Radio frequency device and communication device

Abstract

The application provides a radio frequency device and a communication device. The radio frequency device comprises a base body, inner electrodes and outer electrodes. The outer electrodes are arranged on the outer wall of the base body and comprise an input end outer electrode, an output end outer electrode and a ground outer electrode group. The inner electrodes comprise a plurality of electrode layers embedded in the base body and arranged in layers. An insulating medium is arranged between each two adjacent electrode layers. At least one transmission inductance capacitance layer is included in the plurality of electrode layers. The transmission inductance capacitance layer is electrically connected with the input end outer electrode and the output end outer electrode. The rest of the electrode layers in the plurality of electrode layers except the transmission inductance capacitance layer are electrically connected with the ground outer electrode group. The plurality of electrode layers form a resonance circuit. The resonance circuit is used for resonant processing of a radio frequency signal input from the input end outer electrode, and the radio frequency signal after the resonant processing is output from the output end outer electrode. Since the insulating medium in the base body does not need to be punched and conductive silver paste needs to be poured in the hole, the volume of the radio frequency device is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radio frequency technology, in particular to a radio frequency device based on LTCC and a communication device. BACKGROUND

[0002] Low temperature co-fired ceramic (LTCC) as a high-density packaging technology with a wide range of applications has become the preferred way for future electronic component integration and modularization due to its excellent electronic, mechanical and thermal properties. The radio frequency devices based on LTCC technology include balun filters, filters, multiplexers, duplexers, antennas, couplers, etc. In addition to the advantages in cost and integrated packaging, it also has many advantages in wiring width and spacing, low impedance metallization, design diversity and high frequency performance. The inner electrode of the radio frequency device includes multiple electrode layers. The vertical interconnection structure is usually used to realize the conduction between layers. However, the setting of the vertical interconnection structure undoubtedly increases the occupied space of the radio frequency device, which is not conducive to the miniaturization development of the radio frequency device. SUMMARY

[0003] The embodiments of the present application provide a radio frequency device based on LTCC and a communication device which can reduce the occupied space.

[0004] In a first aspect, the present application provides a radio frequency device, comprising: a substrate made of insulating medium; an outer electrode disposed on the outer wall of the substrate, including an input end outer electrode, an output end outer electrode and a ground outer electrode group, the ground outer electrode group including one or more ground outer electrodes; and an inner electrode. The inner electrode includes a plurality of electrode layers embedded in the substrate and stacked, and the insulating medium is disposed between each adjacent two electrode layers; the plurality of electrode layers includes at least one transmission inductance and capacitance layer, the at least one transmission inductance and capacitance layer is electrically connected with the input end outer electrode and the output end outer electrode, and the remaining electrode layers except the at least one transmission inductance and capacitance layer in the plurality of electrode layers are electrically connected with the ground outer electrode group, the plurality of electrode layers form a resonant circuit, the resonant circuit is used for resonant processing of the radio frequency signal input from the input end outer electrode, and the radio frequency signal after resonant processing is output from the output end outer electrode.

[0005] The traditional vertical interconnection structure adopts the method of punching and pouring conductive silver paste in the hole to realize the electrical conduction between the electrode layers. However, the vertical interconnection structure needs to reach a certain size, so that the radio frequency device usually needs to be made larger in size.

[0006] The radio frequency device provided in the present application has the advantages that: since the rest of the electrode layers in the inner electrode except the transmission inductance and capacitance layer are electrically connected with the ground outer electrode, that is, the plurality of electrode layers are electrically connected outside the base body, thus, it is not necessary to punch holes in the insulating medium in the base body and fill the conductive silver paste in the holes, which is beneficial to reduce the size of the radio frequency device, for example, the radio frequency device with a size of 3.2mm*2.5mm can be reduced to 2.5mm*2.0mm. Since it is not necessary to punch holes and fill the conductive silver paste, the process and manufacturing cost of the radio frequency device are also simplified.

[0007] Since the interior of the radio frequency device is not punched, the electromagnetic radiation and leakage of the radio frequency device are reduced, which is beneficial to improve the quality factor of the radio frequency device.

[0008] The radio frequency device is widely used in the fields of 5G communication radio frequency TRX link and terminal mobile phone, and the miniaturization of the radio frequency device is helpful to reduce the board area of the circuit board and realize the miniaturization of the whole machine.

[0009] According to the first aspect of the present application, in a first possible implementation manner of the first aspect of the present application, the resonant circuit includes at least two resonant units arranged in parallel, the plurality of electrode layers include at least two coupling capacitance layers, the at least two coupling capacitance layers are electromagnetically coupled with the at least one transmission line inductance layer to form the at least two resonant units, each of the coupling capacitance layers includes at least two interdigital parts, and each adjacent two interdigital parts are arranged at intervals.

[0010] The coupling capacitance layer is an interdigital structure layer. The interdigital structure layer can generate a transmission zero point at the far end of the passband of the radio frequency device, thereby improving the stopband attenuation depth of the radio frequency device. The interdigital part can also improve the flexibility of the layout of small inductance and improve the convenience of the production process of the coupling capacitance layer.

[0011] According to the first aspect of the present application or the first possible implementation manner of the present application, in a second possible implementation manner of the first aspect of the present application, the plurality of electrode layers further include at least one Z-shaped folded line layer, and the at least two coupling capacitance layers are electromagnetically coupled with the Z-shaped folded line layer. The Z-shaped folded line layer can generate a transmission zero point at the near end of the passband of the radio frequency device, thereby generating deep suppression at the near end of the radio frequency device.

[0012] According to the first aspect of the present application or the first to second possible implementation manners of the present application, in a third possible implementation manner of the first aspect of the present application, the number of the at least one transmission inductance and capacitance layer is one, the at least one transmission inductance and capacitance layer includes an input port and an output port, the input port is electrically connected with the input end outer electrode, and the output port is electrically connected with the output end outer electrode. The input port and the output port are arranged on the same transmission inductance and capacitance layer, which simplifies the structure of the radio frequency device and facilitates the preparation of the radio frequency device.

[0013] In a fourth possible implementation manner of the first aspect of the present application, according to the first aspect or the first to third possible implementation manners of the present application, the at least two coupling capacitor layers include a first coupling capacitor layer, a second coupling capacitor layer and a third coupling capacitor layer, and each of the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer includes four interdigital parts. The at least one transmission inductance and capacitance layer, the at least one Z-shaped meander layer, the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer are electromagnetically coupled with each other.

