LC duplexer

Abstract

The utility model discloses an LC duplexer, which comprises a shell and a circuit board arranged in the shell, a long hole is arranged in the middle of the circuit board, a partition plate is arranged in the shell, the partition plate corresponds to the long hole, and the partition plate penetrates through the long hole; the bottom of the circuit board is provided with a copper sheet, and the boundary of the long hole is not in contact with the copper sheet. The LC duplexer single-in and double-out duplexer network provided by the utility model has the advantages of high out-of-band rejection, low loss and wide working bandwidth, can have a wider working frequency band, and can effectively resist signal interference. The duplexer is wide in relative bandwidth, low in-band loss and small in size, better loss can be achieved under the condition that the small size requirement is met, and when a conventional LC filter and a duplexer can only achieve the frequency band of about 4G, the design of slotting in the shell is innovated, so that the frequency can be 6G.

Description

Technical Field

[0001] The utility model relates to the field of duplexers, in particular to an LC duplexer. Background Art

[0002] As the signal transmission distance requirements in current wireless communication technologies become increasingly higher and signal interference increases, the requirements for the squareness ratio and transmission rate of the filter are becoming increasingly higher.

[0003] LC filters are widely used in fields such as wireless communications and electronic countermeasures due to their simple structure, low equipment investment, high operational reliability, and low operating costs.

[0004] In conventional circuit design and practical applications, while maintaining a small size, conventional LC duplexers experience passband collapse at high cutoff frequencies around 4 GHz, resulting in high losses, poor suppression, a significant impact on the operating frequency band, and weak filtering capabilities. At high frequencies, the capacitor and inductor values ​​used in LC filters are small, making implementation difficult and requiring higher precision, increasing manufacturing complexity and cost. Utility Model Content

[0005] The present invention overcomes the shortcomings of the prior art LC duplexer, such as small inductance and low frequency, and provides an LC duplexer. To achieve the above-mentioned purpose, the present invention adopts the following technical solution: an LC duplexer, characterized by comprising: a housing, a circuit board disposed in the housing, a long hole disposed in the middle of the circuit board, a partition disposed in the housing, the partition corresponding to the long hole, and the partition passing through the long hole;

[0006] The bottom of the circuit board is divided into a first area and a second area. The first area is the area corresponding to the high-pass filter circuit. The second area is provided with copper foil, and the first area is not provided with copper foil.

[0007] In a preferred embodiment of the present invention, a circuit is welded on the circuit board, the circuit having one input end, two output ends, and a high-pass filter circuit and a low-pass filter circuit arranged between the input end and the output end.

[0008] In a preferred embodiment of the present invention, the two output ends are the output end of the high-pass filter circuit and the output end of the low-pass filter circuit.

[0009] In a preferred embodiment of the present invention, the long hole is provided between the high-pass filter circuit and the low-pass filter circuit.

[0010] In a preferred embodiment of the present invention, the bottom of the circuit board is divided into a first area and a second area, the first area is the area corresponding to the high-pass filter circuit, the second area is provided with copper foil, and the first area is not provided with copper foil.

[0011] In a preferred embodiment of the present invention, the high-pass filter circuit includes four combination circuits, each of which includes a first capacitor, an inductor, and a second capacitor. The first capacitors of the four combination circuits are connected in series in sequence, the input end of the inductor is connected to the input end of the first capacitor, the output end of the inductor is connected to the input end of the second capacitor, and the output end of the second capacitor is grounded.

[0012] In a preferred embodiment of the present invention, a coupling inductor L1 is provided between the low-pass filter circuit and the input end.

[0013] In a preferred embodiment of the present invention, the low-pass filter circuit includes an inductor L_11, an inductor L_12, an inductor L_13, an inductor L_14, and an inductor L_15 connected in series in sequence;

[0014] The output end of the inductor L_11 is connected to the input end of the capacitor C_15, and the output end of the capacitor C_15 is grounded;

[0015] The output end of the inductor L_12 is connected to the input end of the capacitor C_16, and the output end of the capacitor C_16 is grounded;

[0016] The output end of the inductor L_13 is connected to the input end of the capacitor C_17, and the output end of the capacitor C_17 is grounded;

[0017] The output end of the inductor L_14 is connected to the input end of the capacitor C_18, and the output end of the capacitor C_18 is grounded.

