CN115473020B - A multi-layer packaged three-band SIW balanced bandpass filter - Google Patents

Abstract

The present application discloses a multi-layer packaged three-passband SIW balanced bandpass filter, including a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, a third metal layer, a third dielectric substrate and a fourth metal layer, wherein the first metal layer is provided with a differential input port and an output port; the first dielectric substrate is provided on the lower surface of the first metal layer; the second metal layer is provided on the lower surface of the first dielectric substrate; the second dielectric substrate is provided on the lower surface of the second metal layer; the third metal layer is provided on the lower surface of the second dielectric substrate; the third dielectric substrate is provided on the lower surface of the third metal layer; and the fourth metal layer is provided on the lower surface of the third dielectric substrate. By providing a differential input port and a differential output port, a balanced circuit is obtained, which can reduce electromagnetic interference and environmental noise in a communication system; at the same time, the multi-layer structure can further reduce the size of the filter. In addition, the structure successfully constructs a column-coupling topology and achieves a three-passband filtering effect.

Description

A multi-layer packaged three-band SIW balanced bandpass filter

Technical Field

The present application relates to the field of microwave passive devices, and in particular to a multi-layer packaged three-passband SIW balanced bandpass filter.

Background technique

With the rapid development of modern wireless communication systems, substrate integrated waveguide (SIW) filter circuits have attracted extensive attention. They have many advantages such as low loss, low cost, high power capacity and high quality factor. At the same time, the balanced filter circuit based on SIW can effectively suppress noise and resist electromagnetic interference. The multi-passband balanced bandpass filter designed by multi-layer package SIW can make the designed filter have a more compact size and better adapt to the multi-band, multi-standard and multi-application working requirements of today's wireless communication systems.

Summary of the invention

The purpose of this application is to design a new type of radio frequency device with a balancing function and a three-passband filtering function, wherein the device includes a dielectric substrate, a metal surface, a metal through hole, a perturbation metal through hole, an energy coupling hole, etc. Therefore, this application designs a multi-layer packaged three-passband SIW balanced bandpass filter, which is based on a multi-mode resonant cavity, a split coupling topology, and a multi-layer physical structure. This design can make the filter smaller in size, more flexible, and more integrated, and can reduce electromagnetic interference in communication systems and suppress environmental noise.

In order to achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: a multi-layer packaged three-passband SIW balanced bandpass filter, comprising: a first metal layer, on which a differential input port and a differential output port are arranged for realizing energy transmission; a first dielectric substrate, on which the first dielectric substrate is arranged on the lower surface of the first metal layer; a second metal layer, on which the second metal layer is arranged on the lower surface of the first dielectric substrate; a second dielectric substrate, on which the second dielectric substrate is arranged on the lower surface of the second metal layer; a third metal layer, on which the third metal layer is arranged on the lower surface of the second dielectric substrate; a third dielectric substrate, on which the third dielectric substrate is arranged on the lower surface of the third metal layer; a fourth metal layer, on which the fourth metal layer is arranged on the lower surface of the third dielectric substrate; the first metal layer, the first dielectric substrate, the second metal layer, the second dielectric substrate, the third metal layer, the third dielectric substrate and the fourth metal layer are arranged in a multi-layer form and centrally stacked.

According to the implementation mode of the present application, the multi-layer packaged three-band SIW balanced bandpass filter has at least the following beneficial effects: the differential input port and the differential output port are arranged on the first metal layer to obtain a balanced filtering functional circuit, thereby reducing electromagnetic interference in the communication system, suppressing environmental noise, and further miniaturizing the filter by utilizing multi-mode characteristics and a multi-layer structure. In addition, the split coupling topology formed can achieve a three-band filtering response.

