Balanced dielectric resonator filter with isolation

Abstract

The application discloses a balanced dielectric resonator filter power divider with isolation characteristics. y 1 mode works in the differential mode, and TE 11 z δ The mode works in the common mode resonator, and the isolation circuit mode of the hollow structure layout in the laminated substrate is combined to realize the balanced dielectric resonator filter power divider with the characteristics of low profile, high isolation performance and high integration.

Description

TECHNICAL FIELD

[0001] The present application relates to a balanced filter power divider, in particular to a balanced dielectric resonator filter power divider. BACKGROUND

[0002] With the rapid development of wireless communication technology, microwave devices need to meet higher and higher requirements. Compared with traditional single-ended devices, balanced circuits are widely concerned due to their strong ability to suppress environmental noise. In addition, the filter circuit is a basic module of the radio frequency front end, which can filter out unwanted signals. The power divider is also an essential device in the wireless system, which can be used as a feed network for antenna arrays. Therefore, the filter power divider can realize the functions of filtering and power distribution in a single device, effectively improving the integration of the system, and has important significance for the development of wireless systems. In summary, the balanced filter power divider has important research value.

[0003] The existing reported balanced filter power divider is mainly realized based on a microstrip resonator, which has a low quality factor and relatively large loss, and the frequency selectivity needs to be improved. As a high-quality factor resonator, the dielectric resonator can effectively reduce the loss and is an excellent choice to improve the performance of the existing balanced filter power divider. However, the existing dielectric resonator filter power divider is mainly realized by combining dielectric ceramics with a metal cavity structure, which has a high profile and is not easy to integrate. Moreover, due to the limitation of the structure, additional isolation measures cannot be added, and isolation performance cannot be achieved. Therefore, it is particularly important to propose a balanced dielectric resonator filter power divider with isolation performance. SUMMARY

[0004] The present application provides a balanced dielectric resonator filter power divider with isolation performance, which reduces the profile height and improves the integration and isolation performance on the basis of ensuring the performance of the balanced dielectric resonator filter power divider.

[0005] The technical scheme is as follows: a balanced dielectric resonator filter power divider with isolation performance, comprising two metal grounds, a first low dielectric constant dielectric substrate, a second low dielectric constant dielectric substrate, a third low dielectric constant dielectric substrate, a fourth low dielectric constant dielectric substrate, and a high dielectric constant dielectric substrate.

[0006] The first rectangular air slot is provided in the center of the third low dielectric constant dielectric substrate, one side of the first rectangular air slot is provided with a pair of balanced input ports, and the other two symmetrical sides of the first rectangular air slot are respectively provided with a pair of balanced output ports. The end of the balanced input port is connected with an input coupling feed line, and the two pairs of balanced output ports are respectively connected with output coupling feed lines.

[0007] The high dielectric constant medium substrate is composed of first to third rectangular medium blocks, the first rectangular medium block and the third rectangular medium block are arranged in parallel on the same side of the long side of the second rectangular medium block; the first to third rectangular medium blocks are arranged above the input coupling feeder and two output coupling feeders respectively;

[0008] The second low dielectric constant medium substrate is located on the upper surface of the high dielectric constant medium substrate and is provided with a second rectangular air slot in the center; the first low dielectric constant medium substrate is arranged on the upper surface of the second low dielectric constant medium substrate;

[0009] The fourth low dielectric constant medium substrate is arranged on the lower surface of the third low dielectric constant medium substrate, and the fourth low dielectric constant medium substrate is provided with an isolation structure; each feeder constituting two pairs of balanced output ports on the third low dielectric constant medium substrate is connected to the isolation structure through a metal column, and the isolation structure forms a 180° phase difference between the two pairs of balanced output ports;

[0010] One of the metal grounds is arranged on the upper surface of the first low dielectric constant medium substrate, and the other metal ground is arranged on the lower surface of the fourth low dielectric constant medium substrate; the isolation structure is connected to the metal ground through a grounding metal column;

[0011] The three strip-shaped dielectric resonators are respectively composed of the metal ground, the first low dielectric constant medium substrate, the second low dielectric constant medium substrate, the third low dielectric constant medium substrate, and the first to third rectangular medium blocks, so that TE1 y 1 mode works in differential mode, TE 11 z δ mode works in common mode.

