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CN-224218374-U - Filter circuit, dielectric filter and duplexer

CN224218374UCN 224218374 UCN224218374 UCN 224218374UCN-224218374-U

Abstract

The utility model relates to a filter circuit, a dielectric filter and a duplexer, which comprise a signal input end, a signal output end, a resonance unit, a coupling inductance unit, a coupling capacitance unit and a signal output end, wherein the signal input end is used for inputting signals, the signal output end is used for outputting signals, the resonance unit comprises a plurality of resonance loops which are sequentially arranged between the signal input end and the signal output end in parallel, the coupling inductance unit is arranged between the signal input end and a grounding end, and between the signal output end and the grounding end, and the coupling capacitance unit is arranged between the signal input end and a first resonance loop and between the signal output end and a last resonance loop. The utility model can solve the problem of larger return loss in the ultra-wide passband, effectively improve standing waves, improve the working efficiency of the filter and improve the communication effect. The dielectric filter is connected with the grounding silver layer on the outer surface of the ceramic matrix by leading out a first connecting wire and a second connecting wire from the input port and the output port respectively, so that the equivalent inductance effect is achieved.

Inventors

  • LIU YADONG

Assignees

  • 苏州捷频电子科技有限公司

Dates

Publication Date
20260508
Application Date
20250328

Claims (10)

  1. 1. A filter circuit is characterized by comprising, A signal input terminal for inputting a signal; A signal output terminal for outputting a signal; the resonance unit comprises a plurality of resonance loops which are sequentially and parallelly arranged between the signal input end and the signal output end; The coupling inductance unit is arranged between the signal input end and the grounding end and between the signal output end and the grounding end; The coupling capacitor unit is arranged between the signal input end and the first resonant circuit and between the signal output end and the last resonant circuit; When in operation, an electric signal is input from the signal input end, passes through the plurality of resonant circuits and is output from the signal output end.
  2. 2. The filter circuit of claim 1, wherein the coupling inductance unit comprises a first coupling inductance and a second coupling inductance, the first coupling inductance is disposed between the signal input terminal and the ground terminal, and the second coupling inductance is disposed between the signal output terminal and the ground terminal.
  3. 3. The filter circuit of claim 1, wherein the coupling capacitor unit comprises a first coupling capacitor and a second coupling capacitor, the first coupling capacitor is disposed between the signal input terminal and the resonance unit, and the second coupling capacitor is disposed between the signal output terminal and the resonance unit.
  4. 4. A dielectric filter is characterized by comprising, A base; the electrode surface is arranged on the base body and used for being connected with a circuit board, and the electrode surface comprises an input port and an output port; The circuit printing surface is arranged on the base body and is provided with a plurality of silver blocks, the signal input end of the filter circuit is connected with the input port, and the signal output end of the filter circuit is connected with the output port; The ground plane is arranged on the base body, and the input port is electrically connected with the ground plane through a first connecting wire; the output port is electrically connected with the ground plane through a second connecting wire; The electrode face, the circuit printed face and the ground plane being capable of carrying a filter circuit as claimed in any one of claims 1 to 3.
  5. 5. A dielectric filter as set forth in claim 4, wherein said circuit printed surface is provided with a first silver block, a second silver block, a third silver block and a fourth silver block in this order, said input port being connected to said first silver block and said output port being connected to said fourth silver block.
  6. 6. The dielectric filter of claim 5, wherein the substrate is provided with a first through hole, a second through hole, a third through hole and a fourth through hole at intervals, wherein the first through hole corresponds to the first silver block, the second through hole corresponds to the second silver block, the third through hole corresponds to the third silver block, and the fourth through hole corresponds to the fourth silver block.
  7. 7. A dielectric filter as set forth in claim 4, wherein the first and second connection lines are silver lines.
  8. 8. A dielectric filter according to claim 4, wherein the substrate is a ceramic body having a dielectric constant of 90.
  9. 9. A dielectric filter according to any one of claims 4 to 8, wherein the electrode surface and the ground plane are disposed opposite to each other in a thickness direction of the substrate, and the circuit printed surface is disposed on a side surface of the substrate.
  10. 10. A diplexer comprising two dielectric filters as claimed in any one of claims 4 to 9.

