A hairpin filter

Abstract

The present invention relates to the field of radio frequency integrated circuits and specifically discloses a hairpin filter, wherein the filter adopts a double-row structure with dielectric through holes to enhance the coupling effect of the hairpin unit; at the same time, the dielectric through hole size with a larger spacing is set to effectively reduce the difficulty of process manufacturing; and the use of a ceramic substrate can further improve the heat dissipation characteristics of the device.

Description

Technical Field

[0001] The present invention belongs to the field of radio frequency integrated circuits, and more specifically relates to a hairpin filter with an operating frequency band of 51.07 GHz to 56.86 GHz. Background Art

[0002] With the rapid development of wireless communication technology, people have been developing the microwave frequency band of electromagnetic waves more and more deeply, which has led to the emergence of problems such as frequency band congestion, transmission delay, signal interference, and transmission loss. ITU defines satellite communication frequency band V: 40~75GHz, which has great application value.

[0003] In the field of wireless communications, RF transceiver systems include active devices and passive devices. Filters are one of the most important components of the front-end network of wireless network base stations, and have four functional forms: bandpass, bandstop, lowpass, and highpass. Passive filters realize the functions of frequency selection and out-of-band suppression in passive devices, and their importance is self-evident.

[0004] Passive filters mainly include two categories: waveguide filters and microstrip filters. Passive filters include microstrip line filters, waveguide filters, coaxial line filters, dielectric filters and substrate integrated waveguide filters. The most widely used are microstrip line filters and substrate integrated waveguide filters. Among them, the most advantageous microstrip line hairpin filter is the hairpin filter. However, the existing hairpin filter with an operating frequency band of 51.07GHz to 56.86GHz is lacking in coupling performance, as well as the excellent characteristics of ceramics and the inability of dielectric through-hole structures to achieve strong coupling. There are deficiencies in the existing technology. Summary of the invention

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The present invention provides a hairpin filter, comprising a dielectric through hole, an interconnection line and a feeder line; the dielectric through hole is a vertical cylindrical structure; the interconnection line and the feeder line are horizontal square strip structures; the interconnection line comprises a front column interconnection line and a rear column interconnection line; the length of the rear column interconnection line is greater than the length of the front column interconnection line; the length of the front column interconnection line is greater than the length of the feeder line;

[0007] Twenty dielectric through holes are arranged vertically on the substrate in an array of two columns and ten rows; the ten dielectric through holes in the rear column correspond to the ten dielectric through holes in the front column;

[0008] In the dielectric through holes of the front row, the ends on the same side of every two dielectric through holes are respectively connected to the two ends of one of the front row interconnection lines to form a U-shaped hairpin unit; the lower end of the dielectric through hole is connected to the front row interconnection line to form a positive U-shaped hairpin unit; the upper end of the dielectric through hole is connected to the front row interconnection line to form a reverse U-shaped hairpin unit; the five U-shaped hairpin units of the front row are arranged in reverse and forward order to form a signal transmission layer; feed lines are respectively arranged on the outer ends of the front row interconnection lines of the reverse U-shaped hairpin units at both ends;

[0009] The ten dielectric through holes in the rear row are simultaneously connected in parallel between two rear row interconnection lines to form a grounding layer; and feed lines are respectively arranged on both ends of the rear row interconnection line connected to the upper ends of the dielectric through holes.

[0010] The filter of the present invention adopts a double-row structure with a dielectric through hole as a hairpin unit arm. The three-dimensional hairpin structure is coupled with the traditional microstrip line form (the thickness of the microstrip is very thin, resulting in a very small coupling area), which increases the coupling area of ​​the hairpin unit, strengthens the coupling effect of the hairpin unit, and is more conducive to signal transmission. At the same time, compared with the existing design of the side spacing of the dielectric through hole generally being 0.5 times the diameter to 1 times the diameter, the spacing of the hairpin unit of the present application is at least 3.6 times the diameter of the dielectric through hole, which effectively reduces the difficulty of process manufacturing. Further use of a ceramic substrate can improve the heat dissipation characteristics of the device.

[0011] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention.

[0013] Figure 1 It is a schematic diagram of the structure of the hairpin filter of the present invention. DETAILED DESCRIPTION

[0014] The following is combined with Figure 1 The present invention is described in further detail so that those skilled in the art can implement it according to the description.

[0015] It should be understood that terms such as “having”, “including” and “comprising” used herein do not specify the existence or addition of one or more other elements or combinations thereof.

[0016] like Figure 1As shown, a hairpin filter comprises a dielectric through hole, an interconnection line and a feed line; the dielectric through hole is a vertical cylindrical structure; the interconnection line and the feed line are horizontal square strip structures; the interconnection line comprises a front column interconnection line and a rear column interconnection line; the length of the rear column interconnection line is greater than the length of the front column interconnection line; the length of the front column interconnection line is greater than the length of the feed line;

[0017] Twenty dielectric through holes are arranged vertically on the substrate in an array of two columns and ten rows; the ten dielectric through holes in the rear column correspond to the ten dielectric through holes in the front column;

[0018] In the dielectric through holes of the front row, the ends on the same side of every two dielectric through holes are respectively connected to the two ends of one of the front row interconnection lines to form a U-shaped hairpin unit; the lower end of the dielectric through hole is connected to the front row interconnection line to form a positive U-shaped hairpin unit; the upper end of the dielectric through hole is connected to the front row interconnection line to form a reverse U-shaped hairpin unit; the five U-shaped hairpin units of the front row are arranged in reverse and forward order to form a signal transmission layer; feed lines are respectively arranged on the outer ends of the front row interconnection lines of the reverse U-shaped hairpin units at both ends;

[0019] The ten dielectric through holes in the rear row are simultaneously connected in parallel between two rear row interconnection lines to form a grounding layer; and feed lines are respectively arranged on both ends of the rear row interconnection line connected to the upper ends of the dielectric through holes.

