Bent line double-conductor miniaturized SSPPs transmission line and band-pass filter

Abstract

The invention provides a bent-line double-conductor miniaturized SSPPs transmission line and a band-pass filter. A low reflection coefficient in a pass band is realized mainly by optimizing a momentum matching structure; the transmission cut-off frequency of the filter is adjusted by adopting reasonable structural parameters and manually setting the bending line width, the gap and the surface current path length when the filter is manufactured; the rectangular coefficient can be adjusted by setting the number N of the bent line double-conductor miniaturized SSPPs units 1, and when N is smaller than 9, the rectangular coefficient in the passband is reduced along with the increase of N; when N is greater than 9, the rectangular coefficient of the bent line double-conductor miniaturized SSPPs band-pass filter is no longer sensitive to the change of the number of units. According to the invention, the design efficiency of the microwave device in the work of the wireless communication system is further improved, and radio frequency circuit integration is facilitated.

Description

Technical field:

[0001] The present invention belongs to the technical field of microwave planar filters for wireless communications. It is made of microwave dielectric substrate and metal and works in the microwave frequency band. It relates to a meander line dual-conductor miniaturized SSPPs transmission line and a bandpass filter. The upper and lower cutoff frequencies can be independently adjusted within a certain range. These SSPPs structures inherit the advantages of light weight, conformal, flatness and easy integration with traditional microwave circuits. Background technology:

[0002] In current broadband wireless electronic communication systems, filtering is an indispensable part of the RF link. In order to cope with various filtering requirements in RF circuits, there are always many filters with different functions in RF circuits, but the size of the filter is always limited by the wavelength. With the increasing requirements for the integration of wireless communication systems, the miniaturization, low crosstalk and adjustability of filters have become one of the research hotspots of filters.

[0003] Surface plasmon polaritons (SPPs) are a type of surface electromagnetic wave mode that propagates at optical frequencies through the surface plasma oscillations of metals at the interface between metals and dielectrics. However, metals are considered to be good conductors below infrared frequencies and cannot produce surface plasma oscillations. In 2004, Professor Pendry's team experimentally demonstrated that etching a periodic groove structure on the metal surface can induce surface plasma oscillations in the terahertz and microwave frequency bands, namely artificial surface plasmons (Spoof Surface Plasmon Polaritons, SSPPs). SSPPs inherit the natural high-frequency cutoff characteristics of surface plasmons and good transmission characteristics such as field confinement, field enhancement effect, and low crosstalk. Therefore, they are widely used in the design of microwave devices, such as power dividers, combiners, couplers, filters, antennas, etc.

[0004] Previously, bandpass filters based on artificial surface plasmons were mostly designed based on the following two points: 1) cascading a waveguide with high-pass characteristics at the front end of the artificial surface plasmon transmission line, such as a substrate integrated waveguide; 2) designing a multi-layer structure to achieve bandpass characteristics through capacitive coupling between layers. The bandpass filters based on the above two designs are relatively large in size, so the present invention proposes a planar miniaturized bandpass filter that can independently adjust the upper and lower cutoff frequencies, namely, a meander line dual-conductor miniaturized SSPPs bandpass filter. Summary of the invention:

[0005] The object of the present invention is to provide a meander line dual-conductor miniaturized SSPPs transmission line and a bandpass filter. The meander line dual-conductor miniaturized SSPPs bandpass filter provided by the present invention uses meander line technology, and the surface current path length of the meander line is equivalent to the groove depth of the traditional artificial surface plasmon unit, thereby significantly reducing the size of the filter; the conversion between the TEM mode and the TM mode uses a ladder matching structure, which further reduces the size of the filter compared to the coplanar waveguide structure. By adopting the mosaic method of the artificial surface plasmon unit provided by the present invention, only a single-layer meander line dual-conductor miniaturized SSPPs transmission line, a ladder matching structure and a 50-ohm microstrip line are required to achieve the bandpass characteristics, and the meander line dual-conductor miniaturized SSPPs bandpass filter provided by the present invention has upper and lower cutoff frequencies that can be adjusted independently, and at the same time, the in-band is flat and the insertion loss is small, the rectangular coefficient is adjustable, and the out-of-band suppression is greater than -50dB.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A meander line dual-conductor miniaturized SSPPs transmission line, characterized in that: the meander line dual-conductor miniaturized SSPPs transmission line is composed of a cascade of meander line dual-conductor miniaturized SSPPs units, the meander line dual-conductor miniaturized SSPPs units are composed of a meander line, a rectangular metal strip and a rectangular waveguide, two rectangular metal strips are arranged in parallel at both ends of the meander line, and the rectangular waveguide is arranged on the lower side of a dielectric substrate.

