阅读说明：本技术 基于SIW结构的Ka波段小型化滤波天线 (Ka-band miniaturized filtering antenna based on SIW structure ) 是由 董刚 旷丁丁 杨银堂 于 2019-07-10 设计创作，主要内容包括：本发明提出了一种基于基片集成波导SIW结构的Ka波段小型化滤波天线,主要解决现有滤波天线尺寸偏大、不易集成的问题。其包括两金属层、两介质层和微带辐射单元。第一金属层(13)上设有共面波导(14)；第一介质层(8)位于第一金属层(13)与第二金属层(5)之间,其周边和中间设有周期性金属化通孔(12),以构成两个谐振腔(9,11),两个谐振腔之间设有感性窗口(8),用于耦合这两个谐振腔；第二金属层设有两个矩形窗口(6,7)；第二介质层(3)的左上方设有第一辐射单元(1),右上方设有第二辐射单元(2),两个辐射单元组成辐射阵列。本发明频率选择性好,增益高,易集成,适用于Ka波段无线通信。(The invention provides a Ka-band miniaturized filter antenna based on a Substrate Integrated Waveguide (SIW) structure, which mainly solves the problems that the conventional filter antenna is large in size and difficult to integrate. The microstrip radiating element comprises two metal layers, two dielectric layers and a microstrip radiating element. A coplanar waveguide (14) is arranged on the first metal layer (13); the first dielectric layer (8) is positioned between the first metal layer (13) and the second metal layer (5), the periphery and the middle of the first dielectric layer are provided with periodic metalized through holes (12) to form two resonant cavities (9, 11), and an inductive window (8) is arranged between the two resonant cavities and is used for coupling the two resonant cavities; the second metal layer is provided with two rectangular windows (6, 7); a first radiation unit (1) is arranged on the upper left side of the second medium layer (3), a second radiation unit (2) is arranged on the upper right side of the second medium layer, and the two radiation units form a radiation array. The invention has good frequency selectivity, high gain and easy integration, and is suitable for Ka-band wireless communication.)

1. a Ka-band miniaturized filter antenna based on an SIW structure comprises two metal layers, two dielectric layers and a microstrip patch; the dielectric waveguide grating is characterized in that a coplanar waveguide (14) is arranged on the first metal layer (13), the first dielectric layer (8) is positioned between the first metal layer (13) and the second metal layer (5), periodic metalized through holes (12) are arranged at the periphery and in the middle of the first dielectric layer to form two SIW resonant cavities (9, 11), an inductive window (10) is arranged between the two SIW resonant cavities, and the dielectric waveguide grating is characterized in that:

Two rectangular windows (6, 7) are formed in the second metal layer (5), the first rectangular window (6) is located above the first SIW resonant cavity (9), and the second rectangular window (7) is located above the second SIW resonant cavity (11);

periodic metalized through holes (4) are formed in the periphery and the middle of the second dielectric layer (3) to form an electromagnetic shielding cavity;

the microstrip patches are divided into two pieces, the first microstrip patch (1) is positioned at the upper left of the second medium layer (3) and corresponds to the first SIW resonant cavity (9), the second microstrip patch (2) is positioned at the upper right of the second medium layer (3) and corresponds to the second SIW resonant cavity (11), and the two microstrip patches form a radiation array.

2. The antenna of claim 1, wherein: the coplanar waveguide (14) is composed of a 50 ohm microstrip line and a rectangular narrow slit, the width of the coplanar waveguide is determined by the thickness H2 of the first medium layer (8), and the coplanar waveguide is positioned at the center of the long side of the first SIW resonant cavity (9).

3. the antenna of claim 1, wherein: the first rectangular window (6) is offset from the center of the first SIW cavity (9) and the second rectangular window (7) is offset from the center of the second SIW cavity (11) to form a magnetic coupling hole.

4. The antenna of claim 1, wherein: the two SIW cavities (9, 11) are axisymmetrical with respect to the inductive window (10) and have dimensions corresponding to those of the electromagnetic shielding cavity constituted by the periodically metallized through holes (4).

