Balun based on microstrip line

Abstract

The utility model provides a microstrip line-based balun, which relates to the field of microstrip line balun, and comprises a top copper-plated layer, the bottom of the top copper-plated layer is fixedly connected with a dielectric plate layer, and the bottom of the dielectric plate layer is fixedly connected with a bottom copper-plated layer; under the condition that excellent performance is achieved, the circuit structure is simple, batch manufacturing can be achieved through the simple printed circuit board technology, the machining precision can be well controlled, the rate of finished products is high, and the low cost is guaranteed. The length of the microstrip line perpendicular to the straight-through port is about half of the wavelength of the center frequency, a balun can be obtained, a grounded rectangular microstrip metal sheet is located in the middle of the square-shaped microstrip coupling structure, a certain signal isolation effect is achieved, spatial signal coupling is not intense, and the S parameter of the balun is optimized.

Description

Technical Field

[0001] The utility model belongs to the field of microstrip baluns, and specifically relates to a balun based on microstrip lines. Background Art

[0002] Microwave and millimeter-wave baluns are very important components in modern radar and communication systems. Their function is to separate a radio frequency signal into two signals with a phase difference of 180 degrees or to combine two signals with a phase difference of 180 degrees into one, playing a role of signal conversion in the circuit. The quality of their performance directly determines the quality of the performance of radar and communication systems.

[0003] There are many differential structures in modern circuits or devices. For example, balanced mixers, combined power synthesizers, differential filters, differential antennas, etc. all need to use baluns for signal type conversion. Especially, the outputs and inputs of many T / R chips are differential ports. Using baluns can greatly reduce the size, power consumption and cost of the circuit. Especially in MIMO and phased array circuit modules, however, the existing baluns have a relatively complex circuit structure and high difficulty in mass production when achieving excellent performance, resulting in a low qualified rate of finished products.

[0004] In summary, the utility model provides a balun based on microstrip lines to solve the above problems. Summary of the Utility Model

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] A balun based on microstrip lines includes a top copper plating layer. The bottom of the top copper plating layer is fixedly connected with a dielectric plate layer, and the bottom of the dielectric plate layer is fixedly connected with a bottom copper plating layer.

[0007] The top copper plating layer includes a signal port, a microstrip coupling structure and a grounded rectangular microstrip metal sheet. The signal port is arranged at the front end of the top of the top copper plating layer, and the microstrip coupling structure is arranged at the rear end of the top of the top copper plating layer. The number of the signal port, the microstrip coupling structure and the grounded rectangular microstrip metal sheet is three each. The three grounded rectangular microstrip metal sheets are respectively arranged between two adjacent microstrip coupling structures.

[0008] In the microstrip coupling structure, the length along the through-port microstrip line is one quarter of the center frequency wavelength, and the length perpendicular to the through-port microstrip line is one half of the center frequency wavelength.

[0009] Further, in the utility model, the thickness of both the top copper plating layer and the bottom copper plating layer is 0.035 mm.

[0010] Further, in the present utility model, the dielectric board layer is a Rogers 5880 substrate with a thickness of 0.127 mm.

[0011] Beneficial effects: The present utility model has the following beneficial effects:

[0012] When the present utility model achieves excellent performance, the circuit structure is simple, and it can be mass-produced by a simple printed circuit board process. Moreover, the processing accuracy can be well controlled, the yield is high, ensuring the advantage of low cost. This balun can achieve a very small size: 10.44 mm * 7.28 mm, excellent bandwidth of 15 - 17 GHz, small insertion loss of 0.35 dB, excellent return loss characteristics of -18.9 dB. In the "mouth"-shaped microstrip coupling structure, the length of the microstrip line along the through port is approximately one-quarter of the wavelength at the center frequency, and the length of the microstrip line perpendicular to the through port is approximately one-half of the wavelength at the center frequency. In this way, the wavelength of the coupling port is one-half of the wavelength at the center frequency more than that of the through port, which means that the phase difference between the coupling port and the through port is 180 degrees. In this way, a balun can be obtained. The grounded rectangular microstrip metal sheet is located in the middle of the "mouth"-shaped microstrip coupling structure, playing a certain role in signal isolation, making the spatial signal coupling not so strong and optimizing the S parameters of the balun. Description of the drawings

