阅读说明：本技术 一种接地共面波导-矩形波导滤波过渡结构 (Grounded coplanar waveguide-rectangular waveguide filtering transition structure ) 是由 喻忠军 袁斌 吴鹏 于 2021-09-10 设计创作，主要内容包括：一种接地共面波导-矩形波导滤波过渡结构,包括：基板(1),上下表面均镀有金属层；接地共面波导传输线(2),印制在基板上表面金属层(1-1)上,用于输入电磁波；宽带滤波过渡结构(3),刻蚀在基板下表面金属层(1-2)上,与矩形波导(5)连接,包括馈电枝节(3-1)、短路枝节(3-3)、耦合枝节(3-2)和谐振腔,用于电磁波的宽带传输和带外抑制性能；第一金属化过孔(4),贯穿基板(1),将接地共面波导传输线(2)的输出端与馈电枝节(3-1)相连。该过渡结构一方面可以通过将宽带滤波过渡结构(3)设于基板(1)底部接地,以避免较大的辐射损耗,另一方面可以通过多种谐振结构之间相互耦合(3),增大了电磁波传输的工作带宽,并具有良好的带外抑制滤波性能。(A grounded coplanar waveguide-rectangular waveguide filter transition structure, comprising: the upper surface and the lower surface of the substrate (1) are plated with metal layers; the grounding coplanar waveguide transmission line (2) is printed on the metal layer (1-1) on the upper surface of the substrate and is used for inputting electromagnetic waves; the broadband filtering transition structure (3) is etched on the metal layer (1-2) on the lower surface of the substrate, is connected with the rectangular waveguide (5), comprises a feed branch (3-1), a short-circuit branch (3-3), a coupling branch (3-2) and a resonant cavity, and is used for broadband transmission and out-of-band rejection performance of electromagnetic waves; and the first metalized through hole (4) penetrates through the substrate (1) and connects the output end of the grounding coplanar waveguide transmission line (2) with the feed branch (3-1). This transition structure can be through locating base plate (1) bottom ground connection with broadband filtering transition structure (3) on the one hand to avoid great radiation loss, on the other hand can be through intercoupling (3) between the multiple resonance structure, has increased the operating bandwidth of electromagnetic wave transmission, and has good outband rejection filtering performance.)

1. A grounded coplanar waveguide-rectangular waveguide filter transition structure, comprising:

the upper surface and the lower surface of the substrate (1) are plated with metal layers;

the grounding coplanar waveguide transmission line (2) is printed on the upper surface metal layer (1-1) of the substrate and is used for inputting electromagnetic waves;

the broadband filtering transition structure (3) is etched on the metal layer (1-2) on the lower surface of the substrate, is connected with the rectangular waveguide (5), comprises a feed branch (3-1), a short-circuit branch (3-3), a coupling branch (3-2) and a resonant cavity, and is used for broadband transmission and out-of-band rejection performance of the electromagnetic waves;

and the first metalized through hole (4) penetrates through the substrate (1) and connects the output end of the grounding coplanar waveguide transmission line (2) with the feed branch (3-1).

2. The grounded coplanar waveguide-rectangular waveguide filter transition structure of claim 1 further comprising:

and the second metalized through holes (6) penetrate through the substrate (1), are respectively arranged around the grounding coplanar waveguide transmission line (2) and the broadband filtering transition structure (3), and are used for preventing the electromagnetic waves from generating a parallel plate mode between the metal layers on the upper surface and the lower surface of the substrate (1).

3. The grounded coplanar waveguide-rectangular waveguide filtering transition structure of claim 1 wherein the resonant cavity comprises:

a U-shaped diaphragm (8) symmetrically arranged with respect to the grounded coplanar waveguide transmission line (2);

the short circuit metalized through hole (7) is formed in the U-shaped membrane (8) and is positioned on the central line of the U-shaped membrane (8);

the U-shaped diaphragm (8) and the short-circuit metallized via hole (7) have capacitive and inductive characteristics, respectively.

4. The transition structure of grounded coplanar waveguide-rectangular waveguide filtering according to claim 3, wherein the number of the feeding branches (3-1) is two, and the feeding branches are located in the concave area of the U-shaped diaphragm (8) and symmetrically arranged at two sides of the center line of the U-shaped diaphragm (8).

5. A grounded coplanar waveguide-rectangular waveguide filtering transition structure according to claim 4, wherein the coupling stub (3-2) is located between the feeding stub (3-1) and the U-shaped patch (8) for controlling the coupling level between the feeding stub (3-1) and the U-shaped patch (8).

