Circuit structure of 46.5 MHz small-size band-pass filter

Abstract

The utility model discloses a circuit structure of a 46.5 MHz small-size band-pass filter, which comprises a capacitor C2, a capacitor C4, a capacitor C7, a capacitor C9, a capacitor C11, a capacitor C14 and a capacitor C16 which are sequentially connected in series from an input end to an output end, two ends of the capacitor C2, the capacitor C7 and the capacitor C16 are respectively connected with an inductor L1, an inductor L3 and an inductor L5 in parallel, the input end is further connected with one end of the capacitor C1, and the other end of the capacitor C1 is connected with the other end of the capacitor C2. The mutual connection end of the capacitor C2 and the capacitor C4 is further connected to one end of a capacitor C3, the mutual connection end of the capacitor C4 and the capacitor C7 is further connected to one end of an inductor L2 and one end of a capacitor C6, the other end of the inductor L2 is connected to one end of a capacitor C5, the mutual connection end of the capacitor C7 and the capacitor C9 is further connected to one end of a capacitor C8, and the mutual connection end of the capacitor C9 and the capacitor C11 is further connected to one end of a capacitor C10. The mutual connection end of the capacitor C11 and the capacitor C14 is further connected to one end of the capacitor C12 and one end of the inductor L4, the other end of the inductor L4 is connected to one end of the capacitor C13, the mutual connection end of the capacitor C14 and the capacitor C16 is further connected to one end of the capacitor C15, and the other ends of the capacitor C1, the capacitor C3, the capacitor C5, the capacitor C6, the capacitor C8, the capacitor C10, the capacitor C12, the capacitor C13 and the capacitor C15 are grounded. According to the utility model, the design of low insertion loss, high suppression and small size is realized.

Description

Technical Field

[0001] The utility model relates to a circuit structure of a 46.5MHz small-size bandpass filter, belonging to the technical field of bandpass filters. Background Art

[0002] The 46.5MHz filter has low insertion loss, high suppression, and small size. Conventional bandpass filters such as Butterworth and Chebyshev models require more orders, and more orders require sufficient size to meet the requirements; more orders correspond to more inductors, and when the size is limited, the Q value of the inductor will be relatively low, resulting in the filter insertion loss failing to meet the requirements. Summary of the invention

[0003] The technical problem to be solved by the utility model is to provide a circuit structure of a 46.5MHz small-size bandpass filter to solve the problems existing in the above-mentioned prior art.

[0004] The technical solution adopted by the utility model is: a circuit structure of a 46.5MHz small-size bandpass filter, including a capacitor C2, a capacitor C4, a capacitor C7, a capacitor C9, a capacitor C11, a capacitor C14 and a capacitor C16 connected in series from the input end to the output end, an inductor L1, an inductor L3 and an inductor L5 are respectively connected in parallel at both ends of the capacitor C2, the capacitor C7 and the capacitor C16, the input end is also connected to one end of the capacitor C1, the end where the capacitor C2 and the capacitor C4 are connected to each other is also connected to one end of the capacitor C3, the end where the capacitor C4 and the capacitor C7 are connected to each other is also connected to one end of the inductor L2 and one end of the capacitor C6, and the inductor L 2 is connected to one end of capacitor C5, the end connected to each other of capacitor C7 and capacitor C9 is also connected to one end of capacitor C8, the end connected to each other of capacitor C9 and capacitor C11 is also connected to one end of capacitor C10, the end connected to each other of capacitor C11 and capacitor C14 is also connected to one end of capacitor C12 and one end of inductor L4, the other end of inductor L4 is connected to one end of capacitor C13, the end connected to each other of capacitor C14 and capacitor C16 is also connected to one end of capacitor C15, and the other ends of capacitor C1, capacitor C3, capacitor C5, capacitor C6, capacitor C8, capacitor C10, capacitor C12, capacitor C13 and capacitor C15 are grounded.

[0005] Furthermore, the capacitors C1 to C16 are 0402 packaged capacitors; and the inductors L1 to L5 are T12-10 magnetic rings.

[0006] Beneficial effects of the utility model: compared with the prior art, the resonant circuit composed of L2, C5, C6 and L4, C12, C3 in the circuit of the utility model is the operating frequency of the bandpass filter; L2, C5 and L4, C13 are connected in series to the ground to increase the out-of-band suppression on the left side of the filter, and L3, C7, C8 and L5, C15, C16 are connected in parallel to increase the out-of-band suppression on the right side of the filter; L1, C1, C2, C3 can increase the far-end suppression of the filter; the utility model realizes low insertion loss, high suppression and small size design. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is the circuit schematic;

[0008] Figure 2 It is a simulation circuit diagram;

[0009] Figure 3 is the simulation parameter;

