Three-dimensional filter and method for manufacturing the same

Abstract

A three-dimensional filter and a manufacturing method thereof. The three-dimensional filter includes a circuit board, a first ring resonator, a second ring resonator, and a via structure. The circuit board includes a first circuit layer, a second circuit layer, and a third circuit layer. The second circuit layer is above the first circuit layer. The third circuit layer is between the first circuit layer and the second circuit layer. The first ring resonator is disposed in the first circuit layer and has a first surrounding area to correspond to a first stopband. The second ring resonator is disposed in the second circuit layer and has a second surrounding area to correspond to a second stopband. The via structure is disposed through the first circuit layer, the second circuit layer, and the third circuit layer and is electrically connected to the first ring resonator and the second ring resonator. The filter uses a three-dimensional staggered architecture to achieve a smaller planar area and to achieve the purposes of low loss and high flatness characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to a three-dimensional filter and a manufacturing method thereof. BACKGROUND

[0002] With the development of wireless communication technology, the transmission frequency of wireless signals is getting higher and higher, so it is necessary to provide filters corresponding to high transmission frequency to meet the needs of wireless communication technology. In particular, in a limited product area, a filter that meets the requirements of electrical characteristics is designed. For example, in the current Antenna Filter In Package (AFIP), the filter used needs to have a small planar area. In addition, the filter designed in the millimeter wave frequency band cannot maintain a transmission loss of less than -1 dB in the passband, and also cannot take into account the flatness of the filter. When the flatness of the filter is not good, it will also affect the linearity problem of the amplifier in the corresponding radio frequency system.

[0003] Therefore, a filter that can take into account low loss and high flatness characteristics and is convenient to set in a limited product area is needed. SUMMARY

[0004] Embodiments of the present application propose a three-dimensional filter and a manufacturing method thereof. The filter uses a three-dimensional staggered structure to achieve the purpose of having a small planar area and taking into account low loss and high flatness characteristics.

[0005] According to embodiments of the present application, the filter described above includes a circuit board, a first ring resonator, a second ring resonator, and a via structure. The circuit board includes a first circuit layer, a second circuit layer, and a third circuit layer. The second circuit layer is located above the first circuit layer, and the third circuit layer is located between the first circuit layer and the second circuit layer. The first ring resonator is disposed in the first circuit layer of the circuit board, wherein the first ring resonator has a first surrounding area to correspond to a first stopband. The second ring resonator is disposed in the second circuit layer of the circuit board, wherein the second ring resonator has a second surrounding area and corresponds to a second stopband. The via structure is disposed through the first circuit layer, the second circuit layer, and the third circuit layer, and is electrically connected to the first ring resonator and the second ring resonator. The first ring resonator and the second ring resonator have different sizes of surrounding areas, and the first stopband and the second stopband have different frequencies. The first ring resonator corresponds to one of the higher frequency stopband and the lower frequency stopband, and the second ring resonator corresponds to the other of the higher frequency stopband and the lower frequency stopband.

[0006] In some embodiments, the three-dimensional filter further comprises a first signal feed line, a first signal output line, a second signal feed line, and a second signal output line. The first signal feed line is disposed in the second circuit layer of the circuit board and electrically connected to the second loop resonator. The first signal output line is disposed in the second circuit layer of the circuit board and electrically connected between the second loop resonator and the via structure. The second signal feed line is disposed in the first circuit layer of the circuit board and electrically connected between the first loop resonator and the via structure. The second signal output line is disposed in the first circuit layer of the circuit board and electrically connected to the first loop resonator. The first signal feed line and the second signal feed line extend in perpendicular directions to each other, and the first signal output line and the second signal output line extend in perpendicular directions to each other to form a quadrature feed architecture. The first signal feed line serves as one of the input port and the output port of the three-dimensional filter, and the second signal output line serves as the other of the input port and the output port of the three-dimensional filter.