[0014] The resonant circuit includes at least two resonant units arranged in parallel, including a first-level resonant unit, a second-level resonant unit, a third-level resonant unit and a fourth-level resonant unit. The at least one transmission inductance and capacitance layer, the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer form the first-level resonant unit, the second-level resonant unit, the third-level resonant unit and the fourth-level resonant unit in the resonant circuit through electromagnetic coupling. The resonant circuit further includes a cross capacitance connected in series between the first-level resonant unit and the fourth-level resonant unit. The Z-shaped meander layer, the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer form the cross capacitance connected in series between the first-level resonant unit and the fourth-level resonant unit through electromagnetic coupling.

[0015] The radio frequency device resonantly processes the radio frequency signal through the first-level resonant unit, the second-level resonant unit, the third-level resonant unit and the fourth-level resonant unit, effectively improving the quality of the radio frequency signal.

[0016] In a fifth possible implementation manner of the first aspect of the present application, according to the first aspect or the first to fourth possible implementation manners of the present application, the plurality of electrode layers further include a cross coupling layer, and the cross coupling layer, the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer are electromagnetically coupled with each other.

[0017] The resonant circuit further includes a first capacitance connected between the first-level resonant unit and the second-level resonant unit, a second capacitance connected between the second-level resonant unit and the third-level resonant unit, and a third capacitance connected between the third-level resonant unit and the fourth-level resonant unit. The cross coupling layer, the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer are electromagnetically coupled to form the first capacitance, the second capacitance and the third capacitance, thereby forming a coupling matrix of the electromagnetic field theory of the radio frequency device, and obtaining the required electrical performance of the radio frequency device.

[0018] In a sixth possible implementation of the first aspect of the application, according to the first aspect of the application or the first to sixth possible implementation of the first aspect of the application, the cross-coupling layer, the first coupling capacitor layer, the second coupling capacitor layer, the at least one transmission inductor-capacitor layer, the third coupling capacitor layer, and the Z-shaped zigzag layer are arranged in sequence to obtain a radio frequency device with excellent electrical performance.

[0019] In a seventh possible implementation of the first aspect of the application, according to the first aspect of the application or the first to sixth possible implementation of the first aspect of the application, the at least one transmission inductor-capacitor layer includes a first transmission inductor-capacitor layer and a second transmission inductor-capacitor layer arranged separately, the first transmission inductor-capacitor layer includes the input port, and the second transmission inductor-capacitor layer includes the output port. The input port is electrically connected to the input terminal external electrode, and the output port is electrically connected to the output terminal external electrode.

[0020] The first transmission inductor-capacitor layer and the second transmission inductor-capacitor layer are arranged in layers, the input port is arranged on the first transmission inductor-capacitor layer, and the output port is arranged on the second transmission inductor-capacitor layer, which is conducive to improving the reliability of the electrical connection between the internal electrode and the input terminal external electrode and the output terminal external electrode, and the flexibility of the layout of the plurality of electrode layers in the internal electrode.

[0021] In an eighth possible implementation of the first aspect of the application, according to the first aspect of the application or the first to seventh possible implementation of the first aspect of the application, the Z-shaped zigzag layer includes a first Z-shaped zigzag layer and a second Z-shaped zigzag layer, the at least two coupling capacitor layers include a first coupling capacitor layer, a second coupling capacitor layer, a third coupling capacitor layer, and a fourth coupling capacitor layer, each of the first coupling capacitor layer, the second coupling capacitor layer, the third coupling capacitor layer, and the fourth coupling capacitor layer includes two interdigital portions, and the first transmission inductor-capacitor layer, the first coupling capacitor layer, and the second coupling capacitor layer are electromagnetically coupled to each other.

[0022] The at least two parallelly arranged resonance units include a first-level resonance unit, a second-level resonance unit, a third-level resonance unit, and a fourth-level resonance unit, and a cross capacitance connected in series between the first-level resonance unit and the fourth-level resonance unit.

[0023] The first transmission inductor-capacitor layer, the first coupling capacitor layer, and the second coupling capacitor layer form the first-level resonance unit and the second-level resonance unit in the resonance circuit through electromagnetic coupling. The second transmission inductor-capacitor layer, the third coupling capacitor layer, and the fourth coupling capacitor layer form the third-level resonance unit and the fourth-level resonance unit in the resonance circuit through electromagnetic coupling. The first Z-shaped zigzag layer and the second Z-shaped zigzag layer form the cross capacitance through electromagnetic coupling.

[0024] The first Z-shaped fold line layer and the second Z-shaped fold line layer jointly form a cross-coupling layer, and a transmission zero point is generated at a near end of a passband of the radio frequency device, thereby generating double suppression at the near end of the radio frequency device.

[0025] In a ninth possible implementation manner of the first aspect of the present application, according to the first aspect or the first to eighth possible implementation manners of the present application, the plurality of electrode layers further comprise a planar capacitor layer, and the planar capacitor layer, the first coupling capacitor layer, the second coupling capacitor layer, the third coupling capacitor layer and the fourth coupling capacitor layer are electromagnetically coupled.

[0026] The resonant circuit further comprises a first capacitor connected between the first-stage resonant unit and the second-stage resonant unit, a second capacitor connected between the second-stage resonant unit and the third-stage resonant unit, and a third capacitor connected between the third-stage resonant unit and the fourth-stage resonant unit. The planar capacitor layer, the first coupling capacitor layer, the second coupling capacitor layer, the third coupling capacitor layer and the fourth coupling capacitor layer form the first capacitor, the second capacitor and the third capacitor through electromagnetic coupling, thereby forming a coupling matrix of electromagnetic field theory of a radio frequency device, and obtaining required electrical performance of the radio frequency device.

[0027] In a tenth possible implementation manner of the first aspect of the present application, according to the first aspect or the first to ninth possible implementation manners of the present application, the first Z-shaped fold line layer, the first coupling capacitor layer, the first transmission inductance-capacitance layer, the second coupling capacitor layer, the planar capacitor layer, the third coupling capacitor layer, the second transmission inductance-capacitance layer, the fourth coupling capacitor layer and the second Z-shaped fold line layer are arranged in sequence, so as to obtain a radio frequency device with excellent electrical performance.

