CN216288881U - An Amplitude and Phase Double Tightly Coupling SIR High Frequency Selective Filter - Google Patents

Abstract

The utility model provides an amplitude-phase double tight coupling SIR high-frequency selective filter. The filter includes: the two resonator units are in mirror symmetry distribution on the dielectric substrate; wherein the resonator unit comprises a first quarter wave SIR resonator, a high impedance feed line and a 50 ohm standard feed line; the first quarter-wavelength SIR resonator comprises a first low-impedance line and a first high-impedance line, the first high-impedance line is divided into a first part and a second part, the first part and the second part are perpendicular to each other, so that the first high-impedance line is integrally L-shaped, one end, far away from an L-shaped right angle, of the first part is connected with the first low-impedance line, and one end, far away from the L-shaped right angle, of the second part is provided with a metal through hole; one end of the high impedance feed line is connected to the first section and parallel to the second section and the other end is connected to the 50 ohm standard feed line.

Description

An Amplitude and Phase Double Tightly Coupled SIR High Frequency Selective Filter

technical field

The utility model relates to the technical field of electromagnetic fields and microwaves, in particular to a high-frequency filter, in particular to a SIR high-frequency selective filter with double tight coupling of amplitude and phase.

Background technique

As one of the key components of modern microwave and millimeter-wave systems, the filter performance directly affects the quality of the entire system, including channel capacity, signal-to-noise ratio, distortion and other indicators. With the development of microwave and millimeter-wave systems for miniaturization, light weight, high reliability, versatility, high integration and low cost, (quasi) elliptical with low insertion loss, high frequency selectivity, and good out-of-band rejection Functional filters are widely used. The number and position distribution of finite frequency transmission zeros are the decisive factors that affect the performance of the (quasi) elliptic function filter.

The design methods of (quasi) elliptic function filters mainly include the introduction of cross-coupling between non-adjacent resonators and the introduction of hybrid electromagnetic coupling between adjacent resonators. Among them, the N-order cross-coupling filter can realize N-2 finite-frequency transmission zeros, but its drawback is that the coupling topology is complex and the position of the transmission zeros cannot be adjusted independently. The N-order hybrid electromagnetic coupling filter can realize N-1 finite frequency transmission zeros, and has the advantages of simple coupling topology and independent adjustment of transmission zero positions. It can be seen that compared with the cross-coupling filter, the hybrid electromagnetic coupling filter of the same order shows better filtering performance, including more transmission zeros with independent and controllable positions, and a compact and simple topology structure. Therefore, the theory and technology of hybrid electromagnetic coupling has quickly become one of the hot frontiers in the research of high-performance quasi-elliptic function filters. However, the current theoretical and applied research on hybrid electromagnetic coupling only uses or considers the electromagnetic amplitude coupling between resonators to introduce and control the transmission zero point, but does not consider the influence and improvement of the electromagnetic phase coupling between the resonators on the performance of the filter. The inventors found that the electromagnetic phase coupling between the resonators actually has a key influence on the improvement of the filter performance.

SUMMARY OF THE INVENTION

Aiming at the problem that the traditional hybrid electromagnetic coupling filter does not consider the influence and improvement of the electromagnetic phase coupling between the resonators on the filter performance, the utility model provides a SIR high frequency selective filter with double tight coupling of amplitude and phase.

The SIR high-frequency selective filter with double tight coupling of amplitude and phase provided by the utility model comprises: two resonator units with the same structure, and the two resonator units are distributed in mirror symmetry on a dielectric substrate; wherein , the resonator unit includes a first quarter-wave SIR resonator, a high-impedance feed line and a 50-ohm standard feed line; the first quarter-wave SIR resonator includes a first low-impedance line and a first high-impedance line The impedance line has two parts. The first high-impedance line is divided into a first part and a second part. The first part and the second part are perpendicular to each other so that the first high-impedance line is L-shaped as a whole. The first part One end away from the L-shaped right angle is connected with the first low-impedance line, and one end of the second part away from the L-shaped right angle is provided with a metal via hole; one end of the high-impedance feed line is connected with the first part and is parallel to the The second part and the other end are connected to the 50-ohm standard feeder.

Further, the length of the high-impedance feed line is greater than the length of the second portion.

Further, the distance between the 50 ohm standard feed lines of the two resonator units is greater than the distance between the metal via holes of the two resonator units, and the distance between the metal via holes of the two resonator units The distance is greater than the distance between the first parts of the two resonator units.