[0007] In some embodiments, the three-dimensional filter further comprises a first open stub, a second open stub, a third open stub, and a fourth open stub. The first open stub is disposed in the first circuit layer of the circuit board and electrically connected to the first loop resonator. The second open stub is disposed in the first circuit layer of the circuit board and electrically connected to the first loop resonator. The third open stub is disposed in the second circuit layer of the circuit board and electrically connected to the second loop resonator. The fourth open stub is disposed in the second circuit layer of the circuit board and electrically connected to the second loop resonator.

[0008] In some embodiments, the first loop resonator has a first side, a second side, a third side, and a fourth side, the first side opposite to the third side, and the second side opposite to the fourth side. The second signal output line is adjacent to the second side. The second signal feed line is adjacent to the first side. The first open stub is adjacent to the fourth side. The second open stub is adjacent to the third side.

[0009] In some embodiments, the second loop resonator has a fifth side, a sixth side, a seventh side, and an eighth side, the fifth side opposite to the seventh side, and the sixth side opposite to the eighth side. The first signal feed line is adjacent to the eighth side. The first signal output line is adjacent to the fifth side. The third open stub is adjacent to the seventh side. The fourth open stub is adjacent to the sixth side.

[0010] In some embodiments, the first open stub, the second open stub, the third open stub, and the fourth open stub are quarter-wavelength open stubs.

[0011] In some embodiments, the first signal feed line has a first end portion adjacent to the second loop resonator, a second end portion distal from the second loop resonator, and an intermediate portion between the first end portion and the second end portion, the width of the first signal output line gradually increases from the first end portion to the second end portion to provide a stepped impedance.

[0012] In some embodiments, the three-dimensional filter further comprises a first metal patch and a second metal patch. The first metal patch is disposed in the first circuit layer of the circuit board and located in the first looped region of the first loop resonator. The second metal patch is disposed in the second circuit layer of the circuit board and located in the second looped region of the second loop resonator.

[0013] In some embodiments, the three-dimensional filter further comprises a ground metal layer. The ground metal layer is disposed in the third circuit layer as a common reference ground plane for the first loop resonator and the second loop resonator. The ground metal layer has an opening, and the via structure passes through the opening to vertically penetrate the ground metal layer.

[0014] In some embodiments, the circuit board further comprises a first liquid crystal polymer (LCP) layer between the first circuit layer and the second circuit layer, and a second liquid crystal polymer layer between the second circuit layer and the third circuit layer, and the via structure further penetrates the first liquid crystal polymer layer and the second liquid crystal polymer layer.

[0015] According to embodiments of the present disclosure, a method for manufacturing the filter comprises: forming a first loop resonator in a first circuit layer and a second loop resonator in a second circuit layer according to a predetermined frequency band of the three-dimensional filter, wherein the first loop resonator has a first looped region corresponding to a first stopband of the predetermined frequency band, the second loop resonator has a second looped region corresponding to a second stopband of the predetermined frequency band, and the first looped region and the second looped region are different in size; forming a ground metal layer in a third circuit layer, wherein the third circuit layer is between the first circuit layer and the second circuit layer, and the ground metal layer serves as a common reference ground plane for the first loop resonator and the second loop resonator; and forming a via structure in the first circuit layer, the second circuit layer, and the third circuit layer, wherein the via structure penetrates the first circuit layer, the second circuit layer, and the third circuit layer to electrically connect to the first loop resonator and the second loop resonator. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 shows a structure schematic diagram of a three-dimensional filter according to an embodiment of the present disclosure.

[0017] Figure 2 FIG. 1 shows a structural diagram of a circuit board of a three-dimensional filter according to an embodiment of the present application.

[0018] Figure 3 FIG. 2 shows a structural diagram of a second ring filter according to an embodiment of the present application.

[0019] Figure 4 FIG. 3 shows a structural diagram of a first ring filter according to an embodiment of the present application.

[0020] Figure 5 FIG. 4 shows a structural diagram of a second ring filter according to another embodiment of the present application.

[0021] Figure 6 FIG. 5 shows a structural diagram of a second ring filter according to another embodiment of the present application.

[0022] Figure 7 FIG. 6 shows a structural diagram of a second ring filter according to another embodiment of the present application.