[0012] Further, the isolation structure is an axisymmetric structure composed of first to sixth metal lines, a first ground metal sheet, a second ground metal sheet, a first resistor, and a second resistor; the first metal line and the second metal line are arranged in opposite parallel, the fourth metal line and the sixth metal line are connected perpendicularly at both ends of the first metal line, the third metal line and the fifth metal line are connected perpendicularly at both ends of the second metal line, forming two opposite U-shaped metal structures; the middle part of the first metal line is connected to the second ground metal sheet through the second resistor, and the middle part of the second metal line is connected to the first ground metal sheet through the first resistor; the third metal line and the fourth metal line are connected to two feeders of a pair of the balanced output ports respectively, and the fifth metal line and the sixth metal line are connected to two feeders of another pair of the balanced output ports respectively; the second ground metal sheet and the first ground metal sheet are connected to the metal ground through grounding metal columns respectively.

[0013] Further, the width of the first rectangular air slot is greater than the width of the isolation structure.

[0014] Beneficial effects: 1. In view of the high profile, difficulty in integration and poor isolation performance of the existing medium resonator filter power divider, the application adopts a strip medium integrated structure, so that TE1 y 1 mode works in differential mode, TE 11 z δ Mode works in common mode resonator, combined with the isolation circuit mode of the layout of the laminated substrate hollow structure, a balanced medium resonator filter power divider with low profile, high isolation performance and high integration is realized.

[0015] 2. The application introduces an isolation structure at two pairs of balanced output ports. The metal line of the isolation structure is printed on the substrate 6 and connected with the balanced output port printed on the upper substrate 5 through the metal via holes 510-513 to form a phase difference of 180°. Combined with the absorption resistance, the isolation level of the filter power divider can be effectively improved. At the same time, the laminated substrate hollow structure layout facilitates the layout of the absorption resistance in the preparation process, and improves the integration of the structure.

[0016] 3. The arrangement mode of the two longitudinal resonators arranged in parallel on the same long side of the transverse resonator is beneficial to the coupling of TE1 y 1 mode, so as to facilitate the realization of filter power distribution, and on the other hand, a smaller planar size can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a three-dimensional structure diagram of the balanced medium resonator filter power divider;

[0018] Figure 2 It is a cross-sectional structure diagram of the balanced medium resonator filter power divider;

[0019] Figure 3 It is a differential mode response curve of the filter power divider;

[0020] Figure 4 It is a common mode response curve of the filter power divider. DETAILED DESCRIPTION

[0021] The application will be further explained below in combination with the drawings.

[0022] The existing balanced filter power divider is mainly realized based on a microstrip resonator, and the loss is relatively large, and the frequency selectivity needs to be improved. On the other hand, the existing medium resonator filter power divider is mainly realized by combining ceramic medium with metal cavity structure, and the profile is relatively high, which is not easy to integrate, and the isolation performance is poor.

[0023] As Figure 1 , Figure 2As shown, a balanced type of dielectric resonator filter power divider with isolation characteristics adopts a strip dielectric integrated structure, including two metal grounds 1, a first low dielectric constant dielectric substrate 2, a second low dielectric constant dielectric substrate 3, a third low dielectric constant dielectric substrate 5, a fourth low dielectric constant dielectric substrate 6, and a high dielectric constant dielectric substrate 4.

[0024] The third low dielectric constant dielectric substrate 5 is centrally provided with a rectangular air slot 514. The third low dielectric constant dielectric substrate 5 is provided with a pair of balanced type input ports and two pairs of balanced type output ports. The balanced type input port is composed of a feed line 51 and a feed line 52 arranged at one side of the rectangular air slot 514, and an input coupling feed line 53 is arranged at the same side, and the ends of the parallel arranged feed line 51 and the feed line 52 are connected to the input coupling feed line 53. The two pairs of balanced type output ports are symmetrically arranged at the other two sides of the rectangular air slot 514, one pair of balanced type output ports is composed of a parallel arranged feed line 54 and a feed line 55, and the ends of the feed line 54 and the feed line 55 are connected to the output coupling feed line 56 at the same side; the other pair of balanced type output ports is composed of a parallel arranged feed line 57 and a feed line 58, and the ends of the feed line 57 and the feed line 58 are connected to the output coupling feed line 59 at the same side.

