CN216288881U - Amplitude-phase double tight coupling SIR high-frequency selective filter - Google Patents
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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
Technical Field
The utility model relates to the technical field of electromagnetic fields and microwaves, in particular to a high-frequency filter, and particularly relates to an amplitude-phase double tight coupling SIR high-frequency selective filter.
Background
The filter is one of the key devices of the modern microwave and millimeter wave system, and the quality of the performance of the filter directly affects the quality of the whole system, including indexes such as channel capacity, signal-to-noise ratio and distortion degree. With the demands for miniaturization, light weight, high reliability, versatility, high integration, and low cost development of microwave and millimeter wave systems, a (quasi-) elliptic function filter having low insertion loss, high frequency selectivity, and good out-of-band rejection has been widely used. The number and position distribution of the finite frequency transmission zeros are determining factors affecting the performance of the (quasi-) elliptic function filter.
The design method of the (quasi-) elliptic function filter mainly comprises the steps of introducing cross coupling between non-adjacent resonators and introducing mixed electromagnetic coupling between adjacent resonators. The N-order cross-coupled filter can realize N-2 finite frequency transmission zeros, but has the defects that the coupling topological structure is complex, and the positions of the transmission zeros cannot be independently adjusted. The N-order hybrid electromagnetic coupling filter can realize N-1 finite frequency transmission zeros, and has the advantages of simple coupling topological structure, independent and adjustable transmission zero position and the like. It can be seen that the hybrid electromagnetic coupling filter of the same order number exhibits superior filtering performance compared to the cross-coupling filter, including a greater number of transmission zeros with independently controllable positions, and a compact and simple topology. Therefore, the hybrid electromagnetic coupling theory and technology is rapidly becoming one of the hot leading-edge fields of the research of the high-performance quasi-elliptic function filter. However, in the current theory and application research related to the hybrid electromagnetic coupling, only the electromagnetic amplitude coupling between the resonators is utilized or considered to introduce and regulate the transmission zero point, and the influence and improvement of the electromagnetic phase coupling between the resonators on the performance of the filter are not considered, but the inventor finds that the electromagnetic phase coupling between the resonators actually has a key influence on the improvement of the performance of the filter.
Disclosure of Invention
Aiming at the problem that the influence and improvement of electromagnetic phase coupling among resonators on the performance of a filter are not considered in the traditional hybrid electromagnetic coupling filter, the utility model provides an amplitude-phase double tight coupling SIR high-frequency selective filter.
The utility model provides an amplitude-phase double tight coupling SIR high-frequency selective filter, which comprises: 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.
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 feeder lines of the two resonator units is larger 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 is larger than the distance between the first parts of the two resonator units.
Further, a second quarter-wavelength SIR resonator is respectively arranged at the outer sides of the two resonator units; 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.
Further, the length of the first low impedance line and the length of the second low impedance line coincide.
The utility model has the beneficial effects that:
after the path lengths of electric coupling and magnetic coupling are introduced into the hybrid coupling filter unit, the ratio of the path lengths is adjusted, namely under the condition of comprehensively considering the amplitude coupling and the phase coupling of the hybrid electromagnetic coupling, a quasi-elliptic function microwave filter of the hybrid electromagnetic coupling technology under the amplitude-phase dual coupling is designed, the filter realizes the high selection technical target of N-order with N transmission zeros (for example, a second-order filter has a transmission zero with limited frequency respectively at an upper stop band and a lower stop band, and a third-order filter has 2 transmission zeros with limited frequency at the upper stop band and 1 transmission zero with limited frequency at the lower stop band), and a new method is provided for the design of the quasi-elliptic function microwave filter.
