A hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high-steepness sideband and a passive microwave device

Abstract

The present invention discloses a hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high-steepness sideband and a passive microwave device, characterized in that it includes a low-pass part, and the low-pass part includes a low-pass series trunk and a plurality of low-pass parallel branches; wherein, the low-pass series trunk includes a plurality of LC resonance units connected in series in sequence; the low-pass parallel branches are connected between the low-pass series trunk and the ground wire, and at least one LC resonance unit is spaced between adjacent two low-pass parallel branches, and the low-pass parallel branch includes a low-pass branch capacitive element, or a plurality of series-connected low-pass branch capacitive elements, and part or all of the low-pass branch capacitive elements adopt piezoelectric acoustic wave resonators. This hybrid filter has a large bandwidth and meets the requirements of a narrow transition band and high adjacent-band rejection.

Description

Technical Field

[0001] The present invention belongs to the technical field of filtering, and particularly relates to a hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high-steepness sideband and a passive microwave device. Background Art

[0002] Filtering devices are widely used in various fields, such as communication systems, audio processing, industrial automation, medical fields, etc. In daily life and work, many electronic devices need to use filters to filter out noise, interference, and other unwanted signals to ensure the normal operation of the devices and the clear transmission of signals.

[0003] With the rapid development of communication technologies, more and more frequency bands are put into use, such as the WIFI6E frequency band. As the operating frequency continues to increase, traditional single filtering devices include two major categories: passive filters and active filters. Passive filters are mainly composed of passive components such as resistors, capacitors, and inductors, and their working principle is based on the combination of inductors, capacitors, and resistors to filter out specific frequency signals. Active filters, in addition to basic passive components, also include active components such as amplifiers and can achieve more complex frequency response characteristics. However, various traditional piezoelectric acoustic wave resonators cannot meet the performance requirements of large bandwidths due to the influence of material factors such as the electromechanical coupling coefficient.

[0004] The invention patent application with the patent number CN104756403A discloses reducing the design cost of an LC filter required to vary the characteristics of an attenuation pole formed by skip coupling. The LC filter unit body (100) includes: a ceramic laminate (10) formed by laminating a plurality of ceramic layers (11 to 61), an LC filter circuit formed inside the ceramic laminate (10), an input terminal, an output terminal, and a ground terminal formed on the surface of the ceramic laminate (10). As circuit elements constituting skip coupling that form an attenuation pole by connecting to the LC filter circuit, mounting electrodes (64a, 64b) for mounting at least one of an external inductor, capacitor, and SAW resonator are formed on the surface of the ceramic laminate (10). However, the low Q value of the LC filter disclosed in this patent cannot meet the requirements.

[0005] An LC filter, also known as a passive filter, is a traditional harmonic compensation device. The LC filter is composed of a proper combination of filter capacitors, reactors, and resistors, and is connected in parallel with the harmonic source. In addition to filtering, it also takes into account the need for reactive power compensation. The most common and easily adopted passive filter structure is to connect an inductor in series with a capacitor, which can form a low-impedance bypass for the main sub-harmonics (3, 5, 7). In addition, LC filters are also divided into several types such as single-tuned filters, high-pass filters, double-tuned filters, and triple-tuned filters. Traditional LC filters such as IPD (Integrated Product) and LTCC (Low Temperature Co-fired Ceramic) cannot meet the requirements of narrow transition bands and high adjacent-band rejection due to the low Q value of the components themselves. They can no longer meet all requirements.

[0006] Therefore, combining a piezoelectric acoustic resonator and an LC filter to bring out the advantages of both, obtaining a hybrid filter that has both a large bandwidth and meets the requirements of a narrow transition band and high adjacent-band rejection is the current development direction of the filter industry. Summary of the Invention

[0007] The present invention provides a hybrid filter integrating a piezoelectric acoustic resonator with a large bandwidth and a high-steepness sideband and a passive microwave device. This hybrid filter has a large bandwidth and meets the requirements of a narrow transition band and high adjacent-band rejection.