[0008] A bandpass filter using a meander line dual-conductor miniaturized SSPPs transmission line is characterized in that: momentum matching converters are respectively arranged at both ends of the meander line dual-conductor miniaturized SSPPs transmission line, and the meander line dual-conductor miniaturized SSPPs transmission line is connected to the momentum matching converter through a TEM transmission line; the momentum matching converter is composed of a depth-gradient trapezoidal corrugated groove and a rectangular metal strip, and two rectangular metal strips with different widths are respectively arranged at both ends of the depth-gradient trapezoidal corrugated groove line, and the depth-gradient trapezoidal corrugated groove line gradually converts the rectangular metal strip into a 50-ohm TEM transmission line to achieve momentum matching, and realizes conversion between TEM mode and TM mode.

[0009] The bend line is formed by two open bend lines embedded in each other; the position of the high-pass cutoff frequency of the filter is controlled by setting the groove depth of the bend line and the gap between the embedded parts; the position of the low-pass cutoff frequency of the filter is controlled by setting the groove depth of the bend line and the width of the bend line.

[0010] The depth of the trapezoidal corrugated groove line with gradual depth increases linearly multiple times, from 0 to the groove depth value of the meander line dual-conductor miniaturized SSPPs unit.

[0011] In the meander line dual conductor miniaturized SSPPs transmission line, the number of the meander line dual conductor miniaturized SSPPs units is set between one and infinity.

[0012] The number of times the depth of the trapezoidal corrugation groove increases linearly is three times; the number of the meander line double-conductor miniaturized SSPPs units is four.

[0013] The rectangular metal strip (3) has a width of h = 0.6 ± 0.1 mm, a length of l1 = 1 mm ± 0.1 mm, a groove depth of the bend line (2) of h0 = 3.5 mm ± 0.1 mm, a line width of w0 = 0.4 mm ± 0.1 mm, and a gap of g0 = 0.2 mm ± 0.1 mm; the period of the bend line dual-conductor miniaturized SSPPs unit (1) is p = 4.6 mm ± 1 mm; the depth of the trapezoidal corrugated groove line (4) is The width of the metal strip is h1 = 1.8 ± 0.1 mm, h2 = 3.33 ± 0.1 mm, h3 = 3.93 ± 0.1 mm, h4 = 5.46 ± 0.1 mm, h5 = 6.06 ± 0.1 mm, h6 = 7.6 ± 0.1 mm, and the length is l2 = 2.6 mm ± 0.1 mm. The width of the rectangular metal strip (5) is w3 = 1.8 mm ± 0.1 mm, and the length is l3 = 4.6 mm ± 0.1 mm. A bandpass filter using a meander line dual-conductor miniaturized SSPPs transmission line is applied in a receiver of a broadband wireless communication system.

[0014] Compared with the prior art, the present invention has the following advantages and effects:

[0015] 1. The present invention proposes a meander line dual-conductor miniaturized SSPPs transmission line, which is composed of a number of meander line dual-conductor miniaturized SSPPs units connected in series, and the number of units is ≥1. The meander line dual-conductor miniaturized SSPPs unit is composed of two mutually interlocking open-circuit meander lines, a rectangular metal strip and a rectangular waveguide. By controlling the surface current path length of the meander line, the upper edge cutoff frequency position of the transmission line can be independently regulated; by controlling the capacitive coupling gap of the meander line, the lower edge cutoff frequency position of the transmission line can be independently regulated. Compared with the SSPPs hybrid circuit and multi-layer coupled SSPPs method, the meander line dual-conductor miniaturized SSPPs bandpass filter made by the meander line dual-conductor miniaturized SSPPs transmission line proposed by the present invention has a smaller volume and higher frequency selectivity, and at the same time has a flatter transmission coefficient and reflection coefficient in the passband, and the center operating frequency can be flexibly adjusted by adjusting the meander line groove depth. Finally, the transmission line can achieve good transmission of surface electromagnetic energy, so that the bandpass filter can be more convenient to integrate in a compact electronic system.