Drawings
Fig. 1 is a schematic structural diagram of an amplitude-phase dual tight-coupled SIR high frequency selectivity filter according to an embodiment of the present invention;
fig. 2 is a second schematic structural diagram of an amplitude-phase dual close-coupled SIR high frequency selectivity filter according to an embodiment of the present invention;
FIG. 3 is a graph of the S parameters of the second order filter response of the filter of FIG. 2 according to an embodiment of the present invention;
fig. 4 is a third schematic structural diagram of an amplitude-phase double tight-coupled SIR high frequency selectivity filter according to an embodiment of the present invention;
fig. 5 is a fourth schematic structural diagram of an amplitude-phase dual close-coupled SIR high frequency selective filter according to an embodiment of the present invention;
FIG. 6 is a graph of the S parameters of the third order filter response of the filter of FIG. 5 according to an embodiment of the present invention;
reference numerals: 1 is a first low impedance line, 2 is a first part in a first high impedance line, 3 is a second part in the first high impedance line, 4 is a high impedance feed line, 5 is a 50 ohm standard feed line, 6 is a metal via, 7 is a second low impedance line, 8 is a third part in a second high impedance line, and 9 is a fourth part in the second high impedance line.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the utility model, the amplitude-phase double coupling means that: simultaneously, coupling is carried out by utilizing the amplitude and the phase between the resonators; the tight coupling means that: the two coupled resonators have a compact structure.
Example 1
As shown in fig. 1, an embodiment of the present invention provides an amplitude-phase dual tight-coupled SIR high frequency selectivity filter, which includes: the two resonator units are in mirror symmetry distribution on the dielectric substrate; wherein the resonator elements comprise a first quarter wave SIR resonator, a high impedance feed 4 and a 50 ohm standard feed 5; the first quarter-wavelength SIR resonator comprises a first low-impedance line 1 and a first high-impedance line, the first high-impedance line is divided into a first part 2 and a second part 3, the first part 2 and the second part 3 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 2 is connected with the first low-impedance line 1, and one end, far away from the L-shaped right angle, of the second part 3 is provided with a metal through hole 6; the high impedance feed line 4 is connected at one end to the first section 2 and parallel to the second section 3 and at the other end to the 50 ohm standard feed line 5.
Specifically, the microstrip line of the filter is manufactured on the dielectric substrate, the back surface of the dielectric substrate is a metal copper sheet, and the metal via hole 6 is arranged at one end of the high-impedance line so as to enable the first quarter-wavelength SIR resonator and the back metal of the dielectric substrate to be short-circuited, so that the resonant 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 by two parts: electromagnetic hybrid coupling exists between the first low-impedance line 1 and the first part 2, and amplitude coupling adjustment is achieved by utilizing distance adjustment between the first low-impedance line 1 and the first part; there is also electromagnetic hybrid coupling between the second part 3 and the high impedance feed line, and amplitude coupling adjustment can also be achieved with adjustment of the spacing between the two.
By arranging the first high-impedance line in an L-shape as a whole, on one hand, the size of the filter can be effectively reduced, and on the other hand, a coupling path can be added, so that energy is transmitted into the first quarter-wavelength SIR resonator from the 50-ohm standard feeder 5 through the high-impedance feeder 4, and can be transmitted into the first part 2 and the second part 3, that is, the energy can be transmitted through different transmission paths, and due to the fact that the electrical lengths of the different transmission paths are different, phase differences must exist between signals on the different transmission paths, and phase coupling adjustment is achieved.
The two resonator units are designed in a mirror symmetry mode, so that the two first quarter-wavelength SIR resonators have electric coupling and magnetic coupling.
In the embodiment of the utility model, the connection between the 50 ohm standard feeder and the resonator is realized through the high-impedance feeder, so that better impedance matching can be realized. For example, in order to satisfy the international standard of impedance matching of 50 Ω, in this embodiment, the 50 ohm standard feeder W0 is set to be 1.57mm, and if the width of the high impedance line is 0.4mm, the value difference between the two is too large, and the impedance matching can be better performed by performing transition through the high impedance feeder, so that more energy signals enter the resonator.
As an implementable way, 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 section to ensure better phase coupling adjustment.
In the embodiment of the present invention, as shown in fig. 1, the length direction of the 50 ohm standard feed line 5 is parallel to the length direction of the second portion 3, and the width direction is perpendicular to the length direction of the second portion 3, so that the whole of the high-impedance feed line 4 and the 50 ohm standard feed line 5 is tightly coupled to the first high-impedance line in phase.