[0008] A specific embodiment of the present invention provides a hybrid filter integrating a piezoelectric acoustic resonator with a large bandwidth and a high-steepness sideband and a passive microwave device, including: a low-pass part, and the low-pass part includes a low-pass series trunk and a plurality of low-pass parallel branches;

[0009] Among them, the low-pass series trunk includes a plurality of LC resonant units connected in series in sequence;

[0010] The low-pass parallel branches are connected between the low-pass series trunk and the ground wire. At least one LC resonant unit is spaced between adjacent two low-pass parallel branches. The low-pass parallel branches include a low-pass branch capacitive element, or a plurality of series-connected low-pass branch capacitive elements, and some or all of the low-pass branch capacitive elements adopt piezoelectric acoustic resonators.

[0011] Therefore, compared with the IPD+BAW disclosed in the prior art, which introduces a piezoelectric acoustic resonator to introduce multiple zeros at the passband edge to improve adjacent-band rejection and the roll-off slope of the transition region, the present invention retains LC resonator units on the trunk to make the passband large and flat, and connects one or more piezoelectric acoustic resonators in parallel on the branches to introduce high-Q transmission zeros in the transition band and at the same time be able to adjust the parameters so that the parallel resonance points of the parallel-connected piezoelectric acoustic resonators are located at the passband position to improve the in-band insertion loss. At the same time, in terms of structure, the present invention disperses and reasonably distributes the piezoelectric acoustic resonators into the framework of the IPD filter, enabling it to not only play the role of introducing zeros and poles, but also play the function of impedance matching.

[0012] In the present invention, LC resonance units are connected in series on a low-pass series main path, so that the passband of the hybrid filter provided by the present invention is large and flat. By adjusting relevant parameters, the series resonance point of the piezoelectric acoustic wave resonator located on the low-pass parallel branch is located at the transition band position, thereby introducing a transmission zero point with a high Q value of the piezoelectric acoustic wave resonator to improve the transition band and adjacent band suppression. At the same time, by adjusting relevant parameters, the parallel resonance point of the piezoelectric acoustic wave resonator is located at the passband position to improve the in-band insertion loss.

[0013] Preferably, there is an LC resonance unit between two adjacent low-pass parallel branches, and all capacitive elements of the low-pass branches are piezoelectric acoustic wave resonators.

[0014] Preferably, the hybrid filter integrating the piezoelectric acoustic wave resonator with a large bandwidth and a high steepness sideband further includes a high-pass part, the high-pass part is connected in series with the low-pass part, and the high-pass part includes a high-pass series main path and a plurality of high-pass parallel branches;

[0015] Among them, the high-pass series main path includes a plurality of high-pass main path capacitive elements connected in series in sequence, and some or all of the high-pass main path capacitive elements are piezoelectric acoustic wave resonators;

[0016] The high-pass parallel branches are connected between the high-pass series main path and the ground wire. There is at least one high-pass main path capacitive element between two adjacent high-pass parallel branches. The high-pass parallel branches include LC resonance units or piezoelectric acoustic wave resonators.

[0017] Compared with the single type of zero point that can only be provided in the prior art, by introducing series piezoelectric acoustic wave resonators and parallel piezoelectric acoustic wave resonators, and adjusting parameters, the zero points of the two can be combined to form a band-stop effect, thereby forming a wider transition band optimization. And by multiple parallel piezoelectric acoustic wave resonators generating poles in the filter passband to achieve the effect of improving the in-band insertion loss.

[0018] By introducing a high-pass part, the hybrid filter has both series piezoelectric acoustic wave resonators in the high-pass series main path and parallel piezoelectric acoustic wave resonators in the low-pass parallel branches. The zero points of the above two piezoelectric acoustic wave resonators can be evenly arranged on the transition band, and after combination, they can also form a band-stop effect, so as to support the optimization of a wider transition band that cannot be satisfied by the zero points generated by a single type of piezoelectric acoustic wave resonator.