Further, a second quarter-wavelength SIR resonator is respectively provided on the outside of the two resonator units; the second quarter-wavelength SIR resonator includes a second low impedance line and a second high impedance line. The impedance line has two parts. The second high-impedance line is divided into a third part and a fourth part. The third part and the fourth part are perpendicular to each other so that the second high-impedance line is L-shaped as a whole. The end of the third part away from the L-shaped right angle is connected with the second low impedance line; the two second second quarter wavelength SIR resonators are connected through their respective fourth parts;

The two first low-impedance lines are adjacent to and located between the two second low-impedance lines, and the two first high-impedance lines are located on the same side of the two first low-impedance lines. is the first side, and the two second high-impedance lines are located on the same side of the two second low-impedance lines, denoted as the second side; the first side and the second side are opposite ends to each other side.

Further, the length of the first low-impedance line is the same as the length of the second low-impedance line.

The beneficial effects of the present utility model:

After the electric and magnetic coupling path lengths are introduced into the hybrid coupling filter unit, the utility model adjusts the ratio of the path lengths, that is, under the condition of comprehensively considering the amplitude coupling and phase coupling of the hybrid electromagnetic coupling, the amplitude-phase coupling is designed. A quasi-elliptic function microwave filter with hybrid electromagnetic coupling technology under double coupling, which achieves the technical goal of high selectivity with N transmission zeros of order N (for example, a second order filter has a finite frequency transmission in the upper and lower stopbands) The third-order filter has 2 transmission zeros of finite frequency in the upper stop and 1 transmission zero of finite frequency in the lower stop), and provides a new method for the design of quasi-elliptic function microwave filters.

Description of drawings

Fig. 1 is one of the structural representations of a kind of amplitude-phase double tightly coupled SIR high frequency selective filter provided by the embodiment of the present utility model;

Fig. 2 is the second structural representation of a kind of amplitude-phase double tightly coupled SIR high-frequency selective filter provided by the embodiment of the present utility model;

3 is an S-parameter diagram of the second-order filter response of the filter shown in FIG. 2 provided by an embodiment of the present invention;

Fig. 4 is the third structural schematic diagram of a kind of amplitude-phase double tightly coupled SIR high-frequency selective filter provided by the embodiment of the present utility model;

FIG. 5 is the fourth schematic structural diagram of a SIR high-frequency selective filter with double tight coupling of amplitude and phase provided by an embodiment of the present utility model;

6 is an S-parameter diagram of the third-order filter response of the filter shown in FIG. 5 provided by an embodiment of the present invention;

Reference numerals: 1 is the first low impedance line, 2 is the first part of the first high impedance line, 3 is the second part of the first high impedance line, 4 is the high impedance feeder, 5 is the 50 ohm standard feeder, 6 is a metal via, 7 is the second low impedance line, 8 is the third part of the second high impedance line, and 9 is the fourth part of the second high impedance line.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are Some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

In the present utility model, the double coupling of amplitude and phase means that the amplitude and phase between the resonators are used for coupling at the same time; the tight coupling means that the structure between the two coupled resonators is compact.

Example 1

As shown in FIG. 1 , an embodiment of the present utility model provides a SIR high frequency selective filter with double tight coupling of amplitude and phase, including: two resonator units with the same structure, the two resonator units are on a dielectric substrate It is mirror-symmetrically distributed; wherein, the resonator unit includes a first quarter-wave SIR resonator, a high-impedance feeder 4 and a 50-ohm standard feeder 5; the first quarter-wave SIR resonator includes The first low-impedance line 1 and the first high-impedance line are divided into two parts, the first high-impedance line is divided into a first part 2 and a second part 3, and the first part 2 and the second part 3 are perpendicular to each other so that the The first high impedance line is L-shaped as a whole, the end of the first part 2 away from the L-shaped right angle is connected to the first low-impedance line 1, and the end of the second part 3 away from the L-shaped right angle is provided with a metal via 6 ; One end of the high-impedance feed line 4 is connected to the first part 2 and parallel to the second part 3 , and the other end is connected to the 50-ohm standard feed line 5 .

Specifically, the microstrip line of the filter is fabricated on a dielectric substrate, and the back of the dielectric substrate is a metal copper sheet. One end of the high-impedance line is provided with a metal via 6 so that the first quarter-wavelength SIR resonator and the The backside metal of the dielectric substrate is short-circuited, so that the resonance frequency of the first quarter-wavelength SIR resonator is the same as the half-wavelength. The amplitude coupling adjustment in this embodiment is mainly realized through two parts: there is electromagnetic hybrid coupling between the first low impedance line 1 and the first part 2, and the amplitude coupling adjustment is realized by adjusting the distance between the two; There is also electromagnetic hybrid coupling between 3 and the high-impedance feeder, and the amplitude coupling adjustment can also be achieved by adjusting the spacing between the two.