[0028] In an eleventh possible implementation manner of the first aspect of the present application, according to the first aspect or the first to tenth possible implementation manners of the present application, the coupling capacitor layer further comprises a connecting portion, one end of each interdigital portion is fixed on the connecting portion, and the other end of all the interdigital portions away from the connecting portion extends in the same direction. The connecting portion is used to connect the interdigital portions, which is beneficial to improve the convenience of preparation of the coupling capacitor layer.

[0029] In a twelfth possible implementation of the first aspect of the application, according to the first aspect of the application or the first to eleventh possible implementation of the first aspect of the application, the plurality of electrode layers further comprise a first inner ground layer and a second inner ground layer, the first inner ground layer is located at the uppermost layer of the plurality of electrode layers, and the second inner ground layer is located at the lowermost layer of the plurality of electrode layers. The first inner ground layer and the second inner ground layer are used for electromagnetic shielding to reduce the interference of the environment on the performance of the radio frequency device.

[0030] In a thirteenth possible implementation of the first aspect of the application, according to the first aspect of the application or the first to twelfth possible implementation of the first aspect of the application, the radio frequency device is a filter, and the size of the radio frequency device is 2.5mm*2.0mm. Compared with a conventional radio frequency device with a size of 3.2mm*2.5mm, the size is reduced more.

[0031] In a second aspect, the application provides a communication device comprising a circuit board and a radio frequency device arranged on the circuit board. The radio frequency device is used to at least one of generating, transmitting, processing and receiving a radio frequency signal.

[0032] Since the base body of the radio frequency device is not perforated, the volume of the radio frequency device is reduced, the device layout density and flexibility of the circuit board are improved, and the miniaturization of the communication device is also facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1a An application scenario diagram of the radio frequency device provided by an embodiment of the application is shown in the figure;

[0034] Figure 1b Another application scenario diagram of the radio frequency device provided by an embodiment of the application is shown in the figure;

[0035] Figure 2 A perspective diagram of the radio frequency device provided by an embodiment of the application is shown in the figure;

[0036] Figure 3a A structure diagram of the radio frequency device provided by an embodiment of the application is shown in the figure, which comprises 11 electrode layers;

[0037] Figure 3b An inner electrode diagram of the radio frequency device provided by an embodiment of the application is shown in the figure; Figure 3a

[0038] An equivalent resonance circuit diagram of the inner electrode provided by an embodiment of the application is shown in the figure; Figure 4

[0039] A test result diagram of the electrical performance of the radio frequency device provided by an embodiment of the application is shown in the figure; Figure 5 Figure 3a

[0040] ​​Figure 6a A structure diagram of a radio frequency device including eight electrode layers according to an embodiment of the present application is provided;

[0041] Figure 6b A structure diagram of a radio frequency device including eight electrode layers according to an embodiment of the present application is provided; Figure 6a A structure diagram of a radio frequency device including eight electrode layers according to an embodiment of the present application is provided;

[0042] Figure 6c A structure diagram of a radio frequency device including eight electrode layers according to an embodiment of the present application is provided;

[0043] Figure 7 A structure diagram of a radio frequency device including eight electrode layers according to an embodiment of the present application is provided; Figure 6a A structure diagram of a radio frequency device including eight electrode layers according to an embodiment of the present application is provided; DETAILED DESCRIPTION

[0044] The radio frequency device designed and produced based on the LTCC technology includes a balun filter, a filter, a multiplexer, a diplexer, an antenna, a coupler, a receiving front-end module, an antenna switch module, etc. The inner electrode of the radio frequency device includes multiple electrode layers. The conventional radio frequency device usually adopts a vertical interconnection structure to realize the conduction between the multiple electrode layers. The so-called vertical interconnection structure is realized by punching a hole in the insulating medium between the adjacent electrode layers and then filling the hole with conductive silver paste. The vertical interconnection structure is relatively flexible in design, but in order to meet the radio frequency index requirements of wireless communication, the vertical interconnection structure needs to reach a certain size, so that the radio frequency device usually needs to be made to a larger size, for example, 3.2mm*2.5mm or 4.5mm*3.2mm. In this way, it is not conducive to the miniaturization development of the radio frequency device. In addition, since the conventional radio frequency device adopts a hole structure, it is easy to cause electromagnetic radiation and leakage, thereby causing the quality factor of the radio frequency device to decrease.

[0045] Based on this, the present application provides a radio frequency device based on LTCC and a related communication device. The multiple electrode layers in the inner electrode are electrically connected with the external ground outer electrode group, and the multiple electrode layers form a resonant circuit. Since the substrate does not need to be provided with a hole and the hole is filled with conductive silver paste, the volume and occupied space of the radio frequency device can be effectively reduced.

[0046] Please refer to Figure 1a , Figure 1a An application scenario suitable for an embodiment of the present application is shown. The communication device 1000 includes a circuit board 200 and a radio frequency device 100 mounted on the circuit board 200, and the radio frequency device 100 is used for at least one of generating, transmitting, processing, and receiving a radio frequency signal. In some possible implementation embodiments, the mounting mode of the radio frequency device 100 and the circuit board 200 is welding or pressure bonding. The communication device 1000 can be a notebook computer, a wearable device, a drone, a mobile phone, a router, an enterprise wireless access device, an access network fixed terminal, etc., which is not limited by the present application.

[0047] Referring to Figure 1b , Figure 1b For another application scenario of the embodiment of the application, the communication device 1000 includes a plurality of radio frequency devices, which include a signal transmitting end (TXIC) 101, a signal receiving end (RXIC) 102, an impedance transformer (balun) 103, a band-pass filter (berkeley packet gilter, BPF) 104, a 3dB electric bridge coupling 105, a power amplifier 106, a low-pass filter 107, a power divider 108, and an antenna 109. The signal transmitting end 101 and the signal receiving end 102 are arranged on the circuit board 300.

[0048] The radio frequency signal generated by the signal transmitting end 101 reaches the antenna 109 after being processed by the impedance transformer 103, the band-pass filter 104, the 3dB electric bridge coupling 105, the power amplifier 106, and the low-pass filter 107. The antenna 109 sends the processed radio frequency signal to a remote end.

[0049] The radio frequency signal received by the antenna 109 reaches the signal receiving end 102 after being processed by the low-pass filter 107 and the band-pass filter 104.

[0050] The radio frequency device 100 is further described below by taking the filter as an example.

[0051] Referring to Figure 2 and Figure 3a , the radio frequency device 100 includes a base body 20, an outer electrode 40, and an inner electrode 60. The outer electrode 40 is arranged on the outer wall of the base body 20. The inner electrode 60 is embedded in the interior of the base body 20.

