Miniaturized broadband terahertz mixer

Abstract

The utility model relates to a miniaturized broadband terahertz mixer, which comprises a quartz substrate, a substrate circuit arranged on the quartz substrate, a radio frequency waveguide connected with the left side of the substrate circuit, a local oscillator waveguide connected with the middle part of the substrate circuit, and an intermediate frequency output end connected with the right side of the substrate circuit, the local oscillator low-pass filter sequentially comprises a plurality of first micro-strip parts distributed in the vertical direction from left to right, and the first micro-strip parts, the second micro-strip parts and the third micro-strip parts form an I-shaped structure. According to the utility model, the width and length of the microstrip substrate are reduced, the processing difficulty of the microstrip is reduced, the assembling difficulty is reduced, and the final volume of the mixer is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of millimeter-wave communication devices and their accessories, and in particular to a miniaturized broadband terahertz mixer. Background Art

[0002] Millimeter-wave and terahertz transceiver front-ends are widely used in almost all millimeter-wave and terahertz application systems such as communication and radar to solve the problem of signal frequency conversion, and are the core part of the entire system. It mainly consists of key devices such as mixers, filters, and amplifiers.

[0003] After a large amount of retrieval, it is found that the Chinese patent publication number is CN213186048U, which discloses a W-band sub-harmonic mixer, including a radio frequency waveguide, a microstrip transmission cavity connected to the radio frequency waveguide, a local oscillator waveguide connected to the microstrip transmission cavity, and a mixing circuit structure is arranged in the microstrip transmission cavity; the mixing circuit structure includes a radio frequency probe, a local oscillator low-pass filter, a local oscillator probe, and an intermediate frequency low-pass filter connected in series by microstrip lines in sequence, and a Schottky diode mounted forward on the microstrip line; the radio frequency probe faces the radio frequency waveguide, and the local oscillator probe faces the local oscillator waveguide. This sub-harmonic mixer has a planar circuit, a simple structure, is easy to assemble, and has low conversion loss, wide intermediate frequency bandwidth, and high isolation between the radio frequency and the local oscillator.

[0004] To sum up, the design of the intermediate frequency low-pass filter, the local oscillator low-pass filter, the radio frequency local oscillator probe, and the matching network in the mixer results in a relatively long length of the microstrip of the final mixer. The microstrip of the terahertz mixer uses quartz with a thickness of 50um as the dielectric substrate, which is thin and brittle, greatly increasing the processing difficulty and cost. To reduce the volume of the mixer and the processing difficulty of the microstrip while ensuring good performance of the mixer, a microstrip with a small volume needs to be designed.

[0005] In view of the above defects, the designer actively conducts research and innovation in order to create a miniaturized broadband terahertz mixer, making it more valuable in the industry. Summary of the Utility Model

[0006] To solve any of the above technical problems, the purpose of the utility model is to provide a miniaturized broadband terahertz mixer.

[0007] To achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A miniaturized broadband terahertz mixer comprises a quartz substrate, on which a substrate circuit is arranged, a radio frequency waveguide connected to the left side of the substrate circuit, a local oscillator waveguide connected to the middle of the substrate circuit, and an intermediate frequency output terminal connected to the right side of the substrate circuit, wherein the substrate circuit comprises a radio frequency probe, a local oscillator low-pass filter, a local oscillator probe and an intermediate frequency low-pass filter connected in sequence from left to right by a plurality of microstrip lines, the radio frequency probe is opposite to the radio frequency waveguide, and the local oscillator probe is opposite to the local oscillator waveguide;

[0009] The local oscillator low-pass filter includes, from left to right, a plurality of first microstrip portions distributed along the vertical direction, a second microstrip portion distributed along the horizontal direction is arranged on the top of the first microstrip portion, and a third microstrip portion distributed along the horizontal direction is arranged at the bottom of the first microstrip portion, and the first microstrip portion, the second microstrip portion and the third microstrip portion form an I-shaped structure.

[0010] As a further improvement of the present invention, the radio frequency probe is a rectangular structure.

[0011] As a further improvement of the present invention, the radio frequency probe is a T-shaped structure.

[0012] As a further improvement of the utility model, the intermediate frequency low-pass filter includes, from left to right, a plurality of fourth microstrip portions distributed along the vertical direction, a fifth microstrip portion distributed along the horizontal direction is arranged on the top of the fourth microstrip portion, and a sixth microstrip portion distributed along the horizontal direction is arranged at the bottom of the fourth microstrip portion, and the fourth microstrip portion, the fifth microstrip portion and the sixth microstrip portion form an I-shaped structure.