According to some embodiments of the present application, two first energy coupling holes are provided on the second metal layer, and the first energy coupling holes are arranged symmetrically about the axis A1A2, and are both arranged on the axis B1B2, so as to realize the transmission of energy from the first dielectric substrate to the second dielectric substrate; two second energy coupling holes are provided on the third metal layer, and the second energy coupling holes are arranged symmetrically about the axis A1A2, and are both arranged on the axis B1B2, so as to realize the transmission of energy from the second dielectric substrate to the third dielectric substrate. In addition, in order to realize the maximum coupling and transmission of energy, the shapes of the first energy coupling hole and the second energy coupling hole are both set to be rectangular and are located at the strongest magnetic field of the resonant mode to realize magnetic coupling.

According to some embodiments of the present application, the first energy coupling hole has a hole length of 3.9 mm and a hole width of 0.8 mm, and the second energy coupling hole has a hole length of 3.2 mm and a hole width of 0.8 mm; the energy coupling hole is used to couple two adjacent layers of resonators. Through simulation optimization, such a size coupling effect is the best for this design.

According to some embodiments of the present application, the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all provided with a plurality of metal through holes, which are respectively arranged around the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate in a rectangular arrangement. The metal through holes are arranged in a rectangular shape, which can limit the electromagnetic waves in the dielectric substrate from spreading to the surroundings, that is, prevent the electromagnetic waves from leaking.

According to some embodiments of the present application, the first dielectric substrate is provided with four first perturbation metal through holes. The second dielectric substrate is provided with six second perturbation metal through holes. The third dielectric substrate is provided with six third perturbation metal through holes, and the perturbation metal through holes are all arranged on the axis A1A2. The resonant frequencies of the TE201 mode and the TE202 mode are different. By providing the perturbation metal through holes, the resonant frequency of the TE201 mode can be increased while the resonant frequency of the TE202 mode is kept unchanged.

According to some embodiments of the present application, the diameter of the first perturbation metal via is 0.6 mm, and the diameters of the second perturbation metal via and the third perturbation metal via are both 1.2 mm.

According to some embodiments of the present application, the number of the differential input port and the differential output port is two, both of which are arranged on the same side of the axis A1A2 of the first metal layer and symmetrical about the axis B1B2 of the first metal layer; the differential input port and the differential output port are symmetrical about the axis A1A2 of the first metal layer. In order to achieve a balancing function and combine the phase characteristics of the resonant mode, this is the most appropriate setting method for the differential input/output port.

According to some embodiments of the present application, the differential input port is composed of a differential input feeder and a coplanar waveguide structure, and the differential output port is composed of a differential output feeder and a coplanar wave conversion structure, wherein the differential input feeder is used to transfer energy from the differential input port to the SIW resonant cavity, and the differential output feeder is used to transfer energy from the SIW resonant cavity to the differential output port. In addition, the coplanar waveguide structure is used to connect the differential feeder and the SIW resonant cavity to obtain matching between the two, the differential feeder has an impedance of 50 ohms, and the SIW resonant cavity also has a certain impedance. Using the coplanar waveguide structure to connect the differential feeder and the SIW resonant cavity can achieve impedance matching between them.

According to some embodiments of the present application, the width of the differential input feeder is equal to that of the differential output feeder, both of which are 1.55 mm. This 1.55 mm is a conventional setting. The port impedance of the measuring instrument is 50 ohms. In order to make the differential feeder impedance also 50 ohms, the feeder width needs to be set to 1.55 mm.

According to some embodiments of the present application, the materials of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all Rogers 5880 substrates; wherein the relative dielectric constant of the substrate is 2.2, and the thickness of the substrate is 0.508 mm.

Compared with the prior art, the advantages of the present invention are as follows: 1) The scheme obtains a balanced circuit by setting a differential input port and a differential output port, thereby reducing electromagnetic interference and environmental noise in the communication system; at the same time, the use of a multi-layer structure can further reduce the size of the filter; 2) The structure successfully constructs a column-type coupling topology and realizes a three-band filtering effect, which is more in line with the multi-band, multi-standard, and multi-application working requirements of today's wireless communication systems; 3) The scheme adopts a multi-layer structure: it can effectively reduce the size of the device and meet the needs of miniaturization of wireless communication systems; 4) Balancing function implantation: by setting differential input and output ports, the balancing function can be achieved, thereby effectively reducing electromagnetic interference and environmental noise in the communication system; 5) Multi-band filtering performance: modern wireless communication systems have the working characteristics of multi-band, multi-standard, and multi-application. The three-band filtering effect achieved by this patent is more in line with the application scenarios of modern wireless communication systems.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