[0023] Figure 8 FIG. 7 shows a structural diagram of a second ring filter according to another embodiment of the present application.

[0024] Figure 9 FIG. 8 shows a structural diagram of an antenna module according to an embodiment of the present application.

[0025] Figure 10 FIG. 9 shows a flow diagram of a manufacturing method of a three-dimensional filter according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] As used herein, "first", "second", or the like are not intended to refer to a specific order or sequence, but are used to distinguish elements or operations from one another.

[0027] Please refer to Figure 1 FIG. 1 shows a structural diagram of a three-dimensional filter 100 according to an embodiment of the present application. The three-dimensional filter 100 includes a first ring filter 110, a second ring filter 120, and a via structure 130 electrically connecting the first ring filter 110 and the second ring filter 120, wherein a ground metal layer 140 is disposed between the first ring filter 110 and the second ring filter 120. The first ring filter 110 and the second ring filter 120 are disposed on opposite sides of the ground metal layer 140, the via structure 130 penetrates the ground metal layer 140, and electrically connects the first ring filter 110 and the second ring filter 120, wherein the via structure 130 is not electrically connected to the ground metal layer 140.

[0028] Please refer to Figure 2Fig. 1 shows a schematic diagram of a circuit board 200 of a three-dimensional filter 100. The circuit board 200 includes a first circuit layer 210, a second circuit layer 220, a third circuit layer 230, a first insulating layer 240, and a second insulating layer 250. The second circuit layer 220 and the third circuit layer 230 are located above the first circuit layer 210, and the third circuit layer 230 is located between the first circuit layer 210 and the second circuit layer 220. The first insulating layer 240 and the second insulating layer 250 are disposed on the first circuit layer 210, wherein the first insulating layer 240 is disposed between the first circuit layer 210 and the third circuit layer 230 to provide electrical insulation between the first circuit layer 210 and the third circuit layer 230, and the second insulating layer 250 is disposed between the third circuit layer 230 and the second circuit layer 220 to provide electrical insulation between the third circuit layer 230 and the second circuit layer 220.

[0029] In the present embodiment, the first circuit layer 210, the second circuit layer 220, and the third circuit layer 230 are made of copper foil, and the first insulating layer 240 and the second insulating layer 250 are made of liquid crystal polymer (LCP) layer. However, the embodiments of the present application are not limited thereto. Other metal materials and insulating materials can be used to form the first circuit layer 210, the second circuit layer 220, the third circuit layer 230, the first insulating layer 240, and the second insulating layer 250 according to actual needs. For example, in some embodiments, the first circuit layer 210, the second circuit layer 220, and the third circuit layer 230 can be made of silver, gold, aluminum, nickel, iron, or compounds of the above-mentioned materials, and the first insulating layer 240 and the second insulating layer 250 can be made of polyimide (PI) or modified PI (MPI).

[0030] Please refer to Figure 1 and Figure 2 In the present embodiment, the first ring filter 110 is located in the first circuit layer 210, the second ring filter 120 is located in the second circuit layer 220, the ground metal layer 140 is located in the third circuit layer 230, and the via structure 130 is disposed through the first circuit layer 210, the second circuit layer 220, and the third circuit layer 230. In this way, the three-dimensional filter 100 as shown in Fig. 1 can be provided. In some embodiments, the via structure 130 can be made of through holes or blind holes. Figure 1

[0031] Please refer to Figure 3 ​Fig. 2 shows a schematic diagram of a second ring filter 120 according to an embodiment of the present application, wherein the second ring filter 120 is located in the second circuit layer 220. The second ring filter 120 comprises a ring resonator 310, a first signal feed line 320 and a first signal output line 330. The ring resonator 310 has a surrounding area A1, and its side edges are electrically connected to the first signal feed line 320 and the first signal output line 330. The first signal feed line 320 is used as an input port of the three-dimensional filter 100 to receive a high-frequency input signal to be processed. The first signal output line 330 is electrically connected between the ring resonator 310 and the end portion 131 of the via structure 130 to provide an output signal to the via structure 130.