By arranging the first high-impedance line in an L-shape as a whole, on the one hand, the size of the filter can be effectively reduced, and on the other hand, a coupling path can be added, so that the energy can pass from the 50-ohm standard feeder 5 through the high-impedance feeder 4 Into the first quarter wavelength SIR resonator, both the first part 2 and the second part 3, that is, the energy can propagate through different propagation paths, due to the electrical length of the different propagation paths Different, there must be a phase difference between the signals on different propagation paths, so as to realize the phase coupling adjustment.

The two resonator units are designed with mirror symmetry, so that there is both an electrical coupling and a magnetic coupling between the two first quarter-wavelength SIR resonators.

In the embodiment of the present invention, better impedance matching can be achieved by realizing the connection between the 50-ohm standard feeder and the resonator through a high-impedance feeder. For example, in order to meet the international standard 50Ω impedance matching, in this embodiment, the 50-ohm standard feeder line W0 is set to 1.57mm, and if the width of the high-impedance line is 0.4mm, the difference between the two values is too large. Impedance feeder transitions allow for better impedance matching, allowing more energy signal to enter the resonator.

As an embodiment, the center frequency is adjusted by adjusting the overall length of the first low-impedance line and the second portion.

As an embodiment, the length of the high-impedance feed line is greater than the length of the second portion, so as to ensure better realization of phase coupling adjustment.

In the embodiment of the present invention, as shown in FIG. 1 , the length direction of the 50 ohm standard feeder 5 is parallel to the length direction of the second part 3 , and the width direction is perpendicular to the length direction of the second part 3 , The whole formed by the high-impedance feed line 4 and the 50-ohm standard feed line 5 is made to realize phase tight coupling with the first high-impedance line.

As an embodiment, the distance between the 50 ohm standard feed lines 5 of the two resonator units is greater than the distance between the two resonator units and the metal vias 6 of the two resonator units. The distance between the metal vias 6 is greater than the distance between the first parts 2 of the two resonator units.

As an embodiment, the distance between the two first low-impedance lines 1 is fixed, and the position of the transmission zero point is adjusted by adjusting the distance between the two first parts 2 .

As an embodiment, the position of the transmission zero point and the return loss can be adjusted by adjusting the position of the connection portion between the first portion 2 and the first low-impedance line 1 in the width direction of the first low-impedance line 1 .

As an embodiment, by adjusting the distance between the second part 3 and the high-impedance feed line 4, the transmission zero point is generated and the return loss and the position of the transmission zero point are adjusted.

Example 2

On the basis of the above-mentioned embodiment, the embodiment of the present utility model provides a specific SIR high-frequency selective second-order filter with double tight coupling of amplitude and phase, using RogersRT/duroid 5880 dielectric substrate, thickness 0.508mm, dielectric The constant is ε _r =2.2, the substrate is copper, and the resonator is SIR.

In Figure 2, the filter structure of the second-order filter is L1=L2=8mm, W1=W2=1.7mm, S1=0.43mm, L3=-L4=5.1mm, W3=W4=0.4mm, L5=L6=2mm , W5=W6=0.4mm, L00=3mm, W00=0.4mm, L0=2mm, W0=1.57mm, D0=0.5mm, D1=0.7mm, S2=0.65mm, S3=0.15mm.

Wherein, L1 and L2 represent the length of the first low-impedance line; W1 and W2 represent the width of the first low-impedance line; S1 represents the distance between the two first low-impedance lines; L3 and L4 represent the first high-impedance line in the The length of the first part; W3 and W4 represent the width of the first part in the first high impedance line; L5 and L6 represent the length of the second part in the first high impedance line; W5 and W6 represent the length of the second part in the first high impedance line Width; L00 and W00 represent the length and width of the high-impedance feeder, respectively; L0 and W0 represent the length and width of the 50-ohm standard feeder, respectively; D0 and D1 represent the inner and outer diameters of the metal via, respectively; S2 represents the first low-impedance In the line width direction, the distance between the first part and one side of the first low-impedance line is used to define the positional relationship of the connecting part between the first part and the first low-impedance line in the width direction of the first low-impedance line, through Adjust the value of S2 to adjust the position of transmission zero and return loss; S3 represents the distance between the high-impedance feeder and the second part.