[0025] The high dielectric constant dielectric substrate 4 is composed of three rectangular dielectric blocks 41-43, and the rectangular dielectric block 41 and the rectangular dielectric block 43 are arranged in parallel at the same side of the long side of the rectangular dielectric block 42. The three rectangular dielectric blocks 41-43 are arranged above the input coupling feed line 53 and the two output coupling feed lines 56 and 59, respectively. The second low dielectric constant dielectric substrate 3 is provided with a rectangular air slot 31, and the second low dielectric constant dielectric substrate 3 is arranged on the upper surface of the high dielectric constant dielectric substrate 4. The first low dielectric constant dielectric substrate 2 is arranged on the upper surface of the second low dielectric constant dielectric substrate 3.

[0026] The fourth low dielectric constant dielectric substrate 6 is arranged on the lower surface of the third low dielectric constant dielectric substrate 5, and the fourth low dielectric constant dielectric substrate 6 is provided with a printed isolation structure. The isolation structure is an axisymmetric structure, and the axis of symmetry is parallel to the input coupling feed line 53, and the isolation structure is composed of metal wires 61-66, ground metal sheets 69 and 610, two resistors 67 and 68. The metal wire 61 and the metal wire 62 are arranged in opposite parallel, the metal wire 64 and the metal wire 66 are vertically connected at both ends of the metal wire 61, the metal wire 63 and the metal wire 65 are vertically connected at both ends of the metal wire 62, the middle part of the metal wire 61 is connected to the ground metal sheet 610 through the resistor 68, and the middle part of the metal wire 62 is connected to the ground metal sheet 69 through the resistor 67. Moreover, the width of the rectangular air slot 514 on the third low dielectric constant dielectric substrate 5 is greater than the width of the isolation structure, which provides space for the welding of the resistors 67 and 68 in the later stage.

[0027] The two pairs of balanced output port feed lines 54, 55, 57, 58 are connected to the isolation structure metal lines 63-66 printed on the fourth low dielectric constant dielectric substrate 6 through metal columns 510-513. One metal ground 1 is provided on the upper surface of the first low dielectric constant dielectric substrate 2, and another metal ground 1 is provided on the lower surface of the fourth low dielectric constant dielectric substrate 6. The ground metal sheet 610 and the ground metal sheet 69 of the isolation structure are connected to the metal ground 1 through ground metal columns 611, 612.

[0028] Each strip dielectric resonator is composed of a metal ground 1, a first low dielectric constant dielectric substrate 2, a second low dielectric constant dielectric substrate 3, a rectangular dielectric block 41-43, and a third low dielectric constant dielectric substrate 5. For the balanced dielectric resonator filter power divider proposed in the present application, a differential signal is input from a pair of balanced input ports, excites a resonant mode in the strip dielectric resonator composed of the rectangular dielectric block 42, the signal is coupled to the strip dielectric resonators composed of the other two rectangular dielectric blocks 41, 43, and is output through the two pairs of balanced output ports, forming a one-to-two filter power divider. Specifically, when the differential signal is excited, a TE1 y 11 mode in the strip dielectric resonator is excited, the signal coupling excites a TE1 y 1 mode in the other two strip dielectric resonators, thereby forming a one-to-two differential filter frequency band. Moreover, due to the coupling between the source and the load, transmission zeros are generated at the upper and lower edges of the two passbands, thereby improving the frequency selectivity. In addition, due to the isolation structure forming a 180° phase difference between the two pairs of balanced output ports and the combination of the absorption resistors 67, 68, isolation between the output ports is achieved. At the same time, when a common mode signal is input, a TE 11 z δ mode in the strip dielectric resonator is excited, and since the common mode and the differential mode do not resonate at the same frequency point, the power divider has good common mode characteristics.

[0029] An embodiment of the present application is listed below, the circuit structure schematic diagram is shown in Figure 1 The dielectric substrates 2 and 6 used are RO4003C substrates with a dielectric constant of 3.55, a loss angle of 0.0027, and a thickness of 0.203 mm; the dielectric substrates 3 and 5 are RO4003C substrates with a dielectric constant of 3.55, a loss angle of 0.0027, and a thickness of 0.913 mm; and the dielectric substrate 4 has a dielectric constant of 9.9, a loss angle of 0.00015, and a thickness of 3.1 mm. The center frequencies of the differential mode frequency bands are set to be 11.62 GHz, and the frequency response simulation diagrams are shown in Figure 3 and Figure 4As shown, the transmission zero points on both sides of the differential mode passband are located at 11.5GHz and 12.1GHz respectively. The 3-dB relative bandwidth is 0.52%, the minimum insertion loss is 1.2dB, the isolation level in the passband reaches 15dB, and the common mode suppression level reaches 28dB, thereby ensuring good isolation performance and common mode performance. The physical size of the filter is 50mmx50mmx5.366mm.