6. The transition structure of grounded coplanar waveguide-rectangular waveguide filtering according to claim 3, wherein the number of the short-circuit branches (3-3) is two, and the two short-circuit branches are symmetrically arranged on two sides of the center line of the U-shaped diaphragm (8) and are respectively connected with one end of the U-shaped diaphragm (8).

7. The transition structure of grounded coplanar waveguide-rectangular waveguide filtering according to claim 1, wherein the junction of the feed stub (3-1) and the first metallized via (4) is provided with two matching semicircular structures (3-4) with different radii.

8. Grounded coplanar waveguide-rectangular waveguide filtering transition structure according to claim 3 characterized in that the transverse dimension of the U-shaped diaphragm (8) is the same as the cross-sectional broadside dimension of the rectangular waveguide (5).

9. Grounded coplanar waveguide-rectangular waveguide filter transition structure according to claim 8 characterized in that the rectangular waveguide (5) is connected perpendicularly to the broadband filter transition structure (3).

10. The grounded coplanar waveguide-rectangular waveguide filtering transition structure according to claim 2, wherein the pitch of the second metalized via (6) is larger than the diameter of the second metalized via (6).

Technical Field

The disclosure relates to the technical field of millimeter wave terahertz research, in particular to a grounded coplanar waveguide-rectangular waveguide filtering transition structure.

Background

With the development of terahertz technology in the field of wireless communication, monolithic integrated circuits, hybrid integrated circuits and integrated microsystems have wide application prospects in the fields of communication, radar and the like. The Grounded Coplanar Waveguide (abbreviated as GCPW) is a planar circuit transmission line with small dispersion and low loss, is very easy to realize the series connection and the parallel connection with passive and active devices, and can obviously improve the circuit density and the transmission efficiency; rectangular Waveguide (abbreviated as RWG) has the characteristics of simple structure, stable mechanical performance, low loss and the like, and becomes the most common packaging interface of terahertz devices or test systems. In the millimeter wave terahertz system, the transmission efficiency of the whole system is determined by the interconnection conversion between the two low-loss transmission lines, so that the realization of a high-performance transition structure between the GCPW and the RWG becomes a key technical research of the millimeter wave terahertz system. In addition, the filter is also an indispensable important device in the front end of the communication system, and the integration of the filtering function in the transition structure can omit the use of an additional filter structure, thereby further reducing the loss and complexity of the system.

The transition from the conventional GCPW to the RWG is realized by probe excitation, ridge waveguide transition, gap coupling and the like. In a terahertz wave band, a waveguide probe has the problems of fragility and high difficulty in processing micro-assembly, and needs a short-circuit back cavity with a quarter wavelength. The gradual change metal ridge needs to be processed inside the waveguide in a ridge waveguide transition mode, so that the processing difficulty is increased, and the metal ridge needs to be in good electric contact with a planar circuit, so that the assembly difficulty is increased. The slot coupling transition method can provide a simple micro-assembly process, but the resonant mode of the slot coupling transition method brings certain radiation loss, so that the insertion loss of the structure is large. Therefore, a transition structure which reduces the difficulty of micro-assembly and has low loss needs to be developed to realize high-efficiency interconnection of the terahertz GCPW planar circuit and the waveguide device.

Disclosure of Invention

In view of the above problems, the invention provides a grounded coplanar waveguide-rectangular waveguide filtering transition structure to at least partially solve the problems of large transmission loss and high processing and assembling difficulty of the conventional GCPW-RWG transition structure in the millimeter wave terahertz frequency band.

One aspect of the present disclosure provides a grounded coplanar waveguide-rectangular waveguide filtering transition structure, including: the upper surface and the lower surface of the substrate are plated with metal layers; the grounding coplanar waveguide transmission line is printed on the metal layer on the upper surface of the substrate and is used for inputting electromagnetic waves; the broadband filtering transition structure is etched on the metal layer on the lower surface of the substrate, is connected with the rectangular waveguide, comprises a feed branch, a short-circuit branch, a coupling branch and a resonant cavity, and is used for broadband transmission and out-of-band rejection performance of the electromagnetic waves; and the first metalized through hole penetrates through the substrate and connects the output end of the grounding coplanar waveguide transmission line with the feed branch.

According to an embodiment of the present disclosure, the transition structure further comprises: and the second metalized through holes penetrate through the substrate and are respectively arranged around the grounding coplanar waveguide transmission line and the broadband filtering transition structure, and are used for preventing the electromagnetic waves from generating a parallel plate mode between the metal layers on the upper surface and the lower surface of the substrate.

According to an embodiment of the present disclosure, the resonant cavity includes: the U-shaped diaphragms are symmetrically arranged relative to the grounded coplanar waveguide transmission line; the short circuit metalized through hole is arranged on the U-shaped diaphragm and is positioned on the central line of the U-shaped diaphragm; the U-shaped diaphragm and the short circuit metalized through hole have capacitance and inductance characteristics to form the resonant cavity.