[0013] As a further improvement of the utility model, the intermediate frequency low-pass filter includes, from left to right, a plurality of fourth microstrip portions distributed along the vertical direction, a fifth microstrip portion distributed along the horizontal direction is arranged on the top of the fourth microstrip portion, and a sixth microstrip portion distributed along the horizontal direction is arranged at the bottom of the fourth microstrip portion, and the fourth microstrip portion, the fifth microstrip portion and the sixth microstrip portion constitute a rectangular structure opening toward the left or right side.

[0014] As a further improvement of the utility model, a Schottky diode is installed in the forward direction on the microstrip line of the substrate circuit, and the Schottky diode is located at one end of the radio frequency probe.

[0015] As a further improvement of the present invention, the thickness of the quartz substrate is 127 um.

[0016] As a further improvement of the utility model, both the local oscillator low-pass filter and the intermediate frequency low-pass filter adopt high-low impedance microstrip.

[0017] By means of the above solution, the utility model has at least the following advantages:

[0018] The present utility model reduces the width and length of the microstrip substrate, reduces the processing difficulty of the microstrip, reduces the assembly difficulty, and reduces the volume of the final mixer.

[0019] The radio frequency probe of the present utility model adopts a T-shaped structure to achieve better return loss, thereby reducing the frequency conversion loss.

[0020] The above description is only an overview of the technical solution of the present utility model. In order to understand the technical means of the present utility model more clearly and implement it according to the content of the specification, the following takes the preferred embodiments of the present utility model and combines the accompanying drawings to describe in detail as follows. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0022] Figure 1 is a schematic structural diagram of the first embodiment of the present utility model;

[0023] Figure 2 is a schematic structural diagram of the second embodiment of the present utility model;

[0024] Figure 3 is a simulation schematic diagram of the first embodiment of the present utility model;

[0025] Figure 4 is a simulation schematic diagram of the second embodiment of the present utility model.

[0026] Among them, the meanings of the reference numerals in the drawings are as follows.

[0027] Radio frequency waveguide 1, local oscillator waveguide 2, quartz substrate 3, radio frequency probe 4, Schottky diode 5, local oscillator low-pass filter 6, local oscillator probe 7, intermediate frequency low-pass filter 8, intermediate frequency output terminal 9. Detailed Embodiments

[0028] The following combines the accompanying drawings and embodiments to further describe in detail the specific embodiments of the present utility model. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.

[0029] To enable those skilled in the art to better understand the solution of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. The components of the embodiments of the present utility model described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present utility model provided in the drawings is not intended to limit the scope of the present utility model to be protected, but only represents the selected embodiments of the present utility model. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative efforts belong to the scope of protection of the present utility model.

[0030] Embodiment

[0031] As Figures 1 to 4 shown,

[0032] The present utility model realizes the design of a 360 - 440 GHz terahertz sub - harmonic mixer through a special radio frequency probe structure.

[0033] A miniaturized broadband terahertz mixer includes a quartz substrate 3, on which a substrate circuit is provided, a radio frequency waveguide 1 connected to the left side of the substrate circuit, a local oscillator waveguide 2 connected to the middle of the substrate circuit, and an intermediate frequency output terminal 9 connected to the right side of the substrate circuit. The substrate circuit includes a radio frequency probe 4, a local oscillator low - pass filter 6, a local oscillator probe 7, and an intermediate frequency low - pass filter 8 connected in sequence from left to right by a plurality of microstrip lines. The radio frequency probe 4 faces the radio frequency waveguide 1, and the local oscillator probe 7 faces the local oscillator waveguide 2. A Schottky diode 5 is mounted forward on the microstrip line of the substrate circuit, and the Schottky diode 5 is located at one end of the radio frequency probe 4. The thickness of the quartz substrate 3 is 127 um. Both the local oscillator low - pass filter 6 and the intermediate frequency low - pass filter 8 adopt high - low impedance microstrip.

[0034] 1. The local oscillator low - pass filter 6 sequentially includes a plurality of first microstrip parts distributed along the vertical direction from left to right. A second microstrip part distributed along the horizontal direction is provided at the top of the first microstrip part, and a third microstrip part distributed along the horizontal direction is provided at the bottom of the first microstrip part. The first microstrip part, the second microstrip part, and the third microstrip part together form an I - shaped structure.

[0035] 2. The intermediate frequency low - pass filter 8 sequentially includes a plurality of fourth microstrip parts distributed along the vertical direction from left to right. A fifth microstrip part distributed along the horizontal direction is provided at the top of the fourth microstrip part, and a sixth microstrip part distributed along the horizontal direction is provided at the bottom of the fourth microstrip part. The fourth microstrip part, the fifth microstrip part, and the sixth microstrip part together form an I - shaped structure.

[0036] 3. The intermediate-frequency low-pass filter 8 successively includes a plurality of fourth microstrip parts distributed vertically from left to right. A fifth microstrip part distributed horizontally is provided at the top of the fourth microstrip part, and a sixth microstrip part distributed horizontally is provided at the bottom of the fourth microstrip part. The fourth microstrip part, the fifth microstrip part, and the sixth microstrip part together form a rectangular structure that opens to the left or right.

