CN117525784A

CN117525784A - LTCC miniaturized millimeter wave filtering-power division-balun module

Info

Publication number: CN117525784A
Application number: CN202311533861.1A
Authority: CN
Inventors: 吴先良; 李媛媛; 吴博; 王刚; 李园园; 汪海港; 王尹; 尹文静; 李晓敏
Original assignee: Anhui Lanxun Communication Technology Co ltd
Current assignee: Anhui Lanxun Communication Technology Co ltd
Priority date: 2023-11-14
Filing date: 2023-11-14
Publication date: 2024-02-06

Abstract

The invention discloses an LTCC miniaturized millimeter wave filtering-power dividing-balun module which comprises a filter, a power divider, a balun and an LTCC medium substrate, wherein the filter, the power divider and the balun are sequentially connected through a similar coaxial structure and are arranged on the LTCC medium substrate in a stacked mode. The filter adopts a folding substrate waveguide structure and comprises four resonant cavities which are vertically arranged and mutually coupled, the power divider is a first-order Wilkinson power divider, and the balun is a Marchand balun structure. The invention integrates the filter, the power divider and the balun device at the front end of the radio frequency in one module based on the LTCC technology, reduces the arrangement of additional matching circuits and components compared with the independent application of a single device in a system, reduces the plane size, has the advantages of high integration level and small volume, can work in the 5G millimeter wave n258 frequency band, and meets the requirements of modern 5G communication.

Description

LTCC miniaturized millimeter wave filtering-power division-balun module

Technical Field

The invention relates to the technical field of millimeter wave communication devices, in particular to an LTCC miniaturized millimeter wave filtering-power division-balun module.

Background

Millimeter wave has higher spectral efficiency and higher data rate, millimeter wave communication has received much attention in recent years than ever before, and has become a necessary trend in upcoming fifth generation (5G) communication and even 5G backward communication. At the front end of millimeter wave, reducing loss is a necessary condition for ensuring the practical trend of millimeter wave technology. Among them, a fusion device integrating two or more functions into one circuit has become a popular design method, which can avoid the use of a connection line of standard 50Ω between a plurality of devices as in the conventional cascade design, and can effectively reduce circuit loss. The filter is a frequency selection element and is widely used at the millimeter wave front end for suppressing harmonic waves or image frequency interference; the power divider is used for dividing or synthesizing signals. In radio frequency systems, therefore, there is a great deal of interest in filter-power splitters formed by the high integration of two important passive components in modern wireless communication systems.

In addition, balun is widely used in radio frequency front ends, such as in the feed network of dipole antennas or other differential antennas, where balun is typically required to convert an unbalanced single-ended signal to a balanced or differential signal. A balanced circuit is essential for modern communication systems because it is highly resistant to ambient noise, electromagnetic interference. Balun is a key component in many microwave millimeter wave systems, and with the continuous development of communication technology today, there is an urgent need for balun with miniaturization, wide frequency band, easy integration and high performance.

Filters, power splitters and balun are all key components of the rf front-end, and are usually designed independently, and are applied to a system, and are required to be cascaded through additional transmission lines, and additional circuits may be required to perform matching between the components.

The advent of LTCC technology (Low Temperature Co-visual Ceramic technology), has been a direction of development in the field of passive components. The LTCC technology is to make low temperature sintered ceramic powder into compact ceramic belt, to make required circuit pattern with laser drilling, micro-hole grouting, precise conductor slurry printing, etc. on the ceramic belt, to embed several passive components, such as capacitor, resistor, filter, impedance converter, coupler, etc. into multilayer ceramic substrate, to laminate, to make internal and external electrodes with silver, copper, gold, etc. metal, to sinter at 900 deg.c to form high density circuit with no mutual interference in three-dimensional space, to form passive or active integrated functional module, to miniaturize the circuit and to make the density higher, and to be used in high frequency communication components.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide an LTCC miniaturized millimeter wave filtering-power dividing-balun module, which adopts the improvement of adopting a filter, a power divider and a balun as a laminated design, thereby solving the problems that a radio frequency device is difficult to integrate and the whole volume of the radio frequency device integrated in a system is larger while the performance of the system is ensured.