As an implementation, the distance between the 50 ohm standard feed lines 5 of the two resonator elements is greater than the distance between the metal vias 6 of the two resonator elements, and the distance between the metal vias 6 of the two resonator elements is greater than the distance between the first portions 2 of the two resonator elements.
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 portions 2.
As an embodiment, the position of the transmission zero point and the return loss are 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 implementable way, the transmission zero is generated by adjusting the distance between the second part 3 and the high impedance feed line 4 and the return loss and the position of the transmission zero are adjusted.
Example 2
On the basis of the above embodiments, the embodiment of the utility model provides a specific amplitude-phase dual tight-coupled SIR high-frequency selective second order filter, which adopts a RogersRT/duroid 5880 dielectric substrate with a thickness of 0.508mm and a dielectric constant of epsilonrAnd =2.2, the substrate is made of copper, and the resonator is made of SIR.
In fig. 2, the second-order filter has a filter structure of 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, and S3=0.15 mm.
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 a distance between two first low impedance lines; l3 and L4 denote the length of the first portion in the first high-impedance line; w3 and W4 denote the width of the first portion in the first high-impedance line; l5 and L6 denote the length of the second portion in the first high-impedance line; w5 and W6 denote the widths of the second portions in the first high-impedance line; l00 and W00 represent the length and width of the high impedance feedline, respectively; l0 and W0 represent the length and width, respectively, of a 50 ohm standard feed line; d0 and D1 represent the inner and outer diameters of the metal via, respectively; s2 represents the distance between the first section and one side of the first low impedance line in the width direction of the first low impedance line, for defining the positional relationship of the connection section between the first section and the first low impedance line in the width direction of the first low impedance line, and adjusting the position of the transmission zero point and the return loss by adjusting the value of S2; s3 denotes the distance between the high impedance feed line and the second portion.
The second order filter has the following implementation indexes: the center frequency of the filter is 2.82GHz, the S11 return loss RL < -20dB, the 3dB bandwidth =215MHz, and the relative bandwidth is 7.6%, because the electromagnetic coupling proportion is calculated by adopting an amplitude-phase double tight coupling technology, two sides of the pass band are respectively provided with a transmission zero point TZ1=0.92GHz and a transmission zero point TZ2=4.5GHz with limited frequency. Compared with the traditional electromagnetic hybrid coupling technology, the utility model can effectively introduce more transmission zeros by adopting amplitude-phase double tight coupling.
The filter can adjust the center frequency by adjusting the length of the resonator. By adjusting the step S2, the position of the transmission zero point of the upper stop band can be adjusted; adjustment S1 may adjust the positions of both zeros simultaneously. The two resonators are quarter-wavelength resonators, so that the size of the filter is effectively reduced, the miniaturization is facilitated, the design is completely a copper strip microstrip line, and the processing is convenient. As can be seen from the filter response shown in fig. 3, the second harmonic is beyond 10GHz, the out-of-band rejection is strong, the filter size and coupling spacing parameter transformation range is large, and the sensitivity is low. The overall filter size was 21.1 mmx13.83mm. The port L0 is an impedance matching independent feed of 50 Ω in international standard. Generally, the filter has a compact structure and high selectivity.
Example 3
The SIR high frequency selectivity filter in embodiment 1 is actually a second order filter, and it is understood that the higher order filter is constructed in the unit of the second order filter. In order to further construct a high-order filter, on the basis of the above embodiment 1, as shown in fig. 3, an embodiment of the present invention further provides an amplitude-phase dual close-coupled SIR high-frequency selective filter, which is different from embodiment 1 in that the filter in the embodiment of the present invention is composed of two quarter-wavelength resonators and one half-wavelength resonator, specifically: a second quarter-wavelength SIR resonator is respectively arranged at the outer sides of the two resonator units; the second quarter-wavelength SIR resonator comprises a second low impedance line 7 and a second high impedance line, the second high impedance line is divided into a third part 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 integrally L-shaped, and one end, far away from the L-shaped right angle, of the third part 8 is connected with the second low impedance line 7; two second said second quarter wave SIR resonators are connected by their respective said fourth part 9;
the two first low impedance lines 1 are adjacent and located between the two second low impedance lines 7, the two first high impedance lines are located on the same side of the two first low impedance lines 1, which is referred to as a first side, and the two second high impedance lines are located on the same side of the two second low impedance lines 7, which is referred to as a second side; the first side and the second side are opposite end sides.