[0032] Referring to Fig. 3, Figure 4 Fig. 4 shows a schematic diagram of a first ring filter 110 according to an embodiment of the present application, wherein the first ring filter 110 is located in the first circuit layer 210. The first ring filter 110 comprises a ring resonator 410, a second signal feed line 420 and a second signal output line 430. The ring resonator 410 has a surrounding area A2, which is smaller than the surrounding area A1 in the above embodiment. In other words, the first ring filter 110 is a small ring filter, while the second ring filter 120 is a large ring filter. The second signal feed line 420 is electrically connected between the ring resonator 410 and the other end portion 132 of the via structure 130 to receive an output signal provided by the second ring filter 120 through the via structure 130. The second signal output line 430 is electrically connected to the ring resonator 410 to serve as an output port of the three-dimensional filter 100. In this way, the first ring filter 110 can output a high-frequency filtered signal from the second signal output line 430 in response to the output signal provided by the second ring filter 120. However, the present application is not limited thereto, and the first ring filter 110 can be larger than the second ring filter 120, as long as the ring filter areas of the two ring filters are different.

[0033] In addition, the three-dimensional filter 100 provides a cross-fed architecture. Specifically, the first signal feed line 320 is perpendicular to the extension direction of the second signal feed line 420, and the first signal output line 330 is perpendicular to the extension direction of the second signal output line 430 to form a cross-fed architecture. In this embodiment, the first signal feed line 320 is the input port of the three-dimensional filter, and the second signal output line 430 is the output port of the three-dimensional filter. In other embodiments, the input port and the output port can be swapped, such that the first signal feed line 320 becomes the output port and the second signal output line 430 becomes the input port. In other words, the signal to be filtered can be input by the first signal feed line 320, and the filtered signal can be output by the second signal output line 430. Alternatively, the signal to be filtered can be input by the second signal output line 430, and the filtered signal can be output by the first signal feed line 320.

[0034] In this embodiment, the first ring filter 110 further includes a first open stub 440, a second open stub 450, and a first metal patch 460. The first open stub 440 is disposed on one side of the ring resonator 410 and opposite one of the second signal feed line 420 and the second signal output line 430, and the second open stub 450 is disposed on the other side of the ring resonator 410 and opposite the other of the second signal feed line 420 and the second signal output line 430. Specifically, the ring resonator 410 has a first side 411, a second side 412, a third side 413, and a fourth side 414, wherein the first side 411 is opposite the third side 413, and the second side 412 is opposite the fourth side 414. The second signal output line 430 is adjacent to the second side 412, and the first open stub 440 is adjacent to the fourth side 414. The second signal feed line 420 is adjacent to the first side 411, and the second open stub 450 is adjacent to the third side 413. The first metal patch 460 is disposed in the surrounding area A2 and corresponds to the first open stub 440 and the second open stub 450. Specifically, the first open stub 440 and the second open stub 450 are adjacent to the fourth side 414 and the third side 413, and the first metal patch 460 is disposed in the corner corresponding to the third side 413 and the fourth side 414. Through the above design, the first open stub 440 and the second open stub 450 can combine with the ring resonator 410 to provide a bandpass filter, and the first metal patch 460 can provide matching for the impedance discontinuity problem caused by the via structure 130. The size of the first metal patch 460 can affect the bandwidth of the first ring filter 110. The larger the size of the first metal patch 460, the larger the bandwidth of the first ring filter 110.

