Band rejection filter

Abstract

FIELD: microwave technology.SUBSTANCE: filter contains a dielectric substrate suspended in a metal housing, on one side of which there is no metallization, and on the other side strip conductors of the common line and resonators electromagnetically connected to it are applied, and the topology of the strip conductors of each resonator is made in the form of a rectangular frame, inside which a rectangular strip conductor is connected to one of its sides, and the input and output of the band rejection filter are connected to the ends of the common line. Due to the fact that the band rejection filter rejection band is formed by two resonators and the distance between the resonators and the common line is selected based on the condition of ensuring the required level of attenuation in the stop band, the distance between the resonators is selected in such a way that the coefficient of electromagnetic coupling between them is close to zero.EFFECT: reduction in the dimensions of the band rejection filter, as well as increase in attenuation in the rejection band.1 cl, 2 dwg

Description

[0001] The invention relates to high and ultra-high frequency technology and can be used in selective paths of radio equipment for various purposes, in particular, in radio navigation systems.

[0002] A microstrip bandstop filter (BSF) is known [AA Leksikov, A O. Afonin, AA Aleksandrovsky, AV Ugryumov, AM Serzhantov, IV Govorun. Microstrip Rejecting Bandstop Filter / / 2022 IEEE International Multi-Conference on Engineering, Computer and Information Sciences (SIBIRCON), Yekaterinburg, Russian Federation. - 2022. - P. 1200-1203.], comprising a dielectric substrate, on one side of which a grounded base is applied, and on the other side - strip conductors of resonators and a common line, wherein all 5 resonators have an S-shape and are electromagnetically coupled to the line and to each other. The input and output of the bandstop filter are connected to the ends of the common line.

[0003] The main drawback of this design is the large size of the device, as five resonators are used to achieve high attenuation levels in the stopband. Furthermore, the attenuation level in the stopband is not high enough.

[0004] The closest analogue (prototype) in terms of the set of essential features is the PZF [A.O. Afonin, I.V. Govorun, A.A. Leksikov, A.V. Ugryumov. Narrow-band band-stop filter on a suspended substrate and loosely coupled stripline resonators / / Advances in modern radio electronics - 2026. - Vol.80 - No.3 - Pp. 146-154.], containing a dielectric substrate suspended in a metal case, on one side of which there is no metallization, and on the second side stripline conductors of a common line and resonators electromagnetically coupled to it are applied, wherein the topology of the stripline conductors of each resonator is made in the form of a rectangular frame, inside which a rectangular stripline conductor is connected to one of its sides, and the input and output of the PZF are connected to the ends of the common line.

[0005] The stopband of this design is slightly smaller than the first analog, but still quite significant. The attenuation level at the center frequency of the stopband of this design is higher than that of the first analog with the same stopband width, but still remains insufficiently high.

[0006] The technical result of the invention is a reduction in the dimensions of the barrier band, as well as an increase in attenuation in the barrier band.

[0007] The specified technical result in the implementation of the invention is achieved in that in a PZF containing a dielectric substrate suspended in a metal housing, on one side of which there is no metallization, and on the second side strip conductors of a common line and resonators electromagnetically connected to it are applied, wherein the topology of the strip conductors of each resonator is a rectangular frame, inside which a rectangular strip conductor is connected to one of its sides, and the input and output of the PZF are connected to the ends of the common line, what is new is that the PZF contains two resonators that form a stopband, and the distance between the resonators and the common line is selected from the condition of ensuring the required level of attenuation in the stopband, and the distance between the resonators is selected such that the coefficient of electromagnetic coupling between them is close to zero.

[0008] A comparative analysis with the prototype shows that the claimed device differs in that the stop band of the PZF is formed by two resonators.

[0009] The second significant difference is that the distance between the resonators and the common line is selected based on the condition of ensuring the required level of attenuation in the stop band, and the distance between the resonators is selected in such a way that the coefficient of electromagnetic coupling between them is close to zero.

[0010] Thus, the above-mentioned distinctive features from the prototype allow us to conclude that the claimed technical solution meets the criterion of “novelty”.