In order to achieve the above purpose, the present invention provides the following technical solutions: an LTCC miniaturized millimeter wave filtering-power division-balun module comprising:

the filter comprises a plurality of resonant cavities, wherein the resonant cavities are all arranged into a folded substrate waveguide structure and are mutually coupled;

the power divider is connected with the filter through a quasi-coaxial structure so as to realize impedance matching between the filter and the power divider;

the balun is connected with the power divider through a coaxial-like structure, so that impedance matching between the power divider and the balun can be realized, and the number of the balun is two;

the LTCC medium substrates are stacked, and the filter, the power divider and the balun are sequentially stacked on the LTCC medium substrates.

In some embodiments, the number of LTCC dielectric substrates is fifteenth, including first to fifteenth dielectric substrates, the filter is disposed on the first to eighth dielectric substrates, the power divider is disposed on the ninth to twelfth dielectric substrates, and the balun is disposed on the thirteenth to fifteenth dielectric substrates.

In some embodiments, the filter includes four resonators including first to fourth resonators, the first resonator is disposed on first to second dielectric substrates, the second resonator is disposed on third to fourth dielectric substrates, the third resonator is disposed on fifth to sixth dielectric substrates, and the fourth resonator is disposed on seventh to eighth dielectric substrates.

In some embodiments, a plurality of metal through holes are regularly distributed around the inside of the first to eighth dielectric substrates, the upper and lower layers of the first to eighth dielectric substrates are respectively provided with a metal grounding layer, the upper metal grounding layers of the second, fourth and sixth dielectric substrates are provided with a first rectangular slot for mutual coupling between the first to fourth resonant cavities, the upper metal grounding layers of the first, third, fifth and seventh dielectric substrates are provided with an L-shaped slot, the metal grounding layers, the L-shaped slots and the metal through holes are jointly used for forming the first to fourth resonant cavities, one side of the L-shaped slot of the upper metal grounding layer of the first dielectric substrate is provided with a first rectangular slot, the number of the first rectangular slots is two, the lower metal grounding layer of the first dielectric substrate is provided with a first circular hole, a first metal column is arranged in the first circular hole, one side of the L-shaped slot of the lower metal grounding layer of the eighth dielectric substrate is provided with a second rectangular slot for feeding and inputting power to the filter, the second rectangular slot is arranged on one side of the L-shaped slot of the lower metal grounding layer of the second dielectric substrate, the second rectangular slot is commonly used for feeding power to the filter, the second rectangular slot is arranged on the second rectangular slot is also arranged on the upper metal grounding layer of the eighth dielectric substrate, and the second rectangular slot is jointly used for feeding power to the second rectangular slot is used for feeding power to the second rectangular slot.

In some embodiments, the power divider is a first-order Wilkinson power divider including a resistor and a metal strip line structure, a metal ground layer is arranged on the upper layer of the twelfth dielectric substrate, a plurality of metal through holes are regularly distributed around the inside of the ninth to twelfth dielectric substrates, so that the metal ground layer between the eighth dielectric substrate and the twelfth dielectric substrate can be well contacted, energy leakage is reduced, the metal strip line structure and the resistor are arranged on the upper layer of the tenth dielectric substrate, a third circular hole and a third metal column are arranged on the lower layer metal ground layer of the ninth dielectric substrate, the third metal column is arranged in the third circular hole, the third metal column is connected with the second metal column through a coaxial-like structure and used for feeding and inputting the metal strip line structure, a fourth circular hole and a fourth metal column are further arranged on the upper layer metal ground layer of the twelfth dielectric substrate and are arranged in the fourth circular hole and used for feeding and outputting the metal strip line structure, and the fourth circular hole is further used for cutting off the upper layer metal ground layer of the twelfth dielectric substrate and outputting the power divider.

In some embodiments, the metal strip line structures have two identical branch structures, each metal strip line structure is composed of three parts, the first part is 0.7mm long, the width is 0.26mm, the second part is 1.4mm long, the width is 0.11mm, the third part is 0.3mm long, the width is 0.26mm, the resistor of the power divider is 120Ω, the material used for the resistor of the power divider is FX87 resistor paste, and the power divider is used for equally dividing the output signal of the filter into two paths of signals.

In some embodiments, the balun is a Marchand balun structure, the number of the balun is two, a layer of metal strip lines are arranged on the upper layers of the thirteenth and fourteenth medium substrates, three grounding metal posts are further arranged on the thirteenth medium substrate, and the grounding metal posts are coupled with the metal strip lines of the thirteenth medium substrate and are commonly used for forming the Marchand balun structure.