[0019] Preferably, the high-pass main path capacitive elements that do not use piezoelectric acoustic wave resonators use capacitors to maintain the corresponding impedance matching.

[0020] Preferably, all capacitive elements of the low-pass branches are piezoelectric acoustic wave resonators to obtain more zero points and improve the optimization effect of the transition band.

[0021] Preferably, a capacitor is used as the capacitive element of the low-pass branch that does not employ a piezoelectric acoustic wave resonator to maintain the corresponding impedance matching.

[0022] Preferably, at least one piezoelectric acoustic wave resonator is spaced between the high-pass part and the low-pass part.

[0023] Preferably, the transmission zeros generated by the self-resonance of the piezoelectric acoustic wave resonators in the high-pass part and the low-pass part are all distributed within the adjacent band range of the edge of the low-frequency end of the passband.

[0024] Preferably, the piezoelectric acoustic wave resonators on the low-pass parallel branch and the high-pass parallel branch both generate poles within the passband.

[0025] Preferably, the piezoelectric acoustic wave resonator can be a bulk acoustic wave resonator, a surface acoustic wave resonator, a Lamb wave resonator, and is not limited thereto.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] While retaining some LC resonator units to make the hybrid filter have a large and flat passband, the present invention introduces piezoelectric acoustic wave resonators on the low-pass parallel branch. By adjusting the parameters of the piezoelectric acoustic wave resonators, the transmission zeros generated by the piezoelectric acoustic wave resonators are located within the adjacent band range of the edge of the low-frequency end of the passband, thereby improving the adjacent band rejection and the roll-off slope. Also, since the piezoelectric acoustic wave resonators generate poles within the passband range, the in-band insertion loss is improved. At the same time, in terms of structure, the present invention reasonably distributes the piezoelectric acoustic wave resonators one by one into the framework of the IPD filter, enabling it to not only introduce zeros and poles but also perform the function of impedance matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the hybrid filter structure provided in Embodiment 1 of the present invention;

[0029] Figure 2 S-parameter simulation diagram of the hybrid filter provided in Embodiment 1 of the present invention;

[0030] Figure 3 Schematic diagram of the hybrid filter structure provided in Embodiment 2 of the present invention;

[0031] Figure 4 S-parameter simulation diagram of the hybrid filter provided in Embodiment 2 of the present invention;

[0032] Figure 5 Schematic diagram of the hybrid filter structure provided in Embodiment 3 of the present invention;

[0033] Figure 6 S-parameter simulation diagram of the hybrid filter provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] The present invention will be described in detail below in conjunction with specific embodiments and the accompanying drawings. For the convenience of description, the structures shown in the drawings are only related parts of the present invention, rather than all structures. For the convenience of description and understanding, some typical embodiments are provided below. The present invention includes, but is not limited to, the listed embodiments, and is applicable to LC filters of various forms and orders and various types of piezoelectric acoustic wave resonators.

[0036] Embodiment 1: As Figure 1 shown, this embodiment provides a hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high steep sideband and a passive microwave device, including:

[0037] The low-pass part provided in this embodiment includes a low-pass series trunk and a plurality of low-pass parallel branches; the low-pass series trunk includes LC resonance units 204 and 205 connected in series between the input end and the output end. Between the LC resonance unit 204 and the input end, between the LC resonance unit 204 and the LC resonance unit 205, and between the LC resonance unit 205 and the output end, a plurality of low-pass parallel branches are respectively connected. Figure 1 As shown in [reference], the three low-pass parallel branches respectively include a piezoelectric acoustic wave resonator 104, a piezoelectric acoustic wave resonator 105, and a piezoelectric acoustic wave resonator 106. It can be understood that in this embodiment, more LC resonance units and piezoelectric acoustic wave resonators can be cascaded on the basis of paralleling three low-pass parallel branches, so as to achieve the required target performance.