The indicators realized by the second-order filter are: the center frequency of the filter is 2.82GHz, the S11 return loss RL<-20dB, the 3dB bandwidth=215MHz, the relative bandwidth is 7.6%, because the double tight coupling technique of amplitude and phase is used to calculate the electromagnetic coupling Therefore, there are a limited frequency transmission zero point TZ1=0.92GHz on both sides of the passband, and TZ2=4.5GHz. Compared with the traditional electromagnetic hybrid coupling technology, the utility model can effectively introduce more transmission zero points by adopting the double tight coupling of amplitude and phase.

The filter of the utility model can adjust the center frequency by adjusting the length of the resonator. By adjusting S2, the position of the transmission zero point of the upper stop band can be adjusted; by adjusting S1, the positions of two zero points can be adjusted at the same time. Both resonators are quarter-wavelength resonators, which effectively reduce the size of the filter and are more conducive to miniaturization. From the filter response shown in Figure 3, it can be known that the second harmonic is outside 10GHz, the out-of-band suppression is strong, the filter size and coupling spacing parameters have a large transformation range, and the sensitivity is low. The overall size of the filter is 21.1mmx13.83mm. Among them, the port L0 is an international standard 50Ω impedance matching independent feeding. Overall, the filter is compact and highly selective.

Example 3

The SIR high frequency selective filter in Embodiment 1 is actually a second-order filter, and it can be understood that the high-order filter is constructed by taking the second-order filter as a unit. In order to further construct a high-order filter, on the basis of the above-mentioned Embodiment 1, as shown in FIG. 3 , the embodiment of the present invention also provides a SIR high-frequency selective filter with double tight coupling of amplitude and phase, which is the same as that of the embodiment. The difference between 1 and 1 is that the filter in the embodiment of the present utility model is composed of two quarter-wavelength resonators and one half-wavelength resonator. A second quarter-wavelength SIR resonator; the second quarter-wavelength SIR resonator includes a second low-impedance line 7 and a second high-impedance line, and the second high-impedance line is divided into Three parts 8 and a fourth part 9, the third part 8 and the fourth part 9 are perpendicular to each other so that the second high impedance line is L-shaped as a whole, and the end of the third part 8 away from the right angle of the L-shaped said second low impedance line 7 is connected; two second said second quarter wavelength SIR resonators are connected by their respective said fourth part 9;

The two first low-impedance lines 1 are adjacent to each other and are located between the two second low-impedance lines 7 , and the two first high-impedance lines are located at the same position of the two first low-impedance lines 1 . side, denoted as the first side, the two second high-impedance lines are located on the same side of the two second low-impedance lines 7, denoted as the second side; the first side and the second side opposite to each other.

In the embodiment of the present utility model, instead of using the traditional cascade scheme to construct the fourth-order filter, the third-order filter is innovatively constructed by combining quarter-wavelength and half-wavelength. This construction method can firstly realize that the N-order filter has a high selection index of N finite transmission zeros, and can more effectively utilize the spatial structure, making the filter more miniaturized, thereby meeting contemporary communication needs. Furthermore, by designing the half-wavelength resonator to surround the two quarter-wavelength resonators, better electromagnetic coupling can be achieved, effectively increasing the bandwidth of the filter.

As an embodiment, the length of the first low-impedance line 1 is the same as the length of the second low-impedance line 7 .

As an embodiment, the resonant frequency can be adjusted by adjusting the length of the third portion 8 so as to be comparable to a filter composed of two resonator units having the same structure (ie, the second-order in the above-mentioned Embodiments 1 and 2). filter) to match the resonant frequency.

Example 4

On the basis of the above-mentioned Embodiment 3, a specific embodiment of the present invention is a SIR high-frequency selective third-order filter with double tight coupling of amplitude and phase, using RogersRT/duroid 5880 dielectric substrate, thickness 0.508mm, dielectric The constant is ε _r =2.2, the substrate is copper, and the resonator is SIR.

In Figure 5, the filtering structure of the third-order filter is L1=L4=8mm, W1=1.7mm, L8=6.49mm, W8=0.4mm, L7=3.1mm, S1=0.33mm, L5=5.1mm, L6= 2.4mm, L00=3mm, W00=0.4mm, L0=2mm, W0=1.57mm, D0=0.5mm, D1=0.7mm, S2=0.65mm, S3=0.75mm.