In some embodiments, a metal grounding layer is disposed on an upper layer of the fifteenth dielectric substrate, a plurality of metal through holes are regularly distributed around the inside of the thirteenth to fifteenth dielectric substrates, so that the metal grounding layer between the twelfth dielectric substrate and the fifteenth dielectric substrate can be well contacted and energy leakage is reduced, a fifth circular hole is further disposed on the thirteenth dielectric substrate, a fifth metal column is disposed in the fifth circular hole, the fifth metal column and the fourth metal column are connected through a coaxial-like structure and used for feeding and inputting the balun, a sixth circular hole is further disposed on the fifteenth dielectric substrate, and a sixth metal column is disposed in the sixth circular hole and used for feeding and outputting the balun.

In some embodiments, the material of the LTCC dielectric substrate is made by using an LTCC process, the material of the LTCC dielectric substrate is Ferro-A6, the dielectric constant is 5.9, and the loss tangent is 0.0015.

In some embodiments, the metal material in the metal ground layer, the metal via, and the first through sixth metal posts is silver.

The beneficial effects of the invention are as follows: the filter, the power divider and the balun device in the radio frequency front end are designed in a laminated mode by using an LTCC technology and integrated in a module, wherein the filter adopts a folded substrate waveguide structure, has the advantages of low radiation loss, high quality factor, small volume, easiness in integration and the like, the power divider adopts a first-order Wilkinson power divider structure, has the advantages of low loss, high isolation and the like, and the balun adopts a Marchand balun structure, so that the conversion from differential to single-ended signals can be realized, and the module has the advantages of simple structure, large broadband, small amplitude imbalance, small phase imbalance and the like, and the working frequency band of the module comprises the whole n258 frequency band, thereby meeting the requirements of modern 5G communication.

Drawings

Fig. 1 is a schematic perspective view of an embodiment of an LTCC miniaturized millimeter wave filtering-power division-balun module according to the present invention;

fig. 2 is a perspective view of the LTCC miniature millimeter wave filter-power division-balun module shown in fig. 1;

fig. 3 is a schematic perspective view of a filter of the LTCC miniaturized millimeter wave filtering-power division-balun module shown in fig. 1;

fig. 4 is a schematic perspective view of a first resonant cavity of a filter of the LTCC miniaturized millimeter wave filtering-power division-balun module shown in fig. 3;

fig. 5 is a schematic perspective view of a second resonant cavity of a filter of the LTCC miniaturized millimeter wave filtering-power division-balun module shown in fig. 3;

fig. 6 is a schematic perspective view of a third resonant cavity of a filter of the LTCC miniaturized millimeter wave filtering-power division-balun module shown in fig. 3;

fig. 7 is a schematic perspective view of a fourth resonant cavity of a filter of the LTCC miniature millimeter wave filtering-power dividing-balun module shown in fig. 3;

fig. 8 is a schematic diagram of a three-dimensional structure of a power divider of the LTCC miniaturized millimeter wave filtering-power dividing-balun module shown in fig. 1;

fig. 9 is a top view of a power divider of the LTCC miniature millimeter wave filter-power divider-balun module shown in fig. 8;

fig. 10 is a schematic diagram of a balun structure of the LTCC miniaturized millimeter wave filter-power division-balun module shown in fig. 1.

Detailed Description

In order that the invention may be readily understood, a more particular description thereof will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Along with the continuous iterative development of information technology, 5G millimeter waves get more and more attention, millimeter waves have the advantages of good transmission directivity, high transmission efficiency, safe communication, strong reliability, high transmission quality and the like, can also realize a plurality of services which cannot be provided by 4G, expand the application range and development space of 5G, and in order to adapt to the development of information technology, a radio frequency front-end device with the advantages of smaller loss, higher integration level, more stable transmission signals and the like is required to increase market competitiveness.

