CN207282679U - A kind of compact-sized bimodule band-pass filter - Google Patents

Abstract

The utility model discloses a dual-mode bandpass filter with compact structure, which comprises a dielectric substrate and a filter structure located on the same plane on the upper surface of the dielectric substrate; the filter structure includes a ring resonator (1), a T-shaped input feeder (2), T-shaped output feeder (3), T-shaped loading (4~7) and perturbation plate (8); T-shaped loading (4~7) is located in the ring resonator (1), including parallel parts and The parallel part is vertically connected to the vertical part, the parallel part of each T-shaped loading (4~7) is respectively arranged in parallel with one side of the ring resonator (1), and the vertical part of each T-shaped loading (4~7) Parts are respectively connected to the midpoint of one side of the ring resonator (1). Through the dual-mode resonator with T-shaped loading, the utility model can not only realize the dual-mode characteristic, but also have a wider passband bandwidth range, and can effectively reduce the working frequency, and realize the miniaturization of the dual-mode bandpass filter.

Description

A Compact Dual-mode Bandpass Filter

technical field

The utility model relates to the field of microwave devices, in particular to a compact double-mode band-pass filter.

Background technique

With the development of wireless communication systems, higher requirements are put forward for microwave filters, and high performance and miniaturization are the future development trends. In the miniaturization design of microwave filters, planar dual-mode bandpass filters have received more attention due to their high performance and compact structure. Dual-mode resonators are widely used in the design of dual-mode bandpass filters. Each dual-mode resonator can be regarded as a dual-frequency tuning circuit, that is, one resonator can generate two resonance frequencies at the same time. Therefore, For n-order filters, when dual-mode resonators are used, the number of resonators is reduced by half compared with single-mode, so that the size of the circuit can be effectively reduced.

The existing dual-mode bandpass filter has the following defects and deficiencies: (1) The size of the filter is large and not compact enough; (2) The passband characteristics are not good; (3) The bandwidth of the passband is narrow; (4) The out-of-band characteristics are not good, and the selectivity is not high; (5) The structure is complex and the processing cost is high.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art and provide a dual-mode band-pass filter with a compact structure.

The purpose of this utility model is achieved through the following technical solutions: a dual-mode bandpass filter with a compact structure, including a dielectric substrate, a metal ground plate located on the lower surface of the dielectric substrate, and a metal ground plate located on the same plane as the upper surface of the dielectric substrate Filter structure; the filter structure includes a ring resonator, a T-shaped input feeder, a T-shaped output feeder, four T-shaped loads and a perturbation sheet;

The T-shaped input feeder and the T-shaped output feeder have the same structure, and both include a 50Ω microstrip line and parallel branches vertically connected to the 50Ω microstrip line; the perturbation plates are located in two of the ring resonator internal At the corner formed by the sides, the T-shaped input feeder and the T-shaped output feeder are located outside the ring resonator, and the respective parallel branches are respectively arranged in parallel with the other two sides of the ring resonator;

The T-shaped loading is located inside the ring resonator, and each includes a parallel part and a vertical part vertically connected to the parallel part. The parallel parts of each T-shaped loading are respectively arranged in parallel with one side of the ring resonator, and each The vertical parts of the T-shaped loading are respectively connected to the midpoint of one side of the ring resonator.

Further, the perturbation sheet is a square perturbation sheet.

Further, the dielectric substrate has a relative permittivity of 9.6 and a thickness of 0.8 mm.

Further, the electrical length of each T-shaped loaded parallel part is 0.14 λ _g , and λ _g is the guided wavelength corresponding to the center frequency of the dual-mode bandpass filter.

The beneficial effect of the utility model is: the utility model not only can maintain the dual-mode characteristic through the dual-mode resonator with T-shaped loading, but also can effectively reduce the working frequency, thereby effectively realizing the miniaturization of the dual-mode bandpass filter. At the same time, the insertion loss in the entire passband is low, the range of the 3dB passband bandwidth is wide, and there are two transmission zeros outside the band, which effectively guarantees good out-of-band suppression characteristics, and the filter has high selectivity.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Figure 2 is a schematic diagram of the S parameters obtained by simulation calculation;

In the figure, 1-ring resonator, 2-T type input feeder, 3-T type output feeder, 4~7-T type loading, 8-perturbation sheet.