[0018] In a preferred embodiment of the present invention, the inductor L_12 is connected in parallel with the capacitor C_11; the inductor L_13 is connected in parallel with the capacitor C_12; and the inductor L_14 is connected in parallel with the capacitor C_13.

[0019] The present invention solves the defects in the background technology and has the following beneficial effects:

[0020] This utility model provides a single-input, dual-output LC duplexer network with high out-of-band rejection, low loss, and a wide operating bandwidth, enabling a wide operating frequency band and effectively resisting signal interference. This duplexer has a relatively wide bandwidth, low in-band loss, and a compact size, achieving improved loss while maintaining a compact footprint. While conventional LC filters and duplexers can only operate at frequencies around 4GHz, the innovative slotted design within the housing enables frequencies up to 6GHz. In practical applications, the issue of low inductance due to high frequencies is also addressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0022] Figure 1 Schematic diagram of an LC duplexer according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of a circuit board of an LC duplexer according to an embodiment of the present invention;

[0024] Figure 3 This is a circuit diagram of an LC duplexer according to one embodiment of the present invention;

[0025] Figure 4 This is a simulation diagram of an LC duplexer described in one embodiment of the present invention;

[0026] Figure 5 Schematic diagram of the simulation of the filter in the prior art.

[0027] The reference numerals are as follows:

[0028] 10 - housing; 101 - partition; 20 - circuit board; 201 - long hole; 202 - first area. DETAILED DESCRIPTION

[0029] In order to more clearly understand the above-mentioned purposes, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner. Therefore, they only show the structures related to the present invention. It should be noted that, unless there is a conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0030] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application. 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 number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0032] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0033] like Figure 1 As shown, an LC duplexer includes a housing 10, a circuit board 20 disposed within the housing 10, a slot 201 disposed in the center of the circuit board 20, and a partition 101 disposed within the housing 10. The partition 101 corresponds to the slot 201 and passes through the slot 201. This can reduce the ground capacitance generated by the pad itself, ensuring the operability of the inductor at high frequencies.

[0034] Reference Figure 2 As shown, copper foil is provided at the bottom of the circuit board 20. The bottom of the circuit board 20 is divided into a first area 202 and a second area. The first area 202 is the area corresponding to the high-pass filter circuit. The second area is provided with copper foil, and the first area 202 is not provided with copper foil.

[0035] Circuit board 20 is soldered with a circuit comprising one input, two outputs, and a high-pass filter circuit and a low-pass filter circuit disposed between the input and output terminals. Slotted hole 201 is disposed between the high-pass filter circuit and the low-pass filter circuit. The two output terminals are the output of the high-pass filter circuit and the output of the low-pass filter circuit.

[0036] Reference Figure 3 As shown, the high-pass filter circuit includes four combination circuits, wherein the combination circuit includes a first capacitor, an inductor and a second capacitor. The first capacitors of the four combination circuits are connected in series in sequence, the input end of the inductor is connected to the input end of the first capacitor, the output end of the inductor is connected to the input end of the second capacitor, and the output end of the second capacitor is grounded.

[0037] Specifically, the high-pass filter circuit includes capacitor C_h1, capacitor C_h2, inductor C_h3, capacitor C_h4, and capacitor C_h5 connected in series in sequence. The input end of capacitor C_h1 is the common input end of the duplexer, and the output end of capacitor C_h5 is the output end of the first path of the duplexer; the output end of capacitor C_h1 is simultaneously connected to the input end of inductor L_h1 and the input end of capacitor C_h2, the output end of inductor L_h1 is connected to the input end of capacitor C_h6, and the output end of capacitor C_h6 is grounded; the output end of capacitor C_h2 is simultaneously connected to the input end of inductor L_h2 and the input end of capacitor C_h3. The output end of inductor L_h2 is connected to the input end of capacitor C_h7, and the output section of capacitor C_h7 is grounded; the output end of capacitor C_h3 is simultaneously connected to the input end of inductor L_h3 and the input end of capacitor C_h4, the output end of inductor L_h3 is connected to the input end of capacitor C_h8, and the output section of capacitor C_h8 is grounded; the output end of capacitor C_h4 is simultaneously connected to the input end of inductor L_h4 and the input end of capacitor C_h5, the output end of inductor L_h4 is connected to the input end of capacitor C_h9, and the output section of capacitor C_h9 is grounded; the output end of capacitor C_h5 is connected to the output end of the first filter.