In view of the foregoing, the present application provides an LTCC miniaturized millimeter wave filtering-power dividing-balun module, referring to fig. 1, fig. 1 is a schematic perspective view of an embodiment of the LTCC miniaturized millimeter wave filtering-power dividing-balun module according to the present invention, where the module includes, but is not limited to, a filter 1, a power divider 2, a balun 3, and an LTCC dielectric substrate 4. It should be noted that the terms "comprising" and "having," and any variations thereof, in the embodiments of the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may alternatively include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Specifically, the number of LTCC dielectric substrates 4 is plural and stacked, and the filter 1, the power splitter 2, and the balun 3 are stacked on the LTCC dielectric substrates 4 in this order, and referring to fig. 1 and 2 together, fig. 2 is a perspective view of the LTCC miniaturized millimeter wave filtering-power splitting balun module shown in fig. 1, and fig. 2 is a perspective view from the right side of fig. 1, optionally, in this embodiment, the number of LTCC dielectric substrates 4 is fifteen, and includes, from bottom to top, a first dielectric substrate 401, a second dielectric substrate 402, a third dielectric substrate 403, a fourth dielectric substrate 404, a fifth dielectric substrate 405, a sixth dielectric substrate 406, a seventh dielectric substrate 407, an eighth dielectric substrate 408, a ninth dielectric substrate 409, a tenth dielectric substrate 410, an eleventh dielectric substrate 411, a twelfth dielectric substrate 412, a thirteenth dielectric substrate 413, a fourteenth dielectric substrate 414, and a fifteenth dielectric substrate 415. It should be noted that the terms "first," "second," and the like in the embodiments of the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining a term "first," "second," etc. may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

With continued reference to fig. 1-2 in conjunction with fig. 3-7, fig. 3 is a schematic perspective view of a filter of the LTCC miniaturized millimeter wave filter-power division-balun module shown in fig. 1, fig. 4 is a schematic perspective view of a first resonant cavity of the filter of the LTCC miniaturized millimeter wave filter-power division-balun module shown in fig. 3, fig. 5 is a schematic perspective view of a second resonant cavity of the filter of the LTCC miniaturized millimeter wave filter-power division-balun module shown in fig. 3, fig. 6 is a schematic perspective view of a third resonant cavity of the filter of the LTCC miniaturized millimeter wave filter-power division-balun module shown in fig. 3, fig. 7 is a schematic perspective view of a fourth resonant cavity of the filter of the LTCC miniaturized millimeter wave filter-power division-balun module shown in fig. 3, the filter 1 is disposed at the bottom of the LTCC dielectric substrate 4, specifically, the filter 1 includes the first resonant cavity 11, the second resonant cavity 12, the third resonant cavity 13 and the fourth resonant cavity 14, the four iw resonant cavities (Folded Substrate Integrated Waveguide) are disposed at the bottom of the LTCC dielectric substrate 4, and the eighth dielectric substrate 408 is disposed between the first and eighth dielectric substrate 408 is disposed. Optionally, the first resonant cavity 11 is disposed on the first dielectric substrate 401 to the second dielectric substrate 402, the second resonant cavity 12 is disposed on the third dielectric substrate 403 to the fourth dielectric substrate 404, the third resonant cavity 13 is disposed on the fifth dielectric substrate 405 to the sixth dielectric substrate 406, and the fourth resonant cavity 14 is disposed on the seventh dielectric substrate 407 to the eighth dielectric substrate 408.

Referring to fig. 1-2 in conjunction with fig. 8, fig. 8 is a schematic perspective view of a power divider of the LTCC miniaturized millimeter wave filtering-power dividing-balun module shown in fig. 1, where the power divider 2 is disposed in the middle of the LTCC dielectric substrate 4, specifically, the power divider 2 is disposed between the ninth dielectric substrate 409 and the twelfth dielectric substrate 412; with continued reference to fig. 1-2 in conjunction with fig. 10, fig. 10 is a schematic perspective view of a balun of the LTCC miniaturized millimeter wave filtering-power dividing-balun module shown in fig. 1, where the balun 3 is disposed on top of the LTCC dielectric substrate 4, specifically, the number of the balun 3 is two, and both of them are disposed between the thirteenth dielectric substrate 413 and the fifteenth dielectric substrate 415.

Alternatively, in the present embodiment, the filter 1, the power divider 2 and the balun 3 are connected by a coaxial-like structure, and impedance matching among the filter 1, the power divider 2 and the balun 3 can be achieved by adjusting the inner and outer diameters of the coaxial-like connector. Wherein, the filter 1, the power divider 2 and the balun 3 all adopt a coaxial line-to-strip line structure for input/output feed.

In this embodiment, the size of the whole LTCC miniaturized millimeter wave filtering-power dividing-balun module is 3.07mm×2.57mm×1.44mm, wherein the material of the LTCC dielectric substrate 4 is manufactured by using an LTCC process, the material of the LTCC dielectric substrate 4 is Ferro-A6, the dielectric constant is 5.9, the loss tangent is 0.0015, and the height of each layer of dielectric substrate is 0.096mm, so that the device has the advantages of high integration level and small volume. It should be noted that the operating frequency band of the whole module is n258 frequency band, n258 frequency band is one of the operating frequency bands of 5G millimeter wave communication, and the frequency spectrum range is 24.25GHz to 27.5GHz.

