A filter circuit and a dielectric filter

Abstract

This utility model relates to a filter circuit and a dielectric filter, including a signal input terminal; a signal output terminal; a resonant unit that receives an input signal from the signal input terminal and outputs a signal from the signal output terminal; the resonant unit includes resonant circuits arranged in parallel; a coupling inductor is provided between two adjacent resonant circuits; a coupling capacitor unit is connected in parallel with the last resonant circuit; an electrical signal is input from the signal input terminal, passes through the resonant unit, and is output from the signal output terminal. This utility model can reduce signal reflection, improve energy transmission efficiency, and enhance communication performance; by adjusting the capacitance value, the resonant frequency or bandwidth of the resonant circuit can be fine-tuned, and the size of the coupling capacitor can determine the degree of coupling. Thus, a small capacitor can achieve weak coupling (narrowband applications), and a large capacitor can enhance coupling (broadband applications), thereby giving the filter circuit of this utility model the characteristics of low loss and high power.

Description

Technical Field

[0001] This utility model relates to the field of filter technology, and in particular to a filter circuit and a dielectric filter. Background Technology

[0002] A low-pass filter (LPF) is a critical passive or active circuit used to allow low-frequency signals to pass through while suppressing high-frequency noise and interference. However, traditional LPFs still face many challenges in design and practical applications, including high insertion loss, low power efficiency, and insufficient frequency selectivity. These factors directly affect the overall performance and energy efficiency of the system. Low-pass filters are typically composed of passive components such as inductors (L), capacitors (C), or resistors (R). During signal transmission, the parasitic resistance of the filter (such as the DC resistance of an inductor and the equivalent series resistance of a capacitor) leads to energy loss, manifested as insertion loss, thus reducing signal transmission efficiency. Furthermore, in high-power applications (such as RF communication or power management), filter losses further exacerbate temperature rise, affecting system stability and lifespan. In addition, traditional LC filters may experience reduced power transmission efficiency at high frequencies due to the non-ideal characteristics of components (such as skin effect and dielectric loss). For example, the core loss of an inductor and the dielectric loss of a capacitor consume some signal energy, leading to a decrease in output power.

[0003] In actual production, silver layers are printed on the surface of the ceramic body to form coupling between different silver layers. However, due to the limited area and volume, the output coupling capacitance cannot be increased indefinitely. Therefore, when designing and manufacturing dielectric filters, there is a problem of excessively wide passband, which leads to severe return loss. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a filter circuit and dielectric filter with low loss and high power, which can solve the problem of large return loss in ultra-wide passband, effectively reduce return loss, improve standing wave ratio, improve filter working efficiency, and enhance communication effect.

[0005] To solve the above-mentioned technical problems, this utility model provides a filter circuit, including,

[0006] Signal input terminal;

[0007] Signal output terminal;

[0008] A resonant unit receives an input signal from the signal input terminal and outputs a signal from the signal output terminal; the resonant unit includes resonant circuits connected in parallel in sequence; a coupling inductor is provided between two adjacent resonant circuits;

[0009] The coupling capacitor unit is connected in parallel with the last resonant circuit;

[0010] During operation, the electrical signal is input from the signal input terminal, passes through the resonant unit, and is output from the signal output terminal.

[0011] In one embodiment of the present invention, the coupling capacitor unit includes a first coupling capacitor, which is connected in parallel with the last resonant circuit.

[0012] This utility model also provides a dielectric filter, including

[0013] Medium matrix,

[0014] An electrode surface is disposed on the dielectric substrate, and an input port and an output port are provided on the electrode surface;

[0015] A ground plane is disposed on the dielectric substrate, and the ground plane is opposite to the electrode surface;

[0016] The circuit printing surface includes a first end face and a second end face disposed opposite to each other; the first end face is provided with a first silver block assembly, and two adjacent silver blocks in the first silver block assembly are connected by a connecting line; the second end face is provided with a second silver block assembly, and the second silver block assembly is connected to the first silver block assembly;

[0017] The electrode surface, the ground surface, and the circuit printing surface support a filter circuit as described above.