FIG1 is a schematic structural diagram of a multi-layer packaged three-band SIW balanced bandpass filter according to an embodiment of the present application;

FIG2 is a schematic structural diagram of the first metal layer and the first dielectric substrate in FIG1 ;

FIG3 is a schematic structural diagram of the second metal layer in FIG1 ;

FIG4 is a schematic structural diagram of the second dielectric substrate in FIG1 ;

FIG5 is a schematic diagram of the structure of the third metal layer in FIG1 ;

FIG6 is a schematic structural diagram of the third dielectric substrate in FIG1 ;

FIG7 is a schematic structural diagram of the fourth metal layer in FIG1 ;

FIG. 8 is a simulation S parameter curve diagram of this embodiment.

Reference numerals:

A first metal layer 100, differential input ports 111 and 112, a first differential input feed line 1111, a second differential input feed line 1112, differential output ports 113 and 114, a first differential output feed line 1113, a second differential output feed line 1114, a first dielectric substrate 200, a first metal via 201, a first perturbation metal via 202, a second metal layer 300, a first energy coupling hole 301, a second dielectric substrate 400, a second metal via 401, a second perturbation metal via 402, a third metal layer 500, a second energy coupling hole 501, a third dielectric substrate 600, a third metal via 601, a third perturbation metal via 602, a fourth metal layer 700, and a coplanar waveguide structure 800.

Detailed ways

In order to deepen the recognition and understanding of the present invention, the scheme is further introduced below in conjunction with the accompanying drawings and specific implementation methods.

Embodiment 1: The following describes a multi-layer packaged three-band SIW balanced bandpass filter according to an embodiment of the present application with reference to FIG. 1 .

As shown in FIG. 1 , the multi-layer packaged three-band SIW balanced bandpass filter according to an embodiment of the present application includes a first metal layer 100 , a first dielectric substrate 200 , a second metal layer 300 , a second dielectric substrate 400 , a third metal layer 500 , a third dielectric substrate 600 and a fourth metal layer 700 .

The first metal layer 100 is provided with differential input ports 111 and 112, and differential output ports 113 and 114. The differential input ports are used to realize the function of receiving input signals, and the differential output ports are used to realize the function of transmitting output signals. The first dielectric substrate 200 is provided on the lower surface of the first metal layer 100; the second metal layer 300 is provided on the lower surface of the first dielectric substrate 200; the second dielectric substrate 400 is provided on the lower surface of the second metal layer 300; the third metal layer 500 is provided on the lower surface of the second dielectric substrate 400; the third dielectric substrate 600 is provided on the lower surface of the third metal layer 500; and the fourth metal layer 700 is provided on the lower surface of the third dielectric substrate 600; wherein the first metal layer 100, the first dielectric substrate 200, the second metal layer 300, the second dielectric substrate 400, the third metal layer 500, the third dielectric substrate 600 and the fourth metal layer 700 are provided in a multi-layer form and centrally stacked.

According to the multi-layer packaged three-band SIW balanced bandpass filter of the embodiment of the present application, a balanced circuit is obtained by setting differential input ports 111 and 112 and differential output ports 113 and 114 on the first metal layer 100, thereby reducing electromagnetic interference in the communication system, suppressing environmental noise, and further miniaturizing the filter by utilizing multi-mode characteristics and a multi-layer structure.