Referring to fig. 2 together with fig. 3 to 7, as shown in fig. 2, a plurality of metal through holes 5 are regularly distributed around the inner portions of the first dielectric substrate 401, the second dielectric substrate 402, the third dielectric substrate 403, the fourth dielectric substrate 404, the fifth dielectric substrate 405, the sixth dielectric substrate 406, the seventh dielectric substrate 407 and the eighth dielectric substrate 408, and the upper layer and the lower layer are both provided with metal grounding layers. Referring to fig. 4-7, the upper metal grounding layer 4021 of the second dielectric substrate, the upper metal grounding layer 4041 of the fourth dielectric substrate, and the upper metal grounding layer 4061 of the sixth dielectric substrate are respectively provided with a first linear groove 40211, a second linear groove 40411, and a third linear groove 40611, which are respectively used for mutual coupling between the first resonant cavity 11 and the second resonant cavity 12, between the second resonant cavity 12 and the third resonant cavity 13, and between the third resonant cavity 13 and the fourth resonant cavity 14, wherein the length of the linear groove 40211 between the first resonant cavity 11 and the second resonant cavity 12 is 1.44mm, the width of the linear groove 40411 between the second resonant cavity 12 and the third resonant cavity 13 is 1.26mm, the width of the linear groove 40611 between the third resonant cavity 13 and the fourth resonant cavity 14 is 0.15mm, and the coupling strength between the resonant cavities is set to be n-type filter according to the common-mode size of the metal grounding grooves of the adjacent resonant cavities 1.

In this embodiment, please refer to fig. 4-7 together with fig. 2, the first L-shaped slot 40111 (fig. 4), the second L-shaped slot 40311 (fig. 5), the third L-shaped slot 40511 (fig. 6) and the fourth L-shaped slot 40711 (fig. 7) are respectively formed in the upper metal ground layer 4011 of the first dielectric substrate, the upper metal ground layer 4031 of the third dielectric substrate, the upper metal ground layer 4051 of the fifth dielectric substrate and the upper metal ground layer 4071 of the seventh dielectric substrate.

Optionally, the first dielectric substrate 401 and upper and lower metal grounding layers (4011, 4012) thereof, the second dielectric substrate 402 and upper and lower metal grounding layers (4021, 4022) thereof, the first L-shaped slot 40111 and the metal through hole 5 are used together to form the first resonant cavity 11. The third dielectric substrate 403, the upper and lower metal grounding layers (4031 and 4032) thereof, the fourth dielectric substrate 404, the upper and lower metal grounding layers (4041 and 4042) thereof, the second L-shaped slot 40311 and the metal through hole 5 are used together to form the second resonant cavity 12. The fifth dielectric substrate 405, the upper and lower metal grounding layers (4051 and 4052) thereof, the sixth dielectric substrate 406, the upper and lower metal grounding layers (4061 and 4062) thereof, the third L-shaped slot 40511 and the metal through hole 5 are used together to form the third resonant cavity 13. The seventh dielectric substrate 407 and its upper and lower metal ground layers (4071, 4072), the eighth dielectric substrate 408 and its upper and lower metal ground layers (4081, 4082), the fourth L-shaped slot 40711, and the metal via 5 are used together to form the fourth resonant cavity 14.

Optionally, the feed input end of the filter 1 is disposed in the first resonant cavity 11, specifically, one side of the first L-shaped slot 40111 is provided with a first rectangular slot 40112, the number of the first rectangular slots 40112 is two, the lower metal grounding layer 4012 of the first dielectric substrate is provided with a first circular hole 40121 and a first metal column 40122, the first metal column 40122 is disposed in the first circular hole 40121, the first metal column 40122 and the first rectangular slot 40112 are jointly used for feeding the filter 1, correspondingly, the feed output end of the filter 1 is disposed in the fourth resonant cavity 14, specifically, one side of the fourth L-shaped slot 40711 is provided with a second rectangular slot 40712, the number of the second rectangular slots 40712 is two, the upper metal grounding layer 4081 of the eighth dielectric substrate is provided with a second circular hole 811 and a second metal column 40812, the second metal column 40812 is disposed in the second circular hole 40811, the second metal column 40812 and the second rectangular slot 712 are jointly used for feeding the filter 1, and the second metal column 408583 and the second rectangular slot 712 are jointly used for feeding the filter 1, and the second rectangular slot 40712 are also used for feeding the filter 1 to the filter output of the eighth dielectric substrate 4081.