According to the embodiment of the disclosure, the number of the feeding branches is two, the feeding branches are located in the concave area in the U-shaped membrane and symmetrically arranged on two sides of the center line of the U-shaped membrane.

According to the embodiment of the disclosure, the coupling branch is located between the feeding branch and the U-shaped membrane, and is used for controlling the coupling level between the feeding branch and the U-shaped membrane.

According to the embodiment of the disclosure, the number of the short circuit branches is two, the short circuit branches are symmetrically arranged on two sides of the center line of the U-shaped membrane and are respectively connected with one end of the U-shaped membrane.

According to the embodiment of the disclosure, two matching semicircular structures with different radiuses are arranged at the joint of the feed branch and the first metalized through hole.

According to an embodiment of the present disclosure, a lateral dimension of the U-shaped iris is the same as a cross-sectional broadside dimension of the rectangular waveguide.

According to an embodiment of the present disclosure, the rectangular waveguide is perpendicularly connected to the broadband filtering transition structure.

According to an embodiment of the present disclosure, a pitch of the second metalized via is larger than a diameter of the second metalized via.

The at least one technical scheme adopted in the embodiment of the disclosure can achieve the following beneficial effects:

the utility model provides a GCPW-RWG filtering transition structure, this structure not only has broadband low-loss transition performance, still possesses good outband rejection filtering characteristic simultaneously, has realized terahertz frequency channel broadband transition and filtering and has fused the technique, and the assembly process requirement is also low.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

fig. 1 schematically illustrates a structural diagram of a transition structure of a grounded coplanar waveguide-rectangular waveguide filter provided by an embodiment of the present disclosure;

fig. 2 schematically illustrates a schematic diagram of a substrate upper surface of a grounded coplanar waveguide-rectangular waveguide filter transition structure provided by an embodiment of the present disclosure;

fig. 3 schematically illustrates a schematic diagram of a lower surface of a substrate of a grounded coplanar waveguide-rectangular waveguide filter transition structure provided by an embodiment of the present disclosure;

fig. 4 schematically illustrates a simulated S-parameter diagram of a transition structure between a grounded coplanar waveguide and a rectangular waveguide filter provided by an embodiment of the present disclosure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.

Fig. 1 schematically illustrates a structural diagram of a transition structure of a grounded coplanar waveguide-rectangular waveguide filter provided by an embodiment of the present disclosure.

As shown in fig. 1, an embodiment of the present disclosure provides a ground coplanar waveguide-rectangular waveguide filtering transition structure, including: the broadband waveguide filter comprises a substrate 1, a grounded coplanar waveguide transmission line 2, a broadband filtering transition structure 3 and a first metalized through hole 4.

Wherein, the upper and lower surfaces of the substrate are plated with metal layers; the grounding coplanar waveguide transmission line 2 is printed on the metal layer 1-1 on the upper surface of the substrate and is used for inputting electromagnetic waves; the broadband filtering transition structure 3 is etched on the metal layer 1-2 on the lower surface of the substrate, is connected with the rectangular waveguide 5, comprises a feed branch 3-1, a short-circuit branch 3-3, a coupling branch 3-2 and a resonant cavity, and is used for the high bandwidth and out-of-band rejection performance of the electromagnetic waves; a first metallized via hole 4 penetrates the substrate 1 to connect the output end of the grounded coplanar waveguide transmission line 2 with the feed stub 3-1.

In the embodiment of the present disclosure, on one hand, the broadband filtering transition structure 3 is disposed on the ground layer at the bottom of the substrate 1, so that a large radiation loss can be avoided; on the other hand, the broadband filtering transition structure 3 comprises a plurality of branch resonant structures, is used for improving the bandwidth and out-of-band rejection performance, and has good filtering characteristics.

Fig. 2 schematically illustrates a schematic diagram of a substrate upper surface of a grounded coplanar waveguide-rectangular waveguide filter transition structure provided by an embodiment of the present disclosure.

As shown in fig. 2, the grounded coplanar waveguide transmission line 2 is printed on the metal layer 1-1 on the upper surface of the substrate, and the end of the grounded coplanar waveguide transmission line 2 is provided with a first metalized via 4, and referring to fig. 1, the first metalized via 4 penetrates through the substrate 1 and is connected to the broadband filtering transition structure 3 on the surface of the substrate. With reference to fig. 1 and 2, a plurality of second metallized via holes 6 are further disposed around the grounded coplanar waveguide transmission line 2 and the broadband filtering transition structure 3, and penetrate through the substrate 1, so as to prevent the electromagnetic waves from generating a parallel plate mode between the metal layers on the upper and lower surfaces of the substrate 1.