[0030] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A balanced mode dielectric resonator filter power divider having isolation characteristics, characterized by, It includes two metal grounds (1), a first low dielectric constant dielectric substrate (2), a second low dielectric constant dielectric substrate (3), a third low dielectric constant dielectric substrate (5), a fourth low dielectric constant dielectric substrate (6), and a high dielectric constant dielectric substrate (4). The third low dielectric constant substrate (5) has a first rectangular air slot (514) in the center. A pair of balanced input ports are provided on one side of the first rectangular air slot (514), and a pair of balanced output ports are provided on the other two symmetrical sides of the first rectangular air slot (514). The end of the balanced input port is connected to the input coupling feed line (53), and the two pairs of balanced output ports are respectively connected to the output coupling feed line. The high dielectric constant dielectric substrate (4) is composed of first to third rectangular dielectric blocks (41-43). The first rectangular dielectric block (41) and the third rectangular dielectric block (43) are arranged in parallel on the same side of the long side of the second rectangular dielectric block (42). The first to third rectangular dielectric blocks (41-43) are respectively arranged above the input coupling feed line (53) and the two output coupling feed lines. The second low dielectric constant dielectric substrate (3) is located on the upper surface of the high dielectric constant dielectric substrate (4) and has a second rectangular air groove (31) in the center; the first low dielectric constant dielectric substrate (2) is disposed on the upper surface of the second low dielectric constant dielectric substrate (3); A fourth low dielectric constant substrate (6) is disposed on the lower surface of the third low dielectric constant substrate (5), and an isolation structure is provided on the fourth low dielectric constant substrate (6); on the third low dielectric constant substrate (5), each feed line constituting two pairs of balanced output ports is connected to the isolation structure through a metal pillar, and the isolation structure forms a 180° phase difference between the two pairs of balanced output ports. One of the metal grounds (1) is disposed on the upper surface of the first low dielectric constant substrate (2), and the other metal ground (1) is disposed on the lower surface of the fourth low dielectric constant substrate (6); the isolation structure is connected to the metal ground (1) through a grounded metal post; The three stripline dielectric resonators are respectively composed of the metal ground (1), the first low dielectric constant dielectric substrate (2), the second low dielectric constant dielectric substrate (3), the third low dielectric constant dielectric substrate (5) and the first to third rectangular dielectric blocks (41-43), so that TE1 y 1 mode works in differential mode, TE 11 z δ mode works in common mode.

2. The balanced dielectric resonator filter power divider with isolation characteristics according to claim 1, characterized in that, The isolation structure is an axisymmetric structure, consisting of first to sixth metal wires (61-66), a first ground metal plate (69), a second ground metal plate (610), a first resistor (67), and a second resistor (68); the first metal wire (61) and the second metal wire (62) are arranged parallel to each other, the fourth metal wire (64) and the sixth metal wire (66) are perpendicularly connected to the two ends of the first metal wire (61), and the third metal wire (63) and the fifth metal wire (65) are perpendicularly connected to the two ends of the second metal wire (62), forming two opposing U-shaped metal structures; the first metal... The middle part of the wire (61) is connected to the second grounding metal piece (610) through the second resistor (68), and the middle part of the second metal wire (62) is connected to the first grounding metal piece (69) through the first resistor (67); the third metal wire (63) and the fourth metal wire (64) are respectively connected to the two feed lines of a pair of balanced output ports, and the fifth metal wire (65) and the sixth metal wire (66) are respectively connected to the two feed lines of another pair of balanced output ports; the second grounding metal piece (610) and the first grounding metal piece (69) are respectively connected to the metal ground (1) through grounding metal posts.

3. The balanced dielectric resonator filter power divider with isolation characteristics according to claim 2, characterized in that, The width of the first rectangular air groove (514) is greater than the width of the isolation structure.

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