[0013] Figure 1 is the front view structural schematic diagram of the present utility model;

[0014] Figure 2 is the size diagram of the 3rd-order 15 - 17 GHz balun based on microstrip lines;

[0015] Figure 3 is the signal analysis diagram of the 3rd-order 15 - 17 GHz balun based on microstrip lines;

[0016] Figure 4 is the S parameter of the 3rd-order 15 - 17 GHz balun based on microstrip lines;

[0017] Figure 5 is the amplitude imbalance of the 3rd-order 15 - 17 GHz balun based on microstrip lines;

[0018] Figure 6 is the phase imbalance of the 3rd-order 15 - 17 GHz balun based on microstrip lines.

[0019] In the figure:

[0020] 1. Top copper plating layer; 2. Dielectric board layer; 3. Bottom copper plating layer; 4. Signal port; 5. Microstrip coupling structure; 6. Grounded rectangular microstrip metal sheet. Specific implementation manners

[0021] To better understand the technical content of the present utility model, specific embodiments are hereby presented and described in conjunction with the accompanying drawings. In this disclosure, various aspects of the present utility model are described with reference to the drawings, in which many illustrative embodiments are shown. The embodiments of this disclosure do not necessarily define all aspects of the present utility model. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed in the present utility model are not limited to any implementation manner. Additionally, some aspects disclosed in the present utility model can be used alone, or in any suitable combination with other aspects disclosed in the present utility model.

[0022] Embodiment 1

[0023] As Figures 1-6 shown, this is the first embodiment of the present utility model. This embodiment provides a balun based on a microstrip line, which includes a top copper plating layer 1. The bottom of the top copper plating layer 1 is fixedly connected to a dielectric layer 2, and the bottom of the dielectric layer 2 is fixedly connected to a bottom copper plating layer 3.

[0024] The top copper plating layer 1 includes a signal port 4, a microstrip coupling structure 5, and a grounded rectangular microstrip metal sheet 6. The signal port 4 is arranged at the front end of the top of the top copper plating layer 1, and the microstrip coupling structure 5 is arranged at the rear end of the top of the top copper plating layer 1. The number of the signal port 4, the microstrip coupling structure 5, and the grounded rectangular microstrip metal sheet 6 is three each. The three grounded rectangular microstrip metal sheets 6 are respectively arranged between two adjacent microstrip coupling structures 5.

[0025] In the microstrip coupling structure 5, the length along the through-port microstrip line is one-quarter of the center frequency wavelength, and the length perpendicular to the through-port microstrip line is one-half of the center frequency wavelength.

[0026] As Figures 1-6 shown, when this balun achieves excellent performance, the circuit structure is simple, it can be mass-produced using a simple printed circuit board process, and the processing accuracy can be well controlled, with a high yield rate, ensuring the advantage of low cost. This balun can achieve a very small size: 10.44mm * 7.28mm, an excellent bandwidth of 15 - 17 GHz, a small insertion loss of 0.35 dB, an excellent return loss of -18.9 dB, and the signal port 4 is a 50-ohm signal input / output port.

[0027] As Figure 2 shown is the size diagram of a 3rd-order 15 - 17 GHz balun based on a microstrip line, which details the sizes of each structure of the balun. The size of the balun is: 10.44mm * 7.28mm.

[0028] Figure 3Signal analysis diagram of a 3rd-order 15 - 17 GHz balun based on a microstrip line. The Z1 signal line is a quarter-wavelength and transmits to the through port; the Z2 and Z3 signal lines are 3 / 4 wavelengths and transmit to the coupled port. In this way, the wavelength at the coupled port is half a wavelength more than that at the through port, which means the phase difference between the coupled port and the through port is 180 degrees, and thus a balun can be obtained.

[0029] Figure 4 S parameters of a 3rd-order 15 - 17 GHz balun based on a microstrip line. The insertion loss is about 0.34 dB and the return loss is -18.9 dB.

[0030] Figure 5 Amplitude imbalance of a 3rd-order 15 - 17 GHz balun based on a microstrip line is basically about 0, and the balance is very good.