[0052] The base body 20 is made of an insulating medium. In some embodiments of the application, the base body 20 can be a low-temperature co-fired ceramic base body, which is made by sintering a low-temperature co-fired ceramic powder.

[0053] In some possible implementations, the sintering temperature can be less than or equal to 900°C, and the optional sintering temperature can be 880°C±10°C. The relative dielectric constant of the ceramic powder can be 4-9.8, and the dielectric loss factor tanα can be less than or equal to 0.002. The optional relative dielectric constant of the ceramic powder can be 7.2±0.5, and the optional dielectric loss factor tanα can be less than or equal to 0.001.

[0054] The base body 20 has a substantially cuboid structure. The base body 20 includes a first outer wall 21, a second outer wall 22, a third outer wall 23, a fourth outer wall 24, a fifth outer wall, and a sixth outer wall. The first outer wall 21 and the second outer wall 22 are arranged opposite to each other along a first direction (for example, the X direction shown in the figure). Figure 2 The third outer wall 23 and the fourth outer wall 24 are arranged opposite to each other along a second direction (for example, the Y direction shown in the figure). The fifth outer wall and the sixth outer wall are arranged opposite to each other along a third direction (for example, the Z direction shown in the figure).Figure 2 The fifth outer wall and the sixth outer wall are arranged opposite to each other along a third direction (e.g., the Z direction as shown). Figure 2 The first direction is perpendicular to the second direction, the second direction is perpendicular to the third direction, and the first direction is perpendicular to the third direction.

[0055] The outer electrodes 40 include an input end outer electrode 42, an output end outer electrode 44, and a ground outer electrode group 46. The input end outer electrode 42 is arranged on the first outer wall 21, and the input end outer electrode 42 extends partially to the third outer wall 23 and the fourth outer wall 24. The input end outer electrode 42 is used to connect with the inner electrodes 60 to input a radio frequency signal to the inner electrodes 60. The output end outer electrode 44 is arranged on the second outer wall 22, and the output end outer electrode 44 extends partially to the third outer wall 23 and the fourth outer wall 24. The output end outer electrode 44 is used to connect with the inner electrodes 60 to output a radio frequency signal after electromagnetic coupling of the inner electrodes 60. The ground outer electrode group 46 includes a first ground outer electrode 462 arranged on the fifth outer wall and a second ground outer electrode 464 arranged on the sixth outer wall, and the first ground outer electrode 462 and the second ground outer electrode 464 are used for electromagnetic shielding. The inner electrodes 60 are located between the first ground outer electrode 462 and the second ground outer electrode 464.

[0056] The base body 20 is not limited to a cuboid structure, and can also be other shapes, such as a square, a cylinder, etc. The positions of the input end outer electrode 42, the output end outer electrode 44, and the ground outer electrode group 46 on the outer walls of the base body 20 are not limited.

[0057] Please refer to Figure 3a and Figure 3b is a structural schematic diagram of a radio frequency device provided by an embodiment of the present application. The inner electrodes 60 include a plurality of electrode layers embedded in the base body 20 and arranged in layers. An insulating medium is arranged between each adjacent two electrode layers. In other words, all the electrode layers are located inside the base body 20, and the outer surface of each electrode layer is surrounded and covered by the insulating medium.

[0058] The plurality of electrode layers include a first inner ground layer P1, a first Z-shaped folded line layer P2, a first coupling capacitor layer P3, a first transmission inductor-capacitor layer P4, a second coupling capacitor layer P5, a planar capacitor layer P6, a third coupling capacitor layer P7, a second transmission inductor-capacitor layer P8, a fourth coupling capacitor layer P9, a second Z-shaped folded line layer P10, and a second inner ground layer P11 arranged in layers in sequence.

[0059] It should be noted that each electrode layer is a trace, and the naming of each electrode layer is mainly based on the main role or shape. For example, the first coupling capacitor layer P3, the second coupling capacitor layer P5, the third coupling capacitor layer P7, and the fourth coupling capacitor layer P9 mainly perform capacitive coupling (play a capacitive role) in electromagnetic coupling, that is, they are named as coupling capacitor layers. The first transmission inductor-capacitor layer P4 and the second transmission inductor-capacitor layer P8 can perform inductive coupling and capacitive coupling (play an inductive and capacitive role) in the electromagnetic coupling of multiple electrode layers, and the first transmission inductor-capacitor layer P4 and the second transmission inductor-capacitor layer P8 are also used for input or output of radio frequency signals in the present application. The first transmission inductor-capacitor layer P4 and the second transmission inductor-capacitor layer P8 are named as transmission inductor-capacitor layers. The first inner ground layer P1 and the second inner ground layer P11 are used for grounding and shielding. The first Z-shaped folded line layer P2 and the second Z-shaped folded line layer P10 have a structure approximately in the shape of Z to increase the transmission zero point of the radio frequency device. The planar capacitor layer P6 is mainly used for capacitive coupling (plays a capacitive role) with other electrode layers (for example, the first coupling capacitor layer P3, the second coupling capacitor layer P5, the third coupling capacitor layer P7, and the fourth coupling capacitor layer P9) in the plane perpendicular to the stacking direction of the multiple electrode layers, that is, it is named as a planar capacitor layer.

[0060] The first transmission inductor-capacitor layer P4 is electrically connected with the input end outer electrode 42. The second transmission inductor-capacitor layer P8 is electrically connected with the output end outer electrode 44. The first inner ground layer P1, the first Z-shaped folded line layer P2, the first coupling capacitor layer P3, the second coupling capacitor layer P5, the planar capacitor layer P6, the third coupling capacitor layer P7, the fourth coupling capacitor layer P9, the second Z-shaped folded line layer P10, and the second inner ground layer P11 are all electrically connected with the ground outer electrode group 46 (the first ground outer electrode 462 or the second ground outer electrode 464). The multiple electrode layers form a resonant circuit 200 (as shown in Figure 4 The resonant circuit 200 is used for resonant processing of the radio frequency signal input from the input end outer electrode 42, and the radio frequency signal after resonant processing is output from the output end outer electrode 44.