Detailed ways

Describe the technical scheme of the utility model in further detail below in conjunction with accompanying drawing:

As shown in Figure 1, a kind of compact dual-mode bandpass filter comprises a dielectric substrate, a metal ground plate positioned on the lower surface of the dielectric substrate and a filter structure positioned on the same plane as the upper surface of the dielectric substrate; the filter The structure of the resonator includes a ring resonator 1, a T-shaped input feeder 2, a T-shaped output feeder 3, four T-shaped loads 4~7 and a perturbation plate 8;

The T-shaped input feeder 2 and the T-shaped output feeder 3 have the same structure, both including a 50Ω microstrip line and parallel branches vertically connected to the 50Ω microstrip line; the perturbation sheet 8 is located inside the ring resonator 1 At the corner formed by two of the sides, the T-shaped input feeder 2 and the T-shaped output feeder 3 are located outside the ring resonator 1, and the respective parallel branches are respectively arranged in parallel with the other two sides of the ring resonator 1;

The T-shaped loads 4-7 are located inside the ring resonator 1, and each includes a parallel part and a vertical part vertically connected to the parallel part, and each parallel part of the T-shaped load 4-7 is respectively connected to the ring resonator 1 One of the sides is arranged in parallel, and the vertical part of each T-shaped loading 4-7 is respectively connected to the midpoint of one of the sides of the ring resonator 1 .

More preferably, in this embodiment, the perturbation sheet 8 is a square perturbation sheet.

More preferably, in this embodiment, the dielectric substrate has a relative permittivity of 9.6 and a thickness of 0.8 mm.

More preferably, in this embodiment, the electrical length of the parallel part of each T-shaped load 4-7 is 0.14 λ _g , and λ _g is the guided wavelength corresponding to the center frequency of the dual-mode bandpass filter.

Among them, the T-shaped feeder structure can well realize the coupling with the ring resonator 1 . By using the ring resonator 1 with T-shaped loads of 4-7, the operating frequency of the dual-mode bandpass filter can be effectively reduced, thereby effectively realizing the miniaturization of the dual-mode bandpass filter.

The model of the above-mentioned dual-mode bandpass filter is established in the simulation software ADS, and the structure is simulated and calculated. The obtained simulation results are shown in Figure 2. It can be seen from the figure that the center frequency of the dual-mode bandpass filter is located at 1.87GHz (if T-type loading 4~7 is not used, the operating frequency of the filter is at 2.15 GHz), and the 3dB bandwidth range is 7.5% , with a wide passband bandwidth, the positions of the two transmission zeros outside the passband are located at 1.66 GHz and 2.21 GHz respectively, and the attenuation of the two transmission zeros are -62dB and -58dB respectively, effectively ensuring good out-of-band rejection characteristics . It can be seen that the operating frequency of the filter can be effectively reduced by T-loading 4~7, thereby realizing the miniaturization design of the filter. The overall size of the filter is 14.93mm×14.93mm, and the structure is very compact.

The utility model is described by the embodiment, but it does not constitute a limitation to the utility model. With reference to the description of the utility model, other changes of the disclosed embodiment are as easily conceivable for those skilled in the art, such Changes should fall within the scope defined by the claims of the present invention.

Claims (4)

1. a kind of compact-sized bimodule band-pass filter, including medium substrate, the metallic ground positioned at medium substrate lower surface Plate and the filter construction being generally aligned in the same plane positioned at medium substrate upper surface；It is characterized in that：The filter construction Including toroidal cavity resonator（1）, T-shaped incoming feeder（2）, T-shaped output feeder（3）, four T-shaped loadings（4~7）With perturbation piece（8）；

The T-shaped incoming feeder（2）With T-shaped output feeder（3）Structure is identical, including 50 Ω microstrip lines and with 50 Ω Microstrip line parallel minor matters connected vertically；The perturbation piece（8）Positioned at toroidal cavity resonator（1）Internal two of which side is formed Angle at, the T-shaped incoming feeder（2）With T-shaped output feeder（3）Positioned at toroidal cavity resonator（1）Outside, respective parallel branch Section respectively with toroidal cavity resonator（1）Two other side be arranged in parallel；

The T-shaped loading（4~7）Positioned at toroidal cavity resonator（1）Inside, hangs down including parallel portion and with the parallel portion The direct-connected vertical component connect, each T-shaped loading（4~7）Parallel portion respectively with toroidal cavity resonator（1）One of side put down Row is set, each T-shaped loading（4~7）Vertical component respectively with toroidal cavity resonator（1）One of side point midway connect Connect.

A kind of 2. compact-sized bimodule band-pass filter according to claim 1, it is characterised in that：The perturbation piece （8）For square perturbation piece.

A kind of 3. compact-sized bimodule band-pass filter according to claim 1, it is characterised in that：The medium base The relative dielectric constant of plate is 9.6, thickness 0.8mm.

A kind of 4. compact-sized bimodule band-pass filter according to claim 1, it is characterised in that：Each T-shaped loading （4~7）Parallel portion electrical length be 0.14λ _g ,λ _g For the guided wave ripple corresponding to the bimodule band-pass filter centre frequency It is long.