In some embodiments of the present application, as shown in FIG1 , the second metal layer 300 is provided with two first energy coupling holes 301. The two first energy coupling holes 301 are symmetrical about the axis A1A2. In addition, the two first energy coupling holes 301 are arranged on the axis B1B2, and the first energy coupling holes realize the transmission of energy from the first dielectric substrate 200 to the second dielectric substrate 400; the third metal layer 500 is provided with two second energy coupling holes 501. The second energy coupling holes 501 are symmetrical about the axis A1A2. In addition, the two second energy coupling holes 501 are arranged on the axis B1B2, and the second energy coupling holes realize the transmission of energy from the second dielectric substrate 400 to the third dielectric substrate 600. The first energy coupling holes 301 and the second energy coupling holes 501 are arranged at the positions where the magnetic fields of the TE ₂₀₁ mode and the TE ₂₀₂ mode are the strongest, so as to realize the magnetic coupling between the first dielectric substrate 200, the second dielectric substrate 400 and the third dielectric substrate 600, thereby realizing the signal transmission between the top layer and the bottom layer. In addition, the number of the first energy coupling hole 301 and the number of the second energy coupling hole 501 are both set to two, which can reduce the difficulty of processing while achieving a good signal transmission function.

In some embodiments of the present application, as shown in FIG3 and FIG5, the first energy coupling hole 301 and the second energy coupling hole 501 include two rectangular energy coupling holes, the first energy coupling hole has a hole length of 3.9 mm and a hole width of 0.8 mm, and the second energy coupling hole has a hole length of 3.2 mm and a hole width of 0.8 mm. In addition, the distance ls from the inner side of the first energy coupling hole 301 to the axis A1A2 is 3.05 mm, and the distance lss from the inner side of the second energy coupling hole 501 to the axis A1A2 is 3.6 mm.

In some embodiments of the present application, as shown in Figures 1, 2, 4 and 6, the first dielectric substrate 200 is provided with a plurality of first metal through holes 201 and four first perturbation metal through holes 202, the plurality of first metal through holes 201 are all arranged around the first dielectric substrate 200, in a rectangular distribution, and the four perturbation metal through holes are arranged on the axis A1A2, with two distributions on each side of the axis B1B2; the second dielectric substrate 400 is provided with a plurality of second metal through holes 401 and six second perturbation metal through holes 402, the plurality of second metal through holes 401 are all arranged around the second dielectric substrate 400, in a rectangular distribution, and the six perturbation metal through holes are arranged on the axis A1A2, with three distributions on each side of the axis B1B2; the third dielectric substrate 600 is provided with a plurality of third metal through holes 601 and six third perturbation metal through holes 602, the plurality of third metal holes 601 are all arranged around the third dielectric substrate 600, in a rectangular distribution, and the six perturbation metal through holes are arranged on the axis A1A2, with three distributions on each side of the axis B1B2. By providing the first metal through hole 201, the second metal through hole 401 and the third metal through hole 601, electromagnetic waves can be limited. A rectangular substrate integrated waveguide resonant cavity is formed between the first metal through hole 201, the second metal through hole 401 and the third metal through hole 601 and the first dielectric substrate 200, the second dielectric substrate 400, the third dielectric substrate 600, the first metal layer 100 and the fourth metal layer 700, thereby exciting a resonant mode and achieving a filtering effect. Among them, the diameter d of the first metal through hole 201 is 0.6 mm, the distance p between two adjacent first metal through holes 201 is 1 mm, and the parameters of the second metal through hole 401 and the third metal through hole 601 are the same as those of the first metal through hole 201.

In some embodiments of the present application, as shown in FIG. 1 , FIG. 2 , FIG. 4 and FIG. 6 , the diameter of the first perturbation metal through hole 202 is 0.6 mm, and the diameter of the second perturbation metal through hole 402 and the third perturbation metal through hole 602 is 1.2 mm. The three-band SIW balanced bandpass filter mainly realizes the desired function by exciting the TE ₂₀₁ and TE ₂₀₂ modes in the cavity formed by the first dielectric substrate 200 , the second dielectric substrate 400 and the third dielectric substrate 600 . The four first perturbation metal through holes 202 are located in the strong electric field region of the TE ₂₀₁ mode, which increases the resonant frequency of the TE ₂₀₁ mode. At the same time, the four first perturbation metal through holes 202 are located in the weak electric field region of the TE ₂₀₂ mode, and the resonant frequency of the TE ₂₀₂ mode remains unchanged, and the resonant frequencies of the TE ₂₀₁ and TE ₂₀₂ modes are controlled to achieve a bandpass response. The working principle of the six second perturbation metal through holes 402 and the six third perturbation metal through holes 602 is the same as that of the first perturbation metal through hole 202, but what they realize is a band-stop response. The passband response and the stopband response are combined to form a split-coupled topology to achieve a three-passband filtering response.