[0035] Similarly, please refer back to Figure 3 The second ring filter 120 also includes a third open stub 350, a fourth open stub 340, and a second metal patch 360. The third open stub 350 is disposed on one side of the ring resonator 310 and opposite one of the first signal feed line 320 and the first signal output line 330, and the fourth open stub 340 is disposed on another side of the ring resonator 310 and opposite the other of the first signal feed line 320 and the first signal output line 330. Specifically, the ring resonator 310 has a fifth side 315, a sixth side 316, a seventh side 317, and an eighth side 318, where the fifth side 315 is opposite the seventh side 317, and the sixth side 316 is opposite the eighth side 318. The first signal feed line 320 is adjacent to the eighth side 318, and the third open stub 350 is adjacent to the seventh side 317. The first signal output line 330 is adjacent to the fifth side 315, and the fourth open stub 340 is adjacent to the sixth side 316. The second metal patch 360 is disposed in the surrounding area Al and is disposed corresponding to the third open stub 350 and the fourth open stub 340. Specifically, the third open stub 350 and the fourth open stub 340 are adjacent to the sixth side 316 and the seventh side 317, and the second metal patch 360 is disposed in the corner corresponding to the sixth side 316 and the seventh side 317. Through the above design, the third open stub 350 and the fourth open stub 340 can combine with the ring resonator 310 to provide a bandpass filter, and the second metal patch 360 can provide matching for the impedance discontinuity problem caused by the via structure 130. The size of the second metal patch 360 can affect the bandwidth of the second ring filter 120. The larger the size of the second metal patch 360, the greater the bandwidth of the second ring filter 120.

[0036] In embodiments of the present application, the surrounding length (or inner circle length) of the ring resonators 310 and 410 is n times the wavelength, where n is an integer greater than or equal to 1. The lengths of the first open stub 440, the second open stub 450, the third open stub 350, and the fourth open stub 340 are one-quarter of the wavelength. In addition, the ring resonators 310 and 410 of the present embodiment are octagonal, but embodiments of the present application are not limited thereto. In other embodiments of the present application, the ring resonators 310 and 410 have an outer shape that is symmetric about both the horizontal and vertical axes, such as a rectangle or a hexagon.

[0037] As described above, the three-dimensional filter 100 of the embodiment of the present application utilizes the two passbands provided by the large annular filter (i.e., the second annular filter 120) and the small annular filter (i.e., the first annular filter 110) to provide a combined passband, wherein the high frequency cutoff point of the combined passband of the three-dimensional filter 100 is determined by the higher frequency passband provided by the second annular filter 120, and the low frequency cutoff point of the combined passband is determined by the lower frequency passband provided by the first annular filter 110. In the embodiment, the high frequency cutoff point of the combined passband is 64 GHz, and the low frequency cutoff point of the combined passband is 54 GHz, so that the operating frequency is 60 GHz. However, the embodiment of the present application is not limited thereto. The user can adjust the first annular filter 110 and the second annular filter 120 according to the user's own needs, so that the combined passband of the three-dimensional filter 100 can meet the user's needs. For example, in the embodiment of the present application, the large annular filter (i.e., the second annular filter 120) can correspond to one of the high frequency cutoff point and the low frequency cutoff point (e.g., the high frequency cutoff point), and the small annular filter (i.e., the first annular filter 110) can correspond to the other of the high frequency cutoff point and the low frequency cutoff point (e.g., the low frequency cutoff point). In some embodiments, the operating frequency of the three-dimensional filter 100 can be 56.13-62.61 GHz.

[0038] Furthermore, the three-dimensional filter 100 of the embodiment of the present application connects the first annular filter 110 and the second annular filter 120 in a three-dimensional connection architecture, wherein the first annular filter 110 and the second annular filter 120 are electrically connected by the through-hole structure 130 penetrating the ground metal layer 140. Since the first annular filter 110 and the second annular filter 120 adopt the three-dimensional connection architecture, the three-dimensional filter 100 has a smaller planar area.

[0039] Please refer to Figure 5 , which shows a structural schematic diagram of the second annular filter 120 according to another embodiment of the present application. In the embodiment, the shape of the annular resonator 310 of the second annular filter 120 is changed, and it also has a plurality of curved sides BS1-BS4, wherein the curved side BS1 is located between the fifth side 315 and the eighth side 318; the curved side BS2 is located between the seventh side 317 and the eighth side 318; the curved side BS3 is located between the sixth side 316 and the seventh side 317; and the curved side BS4 is located between the fifth side 315 and the sixth side 316. Through such a design, the length of the annular resonator 310 can be increased in a limited planar area, thereby changing the size and passband range provided by the three-dimensional filter 100.