[0061] In other words, the remaining electrode layers in the multiple electrode layers, except for the first transmission inductor-capacitor layer P4 and the second transmission inductor-capacitor layer P8, are all electrically connected with the ground outer electrode group 46 (the first ground outer electrode 462 or the second ground outer electrode 464), so that the multiple electrode layers form a resonant circuit 200 (as shown in Figure 4

[0062] ​In some possible implementations of this application, the electrode layer is electrically connected to the grounded external electrode group 46 (first grounded external electrode 462 or second grounded external electrode 464) by applying liquid silver paste to the substrate 20 and the lead-out surfaces of each electrode layer using a silver-plating device to form a silver coating, followed by sintering (e.g., at a sintering temperature of approximately 800-900 degrees Celsius), resulting in a stable conductive connection layer. This application does not limit the method of electrical connection between the electrode layer and the grounded external electrode group 46.

[0063] Since each of the multiple electrode layers, excluding the first transmission inductor-capacitor layer P4 and the second transmission inductor-capacitor layer P8, is electrically connected to the grounded external electrode group 46, meaning that the multiple electrode layers are electrically conductive outside the substrate 20, there is no need to drill holes or fill conductive silver paste in the insulating medium within the substrate 20. This helps to reduce the size of the RF device; for example, a 3.2mm*2.5mm RF device can be reduced to 2.5mm*2.0mm. The elimination of the need for drilling and filling conductive silver paste also simplifies the fabrication process and reduces manufacturing costs for the RF device 100.

[0064] Please refer to the following: Figure 4 The resonant circuit 200 includes an input port 201, an output port 202, a first-stage resonant unit 203, a second-stage resonant unit 204, a third-stage resonant unit 205, and a fourth-stage resonant unit 206. The first-stage resonant unit 203, the second-stage resonant unit 204, the third-stage resonant unit 205, and the fourth-stage resonant unit 206 are connected in parallel. Each of the first-stage resonant unit 203, the second-stage resonant unit 204, the third-stage resonant unit 205, and the fourth-stage resonant unit 206 is grounded. The radio frequency (RF) signal enters the resonant circuit 200 through the input port 201. The resonant circuit 200 filters the RF signal, allowing RF signals within the target band to be output from the output port 202 while filtering out stray signals outside the target band.

[0065] The first transmission inductor-capacitor layer P4 includes an input port P41, and the second transmission inductor-capacitor layer P8 includes an output port P81. The input port P41 is electrically connected to the external input electrode 42 and is used to input radio frequency (RF) signals. The output port P81 is electrically connected to the external output electrode 44 and is used to output the RF signal after resonance processing. Input port P41 is the input port 201 of the resonant circuit 200. Output port P81 is the output port 202 of the resonant circuit 200. Input port 201 is connected to the first-stage resonant unit 203. Output port 202 is connected to the fourth-stage resonant unit 206.

[0066] The first transmission inductance and capacitance layer P4 and the second transmission inductance and capacitance layer P8 are arranged in layers, the input port P41 is arranged on the first transmission inductance and capacitance layer P4, and the output port P81 is arranged on the second transmission inductance and capacitance layer P8, which is beneficial to improving the reliability of electrical connection between the inner electrode 60 and the input end outer electrode 42 and the output end outer electrode 44 and the flexibility of layout of the plurality of electrode layers in the inner electrode 60.

[0067] The first-level resonance unit 203, the second-level resonance unit 204, the third-level resonance unit 205, and the fourth-level resonance unit 206 are arranged in parallel. The first-level resonance unit 203, the second-level resonance unit 204, the third-level resonance unit 205, and the fourth-level resonance unit 206 are respectively grounded. The first-level resonance unit 203, the second-level resonance unit 204, the third-level resonance unit 205, and the fourth-level resonance unit 206 each include a resonance capacitance and a resonance inductance.

[0068] The first-level resonance unit 203 and the third-level resonance unit 205 can be cross-coupled and form an inductive cross-coupled structure (also referred to as a CT structure), and the first-level resonance unit 203 and the fourth-level resonance unit 206 can be cross-coupled and form a capacitive cross-coupled structure (also referred to as a CQ structure).

[0069] The resonance circuit 200 further includes a first capacitance 207, a second capacitance 208, a third capacitance 209, a cross capacitance 211, a first node 213, a second node 215, a third node 217, and a fourth node 219. The input port 201 and the first-level resonance unit 203 are connected to the first node 213. The first capacitance 207 is connected between the first node 213 and the second node 215. The second-level resonance unit 204 is connected to the second node 215. The second capacitance 208 is connected between the second node 215 and the third node 217. The third-level resonance unit 205 is connected to the third node 217. The third capacitance 209 is connected between the third node 217 and the fourth node 219. The output port 202 and the fourth-level resonance unit 206 are connected to the fourth node 219. The cross capacitance 211 is connected between the first node 213 and the fourth node 219. It should be noted that the first capacitance 207, the second capacitance 208, the third capacitance 209, and the cross capacitance 211 are not real physical structures, but equivalent capacitor devices in the resonance circuit 200 formed by electromagnetic coupling between a plurality of electrode layers.

[0070] The first capacitance 207 is connected between the first-level resonance unit 203 and the second-level resonance unit 204. The second capacitance 208 is connected between the second-level resonance unit 204 and the third-level resonance unit 205. The third capacitance 209 is connected between the third-level resonance unit 205 and the fourth-level resonance unit 206. The cross capacitance 211 is connected across the first-level resonance unit 203 and the fourth-level resonance unit 206.

[0071] The first transmission inductance-capacitance layer P4, the first coupling capacitance layer P3, and the second coupling capacitance layer P5 form, through electromagnetic coupling, the first-stage resonant unit 203 and the second-stage resonant unit 204 in the resonant circuit 200. The second transmission inductance-capacitance layer P8, the third coupling capacitance layer P7, and the fourth coupling capacitance layer P9 form, through electromagnetic coupling, the third-stage resonant unit 205 and the fourth-stage resonant unit 206 in the resonant circuit 200.