Preferably, the distance between the second metalized vias 6 is greater than the diameter of the second metalized vias 6, so as to reduce the processing difficulty and improve the manufacturing and processing yield.

Fig. 3 schematically illustrates a schematic diagram of a lower surface of a substrate of a transition structure of a grounded coplanar waveguide-rectangular waveguide filter provided by an embodiment of the present disclosure.

As shown in FIG. 3, the broadband filtering transition structure 3 is etched on the metal layer 1-2 on the lower surface of the substrate, and comprises a feed branch 3-1, a short-circuit branch 3-3, a coupling branch 3-2 and a resonant cavity. In addition to the two resonances from the feed stub 3-1 and the resonant cavity, the other resonance is from the coupling stub 3-2, the coupling stub width controlling the level of coupling between the feed stub 3-1 and the resonant cavity. In addition, short-circuited branch 3-3 generates a transmission zero. The broadband filtering transition structure 3 may be fabricated by a quartz thin film circuit process.

Specifically, the resonant cavity includes: a U-shaped membrane 8 and a short-circuited metallized via 7. The U-shaped diaphragms 8 are symmetrically arranged relative to the grounded coplanar waveguide transmission line 2; the short circuit metallized via hole 7 is arranged on the U-shaped diaphragm 8 and is positioned on a central line of the U-shaped diaphragm 8 (the central line of the U-shaped diaphragm 8 is parallel to the grounded coplanar waveguide transmission line 2). The U-shaped diaphragm 8 and the short-circuit metallized via hole 7 have capacitance and inductance characteristics, respectively, thereby forming a resonant cavity. The number of the feed branches 3-1 is two, the feed branches are positioned in a concave area in the U-shaped membrane 8 and are symmetrically arranged on two sides of the center line of the U-shaped membrane 8. The coupling branch 3-2 is located between the feeding branch 3-1 and the U-shaped diaphragm 8, and is used for controlling the coupling level between the feeding branch 3-1 and the U-shaped diaphragm 8. The number of the short circuit branches 3-3 is two, the short circuit branches are symmetrically arranged on two sides of the center line of the U-shaped membrane 8 and are respectively connected with one end of the U-shaped membrane 8.

Particularly, the first metalized via hole 4 is arranged in the middle of a concave area in the U-shaped membrane 8 and is connected with the feed branch 3-1, and two matching semicircular structures 3-4 with different radiuses are arranged at the joint of the feed branch 3-1 and the first metalized via hole 4 so as to improve impedance matching.

As shown in fig. 3, the U-shaped diaphragm 8 is actually a semi-enclosed rectangle, and the lateral dimension is the same as the dimension of the wide side of the cross section of the rectangular waveguide 5. The rectangular waveguide 5 is vertically connected with the broadband filtering transition structure 3, and when the rectangular waveguide 5 is connected with the broadband filtering transition structure, the rectangular waveguide 5 is aligned with the U-shaped diaphragm 8.

Fig. 4 schematically illustrates a simulated S-parameter diagram of a transition structure between a grounded coplanar waveguide and a rectangular waveguide filter provided by an embodiment of the present disclosure.

As shown in fig. 4, simulation results show that the grounded coplanar waveguide-rectangular waveguide transition structure of the present disclosure has a return loss S11 better than 15dB, an insertion loss S21 lower than 0.4dB, an out-of-band rejection level exceeding 15dB on a stop band, and a rejection level of 40dB at a specific frequency point in a frequency range from 0.182THz to 0.227THz (22%), and both S11 and S21 parameters of the structure have good performance and achieve design targets.

In conclusion, the disclosure provides a transition structure of a grounded coplanar waveguide and a rectangular waveguide, the new structure not only has a broadband low-loss transition performance, but also has a good out-of-band rejection filter characteristic, a terahertz frequency band broadband transition and filter fusion technology can be realized, and the assembly process requirement is low. The filtering transition scheme proposed by the present disclosure may be applicable to high-efficiency, high-integration filtering interconnects in monolithic integrated circuits, waveguides, and antenna feed applications.

Those skilled in the art will appreciate that various combinations and/or combinations of features recited in the various embodiments and/or claims of the present disclosure can be made, even if such combinations or combinations are not expressly recited in the present disclosure. In particular, various combinations and/or combinations of the features recited in the various embodiments and/or claims of the present disclosure may be made without departing from the spirit or teaching of the present disclosure. All such combinations and/or associations are within the scope of the present disclosure.

While the disclosure has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Accordingly, the scope of the present disclosure should not be limited to the above-described embodiments, but should be defined not only by the appended claims, but also by equivalents thereof.