5. The antenna of claim 4, wherein: the size calculation formula of the SIW resonant cavity is as follows:

Wherein D represents the diameter of the through hole, S represents the distance between adjacent through holes, W represents the actual length of the cavity, L represents the actual width of the cavity, Weff represents the corrected width of the cavity, Leff represents the corrected length of the cavity, f0 represents the resonant frequency of the cavity, c represents the speed of light in vacuum, ε r represents the relative dielectric constant of the medium, and different m and n represent different wave modes.

6. The antenna of claim 1, wherein: the two microstrip patches (1, 2) are rectangular patch structures and have the same size, and the resonant frequency of the two microstrip patches is equal to the resonant frequency of the two SIW resonant cavities (9, 11).

7. The antenna of claim 6, wherein: the size calculation formula of the rectangular microstrip patch is as follows:

Where W1 denotes the width of the microstrip patch, ∈ r denotes the relative dielectric constant of the medium, f1 denotes the center frequency of operation of the microstrip patch, ∈ e denotes the effective dielectric constant, h denotes the thickness of the dielectric substrate, L1 denotes the length of the microstrip patch, and c denotes the speed of light in vacuum.

Technical Field

The invention belongs to the technical field of microwave and millimeter wave communication, and particularly relates to a filtering antenna which can be used for Ka-band wireless communication.

background

In recent years, wireless communication technology has been rapidly developed, and wireless communication systems tend to be miniaturized. The filter and the antenna are used as key components in a wireless communication system, and the filter and the antenna are cooperatively designed into a filter antenna, so that the requirement of miniaturization can be met. At present, a filter antenna which is easy to process and integrate becomes a new research hotspot.

chinese patent CN202275943U discloses a horizontally polarized planar filtering antenna, which realizes a filtering antenna by coupling an inductive window with a SIW slot radiation array after a third-order SIW resonant cavity.

Chinese patent CN202308303U discloses a vertically polarized omnidirectional printed filter antenna, which is manufactured by printed circuit board process, and two serial microstrip arrays are connected on the upper and lower metal layers behind the three-order SIW resonant cavity by using microstrip transition lines. The patent uses the microstrip gradual change line as a connecting line, which is not beneficial to miniaturization; meanwhile, the serial microstrip array and the SIW resonant cavity are horizontally arranged, and the problem that the plane size is too large to facilitate integration is also faced.

Disclosure of Invention

The invention aims to provide a Ka-band miniaturized filter antenna based on a SIW structure, and aims to solve the problems that the conventional filter antenna is large in size and difficult to integrate.

In order to achieve the purpose, the technical idea of the invention is as follows: two micro-strip antennas are used for replacing an upper-layer resonant cavity of a four-order SIW filter with a folding structure, so that the two micro-strip antennas have the function of a filter resonant unit and form a radiation array, and the antenna gain is improved.

according to the above thought, the Ka-band miniaturized filter antenna based on the SIW structure comprises two metal layers, two dielectric layers and a microstrip patch; the first metal layer is provided with a coplanar waveguide; the first medium layer is positioned between the first metal layer and the second metal layer, and periodic metalized through holes are arranged at the periphery and the middle of the first medium layer to form two SIW resonant cavities, and an inductive window is arranged between the two SIW resonant cavities, and the first medium layer is characterized in that:

Two rectangular windows are formed in the second metal layer, the first rectangular window is located above the first SIW resonant cavity, and the second rectangular window is located above the second SIW resonant cavity;

The periphery and the middle of the second dielectric layer are provided with periodic metalized through holes to form an electromagnetic shielding cavity;

The microstrip patches are arranged into two pieces, the first microstrip patch is positioned at the upper left of the second medium layer and corresponds to the first SIW resonant cavity, the second microstrip patch is positioned at the upper right of the second medium layer and corresponds to the second SIW resonant cavity, and the two microstrip patches form a radiation array.

Preferably, the coplanar waveguide is composed of a 50 ohm microstrip line and a rectangular narrow slit, the width of the coplanar waveguide is determined by the thickness H2 of the first medium layer, and the coplanar waveguide is located at the center of the long side of the first SIW resonant cavity.

Preferably, the first rectangular window is offset from the center of the first SIW resonator and the second rectangular window is offset from the center of the second SIW resonator to form a magnetic coupling hole.