[0072] Each of the first coupling capacitance layer P3, the second coupling capacitance layer P5, the third coupling capacitance layer P7, and the fourth coupling capacitance layer P9 includes two interdigital sections 634. In other words, the first coupling capacitance layer P3, the second coupling capacitance layer P5, the third coupling capacitance layer P7, and the fourth coupling capacitance layer P9 are interdigital structure layers. The interdigital structure layers can generate a transmission zero point at the far end of the passband of the radio frequency device 100 (as shown in FIG. 6B), thereby improving the stopband attenuation depth of the radio frequency device 100. Figure 5

[0073] The first Z-shaped zigzag layer P2 and the second Z-shaped zigzag layer P10 form, through electromagnetic coupling, a cross-over capacitance 211 across the first-stage resonant unit 203 and the fourth-stage resonant unit 206. The first Z-shaped zigzag layer P2 and the second Z-shaped zigzag layer P10 jointly form a cross-over coupling layer, which generates a transmission zero point at the near end of the passband of the radio frequency device 100 (as shown in FIG. 6A), thereby producing a deep suppression at the near end of the radio frequency device 100, achieving deep attenuation, and greatly improving the radio frequency index of the radio frequency device 100. Figure 5

[0074] The planar capacitance layer P6, the first coupling capacitance layer P3, the second coupling capacitance layer P5, the third coupling capacitance layer P7, and the fourth coupling capacitance layer P9 form, through electromagnetic coupling, a first capacitance 207 connected between the first-stage resonant unit 203 and the second-stage resonant unit 204, a second capacitance 208 connected between the second-stage resonant unit 204 and the third-stage resonant unit 205, and a third capacitance 209 connected between the third-stage resonant unit 205 and the fourth-stage resonant unit 206.

[0075] ​​The first inner ground layer P1 and the second inner ground layer P11 are located at the outermost side of the inner electrodes 60. The first inner ground layer P1 is located at the uppermost layer of the plurality of electrode layers, and the second inner ground layer P11 is located at the lowermost layer of the plurality of electrode layers. The first inner ground layer P1 and the second inner ground layer P11 are both used for electromagnetic shielding to reduce the interference of the environment on the performance of the radio frequency device 100. The first inner ground layer P1 and the second inner ground layer P11 have similar structures. The area of both the first inner ground layer P1 and the second inner ground layer P11 is not less than the area of the remaining electrode layers (the first Z-shaped folded line layer P2, the first coupling capacitance layer P3, the first transmission inductance capacitance layer P4, the second coupling capacitance layer P5, the second transmission inductance capacitance layer P8, the third coupling capacitance layer P7, the fourth coupling capacitance layer P9, and the second Z-shaped folded line layer P10) in the inner electrodes 60, so as to improve the electromagnetic shielding effect and reduce the influence of the environment on the performance of the inner electrodes 60.

[0076] In this embodiment, the radio frequency device 100 is simulated by S parameters, and the simulation data in Table 1 below can be obtained.

[0077] Table 1 Comparison table of parameters of a conventional filter with a via and the radio frequency device 100

[0078]

[0079] The radio frequency device 100 provided in the present application includes 11 electrode layers. On the one hand, the first coupling capacitance layer P3, the second coupling capacitance layer P5, the third coupling capacitance layer P7, and the fourth coupling capacitance layer P9 adopt an interdigital structure, which can generate a transmission zero point at the far end of the passband of the radio frequency device 100, thereby improving the quality factor (Q value) of the radio frequency device 100. On the other hand, the first Z-shaped folded line layer P2 and the second Z-shaped folded line layer P10 are both Z-shaped, which can generate a transmission zero point at the near end of the passband of the radio frequency device 100, thereby improving the quality factor (Q value) of the radio frequency device 100. In this way, the insertion loss and the out-of-band suppression index of the radio frequency device 100 are improved.

[0080] The radio frequency device 100 does not have any via, and the transmission zero point is realized by the interdigital coupling capacitance layer and the Z-shaped folded line layer. The performance of the radio frequency device 100 is greatly improved by three combined technologies of transmission line resonance (forming a resonance circuit), planar cross-coupling (inductive cross-coupling and capacitive cross-coupling between resonance units), and large-area grounding.

[0081] In other embodiments of the present application, the substrate 20 can include a plurality of ceramic slurry cast layers, and the electrode layers are printed on the surface of the ceramic cast layers, and the printing between each layer is performed separately. After all the printing is completed, the first inner ground layer P1, the first Z-shaped folded line layer P2, the first coupling capacitor layer P3, the first transmission inductor-capacitor layer P4, the second coupling capacitor layer P5, the planar capacitor layer P6, the third coupling capacitor layer P7, the second transmission inductor-capacitor layer P8, the fourth coupling capacitor layer P9, the second Z-shaped folded line layer P10, and the second inner ground layer P11 are sequentially laminated according to the order of the stack, sintered, and the end electrodes are formed to form a complete via-free radio frequency device.

[0082] In other embodiments, the radio frequency device 100 can be other devices, for example, the radio frequency device 100 can be one of an impedance transformer, a band-pass filter, a 3dB bridge, a power amplifier, a low-pass filter, a power divider, and an antenna.

[0083] Please refer to Figure 6a With Figure 6b , an embodiment of the present application further provides a radio frequency device 100B. The structure of the radio frequency device 100B is substantially similar to that of the radio frequency device 100 shown in Figure 3b , the difference is that the inner electrode of the radio frequency device 100B includes 8 electrode layers.

[0084] The 8 electrode layers include a first inner ground layer L1, a cross-coupling layer L2, a first coupling capacitor layer L3, a second coupling capacitor layer L4, a transmission inductor-capacitor layer L5, a third coupling capacitor layer L6, a Z-shaped folded line layer L7, and a second inner ground layer L8 arranged in sequence. The first inner ground layer L1, the cross-coupling layer L2, the first coupling capacitor layer L3, the second coupling capacitor layer L4, the transmission inductor-capacitor layer L5, the third coupling capacitor layer L6, the Z-shaped folded line layer L7, and the second inner ground layer L8. Among them, the transmission inductor-capacitor layer L5 is electrically connected with the input end outer electrode 42B. The transmission inductor-capacitor layer L5 is electrically connected with the output end outer electrode 44B. The first inner ground layer L1, the cross-coupling layer L2, the first coupling capacitor layer L3, the second coupling capacitor layer L4, the third coupling capacitor layer L6, the Z-shaped folded line layer L7, and the second inner ground layer L8 are all electrically connected with the group of grounding outer electrodes (the first grounding outer electrode 462B or the second grounding outer electrode 464B), and the plurality of electrode layers form a resonance circuit 200 (as shown in Figure 4 The resonance circuit 200 is used to perform resonance processing on the radio frequency signal input from the input end outer electrode 42B, and the radio frequency signal after the resonance processing is output from the output end outer electrode 44B.

[0085] In other words, each of the remaining electrode layers in the plurality of electrode layers except the transmission inductor-capacitor layer L5 is electrically connected with the group of grounding outer electrodes 46, and the plurality of electrode layers form a resonance circuit 200 (as shown in Figure 4(As shown).