[0038] The hybrid filter provided in this embodiment is optimized from a traditional LC low-pass filter, and the traditional LC low-pass filter is obtained by replacing the Figure 1 shown piezoelectric acoustic wave resonator with an LC resonator. The elements of the resonance unit part of the hybrid filter provided in this embodiment retain part of the LC low-pass filter circuit to maintain the excellent performance of the LC filter, that is, the passband is large and flat. The elements of the non-resonance unit part are composed of respective piezoelectric acoustic wave resonators. On the basis of the LC filter circuit, by adjusting relevant parameters, the series resonance points of the parallel piezoelectric acoustic wave resonators located in the low-pass parallel branches are located in the transition band position, so as to introduce the high-Q transmission zeros of the piezoelectric acoustic wave resonators to improve the transition band and adjacent band rejection. At the same time, by adjusting relevant parameters, the parallel resonance points of the parallel piezoelectric acoustic wave resonators are located in the passband position to improve the in-band insertion loss.

[0039] As Figure 2As shown, curve 01 is the frequency response curve of the hybrid low-pass filter circuit provided in this embodiment, curve 02 is the frequency response curve of the traditional LC low-pass filter for comparison with the curve of the hybrid low-pass filter circuit provided in this embodiment, and curve 03 is the impedance curve of the parallel resonator located on the low-pass parallel branch. It can be seen that due to the effect of the parallel resonator, two extremely narrow transmission zeros are additionally obtained on the basis of curve 02 for curve 01, thereby rapidly reducing the insertion loss in this region; at the same time, it can be seen from curve 03 that the parallel resonance point of the parallel resonator is located at 5.1 GHz, and the pole generated at this point increases the passband insertion loss of the filter by a certain amount.

[0040] Embodiment 2: As Figure 3 shown, this embodiment provides a hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high steepness sideband and a passive microwave device, including a low-pass part and a high-pass part, and the high-pass part is connected in series with the low-pass part.

[0041] The low-pass part provided in this embodiment includes a low-pass series trunk and a plurality of low-pass parallel branches; the low-pass series trunk includes LC resonance units 209 and 210 connected in series between one end of the high-pass part and the output end, and a plurality of low-pass parallel branches are respectively connected between LC resonance unit 209 and one end of the high-pass part, between LC resonance units 210 and 209, and between LC resonance unit 210 and the output end. Figure 3 Three low-pass parallel branches are shown, and the three low-pass parallel branches respectively include piezoelectric acoustic wave resonators 110, 111, and 112.

[0042] The high-pass part provided in this embodiment includes a high-pass series trunk and a plurality of high-pass parallel branches. The high-pass series trunk includes piezoelectric acoustic wave resonators 107, capacitor C1, capacitor C2, and piezoelectric acoustic wave resonator 108 connected in series between the input end and one end of the low-pass part. The high-pass parallel branch connected in parallel between the input end and piezoelectric acoustic wave resonator 107 includes piezoelectric acoustic wave resonator 109, and the high-pass parallel branches respectively connected in parallel between piezoelectric acoustic wave resonator 107 and capacitor C1, between capacitor C1 and capacitor C2, and between capacitor C2 and piezoelectric acoustic wave resonator 108 include corresponding LC resonance units 206, 207, and 208.

[0043] In the hybrid filter provided in this embodiment, the characteristics of a large bandwidth are supported by each resonant unit. The piezoelectric acoustic wave resonators 107, 108, 109, 110, 111, and 112 can all self-resonate to generate transmission zeros with high Q values. By adjusting the material parameters of the piezoelectric acoustic wave resonators to shift the transmission zeros and distribute them on the adjacent band at the edge of the low-frequency end of the passband, the adjacent band rejection and roll-off slope are improved. At the same time, since there are both series piezoelectric acoustic wave resonators and parallel piezoelectric acoustic wave resonators in the overall circuit, the combination of their zeros can form a band-stop effect to support the optimization of a relatively wide transition band that cannot be satisfied by a single type of zero. The piezoelectric acoustic wave resonators 109, 110, 111, and 112 can all generate poles in the filter passband to improve the insertion loss within the passband, thereby enhancing the filtering performance.