Description

Filter circuit, dielectric filter and duplexer Technical Field The present utility model relates to the field of communications devices, and in particular, to a filter circuit, a dielectric filter, and a duplexer. Background In the working process of the filter, when a signal passes through the filter, a standing wave phenomenon (also called return loss) is formed by superposition of a reflected wave and an incident wave caused by impedance mismatch or filter characteristics, and the standing wave can influence the performance and signal transmission quality of the system, so that signal energy loss is caused, the working efficiency of the system is reduced, signal distortion is caused, the communication effect is influenced, equipment is overheated and even damaged when the standing wave ratio is too high, so that the control of the standing wave in a radio frequency and microwave system is particularly important. Specifically, the smaller the amount of the reflected back signal when passing through the filter, the smaller the return loss of the filter, the smaller the signal attenuation or distortion, and conversely, the larger the return loss. The requirements of the filter on passband width are different, the signal frequencies which can be allowed to pass through by different passband widths are different, when the passband is wider, the signal frequency range which can be passed through is larger, for example, in a 5G passing system, the frequency band which is issued to China mobile and UNICOM by the industrial information department is 3400 Hz-3600 Hz. The edges of the input port and the output port with the filter circuit of the filter are called input coupling and output coupling (or input-output matching), and whether the coupling or matching is proper or not directly determines whether the return loss of the passband of the filter is good or not. In general, the wider the passband, the greater the required input and output coupling capacitances. In the actual production process, the silver layers are printed on the surface of the ceramic body, and the coupling is formed between the different silver layers, however, the input-output coupling capacitance cannot be infinitely increased due to the limited area and volume, so that the problem of over-wide passband exists when the dielectric filter is designed and manufactured, and the return loss is serious. Disclosure of utility model Therefore, the utility model aims to overcome the defects in the prior art, and provides a filter circuit, a dielectric filter and a duplexer, which can solve the problem of larger return loss in an ultra-wide passband, effectively reduce return loss, improve standing waves, improve the working efficiency of the filter and improve the communication effect. In order to solve the above technical problems, the present utility model provides a filter circuit, comprising, A signal input terminal for inputting a signal; A signal output terminal for outputting a signal; The coupling inductance unit is arranged between the signal input end and the grounding end and between the signal output end and the grounding end; The coupling capacitor unit is arranged between the signal input end and the first resonant circuit and between the signal output end and the last resonant circuit; When in operation, an electric signal is input from the signal input end, passes through the plurality of resonant circuits and is output from the signal output end. In one embodiment of the present utility model, the coupling inductance unit includes a first coupling inductance and a second coupling inductance, the first coupling inductance is disposed between the signal input terminal and the ground terminal, and the second coupling inductance is disposed between the signal output terminal and the ground terminal. In one embodiment of the present utility model, the coupling capacitor unit includes a first coupling capacitor and a second coupling capacitor, the first coupling capacitor is disposed between the signal input terminal and the resonance unit, and the second coupling capacitor is disposed between the signal output terminal and the resonance unit. The utility model also provides a dielectric filter comprising, A base; the electrode surface is arranged on the base body and used for being connected with a circuit board, and the electrode surface comprises an input port and an output port; The circuit printing surface is arranged on the base body and is provided with a plurality of silver blocks, the signal input end of the filter circuit is connected with the input port, and the signal output end of the filter circuit is connected with the output port; The ground plane is arranged on the base body, and the input port is electrically connected with the ground plane through a first connecting wire; the output port is electrically connected with the ground plane through a second connecting wire; the electrode face, the circuit printed face and th