In some embodiments of the present application, as shown in Figures 1 and 2, differential input ports 111 and 112 are arranged on the same side of the axis A1A2 of the first metal layer 100; differential output ports 113 and 114 are arranged on the same side of the axis A1A2 of the first metal layer 100; wherein the differential input ports 111 and 112 are symmetrical with the differential output ports 113 and 114 about the axis A1A2 of the first metal layer 100.

In some embodiments of the present application, as shown in Figures 1 and 2, the differential input ports 111 and 112 include differential input feeders 1111, 1112 and a coplanar waveguide structure 800, and the differential output ports 113 and 114 include differential output feeders 1113, 1114 and a coplanar waveguide structure 800. The differential input ports 111 and 112 are used to receive signals, and the differential input feeders 1111 and 1112 are used to transfer energy from the differential input ports 111 and 112 to the first dielectric substrate 200. The differential output ports 113 and 114 are used to transmit the signals, and the differential output feeders 1113 and 1114 are used to transfer energy from the first dielectric substrate 200 to the differential output ports 113 and 114. In addition, the coplanar waveguide structure 800 is used to connect the differential feed lines 1111, 1112, 1113, 1114 and the SIW resonant cavity formed by the first metal layer 100, the first dielectric substrate 200, the second metal layer 300 and the first metal through hole 201 to achieve matching between the two.

When the differential input ports 111 and 112 are loaded with differential signals, TE ₂₀₁ and TE ₂₀₂ modes are excited in the first dielectric substrate 200 and output from the differential output ports 113 and 114 to form a wide passband. At the same time, the differential signal is transmitted to the second dielectric substrate 400 through the first energy coupling hole 301 and TE ₂₀₁ and TE ₂₀₂ modes are excited. The second dielectric substrate 400 is regarded as a band-stop resonant cavity. The first dielectric substrate 200 and the second dielectric substrate 400 are used in combination to split the wide passband formed above into two narrow passbands. Then, the differential signal is transmitted to the third dielectric substrate 600 through the second energy coupling hole 501 and TE ₂₀₁ and TE ₂₀₂ modes are excited. The third dielectric substrate 600 is regarded as a band-stop resonant cavity. The first dielectric substrate 200, the second dielectric substrate 400, and the third dielectric substrate 600 are used in combination to split the wide passband into three narrow passbands. Therefore, the design can finally achieve three passbands.

In some embodiments of the present application, as shown in FIG. 2 , the widths of the differential input feed lines 1111 , 1112 and the differential output feed lines 1113 , 1114 are equal and are both 1.55 mm.

In some embodiments of the present application, the materials of the first dielectric substrate 200, the second dielectric substrate 400, and the third dielectric substrate 600 are all Rogers 5880; wherein the relative dielectric constant of the substrate is 2.2, the thickness of the substrate is 0.508 mm, and the loss tangent value of the substrate is 0.0009.

In some embodiments of the present application, as shown in FIG8 , the operating frequencies of the multilayer packaged SIW three-passband balanced bandpass filter in the transmission channel (differential input feed lines 1111 and 1112 combined to excite equal-amplitude inverted input signals, differential output feed lines 1113 and 1114 combined to excite equal-amplitude inverted output signals) are 13.3 GHz, 13.7 GHz, and 14.2 GHz; the 3-dB passband relative bandwidth is 2%, 1.1%, and 1.2%. The simulated return loss in these three passbands is better than 17 dB, and the insertion loss in the passband is less than 0.78 dB, 1.25 dB, and 1.09 dB, respectively. The common-mode rejection of the first passband is better than 23.5 dB, the common-mode rejection of the second passband is better than 24.1 dB, and the common-mode rejection of the third passband is better than 24 dB.