[0018] In one embodiment of the present invention, the first silver block assembly includes a first silver block, a second silver block, a third silver block and a fourth silver block arranged sequentially along the signal input direction to the signal output direction. The first silver block is connected to the input port and the fourth silver block is connected to the output port.

[0019] In one embodiment of the present invention, the second silver block assembly includes a fifth silver block, a sixth silver block, and a seventh silver block arranged sequentially along the signal input direction to the signal output direction.

[0020] In one embodiment of this utility model, the medium substrate is provided with a first through hole, a second through hole and a third through hole at intervals, wherein one end of the first through hole is connected to the first silver block and the other end is connected to the fifth silver block; one end of the second through hole is connected to the second silver block and the other end is connected to the sixth silver block; and one end of the third through hole is connected to the third silver block and the other end is connected to the seventh silver block.

[0021] In one embodiment of this utility model, the connecting wire includes a silver wire.

[0022] In one embodiment of this utility model, the connecting line is bent and disposed between two adjacent silver blocks in the first silver block assembly.

[0023] In one embodiment of this utility model, the sixth silver block and the seventh silver block have the same area, and the area of ​​the fifth silver block is smaller than that of the sixth silver block.

[0024] In one embodiment of the present invention, the ground plane extends along the first end face to form a grounding connection post, and the grounding connection post is opposite to one of the connecting lines.

[0025] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art:

[0026] The filter circuit described in this utility model includes a signal input terminal, a signal output terminal, a resonant unit, and a coupling capacitor. The resonant unit comprises multiple resonant circuits connected in parallel between the signal input terminal and the signal output terminal. The coupling capacitor is connected in parallel with the last resonant circuit. This arrangement allows adjustment of the equivalent impedance of the resonant circuits, making them more impedance-matched with the preceding and following circuits, thereby reducing signal reflection, improving energy transmission efficiency, and enhancing communication performance. Furthermore, by adjusting the capacitance of the coupling capacitor, the resonant frequency or bandwidth of the resonant circuit can be fine-tuned. The size of the coupling capacitor determines the degree of coupling; thus, a small capacitor achieves weak coupling (narrowband applications), while a large capacitor enhances coupling (wideband applications), adapting to different design requirements. This results in a filter circuit with low loss and high power characteristics. Attached Figure Description

[0027] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0028] Figure 1 This is a circuit diagram of a filter circuit according to a preferred embodiment of the present invention.

[0029] Figure 2 This is a test curve diagram of the filter circuit of a preferred embodiment of this utility model.

[0030] Figure 3 These are test data charts of the filter circuit according to a preferred embodiment of this utility model.

[0031] Figure 4 This is a simulation diagram of the filter circuit of a preferred embodiment of this utility model.

[0032] Figure 5 This is a first-view schematic diagram of a dielectric filter according to a preferred embodiment of the present invention.

[0033] Figure 6 yes Figure 5 The main view.

[0034] Figure 7 This is a second-view schematic diagram of the dielectric filter according to a preferred embodiment of the present invention.

[0035] Explanation of reference numerals in the accompanying drawings: P1, signal input terminal; P2, signal output terminal; L1, first inductor; L2, second inductor; L3, third inductor; L4, first coupling inductor; L5, second coupling inductor; L6, third coupling inductor; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, first coupling capacitor; 1, electrode surface; 10, input port; 11, output port; 2, ground plane; 21, ground connection post; 31, first end face; 311, first silver block; 312, second silver block; 313, third silver block; 314, fourth silver block; 32, second end face; 321, fifth silver block; 322, sixth silver block; 323, seventh silver block; 41, first through hole; 42, second through hole; 43, third through hole; 45, first silver wire; 46, second silver wire; 47, third silver wire. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention. Example 1

[0037] Reference Figures 1 to 4 As shown, this utility model discloses a filter circuit, including a signal input terminal P1 and a signal output terminal P2, wherein the signal input terminal P1 is used for electrical signal input and the signal output terminal P2 is used for electrical signal output;

[0038] The filter circuit further includes a resonant unit, which receives an input signal from the signal input terminal P1 and outputs a signal from the signal output terminal P2. Specifically, the resonant unit includes multiple resonant circuits connected in parallel in sequence; the resonant circuit is a capacitive-inductive resonant circuit.