[0044] As Figure 4 shown, curve 04 is the frequency response curve of the hybrid band-pass filter provided in this embodiment, and curve 05 is the frequency response curve of a traditional band-pass filter for comparison with the curve of the hybrid band-pass filter circuit provided in this embodiment. The filter structure corresponding to the frequency response curve of this traditional band-pass filter is obtained by replacing the piezoelectric acoustic wave resonators in the hybrid band-pass filter provided in this embodiment with LC resonators. Curve 06 is the impedance curve of the parallel resonator located on the high-pass parallel branch or the low-pass parallel branch.

[0045] In curve 04, the sharp transmission zeros in the 4.4 GHz - 5 GHz range are all generated by the piezoelectric acoustic wave resonators. Several additional transmission zeros generated by the piezoelectric acoustic wave resonators are all located on the adjacent band at the edge of the low-frequency end of the passband to improve the transition band and adjacent band rejection of the band-pass filter circuit and enhance the filtering performance. Compared with curve 05, due to the effect of the sharp transmission zeros in the 4.4 GHz - 5 GHz range, the transition band of the filter shown in curve 04 is reduced from nearly 750 MHz to 150 MHz. At the same time, as can be seen from curve 06, the parallel resonance point of the parallel resonator is located in the left region within the passband, and the poles generated in this region increase the in-band insertion loss on the left side of the filter passband.

[0046] As Figure 4As shown, the passband of curve 04 is in the range of 5.15 - 7.15 GHz, the passband reaches 2 GHz, and the in-band insertion loss is within -1.5 dB (the minimum in-band insertion loss is -1.24 dB). The parallel resonance points of the piezoelectric acoustic wave resonator 107 and the piezoelectric acoustic wave resonator 108 are located on the adjacent band of the low-frequency end edge of the passband to block the noise signals with frequencies in the range of this adjacent band; the series resonance points of the piezoelectric acoustic wave resonator 109, the piezoelectric acoustic wave resonator 110, the piezoelectric acoustic wave resonator 111, and the piezoelectric acoustic wave resonator 112 are located on the adjacent band of the low-frequency end edge of the passband to block the noise signals with frequencies in the range of this adjacent band, while their parallel resonance points are located on the left side within the passband to increase the in-band insertion loss of the filter, thereby improving the filtering performance. As shown in curve 04, on the premise of ensuring that the passband is in the range of 5.15 - 7.15 GHz (the filtering circuit composed of a single piezoelectric acoustic wave resonator cannot achieve this performance), the transition region at the low-frequency end edge of the passband is maintained within 150 MHz (a single LC filtering circuit cannot meet this performance) and the out-of-band rejection is overall maintained below -30 dB, greatly improving the roll-off slope and adjacent band rejection, and compared with the traditional band-pass filter, its in-band insertion loss is also improved.

[0047] Embodiment 3: As Figure 5 shown, this embodiment provides a hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high steep drop sideband and a passive microwave device, including: This embodiment provides a hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high steep drop sideband and a passive microwave device, including a low-pass part and a high-pass part, and the high-pass part is connected in series with the low-pass part.

[0048] The low-pass part provided in this embodiment includes a low-pass series trunk and a plurality of low-pass parallel branches: the low-pass series trunk includes LC resonance units 214 and 215 connected in series between one end of the high-pass part and the output end, a low-pass parallel branch including a piezoelectric acoustic wave resonator 116 and a piezoelectric acoustic wave resonator 117 connected in series is connected between the LC resonance unit 214 and one end of the high-pass part, a low-pass parallel branch including a piezoelectric acoustic wave resonator 118 is connected between the LC resonance unit 214 and the LC resonance unit 215, and low-pass parallel branches including a capacitor C5 are respectively connected between the LC resonance unit 215 and the output end.