It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims (4)

1. A multilayer packaged three passband SIW balanced bandpass filter comprising:

The first metal layer is provided with a differential input port and a differential output port for realizing energy transmission;

The first dielectric substrate is arranged on the lower surface of the first metal layer;

the second metal layer is arranged on the lower surface of the first dielectric substrate;

The second dielectric substrate is arranged on the lower surface of the second metal layer;

the third metal layer is arranged on the lower surface of the second dielectric substrate;

The third dielectric substrate is arranged on the lower surface of the third metal layer;

the fourth metal layer is arranged on the lower surface of the third dielectric substrate;

The first metal layer, the first dielectric substrate, the second metal layer, the second dielectric substrate, the third metal layer, the third dielectric substrate and the fourth metal layer are stacked in a multi-layer mode at the center;

The second metal layer is provided with two first energy coupling holes, the two first energy coupling holes are symmetrical about an axis A1A2, the two first energy coupling holes are arranged on an axis B1B2, and the first energy coupling holes realize coupling transmission of energy from the first medium substrate to the second medium substrate; the third metal layer is provided with two second energy coupling holes which are symmetrical about the axis A1A2, the two second energy coupling holes are arranged on the axis B1B2, the second energy coupling holes realize the coupling transmission of energy from the second medium substrate to the third medium substrate,

Wherein the first energy coupling hole and the second energy coupling hole are both rectangular and positioned at the strongest magnetic field of the resonant mode to realize magnetic coupling,

Wherein, the first medium substrate is provided with four first perturbation metal through holes on the axis A1A2, the four first perturbation metal through holes are respectively arranged at two sides of the axis B1B2 and are symmetrical relative to the axis B1B2, the diameters of the four first perturbation metal through holes are 0.6mm, the first medium substrate is provided with a plurality of first metal through holes, the first metal through holes are arranged around the first medium substrate and are in rectangular arrangement,

Wherein six second perturbation metal through holes are arranged on the axis A1A2 of the second medium substrate, three second perturbation metal through holes are respectively arranged on two sides of the axis B1B2 and are symmetrical relative to the axis B1B2, the diameters of the six second perturbation metal through holes are 1.2mm, a plurality of second metal through holes are arranged on the second medium substrate, the second metal through holes are arranged around the second medium substrate and are in rectangular arrangement,

Wherein six third perturbation metal through holes are arranged on the axis A1A2 of the third dielectric substrate, three of the six third perturbation metal through holes are respectively arranged on two sides of the axis B1B2 and are symmetrical relative to the axis B1B2, the diameter of each of the six third perturbation metal through holes is 1.2mm, a plurality of third metal through holes are arranged on the third dielectric substrate, the third metal through holes are arranged around the third dielectric substrate and are in rectangular arrangement,

The number of the differential input ports and the differential output ports is two, the differential input ports and the differential output ports are respectively arranged on two sides of the axis A1A2 on the first metal layer, two differential input ports are arranged on one side, two differential output ports are arranged on one side, and meanwhile, the differential input ports and the differential output ports are symmetrical relative to the axis B1B2 of the first metal layer.

2. The multilayer packaged three passband SIW balanced bandpass filter of claim 1, wherein the first energy coupling hole has a hole length of 3.9mm and a hole width of 0.8mm; the second energy coupling hole has a hole length of 3.2mm and a hole width of 0.8mm.

3. The multilayer packaged three passband SIW balanced bandpass filter of claim 1, wherein the differential input port is comprised of a differential input feed line for transmitting energy from the differential input port to the SIW cavity and a coplanar waveguide structure for connecting the differential feed line and the SIW cavity to obtain a match of the two; the widths of the differential input feeder line and the differential output feeder line are equal, and are 1.55mm.

4. The multilayer packaged three-passband SIW balanced bandpass filter of claim 1, wherein the materials of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are Rogers 5880 substrates; the relative dielectric constants of the first dielectric substrate, the second dielectric substrate and the third dielectric substrate are 2.2, and the thicknesses of the first dielectric substrate, the second dielectric substrate and the third dielectric substrate are 0.508mm.