In the embodiment of the utility model, a traditional cascade scheme is not adopted to construct a fourth-order filter, but a mode of combining a quarter wavelength and a half wavelength is innovatively adopted to construct a third-order filter. According to the construction mode, the N-order filter can have high selection indexes of N limited transmission zeros, and a space structure can be effectively utilized, so that the filter is more miniaturized, and the current communication requirement is met. And the half-wavelength resonator is designed to surround the two quarter-wavelength resonators, so that better electromagnetic coupling can be realized, and the bandwidth of the filter is effectively increased.
As an embodiment, the length of the first low impedance line 1 and the length of the second low impedance line 7 are the same.
As an implementable manner, the resonance frequency is adjusted by adjusting the length of the third section 8 so as to match the resonance frequency of a filter composed of two resonator elements having the same structure (i.e., the second order filter in embodiments 1 and 2 described above).
Example 4
Based on the above embodiment 3, the specific amplitude-phase dual tight-coupled SIR high-frequency selectivity third-order filter of the embodiment of the present invention adopts a rogerstr/duroid 5880 dielectric substrate with a thickness of 0.508mm and a dielectric constantConstant is epsilonrAnd =2.2, the substrate is made of copper, and the resonator is made of SIR.
In fig. 5, the filter 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, and S3=0.75 mm.
Wherein L1 and L4 represent the length of the second low impedance line; w1 denotes the width of the second low impedance line; l8 denotes the sum of the lengths of the fourth portions of the two second high-impedance lines; w8 denotes the width of the fourth portion in the second high-impedance line; l7 denotes the length of the third portion in the second high-impedance line; s1 represents a distance between the second low impedance line and the first low impedance line; l5 denotes the length of the first portion in the first high impedance line; l6 denotes the length of the second portion in the first high-impedance line; l00 and W00 (see also fig. 2, which is not shown in this figure) represent the length and width, respectively, of the high impedance feedline; l0 and W0 (see also fig. 2, which is not shown in this figure) represent the length and width, respectively, of a 50 ohm standard feed line; d0 and D1 represent the inner and outer diameters of the metal via, respectively; s2 represents the distance between the first part and one side of the first low impedance line in the width direction of the first low impedance line, for defining the connection position relationship of the first low impedance line and the first part; s3 denotes the distance between the high impedance feed line and the second portion.
Fig. 6 shows a diagram of S parameters of the third-order filter, and it can be seen from the diagram 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%, because the electromagnetic coupling ratio is calculated by using the amplitude-phase dual tight coupling technique, the lower resistance of the pass band has a transmission zero TZ1=0.92GHz with a finite frequency, and the upper resistance band has two transmission zeros TZ2=3.29GHz and TZ3=5.04GHz, respectively.
The third-order filter of the embodiment of the utility model can adjust the center frequency by adjusting the length of the resonator. By adjusting S2, the position of the upper stop band transmission zero TZ2 can be adjusted; adjusting S1 may simultaneously adjust the positions of the zero points of TZ1 and TZ 3. Two resonators in the middle are quarter-wavelength resonators, and then two quarter-wavelength resonators are additionally arranged on the half-wavelength resonators, so that the size of the filter is reduced more effectively, the overall size of a high-order filter and a second-order filter unit is close, miniaturization is facilitated, the design is totally designed for a copper strip microstrip line, and the processing is convenient. As can be seen from the filter response shown in fig. 6, the second harmonic is also beyond 10GHz, the out-of-band rejection is strong, the filter size and coupling gap parameter conversion range is large, and the sensitivity is low. The overall filter size was 21.1 mmx13.79mm. Wherein the port L0 is an international standard 50 Ω impedance matching independent feed. Generally, the filter has a more compact structure and higher selectivity.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
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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