[0037] As Figure 1 , the radio frequency probe 4 is a rectangular structure.

[0038] As Figure 2 , the radio frequency probe 4 is a T-shaped structure. Compared with the radio frequency probe of the rectangular structure, the T-shaped structure of the radio frequency probe achieves better return loss, thereby reducing the conversion loss.

[0039] The original design mixer has a relatively large conversion loss. Without changing the length of the microstrip probe, by changing the shape of the probe, the return loss of the radio frequency port of the mixer is optimized, and the conversion loss of the mixer is reduced. To reduce the length and width of the microstrip substrate of the sub-harmonic mixer, a new microstrip design method is provided.

[0040] The present utility model is implemented by the following technical solutions: Both the sub-harmonic local oscillator low-pass filter and the intermediate-frequency low-pass filter adopt filters with an I-shaped structure that has good filtering effects. They have good filtering performance and short lengths, greatly reducing the length of the microstrip of the mixer. The radio frequency probe adopts a T-shaped structure to achieve better return loss, thereby reducing the conversion loss.

[0041] The advantages of the microstrip of the present utility model for the sub-harmonic mixer are: reducing the width and length of the microstrip substrate, reducing the processing difficulty of the microstrip, reducing the assembly difficulty, and reducing the volume of the final mixer.

[0042] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. They are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality" is two or more.

[0043] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood through specific circumstances.

[0044] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. It should be pointed out that for those of ordinary skill in the technical field, without departing from the technical principle of the present utility model, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present utility model.

Claims

1. A miniaturized broadband terahertz mixer, comprising a quartz substrate (3), on which a substrate circuit is arranged, a radio frequency waveguide (1) connected to the left side of the substrate circuit, a local oscillator waveguide (2) connected to the middle of the substrate circuit, and an intermediate frequency output end (9) connected to the right side of the substrate circuit, wherein the substrate circuit comprises a radio frequency probe (4), a local oscillator low-pass filter (6), a local oscillator probe (7), and an intermediate frequency low-pass filter (8) connected in sequence from left to right by a plurality of microstrip lines, wherein the radio frequency probe (4) is opposite to the radio frequency waveguide (1), and the local oscillator probe (7) is opposite to the local oscillator waveguide (2); Features: The local oscillator low-pass filter (6) comprises, from left to right, a plurality of first microstrip portions distributed along the vertical direction, a second microstrip portion distributed along the horizontal direction is arranged on the top of the first microstrip portion, and a third microstrip portion distributed along the horizontal direction is arranged on the bottom of the first microstrip portion, and the first microstrip portion, the second microstrip portion and the third microstrip portion form an I-shaped structure.

2. A miniaturized broadband terahertz mixer as claimed in claim 1, characterized in that: The radio frequency probe (4) is a rectangular structure.

3. A miniaturized broadband terahertz mixer as claimed in claim 1, characterized in that: The radio frequency probe (4) is of a T-shaped structure.

4. A miniaturized broadband terahertz mixer as claimed in claim 1, characterized in that: The intermediate frequency low-pass filter (8) comprises, from left to right, a plurality of fourth microstrip portions distributed along the vertical direction, a fifth microstrip portion distributed along the horizontal direction is arranged on the top of the fourth microstrip portion, and a sixth microstrip portion distributed along the horizontal direction is arranged at the bottom of the fourth microstrip portion, and the fourth microstrip portion, the fifth microstrip portion and the sixth microstrip portion form an I-shaped structure.

5. A miniaturized broadband terahertz mixer as claimed in claim 1, characterized in that: The intermediate frequency low-pass filter (8) comprises, from left to right, a plurality of fourth microstrip portions distributed along the vertical direction, a fifth microstrip portion distributed along the horizontal direction is arranged on the top of the fourth microstrip portion, and a sixth microstrip portion distributed along the horizontal direction is arranged at the bottom of the fourth microstrip portion, and the fourth microstrip portion, the fifth microstrip portion and the sixth microstrip portion together form a rectangular structure that is open to the left or right.

6. A miniaturized broadband terahertz mixer as claimed in claim 1, characterized in that: A Schottky diode (5) is mounted in the forward direction on the microstrip line of the substrate circuit, and the Schottky diode (5) is located at one end of the radio frequency probe (4).

7. A miniaturized broadband terahertz mixer as claimed in claim 1, characterized in that: The thickness of the quartz substrate (3) is 127 um.

8. The miniaturized broadband terahertz mixer according to claim 1, characterized in that: The local oscillator low-pass filter (6) and the intermediate frequency low-pass filter (8) both adopt high-low impedance microstrip.

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