In the present embodiment, the filter 1 adopts an FSIW structure, and in the 5G millimeter wave band, the FSIW filter structure has the advantages of small in-band insertion loss, high quality factor, small size, small energy leakage of a closed structure, and easy integration with other devices.

Referring to fig. 8-9 together, fig. 9 is a top view of a power divider of the LTCC miniaturized millimeter wave filter-power divider-balun module shown in fig. 8. Alternatively, the power divider 2 is a first-order Wilkinson power divider including a resistor 22 and a metal strip line structure 21, specifically, the metal strip line structure 21 and the resistor 22 are disposed on an upper layer of the tenth dielectric substrate 410, and in this embodiment, the power divider 2 is used to equally divide the signal of the filter 1 into two signals, and correspondingly, the metal strip line structure 21 has two identical branch structures.

Optionally, a metal ground layer 4121 is disposed on the top layer of the twelfth dielectric substrate 412. A plurality of metal through holes 5 are regularly distributed around the inside of the ninth dielectric substrate 409 to the twelfth dielectric substrate 412, so that the eighth dielectric substrate 408 and the upper metal grounding layers (4081 and 4121) of the twelfth dielectric substrate 412 can be well contacted, and the energy leakage is reduced. The feed input of the power divider 2 is provided in the ninth dielectric substrate 409. Specifically, the lower metal ground layer 4091 of the ninth dielectric substrate is provided with a third circular hole 40911 and a third metal post 40912, the third metal post 40912 is disposed in the third circular hole 40911, and the third metal post 40912 is connected to the second metal post 40812 (fig. 7) through a coaxial-like structure for feeding the metal strip-shaped line structure 21, thereby realizing the feeding connection of the lower filter and the power divider.

Correspondingly, the power divider 2 has two power feeding output ends provided on the twelfth dielectric substrate 412, specifically, the upper metal ground layer 4121 of the twelfth dielectric substrate is further provided with a fourth circular hole 41211 and a fourth metal column 41212, the fourth metal column 41212 is provided in the fourth circular hole 41211, and since the power divider 2 divides the signal of the filter 1 into two paths of signals, correspondingly, the number of the fourth circular holes 41211 is two, correspondingly, the number of the fourth metal columns 41212 is two, for feeding and outputting the metal strip-shaped wire structure 21, and the fourth circular hole 41211 also plays a role of blocking the upper metal ground layer 4121 of the twelfth dielectric substrate from the output feeder line of the power divider 2.

With continued reference to fig. 9, in this embodiment, the metal strip line structure 21 of the first-order Wilkinson power divider is optionally formed of three parts, where the length L1 of the first part strip line 211 is 0.7mm and the width W1 is 0.26mm. It can be seen that the first portion of strip line 211 is divided into two branches, correspondingly connected to the two output ends of the first-order Wilkinson power divider, and correspondingly connected to the two fourth metal posts 41212 (fig. 8). The second portion of the strip line 212 has a length L2 of 1.4mm, a width W2 of 0.11mm, and the third portion of the strip line 213 has a length L3 of 0.3mm and a width W3 of 0.26mm. The resistor 22 of the power divider 2 is 120Ω, and the material used for the resistor 22 of the power divider 2 is FX87 resistor paste. In this embodiment, the operating frequency band of the first-order Wilkinson power divider includes the entire n258 frequency band, and is used as a power divider to divide a signal into two or more equal signals, which has the advantages of low loss, low phase offset and high isolation.

Referring to fig. 10, fig. 10 is a schematic diagram of a balun structure of the LTCC miniaturized millimeter wave filtering-power division-balun module shown in fig. 1. In this embodiment, optionally, the number of balun 3 is two, the balun 3 is a Marchand balun structure, the thirteenth dielectric substrate 413 and the fourteenth dielectric substrate 414 are both provided with a layer of metal strip lines (4131, 4141), the thirteenth dielectric substrate 413 is further provided with three grounding metal posts 4133, and the grounding metal posts 4133 are coupled with the upper layer metal strip lines 4131 of the thirteenth dielectric substrate to form a Marchand balun structure together.