[0040] Similarly, the ring resonator 410 of the first ring filter 110 can also have its length changed by the provision of the curved side. Since the details of the provision have been described in the above paragraph, they are not repeated here.

[0041] Referring to Figure 6 , a schematic diagram of the structure of the second ring filter 120 according to another embodiment of the present application is shown. In this embodiment, the outer shape of the third open stub 350 and the fourth open stub 340 of the second ring filter 120 is changed so that it also has a curved portion 340B and 350B. With such a design, the third open stub 350 and the fourth open stub 340 can have their lengths increased in a limited planar area, and thus the size and the passband range provided by the three-dimensional filter 100 can be changed. Similarly, the first open stub 440 and the second open stub 450 of the first ring filter 110 can also have their lengths changed by the provision of the curved portion.

[0042] Referring to Figure 7 , a schematic diagram of the structure of the second ring filter 120 according to another embodiment of the present application is shown. In this embodiment, the outer shape of the first signal feed line 320 of the second ring filter 120 is changed so that it has a stepped change in width. Specifically, the first signal feed line 320 includes a first end portion 320a, a second end portion 320b and an intermediate portion 320c. The first end portion 320a is adjacent to the ring resonator 310, the second end portion 320b is away from the ring resonator 310, and the intermediate portion 320c is between the first end portion 320a and the second end portion 320b. The width of the first signal feed line 320 gradually increases from the first end portion 320a to the second end portion 320b to provide a stepped impedance.

[0043] Referring to Figure 8 , a schematic diagram of the structure of the second ring filter 120 according to another embodiment of the present application is shown. In this embodiment, the outer shape of the first signal feed line 320 of the second ring filter 120 is changed so that it has a gradual change in width. Specifically, the width of the first end portion 320a, the second end portion 320b and the intermediate portion 320c of the first signal feed line 320 gradually changes instead of having a stepped change as shown in Figure 7 .

[0044] Referring to Figure 9The diagram illustrates a structural schematic of an antenna module 900 according to an embodiment of the present invention. The antenna module 900 includes a radio frequency (RF) chip (RF IC) 910, an antenna device 920, an antenna device 930, and a circuit board 940. The RF chip 910, the antenna device 920, and the antenna device 930 are disposed on the circuit board 940, which may have a multi-layer circuit structure to form various different circuits. For example, it includes the structure of the circuit board 200 described above to provide the stereo filter 100 described above (see also reference 200). Figure 1 and Figure 2 In this embodiment, the antenna module 900 can be an antenna filter in package (AFIP). Compared to existing system in package (SiP), the antenna package of this embodiment integrates the antenna device and the filter, and has a smaller size. In some embodiments, the antenna device can be formed using the circuitry of the circuit board 200, thus omitting antenna device 920 and antenna device 930, and further reducing the space occupied by the antenna module 900.

[0045] Please refer to Figure 10 The diagram illustrates a flow chart of a method 1000 for manufacturing a stereo filter 100 according to an embodiment of the present invention. The method 1000 for manufacturing the stereo filter 100 can be performed, for example, using an automated antenna manufacturing apparatus. The automated antenna manufacturing apparatus may include a memory and a processor, wherein the memory stores a plurality of instructions, and the processor can load these instructions to perform the manufacturing method 1000.

[0046] In manufacturing method 1000, step 1100 is first performed to form a ring resonator 410 in the first circuit layer 210 and a ring resonator 310 in the second circuit layer 220 according to the preset frequency band required by the stereo filter 100. The ring resonator 410 has a surrounding region A2 corresponding to the first cutoff band (corresponding to the low-frequency cutoff point) of the preset frequency band, and the ring resonator 310 has a surrounding region A1 corresponding to the second cutoff band (corresponding to the high-frequency cutoff point) of the preset frequency band. The surrounding region A2 is smaller than the surrounding region A1.

[0047] Then, step 1200 is performed, in which a first signal feed line 320, a first signal output line 330, a third open-circuit segment 350, a fourth open-circuit segment 340 and a second metal patch 360 are formed in the second circuit layer 220 according to the preset frequency band of the stereo filter 100.