[0016] 2. The present invention includes a meander line dual-conductor miniaturized SSPPs bandpass filter composed of a meander line dual-conductor miniaturized SSPPs transmission line, a momentum matching structure, and a 50ohm microstrip line. The bandpass filter using the meander line dual-conductor miniaturized SSPPs transmission line proposed by the present invention 1) realizes bandpass filtering in the form of meander line winding for the first time in terms of electrical performance, and can independently adjust its upper and lower cutoff frequencies and the center frequency of operation, thereby improving the design efficiency of microwave devices and reducing the pressure on device resources when broadband systems perform digital filtering in the digital domain; 2) can be assembled into broadband electronic systems in terms of structure, effectively reducing the volume and weight of electronic equipment and realizing high-density component assembly of electronic systems. Description of the drawings:

[0017] Figure 1 It is a structural diagram of the meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention;

[0018] Figure 2 It is a schematic diagram of the installation structure of the meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention;

[0019] Figure 3 It is the frequency response characteristic curve of the meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention.

[0020] Figure 2 Among them, 1. Meander line dual-conductor miniaturized SSPPs unit, 2. Meander line, 3. Rectangular metal strip, 4. Depth-gradient trapezoidal corrugated slot line, 5. Rectangular metal strip II, 6. 50 ohm TEM transmission line, 7. Broadband antenna, 8. Broadband low-noise amplifier I, 9. Gain amplifier II, 10. Meander line dual-conductor miniaturized SSPPs bandpass filter, 11. Down-conversion circuit, 12. Intermediate frequency filter, 13. Gain amplifier III, 14. Reference crystal oscillator, 15. Frequency synthesizer, 16. AGC module, 17. A / D converter, 18. Microprocessor, 19. Related channels, 20. Memory. Specific implementation method:

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] In view of the increasing demand for integrated communication systems, the adjustable and miniaturized RF devices have become an important development trend. Therefore, the present invention proposes a miniaturized microwave device design with independently adjustable upper and lower edge cutoff frequencies, namely, a meander line dual-conductor miniaturized SSPPs bandpass filter.

[0023] In the meander line dual-conductor miniaturized SSPPs transmission line proposed in the present invention, the meander line dual-conductor miniaturized SSPPs unit is composed of two mutually interlocking open-circuit meander lines, a rectangular metal strip, and a rectangular waveguide. By controlling the surface current path length of the meander line, the upper edge cutoff frequency position of the transmission line can be independently regulated; by controlling the capacitive coupling gap of the meander line, the lower edge cutoff frequency position of the transmission line can be independently regulated. Compared with the SSPPs hybrid circuit and the multi-layer coupled SSPPs method, the meander line dual-conductor miniaturized SSPPs bandpass filter made by the meander line dual-conductor miniaturized SSPPs transmission line proposed in the present invention has a smaller volume and higher frequency selectivity, and at the same time has a flatter transmission coefficient and reflection coefficient in the passband, and the center operating frequency can be flexibly regulated by adjusting the meander line groove depth.

[0024] The present invention is a meander line dual-conductor miniaturized SSPPs bandpass filter, and the technical solution adopted is: a 50-ohm TEM transmission line, a momentum matching converter, and a meander line dual-conductor miniaturized SSPPs transmission line are cascaded, wherein momentum matching converters are respectively provided at both ends of the meander line dual-conductor miniaturized SSPPs transmission line, and the meander line dual-conductor miniaturized SSPPs transmission line is connected to the 50-ohm TEM transmission line through the momentum matching converter; the meander line dual-conductor miniaturized SSPPs transmission line is composed of a basic meander line dual-conductor miniaturized SSPPs unit, and this meander line dual-conductor miniaturized SSPPs transmission line is a double-line structure. The meander line dual-conductor miniaturized SSPPs unit is composed of a meander line, a rectangular metal strip, and a rectangular waveguide, wherein two rectangular metal strips are electrically connected to two mutually embedded open-circuit meander lines. The position of the lower edge cutoff frequency of the bandpass filter is adjusted by the surface current path length of the meander line; by regulating the width of the capacitive coupling gap between the meander lines, the position of the high-pass cutoff frequency can be independently adjusted within a certain range. In the meander line dual-conductor miniaturized SSPPs transmission line, the number of meander line dual-conductor miniaturized SSPPs units can be set between 1 and infinity according to actual conditions. When the number is less than 9, the rectangular coefficient of the bandpass filter decreases as the number of units increases; when the number is greater than 9, the rectangular coefficient of the bandpass filter is no longer sensitive to the number of units. The momentum matching converter is composed of a trapezoidal corrugated groove line with a gradient depth, a rectangular metal strip, and a rectangular metal strip. The depth of the rectangular corrugated groove line is linearly increased multiple times, from 0 to the groove depth value of the meander line dual-conductor miniaturized SSPPs unit, and the present invention defaults to 3 times; the momentum matching converter can smoothly convert the TEM transmission wave on the 50 ohm transmission line to the TM polarized surface wave, and at the same time realize the impedance matching between the input and output ports and the meander line dual-conductor miniaturized SSPPs transmission line. The 50 ohm TEM transmission line is composed of a microstrip line.