[0049] The high-pass part provided in this embodiment includes a high-pass series main path and multiple high-pass parallel branches. The high-pass series main path includes a piezoelectric acoustic resonator 114, a capacitor C3, a capacitor C4, and a piezoelectric acoustic resonator 113 connected in series between the input end and one end of the low-pass part. The high-pass parallel branch connected in parallel between the input end and the piezoelectric acoustic resonator 113 includes a piezoelectric acoustic resonator 115. The high-pass parallel branches respectively connected in parallel between the piezoelectric acoustic resonator 113 and the capacitor C3, between the capacitor C3 and the capacitor C4, and between the capacitor C4 and the piezoelectric acoustic resonator 114 include corresponding LC resonance units 211, LC resonance units 212, and LC resonance units 213.

[0050] The hybrid filter provided in this embodiment still has the characteristic of a large bandwidth supported by each resonance unit. The piezoelectric acoustic resonators 113, 114, 115, 116, 117, and 118 can all self-resonate to generate transmission zeros with high Q values. By adjusting the material parameters of the piezoelectric acoustic resonators to move the transmission zeros and distribute them on the adjacent band at the edge of the low-frequency end of the passband, the adjacent band rejection and roll-off slope can be improved, and the filtering performance can be enhanced. At the same time, since there are both series piezoelectric acoustic resonators and parallel piezoelectric acoustic resonators in the overall circuit, the combination of their zeros can form a band-stop effect, thus supporting the optimization of a relatively wide transition band that cannot be satisfied by a single type of zero. The piezoelectric acoustic resonators 116, 117, and 118 can all generate poles in the filter passband to improve the in-band insertion loss. It should be noted that the piezoelectric acoustic resonators 116 and 117 are connected in series in the same parallel branch. Due to the limitation of the area process of a single piezoelectric acoustic resonator, there is a minimum value for the equivalent capacitance. Connecting two or more piezoelectric acoustic resonators in series in the same branch can break through the minimum capacitance value limited by the process and obtain a smaller equivalent capacitance.

[0051] Such as Figure 6As shown, curve 08 is the frequency response curve of the hybrid filter provided in this embodiment, curve 09 is the frequency response curve of a traditional band-pass filter for comparison with the curve of the hybrid filter provided in this embodiment. The structure of the traditional band-pass filter is obtained by replacing the piezoelectric acoustic wave resonator in the hybrid band-pass filter provided in this embodiment with a capacitive element. Curve 10 is the impedance curve of the parallel resonator located on the high-pass parallel branch or the low-pass parallel branch. In curve 08, the sharp transmission zeros in the range of 4.4 GHz to 5 GHz are all generated by the piezoelectric acoustic wave resonator. These additional transmission zeros are all located on the adjacent band at the edge of the low-frequency end of the passband, so as to improve the transition band and adjacent band rejection of the band-pass filter circuit and enhance the filtering performance. Compared with curve 09, due to the effect of the sharp transmission zeros in the range of 4.4 GHz to 5 GHz, the transition band of the filter shown in curve 08 is reduced from nearly 650 MHz to 150 MHz. At the same time, as can be seen from curve 10, the parallel resonance point of the parallel resonator is located in the left region within the passband, and the poles generated in this region cause an increase in the in-band insertion loss of the filter passband.