[0039] Specifically, a coupling inductor is provided between two adjacent resonant circuits.

[0040] The filter circuit also includes a coupling capacitor unit, which is connected in parallel with the last resonant circuit.

[0041] During operation, the electrical signal is input from the signal input terminal, passes through the resonant unit, and is output from the signal output terminal.

[0042] Therefore, it can be seen that the filter circuit protected by this utility model includes a signal input terminal, a signal output terminal, a resonant unit, and a coupling capacitor. The resonant unit comprises multiple resonant circuits connected in parallel between the signal input terminal and the signal output terminal. The coupling capacitor is connected in parallel with the last resonant circuit. This arrangement allows for adjustment of the equivalent impedance of the resonant circuits, making them more impedance-matched with the preceding and following circuits, thereby reducing signal reflection, improving energy transmission efficiency, and enhancing communication performance. Impedance matching is particularly crucial for power transmission in radio frequency (RF) circuits. Furthermore, by adjusting the capacitance of the coupling capacitor, the resonant frequency or bandwidth of the resonant circuit can be adjusted. The size of the coupling capacitor determines the degree of coupling, allowing for weak coupling (narrowband applications) with a small capacitor and enhanced coupling (broadband applications) with a large capacitor, thus adapting to different design requirements. This results in the filter circuit of this utility model possessing low loss and high power characteristics.

[0043] In detail, the coupling capacitor unit includes a first coupling capacitor C4, which is connected in parallel with the last resonant circuit.

[0044] In a preferred embodiment, the resonant unit includes a first resonant circuit, a second resonant circuit, and a third resonant circuit arranged in parallel along the signal transmission direction; specifically, the first resonant circuit includes a first inductor L1 and a first capacitor C1 connected in series; the second resonant circuit includes a second inductor L2 and a second capacitor C2 connected in series; and the third resonant circuit includes a third inductor L3 and a third capacitor C3 connected in series.

[0045] In detail, a first coupling inductor L4 is provided between the first resonant circuit and the second resonant circuit, a second coupling inductor L5 is provided between the second resonant circuit and the third resonant circuit, and a third coupling inductor L6 is provided between the third resonant circuit and the first coupling capacitor C4.

[0046] The present invention will be described below with reference to specific embodiments. Figure 2 The figure shown is a test curve of the filter circuit of this utility model.

[0047] Combination Figure 3 and Figure 4 As shown in the charts and simulation curves, the requirements are met. At the 5G frequency, the suppression reaches over 40dB, and at 2.515G~3.6G, the echo is over 20dB. The 40dB suppression occurs near the 4.7G frequency point.

[0048] Therefore, the passband of this filter circuit covers 2.515G~3.6G, and it can achieve a suppression of more than 40dB at the 5G position. Example 2

[0049] This utility model also discloses a dielectric filter, referenced... Figures 5 to 7 As shown, the dielectric filter includes a dielectric substrate, and the material of the dielectric substrate includes, but is not limited to, dielectric ceramic.

[0050] The dielectric filter further includes an electrode surface 1, which is disposed on the dielectric substrate. The electrode surface has an input port 10 and an output port 11. The input port 10 corresponds to the signal input terminal in Embodiment 1, and the output port 11 corresponds to the signal output terminal in Embodiment 1. The electrode surface 1 is used to connect to a circuit board.

[0051] The dielectric filter further includes a ground plane 2, which is disposed on the dielectric substrate and is opposite to the electrode surface 1;

[0052] The dielectric filter further includes a circuit printing surface, on which the resonant circuit described in Embodiment 1 is formed. The circuit printing surface includes a first end face 31 and a second end face 32 disposed opposite to each other on the dielectric substrate.