[0010] Figure 4 is the simulation curve. DETAILED DESCRIPTION

[0011] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0012] Example 1: Figure 1-4 As shown, a circuit structure of a 46.5MHz small-size bandpass filter includes a capacitor C2, a capacitor C4, a capacitor C7, a capacitor C9, a capacitor C11, a capacitor C14 and a capacitor C16 connected in series from the input end to the output end, an inductor L1, an inductor L3 and an inductor L5 are connected in parallel at both ends of the capacitor C2, the capacitor C7 and the capacitor C16, the input end is also connected to one end of the capacitor C1, the end where the capacitor C2 and the capacitor C4 are connected to each other is also connected to one end of the capacitor C3, the end where the capacitor C4 and the capacitor C7 are connected to each other is also connected to one end of the inductor L2 and one end of the capacitor C6, and the other end of the inductor L2 is connected to The interconnected end of capacitor C7 and capacitor C9 is also connected to one end of capacitor C8, the interconnected end of capacitor C9 and capacitor C11 is also connected to one end of capacitor C10, the interconnected end of capacitor C11 and capacitor C14 is also connected to one end of capacitor C12 and one end of inductor L4, the other end of inductor L4 is connected to one end of capacitor C13, the interconnected end of capacitor C14 and capacitor C16 is also connected to one end of capacitor C15, and the other ends of capacitor C1, capacitor C3, capacitor C5, capacitor C6, capacitor C8, capacitor C10, capacitor C12, capacitor C13 and capacitor C15 are grounded.

[0013] In order to meet the design size, the capacitors C1 to C16 used are 0402 package capacitors; the inductors L1 to L5 are made of T12-10 magnetic rings, which can ensure the inductor Q value and meet the size requirements.

[0014] The circuit of the utility model is transformed from the low-pass prototype of the LC filter. The resonant circuit composed of L2, C5, C6 and L4, C12, C3 is the working frequency of the bandpass filter; L2, C5 and L4, C13 are connected in series to the ground to increase the out-of-band suppression on the left side of the filter, and L3, C7, C8 and L5, C15, C16 are connected in parallel to increase the out-of-band suppression on the right side of the filter; L1, C1, C2, C3 can increase the far-end suppression of the filter; C4, C9, C10, C11, C14 are coupling capacitors.

[0015] The utility model has the following advantages:

[0016] Small insertion loss: The selected inductor has a smaller Q value, and the inductor used is less, which can reduce the filter insertion loss;

[0017] High suppression: The zero points generated by L2, C5, L4, C13 can increase the out-of-band suppression on the left side of the filter, and the zero points generated by L3, C7, C8, L5, C15, C16 can increase the out-of-band suppression on the right side of the filter;

[0018] Small size: The 0402 package capacitors and T12-10 magnetic ring-wrapped inductors used can meet the small size requirements.

[0019] The size of the bandpass filter is 13.3*6.8*3.8 (max) mm.

[0020] The following simulation is carried out taking the main index requirements of the filter as an example.

[0021] Center frequency 46.5MHz;

[0022] Insertion loss 1.2dB;

[0023] 3dB relative bandwidth 21~22.5MHz;

[0024] Out-of-band suppression ≥60dBc@Fo±23M.

[0025] Simulation schematic diagram Figure 2 By setting the bandpass filter operating bandwidth and stopband suppression requirements, the corresponding parameters and simulation results can be generated, such as Figure 3 , Figure 4 .

[0026] It can be seen from the simulation results that this solution can meet the product index requirements.

[0027] The above description is only a specific implementation method of the present utility model, but the protection scope of the present utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present utility model, which should be included in the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims

1. A circuit structure of a 46.5MHz small-size bandpass filter, characterized in that: The circuit includes capacitors C2, C4, C7, C9, C11, C14 and C16 connected in series from the input end to the output end, inductors L1, L3 and L5 are connected in parallel at both ends of capacitors C2, C7 and C16 respectively, the input end is also connected to one end of capacitor C1, the end connected to each other by capacitors C2 and C4 is also connected to one end of capacitor C3, the end connected to each other by capacitors C4 and C7 is also connected to one end of inductor L2 and one end of capacitor C6, the other end of inductor L2 is connected to one end of capacitor C5, and capacitor C The interconnected end of capacitor C7 and capacitor C9 is also connected to one end of capacitor C8, the interconnected end of capacitor C9 and capacitor C11 is also connected to one end of capacitor C10, the interconnected end of capacitor C11 and capacitor C14 is also connected to one end of capacitor C12 and one end of inductor L4, the other end of inductor L4 is connected to one end of capacitor C13, the interconnected end of capacitor C14 and capacitor C16 is also connected to one end of capacitor C15, and the other ends of capacitors C1, capacitor C3, capacitor C5, capacitor C6, capacitor C8, capacitor C10, capacitor C12, capacitor C13 and capacitor C15 are grounded.

2. The circuit structure of a 46.5MHz small-size bandpass filter according to claim 1, characterized in that: Capacitor C1 to capacitor C16 are 0402 package capacitors; inductor L1 to inductor L5 are T12-10 magnetic rings.

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