[0048] Next, step 1300 is performed to form the second signal feed line 420, the second signal output line 430, the first open stub 440, the second open stub 450, and the first metal patch 460 in the first circuit layer 210 according to the preset frequency band of the three-dimensional filter.

[0049] Then, step 1400 is performed to form the ground metal layer 140 in the third circuit layer 230 as the common reference ground plane of the loop resonators 310 and 410.

[0050] Next, step 1500 is performed to form the via structure 130 in the first circuit layer 210, the second circuit layer 220, and the third circuit layer 230, wherein the via structure 130 is disposed through the first circuit layer 210, the second circuit layer 220, and the third circuit layer 230 to electrically connect the loop resonators 310 and 410.

[0051] In some embodiments, the manufacturing method 1000 forms an opening in the ground metal layer 140 for the via structure 130 to pass through the opening to achieve the electrical connection of the loop resonators 310 and 410. In addition, an insulating material is disposed around the opening to avoid the electrical connection of the via structure 130 and the ground metal layer 140.

[0052] Although the present application has been disclosed with reference to the embodiments above, it is not intended to limit the present application, and any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application is defined by the appended claims.

[0053]

Symbol Description

[0054] 100: three-dimensional filter

[0055] 110: first loop filter

[0056] 120: second loop filter

[0057] 130: via structure

[0058] 131, 132: end portion

[0059] 140: ground metal layer

[0060] 200: circuit board

[0061] 210: first circuit layer

[0062] 220: second circuit layer

[0063] 230: third circuit layer

[0064] 240: first insulating layer

[0065] 250: second insulating layer

[0066] 310: ring resonator

[0067] 315: fifth side

[0068] 316: sixth side

[0069] 317: seventh side

[0070] 318: eighth side

[0071] 320: first signal feed line

[0072] 320a: first end portion

[0073] 320b: second end portion

[0074] 320c: intermediate portion

[0075] 330: first signal output line

[0076] 340: fourth open stub

[0077] 340B, 350B: bend

[0078] 350: third open stub

[0079] 360: second metal patch

[0080] 410: ring resonator

[0081] 411: first side

[0082] 412: second side

[0083] 413: third side

[0084] 414: fourth side

[0085] 420: second signal feed line

[0086] 430: second signal output line

[0087] 440: first open stub

[0088] 450: second open stub

[0089] 460: first metal patch

[0090] 900: antenna module

[0091] 920, 930: antenna device

[0092] 940: circuit board

[0093] 1000: Method of manufacturing a three-dimensional filter

[0094] 1100-1500: Steps

[0095] A1, : Surrounding area

[0096] BS1-BS4: Bending side.

Claims

1. A three-dimensional filter, characterized by, The three-dimensional filter comprises: a circuit board comprising a first circuit layer, a second circuit layer, and a third circuit layer, wherein the second circuit layer is located above the first circuit layer, and the third circuit layer is located between the first circuit layer and the second circuit layer; a first ring resonator disposed in the first circuit layer of the circuit board, wherein the first ring resonator has a first surrounding area corresponding to a first stopband; a second ring resonator disposed in the second circuit layer of the circuit board, wherein the second ring resonator has a second surrounding area corresponding to a second stopband; and a via structure disposed through the first circuit layer, the second circuit layer, and the third circuit layer, and electrically connected to the first ring resonator and the second ring resonator; wherein the first ring resonator and the second ring resonator have different surrounding area sizes, and the first stopband and the second stopband have different frequency levels; the first ring resonator corresponds to one of a higher frequency stopband and a lower frequency stopband, and the second ring resonator corresponds to the other of the higher frequency stopband and the lower frequency stopband. Further comprising:

2. The three-dimensional filter of claim 1, wherein, a first signal feed line disposed in the second circuit layer of the circuit board and electrically connected to the second ring resonator; a first signal output line disposed in the second circuit layer of the circuit board and electrically connected between the second ring resonator and the via structure; a second signal feed line disposed in the first circuit layer of the circuit board and electrically connected between the first ring resonator and the via structure; and a second signal output line disposed in the first circuit layer of the circuit board and electrically connected to the first ring resonator; wherein the extension directions of the first signal feed line and the second signal feed line are perpendicular to each other, and the extension directions of the first signal output line and the second signal output line are perpendicular to each other to form a quadrature feed architecture; wherein the first signal feed line serves as one of an input port and an output port of the three-dimensional filter, and the second signal output line serves as the other of the input port and the output port of the three-dimensional filter. Further comprising: a first open stub disposed in the first circuit layer of the circuit board and electrically connected to the first ring resonator; 3. The three-dimensional filter of claim 2, wherein, a second open stub disposed in the first circuit layer of the circuit board and electrically connected to the first ring resonator; a third open stub disposed in the second circuit layer of the circuit board and electrically connected to the second ring resonator; and a fourth open stub disposed in the second circuit layer of the circuit board and electrically connected to the second ring resonator.

4. The three-dimensional filter according to claim 3, wherein: the first ring resonator has a first side, a second side, a third side, and a fourth side, the first side is opposite to the third side, and the second side is opposite to the fourth side; the second signal output line is adjacent to the second side; the second signal feed line is adjacent to the first side; the first open stub is adjacent to the fourth side; and the second open stub is adjacent to the third side. ​ ​ ​ 5. The filter according to claim 3, wherein: The second ring resonator has a fifth side, a sixth side, a seventh side, and an eighth side, the fifth side is opposite to the seventh side, and the sixth side is opposite to the eighth side; The first signal output line is adjacent to the fifth side; The first signal feed line is adjacent to the eighth side; The third open stub is adjacent to the seventh side; and The fourth open stub is adjacent to the sixth side. The first open stub, the second open stub, the third open stub, and the fourth open stub are quarter-wavelength open stubs.

6. The three-dimensional filter of claim 3, wherein, The first signal feed line has a first end portion, a second end portion, and an intermediate portion, the first end portion is adjacent to the second ring resonator, the second end portion is away from the second ring resonator, the intermediate portion is between the first end portion and the second end portion, and the width of the first signal output line gradually increases from the first end portion to the second end portion to provide a stepped impedance.

7. The three-dimensional filter of claim 2, wherein, Further comprising:

8. The three-dimensional filter of claim 1, wherein, a first metal patch disposed in the first circuit layer of the circuit board and located in the first surrounding area of the first ring resonator; and a second metal patch disposed in the second circuit layer of the circuit board and located in the second surrounding area of the second ring resonator. Further comprising:

9. The filter according to claim 1, wherein a ground metal layer disposed in the third circuit layer as a common reference ground plane for the first ring resonator and the second ring resonator; wherein the ground metal layer has an opening, and the through-hole structure penetrates through the opening to vertically penetrate the ground metal layer. The circuit board further comprises a first liquid crystal polymer layer and a second liquid crystal polymer layer, the first liquid crystal polymer layer is between the first circuit layer and the second circuit layer, the second liquid crystal polymer layer is between the second circuit layer and the third circuit layer, and the through-hole structure also penetrates through the first liquid crystal polymer layer and the second liquid crystal polymer layer.

10. The three-dimensional filter of claim 1, wherein, Comprising:

11. A method of manufacturing a three-dimensional filter, characterized by: forming a first ring resonator in a first circuit layer and a second ring resonator in a second circuit layer according to a predetermined frequency band of the three-dimensional filter, wherein the first ring resonator has a first surrounding area corresponding to a first cutoff band of the predetermined frequency band, and the second ring resonator has a second surrounding area corresponding to a second cutoff band of the predetermined frequency band, the first surrounding area and the second surrounding area are different in size; forming a ground metal layer in a third circuit layer, wherein the third circuit layer is between the first circuit layer and the second circuit layer, and the ground metal layer serves as a common reference ground plane for the first ring resonator and the second ring resonator; and forming a through-hole structure in the first circuit layer, the second circuit layer, and the third circuit layer, wherein the through-hole structure is disposed through the first circuit layer, the second circuit layer, and the third circuit layer to be electrically connected to the first ring resonator and the second ring resonator. ​

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