Preferably, the two SIW resonant cavities are axisymmetric with respect to the inductive window, and have a size identical to that of the electromagnetic shielding cavity formed by the periodically metallized through holes.

preferably, the two microstrip patches are rectangular patch structures, and have the same size, and the resonant frequency of the two microstrip patches is equal to the resonant frequency of the SIW resonant cavity.

the invention has the following advantages:

1. The invention adopts a design method of combining the SIW filter technology and the microstrip radiating array and combines a folding topological structure, namely, the upper surface metal layer of the original filter is replaced by two microstrip patches, so that the extra size is not increased, and the loss caused by the connection of a universal cable can be avoided.

2. the invention utilizes two microstrip patches as the last two-order resonance unit of the filter, so that the microstrip patches are coupled with the SIW resonance cavity to realize the function of the filter while fully radiating electromagnetic waves, and the two microstrip patches form an array, thereby improving the gain of the antenna compared with the traditional filtering antenna with a single radiation unit serving as a first-order resonance unit.

drawings

FIG. 1 is an expanded view of the overall structure of the present invention;

FIG. 2 is a schematic plan view of two radiating elements in the present invention;

FIG. 3 is a schematic plan view of a second dielectric layer in the present invention;

FIG. 4 is a schematic plan view of a second metal layer in the present invention;

FIG. 5 is a schematic plan view of a first dielectric layer in the present invention;

FIG. 6 is a schematic plan view of a first metal layer in the present invention;

FIG. 7 is a graph of simulation results of reflection loss S11 of the present invention;

fig. 8 is an E-plane and H-plane gain pattern of the present invention.

Detailed Description

the invention is further described below with reference to the accompanying drawings and specific embodiments.

referring to fig. 1, the present embodiment includes a first radiation unit 1, a second radiation unit 2, a second dielectric layer 3, a second metal layer 5, a first dielectric layer 8, and a first metal layer 13, wherein: a coplanar waveguide 14 is arranged on the first metal layer 13; the first medium layer 8 is positioned between the first metal layer 13 and the second metal layer 5, and periodic metalized through holes 12 are arranged at the periphery and the middle to form a first SIW resonant cavity 9 and a second SIW resonant cavity 11, and an inductive window 10 is arranged between the two SIW resonant cavities; the second metal layer 5 is positioned on the first medium layer 8, the left side of the second metal layer is provided with a first rectangular window 6, and the right side of the second metal layer is provided with a second rectangular window 7; the periphery and the middle of the second dielectric layer 3 are provided with periodic metalized through holes 4 to form an electromagnetic shielding cavity; the first radiation unit 1 is positioned at the upper left of the second medium layer 3 and corresponds to the first SIW resonant cavity 9; the second radiation unit 2 is located at the upper right of the second dielectric layer 3 and corresponds to the second SIW resonant cavity 11. The working principle is as follows: the coplanar waveguide 14 feeds the first SIW resonant cavity 9, coupled to the second SIW resonant cavity 11 through the inductive window 8; the first radiating element 1 is coupled to a first SIW resonator 9 via a first rectangular window 6 and the second radiating element 2 is coupled to a second SIW resonator 11 via a second rectangular window 7.

referring to fig. 2, the radiating elements are rectangular microstrip patches with equal size, and the resonant frequency of the radiating elements is consistent with the central frequency of the SIW resonant cavity.

In this embodiment, the selected frequency is not limited to 30GHz, the second dielectric layer 3 is made of a Ferro-A6M low-temperature co-fired ceramic material with a dielectric constant of 5.9, a loss tangent of 0.002 and a single-layer ceramic chip thickness of 0.096mm, the thickness of the ceramic material is two-layer ceramic chip thickness, that is, H1 is 0.192mm, and the calculation process of the microstrip patch size is as follows:

First, the microstrip patch width W1 is calculated:

Wherein ∈ r denotes a relative dielectric constant of the medium, f1 denotes a center frequency of operation of the microstrip patch, and c denotes an optical velocity in vacuum, and calculated W1 is 2.69 mm;

next, the effective dielectric constant ∈ e is calculated using the obtained width W1:

In the formula, h represents the thickness of the dielectric substrate, and calculated as ∈ e is 4.75.

finally, calculating the microstrip patch length L1:

Calculated to give L1 ═ 1.97 mm.