[0011] The features that distinguish the claimed technical solution from the prototype have not been identified in other technical solutions during the study of this and related fields of technology and, therefore, ensure that the claimed solution meets the criterion of “inventive step”.

[0012] The essence of the device is explained with the help of the following graphic materials.

[0013] Fig. 1 shows the topology of strip conductors of the claimed PZF design;

[0014] Fig. 2a shows the frequency dependences of the transmission coefficient (S21) and the reflection coefficient (S11) of the RFI of the claimed design, and Fig. 2b shows the frequency dependence of the transmission coefficient (S21) of the RFI of the claimed design in a narrow frequency range in the vicinity of the center frequency of the stop band.

[0015] The claimed PZF consists of a dielectric substrate 1 (Fig. 1) suspended in a metal housing 2, on one side of which there is no metallization, and on the upper surface a strip conductor of a common line 3 and strip conductors of two resonators 4 are applied. The topology of the strip conductors of each resonator is a rectangular frame, inside which a rectangular strip conductor is connected to one of its sides. The input port "P1" is connected to one end of the strip conductor of the common line, and the output port "P2" is connected to the other. The fundamental difference between the claimed design of the PZF (Fig. 1) and the design of the prototype PZF is that the PZF has 2 resonators, and the distance between the resonators and the common line is selected based on the condition of ensuring the required level of attenuation in the stop band, and the distance between the resonators is selected in such a way that the coefficient of electromagnetic coupling between them is close to zero.

[0016] The distance between the resonators is chosen so that the electromagnetic coupling between them is close to zero, which is achieved by compensating for their inductive and capacitive interactions.

[0017] To illustrate the operability of the claimed device, a model of the claimed PZF was made (Fig. 1). A dielectric substrate (1) made of ceramics with a high permittivity, for example, B80 with ε=80 and a thickness of 0.5 mm, was placed in a metal case (2). The distance from the substrate to the upper and lower covers is 0.8 mm and 5 mm, respectively; the width and length of the common line are 0.6 mm × 26.3 mm; the overall dimensions of the strip conductors of the filter resonators are 8.9 mm × 9.5 mm; the width of the strip conductor of the resonator forming the frame is 0.6 mm, the width and length of the rectangular conductor located inside the frame are 5.7 mm and 7.15 mm; the distance between the resonators is 3.5 mm; The gap between the resonators and the common line is 0.4 mm, and the distance from the common line to the wall is 3 mm. The conductor topology area of ​​the claimed PZF is 26.3 x 16.5 mm. 2 , and the prototype is 48.8×18 mm 2 , i.e. the area of ​​the topology of the claimed design is 2 times smaller.

[0018] In the passbands of the stopband, the reflection coefficient does not exceed -14 dB (VSWR≈1.5) Insertion loss in the passbands of the stopband does not exceed 0.4 dB. The center frequency of the stopband is 1463 MHz, the attenuation at this frequency is 76 dB; and for the prototype stopband, it was 60.6 dB. The relative width of the stopband was 0.07%, 0.22%, 0.62% and 2.76% at the level of -60 dB, -50 dB, -40 dB and -20 dB, respectively. The PZF prototype has the same relative bandwidth at the -20 dB level, but at the -60 dB, -50 dB and -40 dB levels it is significantly larger and amounts to 0.49%, 0.94% and 1.43%, respectively.

[0019] Thus, the claimed PZF has, in comparison with the existing PZF prototype, the following advantages: smaller dimensions and a greater amount of attenuation at the central frequency of the stop band.

Claims

A band-stop filter comprising a dielectric substrate suspended in a metal housing, on one side of which there is no metallization, and on the other side of which strip conductors of a common line and resonators electromagnetically coupled to it are applied, wherein the topology of the strip conductors of each resonator is a rectangular frame, inside which a rectangular strip conductor is connected to one of its sides, and the input and output of the band-stop filter are connected to the ends of the common line, characterized in that the band-stop filter contains two resonators that form a stop band, and the distance between the resonators and the common line is selected from the condition of ensuring the required level of attenuation in the stop band, and the distance between the resonators is selected in such a way that the coefficient of electromagnetic coupling between them is close to zero.

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