra-wideband detection and preparation method thereof |
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| CN114188709A (en) * | 2021-10-22 | 2022-03-15 | 山东师范大学 | Vivaldi antenna for medical imaging and manufacturing method thereof |
| CN114824773A (en) * | 2022-05-07 | 2022-07-29 | 山东师范大学 | Vivaldi antenna for ultra-wideband detection and preparation method thereof |
| CN115810915A (en) * | 2022-04-22 | 2023-03-17 | 中际医学科技(山东)有限公司 | Antenna dielectric substrate design drawing method |
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| CN114188709A (en) * | 2021-10-22 | 2022-03-15 | 山东师范大学 | Vivaldi antenna for medical imaging and manufacturing method thereof |
| CN115810915A (en) * | 2022-04-22 | 2023-03-17 | 中际医学科技(山东)有限公司 | Antenna dielectric substrate design drawing method |
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| CN114824773A (en) * | 2022-05-07 | 2022-07-29 | 山东师范大学 | Vivaldi antenna for ultra-wideband detection and preparation method thereof |
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