[0086] The first coupling capacitor layer L3, the second coupling capacitor layer L4, and the third coupling capacitor layer L6 are used to form the first-stage resonant unit 203, the second-stage resonant unit 204, the third-stage resonant unit 205, and the fourth-stage resonant unit 206 in the resonant circuit 200 through electromagnetic coupling with the transmission inductor-capacitor layer L5.

[0087] Each of the cross-coupling layer L2, the first coupling capacitor layer L3, the second coupling capacitor layer L4, and the third coupling capacitor layer L6 includes a connecting portion 632 and four interdigitated portions 634 spaced apart on the connecting portion 632. A slot 6340 is formed between every two adjacent interdigitated portions 634. One end of each interdigitated portion 634 is fixed to the connecting portion 632, and the other ends of all interdigitated portions 634 away from the connecting portion 632 extend in the same direction. The interdigitated portions 634 are used to achieve deep attenuation at the far end of the RF device 100B. The widths of the slots 6340 may be the same or different. The lengths of the interdigitated portions 634 may be the same (e.g., ...). Figure 6b The interdigitated portion 634 in L6 of the RF device shown can also be different (e.g. Figure 6c (The interdigitated portion 634 is shown).

[0088] The cross-coupling layer L2 is electromagnetically coupled with the first coupling capacitor layer L3, the second coupling capacitor layer L4 and the third coupling capacitor layer L6 to form a first capacitor 207 connected between the first resonant unit 203 and the second resonant unit 204, a second capacitor 208 connected between the second resonant unit 204 and the third resonant unit 205, and a third capacitor 209 connected between the third resonant unit 205 and the fourth resonant unit 206.

[0089] The first capacitor 207, the second capacitor 208, and the third capacitor 209, formed by electromagnetic coupling through the cross-coupling layer L2, the first coupling capacitor layer L3, the second coupling capacitor layer L4, and the third coupling capacitor layer L6, achieve the transmission null point of the radio frequency device 100B, thereby generating dual suppression at the near end of the radio frequency device 100B (such as...). Figure 7 (As shown). Compared to traditional punched-hole LTCC RF devices, the 100B RF device has steeper near-end rejection, deeper far-end rejection, and lower insertion loss. For example... Figure 7 As shown, out-of-band suppression in the 4.3–5.3 GHz frequency range is considered near-end, and out-of-band suppression in the 7–9 GHz range is considered far-end.

[0090] The four interdigitated portions 634 are spaced apart along the first direction, and the width of all the slots 6340 along the first direction may be the same or different.

[0091] The transmission inductance and capacitance layer L5 includes an input port L51 and an output port L52. The input port L51 is electrically connected to the input outer electrode 42B, and the output port L52 is electrically connected to the output outer electrode 44B. The input port L51 is an input port 201 in the resonant circuit 200, and the output port L52 is an output port 202 in the resonant circuit 200.

[0092] Inside the substrate 20, the transmission inductance and capacitance layer L5, the first inner ground layer L1, the cross-coupling layer L2, the first coupling capacitance layer L3, the second coupling capacitance layer L4, the third coupling capacitance layer L6, the Z-shaped zigzag layer L7, and the second inner ground layer L8 have no direct conduction relationship. The transmission inductance and capacitance layer L5 and the remaining electrode layers in the inner electrode 60 are coupled by electromagnetic coupling of the radio frequency signal to realize the coupling matrix of the radio frequency device.

[0093] In other embodiments of the present application, the substrate can include a plurality of ceramic slurry casting layers, and the electrode layers are printed on the surfaces of the ceramic casting layers, and the printing between each layer is performed separately. After all the printing is completed, the layers are laminated in the order of the first inner ground layer L1, the cross-coupling layer L2, the first coupling capacitance layer L3, the second coupling capacitance layer L4, the transmission inductance and capacitance layer L5, the third coupling capacitance layer L6, the Z-shaped zigzag layer L7, and the second inner ground layer L8, and then sintered to form a complete via-free radio frequency device after the end electrodes are formed.

[0094] The present application does not limit the arrangement order of the plurality of electrode layers in the inner electrode.

[0095] In some embodiments of the present application, the number of transmission inductance and capacitance layers can be one or two or more. When the number of transmission inductance and capacitance layers is one, the transmission inductance and capacitance layer includes an input port and an output port. When the number of transmission inductance and capacitance layers is two, one transmission inductance and capacitance layer includes an input port, and the other transmission inductance and capacitance layer includes an output port. The two transmission inductance and capacitance layers are arranged in layers to improve the layout flexibility of the inner electrode.

[0096] In some embodiments of the present application, the ground electrodes in the ground outer electrode group can be one or more.

[0097] In other embodiments of the present application, the radio frequency device includes a substrate made of an insulating medium; external electrodes disposed on an outer wall of the substrate, including an input external electrode, an output external electrode, and a ground external electrode group; and internal electrodes including a plurality of electrode layers embedded in the substrate and disposed in layers, with the insulating medium disposed between each adjacent two of the electrode layers; the plurality of electrode layers including at least one transmission inductance-capacitance layer, the at least one transmission inductance-capacitance layer being electrically connected to the input external electrode and the output external electrode, the remaining electrode layers of the plurality of electrode layers, excluding the transmission inductance-capacitance layer, being electrically connected to the ground external electrode group, the plurality of electrode layers forming a resonant circuit, the resonant circuit being configured to perform resonant processing on a radio frequency signal input from the input external electrode, and the radio frequency signal after the resonant processing being output from the output external electrode.

[0098] In other embodiments of the present application, the number of coupling capacitance layers is at least two, and the number of interdigital electrodes of each coupling capacitance layer is at least two. The at least two coupling capacitance layers are electromagnetically coupled to the at least one transmission line inductance layer to form at least two resonant units disposed in parallel in the resonant circuit.

[0099] It should be understood that expressions such as "include" and "may include" used in the present application indicate the presence of the disclosed functions, operations, or components, and do not limit one or more additional functions, operations, and components. In the present application, terms such as "include" and / or "have" can be interpreted as indicating the presence of a specific characteristic, number, operation, component, element, or combination thereof, but can not be interpreted as excluding the presence or addition of one or more other characteristics, numbers, operations, components, elements, or combinations thereof.

[0100] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed terms. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0101] In the present application, expressions including ordinal numbers such as "first" and "second" can modify elements. However, such elements are not limited by the above expressions. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are used merely to distinguish one element from another. For example, a first user device and a second user device indicate different user devices, although the first user device and the second user device are both user devices. Similarly, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element, without departing from the scope of the present application.