Wherein, L1 and L4 represent the length of the second low-impedance line; W1 represents the width of the second low-impedance line; L8 represents the sum of the lengths of the fourth parts of the two second high-impedance lines; W8 represents the second high-impedance line The width of the fourth part in L6 represents the length of the second part of the first high-impedance line; L00 and W00 (refer to Figure 2, which is not shown in the figure) represent the length and width of the high-impedance feeder respectively; L0 and W0 (refer to Figure 2) 2, not shown in the figure) respectively represent the length and width of the 50 ohm standard feeder; D0 and D1 represent the inner diameter and outer diameter of the metal via respectively; S2 represents the width direction of the first low impedance line, the first part and the first The distance on one side of the low-impedance line is used to define the connection position relationship between the first low-impedance line and the first part; S3 represents the distance between the high-impedance feeder and the second part.

Figure 6 shows the S-parameter diagram of the third-order filter. It can be seen from the figure that the center frequency of the filter is 2.82GHz, the S11 return loss RL<-20dB, the 3dB bandwidth=423MHz, and the relative bandwidth is 15%. The ratio of electromagnetic coupling is calculated by using the double tight coupling technique of amplitude and phase, so the lower stop band of the pass band has a transmission zero point of finite frequency TZ1=0.92GHz, and the upper stop band has two transmission zero points of finite frequency TZ2=3.29GHz, TZ3= 5.04GHz.

The third-order filter of the embodiment of the present invention can adjust the center frequency by adjusting the length of the resonator. By adjusting S2, the position of the upper stopband transmission zero point TZ2 can be adjusted; by adjusting S1, the positions of the zero points of TZ1 and TZ3 can be adjusted at the same time. The two middle resonators are both quarter-wavelength resonators, and then a half-wavelength resonator plus two quarter-wavelength resonators are used. This design reduces the size of the filter more effectively, making the high-order filter more efficient. The overall size of the second-order filter unit is similar to that of the second-order filter unit, which is more conducive to miniaturization. From the filter response shown in Figure 6, it can be known that the second harmonic is also outside 10 GHz, the out-of-band suppression is strong, the filter size and coupling spacing parameters have a large transformation range, and the sensitivity is low. The overall size of the filter is 21.1mmx13.79mm. Among them, the port L0 is an independent feeder for the international standard 50Ω impedance matching. In general, the filter structure is more compact and the selectivity is higher.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, but not to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions recorded in the foregoing embodiments, or to perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit of the technical solutions of the embodiments of the present invention. and range.

Claims (5)

1. An amplitude-phase double tightly coupled SIR high frequency selectivity filter, comprising: the two resonator units are in mirror symmetry distribution on the dielectric substrate; wherein the resonator unit comprises a first quarter wave SIR resonator, a high impedance feed line and a 50 ohm standard feed line; the first quarter-wavelength SIR resonator comprises a first low-impedance line and a first high-impedance line, the first high-impedance line is divided into a first part and a second part, the first part and the second part are perpendicular to each other, so that the first high-impedance line is integrally L-shaped, one end, far away from an L-shaped right angle, of the first part is connected with the first low-impedance line, and one end, far away from the L-shaped right angle, of the second part is provided with a metal through hole; one end of the high impedance feed line is connected to the first section and parallel to the second section and the other end is connected to the 50 ohm standard feed line.

2. An amplitude-phase double close-coupled SIR high frequency selectivity filter as claimed in claim 1, wherein the length of the high impedance feed line is greater than the length of the second section.

3. An amplitude-phase double close-coupled SIR high frequency selectivity filter as claimed in claim 1, wherein the distance between the 50 ohm feedlines of two of the resonator elements is greater than the distance between the metal vias of two of the resonator elements, the distance between the metal vias of two of the resonator elements being greater than the distance between the first portions of two of the resonator elements.

4. An amplitude-phase double close-coupled SIR high frequency selectivity filter as claimed in any one of claims 1 to 3, wherein a second quarter wavelength SIR resonator is provided outside each of the two resonator elements; the second quarter-wavelength SIR resonator comprises a second low-impedance line and a second high-impedance line, the second high-impedance line is divided into a third part and a fourth part, the third part and the fourth part are perpendicular to each other, so that the second high-impedance line is integrally L-shaped, and one end, far away from the L-shaped right angle, of the third part is connected with the second low-impedance line; two second said second quarter wave SIR resonators are connected by their respective said fourth sections;

the two first low-impedance lines are adjacent and positioned between the two second low-impedance lines, the two first high-impedance lines are positioned on the same side of the two first low-impedance lines and are marked as a first side, and the two second high-impedance lines are positioned on the same side of the two second low-impedance lines and are marked as a second side; the first side and the second side are opposite end sides.

5. The amplitude-phase double close-coupled SIR high frequency selectivity filter of claim 4, wherein the length of the first low impedance line is the same as the length of the second low impedance line.

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