[0052] As Figure 6 shown, the passband of curve 08 is in the range of 5.15 to 5.9 GHz, the passband reaches 750 MHz, and the in-band insertion loss is within -2 dB (the minimum in-band insertion loss is -1.80 dB). The parallel resonance points of the piezoelectric acoustic wave resonator 113 and the piezoelectric acoustic wave resonator 114 are located on the adjacent band at the edge of the low-frequency end of the passband to block the noise signals with frequencies in the range of this adjacent band. The series resonance points of the piezoelectric acoustic wave resonator 115, the piezoelectric acoustic wave resonator 116, the piezoelectric acoustic wave resonator 117, and the piezoelectric acoustic wave resonator 118 are located on the adjacent band at the edge of the low-frequency end of the passband to block the noise signals with frequencies in the range of this adjacent band, while their parallel resonance points are located on the left side within the passband to increase the in-band insertion loss of the filter and enhance the filtering performance. As shown in curve 08, on the premise of ensuring that the passband is in the range of 5.15 to 5.9 GHz (the filtering circuit composed of a single piezoelectric acoustic wave resonator cannot achieve this performance), the transition region at the edge of the low-frequency end of the passband is maintained within 150 MHz (a single LC filter circuit cannot meet this performance), and the out-of-band rejection is overall maintained below -30 dB, greatly enhancing the roll-off slope and adjacent band rejection. Compared with the traditional band-pass filter, its in-band insertion loss is also increased.

Claims

1. A hybrid filter integrating a piezoelectric acoustic wave resonator with a large bandwidth and a high-steepness sideband and a passive microwave device, characterized in that It includes a low-pass part, and the low-pass part includes a low-pass series trunk and multiple low-pass parallel branches; Among them, the low-pass series trunk includes multiple LC resonance units connected in series in sequence; The low-pass parallel branches are connected between the low-pass series trunk and the ground wire. There is at least one LC resonance unit spaced between adjacent two low-pass parallel branches. The low-pass parallel branch includes a low-pass branch capacitive element, or multiple series-connected low-pass branch capacitive elements, and some or all of the low-pass branch capacitive elements adopt piezoelectric acoustic wave resonators; It further includes a high-pass part. The high-pass part is connected in series with the low-pass part. The high-pass part includes a high-pass series trunk and multiple high-pass parallel branches; Among them, the high-pass series trunk includes multiple high-pass trunk capacitive elements connected in series in sequence, and some of the high-pass trunk capacitive elements adopt piezoelectric acoustic wave resonators; The high-pass parallel branches are connected between the high-pass series trunk and the ground wire. There is at least one high-pass trunk capacitive element spaced between adjacent two high-pass parallel branches. The high-pass parallel branch includes an LC resonance unit and a piezoelectric acoustic wave resonator; The piezoelectric acoustic wave resonators on the low-pass parallel branches and the high-pass parallel branches all generate poles within the passband range.

2. The hybrid filter integrating the piezoelectric acoustic wave resonator with large bandwidth and high steep drop sideband and the passive microwave device according to claim 1, characterized in that, There is one LC resonance unit spaced between adjacent two low-pass parallel branches, and all the low-pass branch capacitive elements adopt piezoelectric acoustic wave resonators.

3. The hybrid filter integrating the piezoelectric acoustic wave resonator with a large bandwidth and a high steepness sideband and a passive microwave device according to claim 1, characterized in that The high-pass trunk capacitive elements that do not adopt piezoelectric acoustic wave resonators adopt capacitors.

4. The hybrid filter integrating the piezoelectric acoustic wave resonator with a large bandwidth and a high-steepness sideband and a passive microwave device according to claim 1, wherein All the low-pass branch capacitive elements adopt piezoelectric acoustic wave resonators.

5. The hybrid filter integrating the piezoelectric acoustic wave resonator with large bandwidth and high steepness of the sideband and the passive microwave device according to claim 1, characterized in that, The low-pass branch capacitive elements that do not adopt piezoelectric acoustic wave resonators adopt capacitors.

6. The hybrid filter integrating the piezoelectric acoustic wave resonator with large bandwidth and high steep drop sideband and the passive microwave device according to claim 1, characterized in that, There is at least one piezoelectric acoustic wave resonator spaced between the high-pass part and the low-pass part.

7. The hybrid filter integrating the piezoelectric acoustic wave resonator with a large bandwidth and a high steep drop sideband and a passive microwave device according to claim 1, characterized in that, The transmission zeros generated by the self-resonance of the piezoelectric acoustic wave resonators in the high-pass part and the low-pass part are all distributed within the adjacent band range of the low-frequency end edge of the passband.

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