[0102] When a component is referred to as being "connected" or "accessed" to another component, it should be understood that another component can be interposed between them, both components being "connected" or "accessed" to each other through the other component. On the other hand, when a component is referred to as being "directly connected" or "directly accessed" to another component, it should be understood that no component is interposed between them.

[0103] The above description is merely that of the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily make changes or substitutions within the technical range disclosed in the present application, and all such changes and substitutions should be encompassed within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A radio frequency device, comprising: A substrate made of an insulating medium; An external electrode is disposed on the outer wall of the substrate and includes an input external electrode, an output external electrode, and a grounded external electrode group, wherein the grounded external electrode group includes one or more grounded external electrodes. as well as The inner electrode includes multiple electrode layers embedded in and stacked within the substrate, with an insulating medium disposed between each pair of adjacent electrode layers. Each electrode layer includes at least one transmission inductor-capacitor layer, which is electrically connected to both the input and output external electrodes. All electrode layers except the at least one transmission inductor-capacitor layer are electrically connected to the grounded external electrode group to achieve external electrical conduction outside the substrate. The multiple electrode layers form a resonant circuit, which resonates the radio frequency signal input from the input external electrode, and the resonant-processed radio frequency signal is output from the output external electrode. The plurality of electrode layers include at least three coupling capacitor layers. The three coupling capacitor layers are electromagnetically coupled with the at least one transmission inductor capacitor layer to form a first-stage resonant unit, a second-stage resonant unit, a third-stage resonant unit, and a fourth-stage resonant unit connected in parallel. The first-stage resonant unit and the third-stage resonant unit are used for cross-coupling to form an inductive cross-coupling structure, and the first-stage resonant unit and the fourth-stage resonant unit are used for cross-coupling to form a capacitive cross-coupling structure.

2. The radio frequency device according to claim 1, characterized in that, The plurality of electrode layers further include at least one Z-shaped zigzag layer, and the at least two coupling capacitor layers are electromagnetically coupled to the at least one Z-shaped zigzag layer.

3. The radio frequency device according to claim 2, characterized in that, The number of the at least one transmission inductor-capacitor layer is one. The transmission inductor-capacitor layer includes an input port and an output port. The input port is electrically connected to the external electrode of the input terminal, and the output port is electrically connected to the external electrode of the output terminal. The input port is the input port of the resonant circuit, and the output port is the output port of the resonant circuit.

4. The radio frequency device according to claim 3, characterized in that, The number of at least one Z-shaped polygonal layer is one. The at least two coupling capacitor layers include a first coupling capacitor layer, a second coupling capacitor layer, and a third coupling capacitor layer, wherein the first coupling capacitor layer, the second coupling capacitor layer, and the third coupling capacitor layer each include four interdigitated portions; The at least one transmission inductor-capacitor layer, the at least one Z-shaped zigzag layer, the first coupling capacitor layer, the second coupling capacitor layer, and the third coupling capacitor layer are electromagnetically coupled to each other.

5. The radio frequency device according to claim 4, characterized in that, The plurality of electrode layers further includes a cross-coupling layer, wherein the cross-coupling layer, the first coupling capacitor layer, the second coupling capacitor layer and the third coupling capacitor layer are electromagnetically coupled to each other.

6. The radio frequency device according to claim 5, characterized in that, The cross-coupling layer, the first coupling capacitor layer, the second coupling capacitor layer, the at least one transmission inductor-capacitor layer, the third coupling capacitor layer, and the Z-shaped zigzag layer are arranged in sequence.

7. The radio frequency device according to claim 2, characterized in that, The at least one transmission inductor-capacitor layer includes a first transmission inductor-capacitor layer and a second transmission inductor-capacitor layer separately disposed. The first transmission inductor-capacitor layer includes an input port, and the second transmission inductor-capacitor layer includes an output port. The input port is electrically connected to the external electrode of the input terminal, and the output port is electrically connected to the external electrode of the output terminal. The input port is the input port of the resonant circuit, and the output port is the output port of the resonant circuit.

8. The radio frequency device according to claim 7, characterized in that, The at least one Z-shaped polygonal layer includes a first Z-shaped polygonal layer and a second Z-shaped polygonal layer. The at least two coupling capacitor layers include a first coupling capacitor layer, a second coupling capacitor layer, a third coupling capacitor layer, and a fourth coupling capacitor layer, wherein the first coupling capacitor layer, the second coupling capacitor layer, the third coupling capacitor layer, and the fourth coupling capacitor layer each include two interdigitated portions; The first transmission inductor-capacitor layer, the second transmission inductor-capacitor layer, the first Z-shaped zigzag layer, the second Z-shaped zigzag layer, the first coupling capacitor layer, the second coupling capacitor layer, the third coupling capacitor layer, and the fourth coupling capacitor layer are electromagnetically coupled to each other.

9. The radio frequency device according to claim 8, characterized in that, The plurality of electrode layers further include a planar capacitor layer, and the planar capacitor layer, the first coupling capacitor layer, the second coupling capacitor layer, the third coupling capacitor layer and the fourth coupling capacitor layer are electromagnetically coupled to each other.

10. The radio frequency device according to claim 9, characterized in that, The first Z-shaped zigzag layer, the first coupling capacitor layer, the first transmission inductor-capacitor layer, the second coupling capacitor layer, the planar capacitor layer, the third coupling capacitor layer, the second transmission inductor-capacitor layer, the fourth coupling capacitor layer, and the second Z-shaped zigzag layer are arranged in sequence.

11. The radio frequency device according to claim 1, characterized in that, The coupling capacitor layer also includes a connecting portion, one end of each interdigitated portion is fixed to the connecting portion, and the other ends of all interdigitated portions away from the connecting portion extend in the same direction.

12. The radio frequency device according to claim 1, characterized in that, The plurality of electrode layers further include a first inner ground layer and a second inner ground layer, wherein the first inner ground layer is located at the topmost layer of the plurality of electrode layers and the second inner ground layer is located at the bottommost layer of the plurality of electrode layers.

13. The radio frequency device according to any one of claims 1-12, characterized in that, The radio frequency device is a filter, and the size of the radio frequency device is 2.5mm. 2.0mm.

14. A communication device, characterized in that, It includes a circuit board and a radio frequency device as described in any one of claims 1-13, wherein the radio frequency device is disposed on the circuit board.

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