[0031] Figure 6 Phase imbalance of a 3rd-order 15 - 17 GHz balun based on a microstrip line is basically about 180, and the balance is very good.

[0032] Embodiment 2

[0033] Refer to Figures 1-6 , which is the second embodiment of the present utility model. This embodiment is based on the previous embodiment.

[0034] In this embodiment, the thickness of both the top copper plating layer 1 and the bottom copper plating layer 3 is 0.035 mm.

[0035] The dielectric plate layer 2 is a Rogers 5880 substrate with a thickness of 0.127 mm.

[0036] As Figures 1-6 shown, in the "mouth"-shaped microstrip coupling structure 5, the length of the microstrip line along the through port is about a quarter of the center frequency wavelength, and the length of the microstrip line perpendicular to the through port is about half of the center frequency wavelength. In this way, the wavelength at the coupled port is half of the center frequency wavelength more than that at the through port, which means the phase difference between the coupled port and the through port is 180 degrees, and thus a balun can be obtained. The grounded rectangular microstrip metal sheet 6 is located in the middle of the "mouth"-shaped microstrip coupling structure 5, playing a certain signal isolation role, making the spatial signal coupling not so strong and optimizing the S parameters of the balun.

[0037] In use, while achieving excellent performance, the balun has a simple circuit structure, can be mass-produced using a simple printed circuit board process, and the processing accuracy can be well controlled, with a high yield rate, ensuring the advantage of low cost. The balun can achieve a very small size: 10.44mm * 7.28mm, excellent bandwidth of 15 - 17GHz, small insertion loss of 0.35dB, excellent return loss of -18.9dB. In the "mouth"-shaped microstrip coupling structure 5, the length of the microstrip line along the through port is approximately one-quarter of the wavelength at the center frequency, and the length of the microstrip line perpendicular to the through port is approximately one-half of the wavelength at the center frequency. Thus, the wavelength of the coupling port is one-half of the wavelength at the center frequency more than that of the through port, which means the phase difference between the coupling port and the through port is 180 degrees, and thus a balun can be obtained. The grounded rectangular microstrip metal sheet 6 is located in the middle of the "mouth"-shaped microstrip coupling structure 5, playing a certain signal isolation role, making the spatial signal coupling less intense and optimizing the S parameters of the balun.

[0038] The standard parts used in this application document can all be purchased from the market, and can also be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment all adopt conventional models in the prior art. The control method is automatically controlled by a controller, and the control circuit of the controller can be realized by simple programming by those skilled in the art, which belongs to the common general knowledge in this field. And this application document is mainly used to protect the mechanical device, so the control method and circuit connection will not be explained in detail in this application document.

[0039] Although the present utility model has been disclosed above with a preferred embodiment, it is not intended to limit the present utility model. Those with ordinary knowledge in the technical field to which the present utility model pertains can make various modifications and refinements without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to that defined by the claims.

Claims

1. A balun based on a microstrip line, comprising a top copper plating layer (1), characterized in that: The bottom of the top copper plating layer (1) is fixedly connected to a dielectric plate layer (2), and the bottom of the dielectric plate layer (2) is fixedly connected to a bottom copper plating layer (3). The top copper plating layer (1) includes signal ports (4), microstrip coupling structures (5), and ground rectangular microstrip metal sheets (6). The signal ports (4) are arranged at the front end of the top of the top copper plating layer (1), and the microstrip coupling structures (5) are arranged at the rear end of the top of the top copper plating layer (1). The number of the signal ports (4), microstrip coupling structures (5), and ground rectangular microstrip metal sheets (6) is three each. The three ground rectangular microstrip metal sheets (6) are respectively arranged between two adjacent microstrip coupling structures (5). In the microstrip coupling structure (5), the length along the through-port microstrip line is one quarter of the center frequency wavelength, and the length perpendicular to the through-port microstrip line is one half of the center frequency wavelength.

2. The balun based on a microstrip line according to claim 1, wherein: The thicknesses of both the top copper plating layer (1) and the bottom copper plating layer (3) are 0.035 mm.

3. The balun based on a microstrip line according to claim 1, characterized in that: The dielectric plate layer (2) is a Rogers 5880 substrate with a thickness of 0.127 mm.

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