referring to fig. 3, the planar size of the second dielectric layer 3 is consistent with the planar sizes of the second metal layer 5, the first dielectric layer 8 and the first metal layer 13, and the planar size should be larger than the size of the SIW resonant cavity, and the embodiment is selected and not limited to the width W2 being 8mm, and the length L2 being 4 mm;

The central frequency of the SIW resonant cavity of this embodiment is the same as the microstrip patch resonant frequency, and is 30GHz, the main mode is used as the operating mode, the first dielectric layer 8 also adopts Ferro-A6M low-temperature co-fired ceramic material, the thickness of the ceramic material is three-layer ceramic chip thickness, that is, H2 ═ 0.288mm, the width-length ratio thereof is the same as the width-length ratio of the microstrip patch, the diameter of the selected metallized through hole is 0.1mm, the hole pitch is 0.2mm, and the calculation formula of the central frequency of the SIW cavity is as follows:

in the formula, m and n respectively represent the transverse edge and the longitudinal edge of the cavity as multiples of the central frequency wavelength, the two parameters jointly determine the working wave mode of the resonant cavity, and m is 1 and n is 1 in the main mode; ε r represents the relative permittivity of the medium; c represents the speed of light in vacuum; weff and Leff represent the equivalent width and length of the SIW cavity, and the determination of these two values requires correction of the actual length and width of the SIW cavity, the correction equation being as follows:

where D represents the via diameter, S is the adjacent via spacing, W3 represents the actual width of the SIW cavity, and L3 represents the actual length of the SIW cavity.

Combining the above formulas, calculating to obtain: w3-3.6 mm and L3-2.6 mm.

Referring to fig. 4, the coupling strength of the SIW cavity and the radiating element is determined by the size and position of the rectangular window, and the embodiment is not limited to the width and length of the first rectangular window 6 being WS 1-1.12 mm, LS 1-0.15 mm, and the distance Y1 from the long side of the first SIW cavity being 1.83 mm; the width and length of the second rectangular window 7 are WS 2-1.14 mm, LS 2-0.15 mm and the distance Y2 from the long side of the second SIW cavity is 2.03 mm.

Referring to fig. 5, the width Lp of the inductive window 8 determines the coupling strength of the two SIW resonators, and the embodiment is not limited to 1.14 mm.

Referring to fig. 6, the width Wj1 of the coplanar waveguide 14 is 0.6mm, the width Wj2 of the microstrip line of the coplanar waveguide is 0.4mm, and the length Lj of the microstrip line entering the SIW cavity determines the coupling strength between the excitation source and the first SIW cavity, which is selected and not limited to 0.9 mm.

the effects of the present invention can be further illustrated by the following simulations:

the embodiment of the invention is subjected to three-dimensional modeling by using three-dimensional electromagnetic full-wave simulation software HFSS _16.0, the result of the reflection loss S11 of a simulation model is shown in FIG. 7, and the gain pattern is shown in FIG. 8.

As can be seen from FIG. 7, in the present embodiment, there are four resonance points within the pass band, which are respectively 27.58GHz, 28.03GHz, 28.62GHz and 29.27GHz, and the reflection coefficients of the resonance points are respectively-22 dB, -20.9dB, -18.86dB and-25.03 dB; the bandwidth of-10 dB is 2.14GHz, and the relative bandwidth reaches 7.51%; the center frequency is 28.36 GHz, which is lower than the initial frequency by 1.64 GHz, because the inductive window and the rectangular window belong to the magnetic coupling hole, and the magnetic coupling reduces the center frequency of the resonance unit.

as can be seen from fig. 8, when this embodiment is operated at the center frequency of the pass band, the maximum gain in the E-plane and H-plane radiation directions reaches 7.44 dBi.

In conclusion, the filtering antenna designed by using the two microstrip patches to replace the filter resonant unit and the folding structure has excellent filtering performance and radiation performance and smaller size, and solves the problems of large size and difficult integration of the conventional filtering antenna.

The above description is only one specific example of the invention, it is to be understood that this example is intended to illustrate the invention and not to limit the scope of the invention, which, after reading the present invention, will fall within the scope of the invention as defined in the appended claims, modified by those skilled in the art, all of which are equivalent forms of the invention.