[0020] Specifically, the present application adopts a three-dimensional hairpin structure to set the filter. Compared with the coupling form of the traditional microstrip line form (the thickness of the microstrip is very thin, resulting in a very small coupling area), it effectively increases the coupling area of ​​the U-shaped hairpin unit, strengthens the coupling effect of the U-shaped hairpin unit, and is more conducive to signal transmission.

[0021] Furthermore, the signal transmission layer has a bilaterally symmetrical structure; and the ground layer has a bilaterally symmetrical structure.

[0022] Furthermore, the intervals between the five U-shaped hairpin units in the front row are 0.127 mm, 0.178 mm, 0.178 mm and 0.127 mm respectively; the spacing between the front row and the rear row is 0.254 mm.

[0023] Furthermore, the dimensions of the medium through hole are: diameter 0.035 mm, height 0.254 mm.

[0024] Furthermore, the dimensions of the front row interconnection lines are: width 0.035 mm, height 0.035 mm, length 0.578 mm; the dimensions of the rear row interconnection lines are: width 0.035 mm, height 0.035 mm, length 3.5 mm.

[0025] Furthermore, the dimensions of the feed line are: width 0.035 mm, height 0.035 mm, and length 0.27 mm.

[0026] Compared with the existing design in which the side spacing of the medium through hole is generally 0.5 times the diameter to 1 times the diameter, the structure of the U-shaped hairpin unit has a spacing of at least 3.6 times the diameter of the medium through hole, which effectively reduces the difficulty of process manufacturing.

[0027] Furthermore, the substrate is made of ceramic material, so that the filter arranged thereon can effectively improve the heat dissipation characteristics of the device and increase the working stability of the filter.

[0028] Furthermore, the operating frequency band of the hairpin filter is 51.07 GHz to 56.86 GHz.

[0029] The filter of the present invention adopts a double-row structure with dielectric through holes to strengthen the coupling effect of the hairpin unit; at the same time, setting the dielectric through hole size with a larger spacing effectively reduces the difficulty of process manufacturing; further adopting a ceramic substrate can improve the heat dissipation characteristics of the device.

[0030] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, other modifications can be easily realized. Therefore, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive. Under the enlightenment of the present invention, those of ordinary skill in the art can also make many forms without departing from the scope of the present invention and the claims, all of which belong to the protection of the present invention.

Claims

1. A hairpin filter, comprising a dielectric through hole, an interconnection line and a feed line; characterized in that: The dielectric through hole is a vertical cylindrical structure; the interconnection line and the feed line are horizontal square strip structures; the interconnection line includes a front column interconnection line and a rear column interconnection line; the length of the rear column interconnection line is greater than the length of the front column interconnection line; the length of the front column interconnection line is greater than the length of the feed line; Twenty dielectric through holes are arranged vertically on the substrate in an array of two columns and ten rows; the ten dielectric through holes in the rear column correspond to the positions of the ten dielectric through holes in the front column; In the dielectric through holes of the front row, the ends on the same side of every two dielectric through holes are respectively connected to the two ends of one of the front row interconnection lines to form a U-shaped hairpin unit; the lower end of the dielectric through hole is connected to the front row interconnection line to form a positive U-shaped hairpin unit; the upper end of the dielectric through hole is connected to the front row interconnection line to form a reverse U-shaped hairpin unit; the five U-shaped hairpin units of the front row are arranged in reverse and forward order to form a signal transmission layer; feed lines are respectively arranged on the outer ends of the front row interconnection lines of the reverse U-shaped hairpin units at both ends; The ten dielectric through holes in the rear row are simultaneously connected in parallel between two rear row interconnection lines to form a grounding layer; and feed lines are respectively arranged on both ends of the rear row interconnection line connected to the upper ends of the dielectric through holes.

2. A hairpin filter as claimed in claim 1, characterized in that: The signal transmission layer has a bilaterally symmetrical structure; the ground layer has a bilaterally symmetrical structure.

3. A hairpin filter as claimed in claim 2, characterized in that: The intervals between the five U-shaped hairpin units in the front row are 0.127 mm, 0.178 mm, 0.178 mm and 0.127 mm respectively; the distance between the front row and the rear row is 0.254 mm.

4. A hairpin filter as claimed in claim 3, characterized in that: The dimensions of the medium through hole are: diameter 0.035 mm, height 0.254 mm.

5. A hairpin filter as claimed in claim 4, characterized in that: The dimensions of the front row interconnection lines are: width 0.035 mm, height 0.035 mm, length 0.578 mm; the dimensions of the rear row interconnection lines are: width 0.035 mm, height 0.035 mm, length 3.5 mm.

6. A hairpin filter as claimed in claim 5, characterized in that: The dimensions of the feed line are: width 0.035 mm, height 0.035 mm, and length 0.27 mm.

7. A hairpin filter as claimed in claim 6, characterized in that: The substrate is made of ceramic material.

8. A hairpin filter as claimed in claim 7, characterized in that: The operating frequency band of the hairpin filter is 51.07 GHz to 56.86 GHz.

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