[0053] The first end face 31 is provided with a first silver block assembly, and two adjacent silver blocks in the first silver block assembly are connected by a connecting line; it should be noted that, in radio frequency characteristics, the connecting line can be equivalent to the coupled inductor in Embodiment 1.

[0054] The second end face 32 is provided with a second silver block assembly, which is connected to the first silver block assembly and has an electrical connection.

[0055] The electrode surface 1, the ground surface 2, and the circuit printing surface cooperate with each other to carry a filter circuit as described in Embodiment 1.

[0056] Therefore, it can be understood that the dielectric filter protected by this utility model comprises a dielectric substrate, an electrode surface, a ground plane, and a circuit printing surface. The electrode surface has input and output ports for connection to a circuit board. The circuit printing surface includes a first end face and a second end face. The first end face has a first silver block assembly comprising multiple silver blocks connected by connecting lines. The second end face has a second silver block assembly electrically connected to the first silver block assembly. Through the interaction of the electrode surface, the ground plane, and the circuit printing surface, a filter circuit as described in Embodiment 1 is formed on the dielectric substrate.

[0057] In a preferred embodiment, the first silver block assembly includes a first silver block 311, a second silver block 312, a third silver block 313, and a fourth silver block 314 arranged sequentially along the signal input direction to the signal output direction, wherein the first silver block 311 is connected to the input port P1;

[0058] The fourth silver block 314 is connected to the output port 11. There is a gap between the fourth silver block 314 and the ground plane 2, forming the first coupling capacitor C4. It should be noted that the edge shape, projected area and spacing of the fourth silver block 314 with the surrounding silver layer can determine the capacitance value of the first coupling capacitor C4.

[0059] Furthermore, the second silver block assembly includes a fifth silver block 321, a sixth silver block 322, and a seventh silver block 323 arranged sequentially along the signal input direction to the signal output direction.

[0060] In detail, the dielectric substrate is provided with a first through-hole 41, a second through-hole 42, and a third through-hole 43 spaced apart. The inner walls of the first through-hole 41, the second through-hole 42, and the third through-hole 43 are coated with a conductive layer, which includes, but is not limited to, a silver layer. One end of the first through-hole 41 is connected to the first silver block 311, and the other end is connected to the fifth silver block 321; one end of the second through-hole 42 is connected to the second silver block 312, and the other end is connected to the sixth silver block 322; one end of the third through-hole 43 is connected to the third silver block 313, and the other end is connected to the seventh silver block 323. Thus, the first through-hole 41 can be equivalent to the first inductor L1 in Embodiment 1, the second through-hole 42 can be equivalent to the second inductor L2 in Embodiment 1, and the third through-hole 43 can be equivalent to the third inductor L3 in Embodiment 1.

[0061] The fifth silver block 321 can be equivalent to the first capacitor C1 in Embodiment 1; the sixth silver block 322 can be equivalent to the second capacitor C2 in Embodiment 1; and the seventh silver block 323 can be equivalent to the third capacitor C3 in Embodiment 1.

[0062] With this configuration, the first through hole 41, the first silver block 311, and the fifth silver block 321 cooperate to form the first resonant circuit in Embodiment 1; the second through hole 42, the second silver block 312, and the sixth silver block 322 cooperate to form the second resonant circuit in Embodiment 1; and the third through hole 43, the third silver block 313, and the seventh silver block 323 cooperate to form the third resonant circuit in Embodiment 1.

[0063] Specifically, the connecting lines include, but are not limited to, silver wires.

[0064] In a preferred embodiment, the connecting line is bent and positioned between two adjacent silver blocks in the first silver block assembly to form a "U"-shaped structure.