[0038] A coupling inductor L1 is provided between the low-pass filter circuit and the input terminal. The low-pass filter circuit includes inductors L_11, L_12, L_13, L_14, and L_15, which are connected in series. The output of inductor L_11 is connected to the input of capacitor C_15, which is grounded. The output of inductor L_12 is connected to the input of capacitor C_16, which is grounded. The output of inductor L_13 is connected to the input of capacitor C_17, which is grounded. The output of inductor L_14 is connected to the input of capacitor C_18, which is grounded. Inductor L_12 is connected in parallel with capacitor C_11; inductor L_13 is connected in parallel with capacitor C_12; and inductor L_14 is connected in parallel with capacitor C_13.

[0039] An LC duplexer in the present invention is simulated, referring to Figure 4 . Figure 4 The maximum operating frequency band of the duplexer reaches 18GHz. Conventional filters such as Figure 5 , in 4G-5G, a notch point will appear, affecting the flatness of the passband.

[0040] In this duplexer circuit, due to the high frequency, the corresponding capacitor and inductor values ​​are very low. The capacitor parameters can be precisely adjusted to achieve high precision and miniaturization. Because the capacitor and inductor components used in the filter are small, even small errors can greatly increase the difficulty of filter debugging. Improving return loss can effectively reduce the reliance on component value accuracy, simplifying debugging and improving production efficiency.

[0041] The utility model slots the bottom of the shell 10 to eliminate the influence of parasitic capacitance on the entire loop, adds shielding strips, reduces parasitics generated between inductors, makes the bandwidth wider, moves the notch point to the far end, reduces debugging difficulty, and enhances filter performance.

[0042] The above embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the concept of the present invention, and these variations and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. An LC duplexer, characterized in that: include: A housing, a circuit board disposed in the housing, a long hole being disposed in the middle of the circuit board, a partition being disposed in the housing, the partition corresponding to the long hole, and the partition passing through the long hole; The bottom of the circuit board is provided with copper sheet.

2. The LC duplexer according to claim 1, wherein: A circuit is welded on the circuit board. The circuit has an input end, two output ends, and a high-pass filter circuit and a low-pass filter circuit arranged between the input end and the output end.

3. The LC duplexer according to claim 2, wherein: The two output ends are the output end of the high-pass filter circuit and the output end of the low-pass filter circuit.

4. The LC duplexer according to claim 2, wherein: The long hole is arranged between the high-pass filter circuit and the low-pass filter circuit.

5. The LC duplexer according to claim 2, wherein: The bottom of the circuit board is divided into a first area and a second area. The first area is the area corresponding to the high-pass filter circuit. The second area is provided with copper foil, and the first area is not provided with copper foil.

6. The LC duplexer according to claim 5, wherein: The high-pass filter circuit includes four combination circuits, each of which includes a first capacitor, an inductor, and a second capacitor. The first capacitors of the four combination circuits are connected in series in sequence, the input end of the inductor is connected to the input end of the first capacitor, the output end of the inductor is connected to the input end of the second capacitor, and the output end of the second capacitor is grounded.

7. The LC duplexer according to claim 2, wherein: A coupling inductor L1 is provided between the low-pass filter circuit and the input end.

8. The LC duplexer according to claim 7, wherein: The low-pass filter circuit includes an inductor L_11, an inductor L_12, an inductor L_13, an inductor L_14, and an inductor L_15 connected in series in sequence; The output end of the inductor L_11 is connected to the input end of the capacitor C_15, and the output end of the capacitor C_15 is grounded; The output end of the inductor L_12 is connected to the input end of the capacitor C_16, and the output end of the capacitor C_16 is grounded; The output end of the inductor L_13 is connected to the input end of the capacitor C_17, and the output end of the capacitor C_17 is grounded; The output end of the inductor L_14 is connected to the input end of the capacitor C_18, and the output end of the capacitor C_18 is grounded.

9. The LC duplexer according to claim 8, wherein: The inductor L_12 is connected in parallel with the capacitor C_11; the inductor L_13 is connected in parallel with the capacitor C_12; and the inductor L_14 is connected in parallel with the capacitor C_13.

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