Optionally, a metal grounding layer 4151 is disposed on the upper layer of the fifteenth dielectric substrate 415, a plurality of metal through holes 5 are regularly distributed around the inside of the thirteenth dielectric substrate 413 to the fifteenth dielectric substrate 415, so that the twelfth dielectric substrate 412 and the upper metal grounding layers (4121 and 4151) of the fifteenth dielectric substrate 415 can be well contacted, and the energy leakage is reduced, and a fifth circular hole 41321 and a fifth metal column 41322 are further disposed on the lower metal grounding layer 4132 of the thirteenth dielectric substrate. Specifically, the fifth metal columns 41322 are disposed in the fifth circular holes 41321, the number of the fifth circular holes 41321 is two, correspondingly, the number of the fifth metal columns 41322 is two, each fifth metal column 41322 is correspondingly connected with each fourth metal column 41212 through a coaxial-like structure, and is used for feeding and inputting the balun 3, so that the feeding connection of the power divider and the balun is realized; correspondingly, a sixth circular hole 41511 and a sixth metal post 41512 are further disposed on the upper metal grounding layer 4151 of the fifteenth dielectric substrate. Specifically, the sixth metal posts 41512 are provided in the six circular holes 41511, and the number of the sixth circular holes 41511 is two, and correspondingly, the number of the sixth metal posts 41512 is two for feeding and outputting the balun 3.

In this embodiment, the working frequency band of the Marchand balun structure includes the entire n258 frequency band, the Marchand balun structure is relatively simple, the broadband performance is excellent, and the energy is transferred by adopting differential signals which are less susceptible to power supply noise and external electromagnetic compatibility interference, so that higher harmonic waves can be reduced, and the dynamic range of the circuit can be improved.

Optionally, referring to fig. 2-10, in the present embodiment, the metal ground layers of the upper and lower layers of the LTCC dielectric substrate 4, the metal vias 5 distributed in each layer of the dielectric substrate, the first to sixth metal pillars (40122, 40812, 40912, 41212, 41322, 41512) for feeding input/output, the metal strip line structure 21 of the power divider 2, and the metal strip lines (4131, 4141) of the balun 3 and the metal ground metal pillars 4133 are silver.

The foregoing is only illustrative of the present invention and is not to be construed as limiting the scope of the invention, and all equivalent structural changes made by the present invention and the accompanying drawings, or direct or indirect application in other related technical fields, are included in the scope of the present invention.

Claims

1. An LTCC miniaturized millimeter wave filtering-power division-balun module, comprising:

the filter comprises a plurality of resonant cavities, wherein the resonant cavities are all arranged into a folded substrate waveguide structure, and the resonant cavities are mutually coupled;

the balun is connected with the power divider through a quasi-coaxial structure, so that impedance matching between the power divider and the balun can be realized, and the number of the balun is two;

the LTCC medium substrates are stacked, the filters, the power dividers and the balun are sequentially stacked on the LTCC medium substrates.

2. The LTCC miniature millimeter wave filter-power divider-balun module of claim 1, wherein the number of LTCC dielectric substrates is fifteen, including first through fifteenth dielectric substrates, the filters are disposed on the first through eighth dielectric substrates, the power divider is disposed on the ninth through twelfth dielectric substrates, and the balun is disposed on the thirteenth through fifteenth dielectric substrates.

3. The LTCC miniature millimeter wave filter-power division-balun module of claim 2, wherein the filter comprises four resonant cavities, including first to fourth resonant cavities, the first resonant cavity being disposed on the first to second dielectric substrates, the second resonant cavity being disposed on the third to fourth dielectric substrates, the third resonant cavity being disposed on the fifth to sixth dielectric substrates, the fourth resonant cavity being disposed on the seventh to eighth dielectric substrates.