[0065] In detail, the connecting lines include a first silver wire 45, a second silver wire 46, and a third silver wire 47. The first silver wire 45 connects the first silver block 311 and the second silver block 312, and is equivalent to a first coupling inductor L4, connecting between the first resonant circuit and the second resonant circuit. The second silver wire 46 connects the second silver block 312 and the third silver block 313, and is equivalent to a second coupling inductor L5, connecting between the second resonant circuit and the third resonant circuit. The third silver wire 47 connects the third silver block 313 and the fourth silver block 314, and is equivalent to a third coupling inductor L6, connecting between the third resonant circuit and the first coupling capacitor C4.

[0066] In a preferred embodiment, the sixth silver block 322 and the seventh silver block 323 have the same area, and the area of ​​the fifth silver block 321 is smaller than the area of ​​the sixth silver block 322.

[0067] In a preferred embodiment, the ground plane 2 extends along the first end face to form a grounding connection post 21, which is opposite to one of the connecting lines.

[0068] Specifically, the grounding connection post 21 is opposite to the second silver wire 46. The extension length of the grounding connection post 21 can determine the inductance value of the second coupling inductor L5 equivalent to the second silver wire 46, so the inductance value of the second coupling inductor L5 can be adjusted by adjusting the extension length of the grounding connection post 21.

[0069] In a preferred embodiment, the dielectric substrate is a ceramic body with a dielectric constant of 90.

[0070] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0071] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0072] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A filter circuit, characterized by: include, Signal input terminal; Signal output terminal; A resonant unit receives an input signal from the signal input terminal and outputs a signal from the signal output terminal; the resonant unit includes resonant circuits connected in parallel in sequence; a coupling inductor is provided between two adjacent resonant circuits; The coupling capacitor unit is connected in parallel with the last resonant circuit; During operation, the electrical signal is input from the signal input terminal, passes through the resonant unit, and is output from the signal output terminal.

2. A filter circuit as claimed in claim 1, characterized in that: The coupling capacitor unit includes a first coupling capacitor, which is connected in parallel with the last resonant circuit.

3. A dielectric filter characterized by: include Medium matrix, An electrode surface is disposed on the dielectric substrate, and an input port and an output port are provided on the electrode surface; A ground plane is disposed on the dielectric substrate, and the ground plane is opposite to the electrode surface; The circuit printing surface includes a first end face and a second end face disposed opposite to each other; the first end face is provided with a first silver block assembly, and two adjacent silver blocks in the first silver block assembly are connected by a connecting line; the second end face is provided with a second silver block assembly, and the second silver block assembly is connected to the first silver block assembly; The electrode surface, the ground surface, and the circuit printing surface bear... A filter circuit as described in claim 1 or 2.

4. A dielectric filter according to claim 3, characterized in that: The first silver block assembly includes a first silver block, a second silver block, a third silver block, and a fourth silver block arranged sequentially along the signal input direction to the signal output direction. The first silver block is connected to the input port, and the fourth silver block is connected to the output port.

5. A dielectric filter according to claim 4, characterized in that: The second silver block assembly includes a fifth silver block, a sixth silver block, and a seventh silver block arranged sequentially from the signal input direction to the signal output direction.

6. A dielectric filter according to claim 5, characterized in that: The medium substrate is provided with a first through hole, a second through hole and a third through hole at intervals. One end of the first through hole is connected to the first silver block and the other end is connected to the fifth silver block; one end of the second through hole is connected to the second silver block and the other end is connected to the sixth silver block; one end of the third through hole is connected to the third silver block and the other end is connected to the seventh silver block.

7. The dielectric filter according to claim 3, wherein: The connecting wire includes silver wire.

8. The dielectric filter according to claim 3, wherein: The connecting line is bent and positioned between two adjacent silver blocks in the first silver block assembly.

9. The dielectric filter of claim 6, wherein: The sixth and seventh silver blocks have the same area, while the fifth silver block has a smaller area than the sixth silver block.

10. A dielectric filter according to claim 3, characterized in that: The grounding surface extends along the first end face to form a grounding connection post, which is opposite to one of the connecting lines.

Images