4. The LTCC miniaturized millimeter wave filtering-power dividing-balun module of claim 3, wherein a plurality of metal through holes are regularly distributed around the inside of the first to eighth dielectric substrates, metal grounding layers are respectively arranged on the upper and lower layers of the first to eighth dielectric substrates, a straight-shaped groove is formed on the upper metal grounding layers of the second, fourth and sixth dielectric substrates for mutual coupling between the first to fourth resonant cavities, an L-shaped groove is formed on the upper metal grounding layers of the first, third, fifth and seventh dielectric substrates, the metal grounding layers, the L-shaped groove and the metal through holes are jointly used for forming the first to fourth resonant cavities, a first rectangular groove is arranged on one side of the L-shaped groove of the upper metal grounding layer of the first dielectric substrate, the number of the first rectangular grooves is two, a first circular hole is formed in the lower metal grounding layer of the first dielectric substrate, a first metal column is arranged in the first circular hole, the first metal column and the first rectangular groove are jointly used for feeding and inputting the filter, one side of an L-shaped groove of the lower metal grounding layer of the eighth dielectric substrate is provided with a second rectangular groove, the number of the second rectangular grooves is two, a second circular hole is formed in the upper metal grounding layer of the eighth dielectric substrate, a second metal column is arranged in the second circular hole, the second metal column and the second rectangular groove are jointly used for feeding and outputting the filter, and the second circular hole is also used for cutting off the upper metal grounding layer of the eighth dielectric substrate and an output feeder line of the filter.

5. The LTCC miniaturized millimeter wave filtering-power division-balun module according to claim 2, wherein the power divider is a first-order Wilkinson power divider comprising a resistor and a metal strip-shaped line structure, a metal grounding layer is arranged on the upper layer of the twelfth dielectric substrate, a plurality of metal through holes are regularly distributed around the inside of the ninth to twelfth dielectric substrates, so that the metal grounding layer between the eighth dielectric substrate and the twelfth dielectric substrate can be well contacted and reduce energy leakage, the metal strip-shaped line structure and the resistor are arranged on the upper layer of the tenth dielectric substrate, a third circular hole and a third metal column are arranged on the lower layer metal grounding layer of the ninth dielectric substrate, the third metal column is arranged in the third circular hole, the third metal column is connected with the second metal column through a coaxial-like structure and used for feeding and inputting the metal strip-shaped line structure, a fourth circular hole and a fourth metal column are further arranged on the upper layer metal grounding layer of the twelfth dielectric substrate, the fourth metal column is arranged in the fourth circular hole and the fourth metal column is used for feeding and outputting the metal strip-shaped line structure, and the fourth metal column is further arranged in the fourth metal strip-shaped grounding layer.

6. The LTCC miniature millimeter wave filter-power divider-balun module of claim 5, wherein the metal strip-like wire structures have two identical branching structures, each of the metal strip-like wire structures is composed of three parts, a first part of the strip-like wire having a length of 0.7mm and a width of 0.26mm, a second part of the strip-like wire having a length of 1.4mm and a width of 0.11mm, a third part of the strip-like wire having a length of 0.3mm and a width of 0.26mm, a resistor of 120 Ω, a material of FX87 resistor paste is used for the resistor of the power divider, and the power divider is used to equally divide the output signal of the filter into two signals.

7. The LTCC miniature millimeter wave filter-power divider-balun module of claim 2, wherein the balun is a Marchand balun structure, the number of the balun is two, a layer of metal strip lines are arranged on the upper layers of the thirteenth and fourteenth dielectric substrates, three grounded metal posts are further arranged on the thirteenth dielectric substrate, and the grounded metal posts are coupled with the metal strip lines of the thirteenth dielectric substrate and are commonly used for forming the Marchand balun structure.

8. The LTCC miniaturized millimeter wave filtering-power dividing-balun module according to claim 7, wherein a metal grounding layer is disposed on an upper layer of the fifteenth dielectric substrate, a plurality of metal through holes are regularly distributed around the inside of the thirteenth to fifteenth dielectric substrates, so that the metal grounding layer between the twelfth dielectric substrate and the fifteenth dielectric substrate can be well contacted and energy leakage is reduced, a fifth circular hole is further disposed on the thirteenth dielectric substrate, a fifth metal column is disposed in the fifth circular hole, the fifth metal column and the fourth metal column are connected through a coaxial-like structure and used for feeding and inputting the balun, a sixth circular hole is further disposed on the fifteenth dielectric substrate, and a sixth metal column is disposed in the sixth circular hole and used for feeding and outputting the balun.

9. The LTCC miniaturized millimeter wave filtering-power division-balun module of claim 1, wherein the LTCC dielectric substrate is made of a material of Ferro-A6, a dielectric constant of 5.9 and a loss tangent of 0.0015.

10. The LTCC miniature millimeter wave filter-power divider-balun module of claim 4, 5, or 8, wherein the metallic material in the metallic ground layer, the metallic via, and the first through sixth metallic posts is silver.