[0025] Example:

[0026] See also Figure 1 and Figure 2 The zigzag line dual-conductor miniaturized SSPPs bandpass filter provided by the present invention realizes the independent adjustment of the upper and lower edge cutoff frequencies and the center frequency inside and outside the passband; the zigzag line dual-conductor miniaturized SSPPs bandpass filter is realized in structure, which significantly reduces the size of the bandpass filter and is more conducive to the integration of wireless electronic systems. Its structure includes a 50-ohm TEM transmission line 6, a momentum matching converter 4, and a zigzag line dual-conductor miniaturized SSPPs transmission line. The zigzag line dual-conductor miniaturized SSPPs transmission line is composed of a cascade of basic zigzag line dual-conductor miniaturized SSPPs units 1. The number of zigzag line dual-conductor miniaturized SSPPs units 1 can be manually set according to actual usage, the number is ≥1, and the default setting is 4. The zigzag line dual-conductor miniaturized SSPPs unit 1 is a double-line structure. The zigzag line dual-conductor miniaturized SSPPs unit 1 is composed of a zigzag line 2, a rectangular metal strip 3, and a rectangular waveguide. Two rectangular metal strips 3 are electrically connected to two mutually embedded open zigzag lines 2. The position of the filter low-pass cutoff frequency is controlled by artificially setting the surface current path length of the meander line 2; the position of the high-pass cutoff frequency can be independently adjusted within a certain range by controlling the capacitive coupling gap between the meander lines. Momentum matching converters are respectively provided at both ends of the meander line dual-conductor miniaturized SSPPs transmission line, and the momentum matching converter is composed of a trapezoidal corrugated groove line 4 with a gradient depth and a rectangular metal strip 5. The depth of the trapezoidal corrugated groove line 4 is increased linearly multiple times from 0 to the groove depth value of the meander line dual-conductor miniaturized SSPPs unit, and the depth-gradient trapezoidal corrugated groove line 4 gradually converts the rectangular metal strip to a 50 ohm TEM transmission line 6 to achieve momentum matching. The momentum matching converter can smoothly convert the TEM transmission wave on the 50 ohm transmission line to a TM-polarized surface wave, and at the same time realize the impedance matching between the input and output ports and the meander line dual-conductor miniaturized SSPPs transmission line. The 50 ohm TEM transmission line is composed of a microstrip line.

[0027] The meander line dual-conductor miniaturized SSPPs bandpass filter proposed by the present invention has a lower edge cutoff frequency of 1.5GHz, an upper edge cutoff frequency of 3.5GHz, and a 3dB bandwidth covering from 2.21GHz to 2.87GHz, i.e. 660MHz; its 3dB bandwidth passband ripple is less than 0.15dB, and the passband is flat; the reflection coefficient in the passband is less than -16.6dB. The stopband suppression capability above the cutoff frequency is better than -53dB, which can effectively suppress out-of-band interference.

[0028] The meander line dual-conductor miniaturized SSPPs bandpass filter proposed by the present invention mainly realizes low reflection coefficient in the passband by optimizing the momentum matching structure; by adopting reasonable structural parameters, the meander line width, gap, and surface current path length are artificially set when the filter is manufactured to adjust the transmission cutoff frequency of the filter. The manufactured meander line dual-conductor miniaturized SSPPs bandpass filter is assembled into a broadband electronic system, effectively reducing the volume and weight of the electronic equipment and realizing high-density component assembly of the electronic system.

[0029] The meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention can also adjust the rectangular coefficient by setting the number N of the meander line dual-conductor miniaturized SSPPs units 1 when other parameters are fixed. When N is less than 9, the rectangular coefficient in the passband decreases as N increases; when N is greater than 9, the rectangular coefficient of the meander line dual-conductor miniaturized SSPPs bandpass filter is no longer sensitive to changes in the number of units. At the same time, the meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention can artificially adjust its upper edge cutoff frequency by changing the line width of the unit structure when other parameters are fixed.

[0030] The size parameter selection range of the meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention is: the width of the rectangular metal strip (3) is h = 0.6 ± 0.1 mm, the length l1 = 1 mm ± 0.1 mm, the meander line (2) groove depth h0 = 3.5 mm ± 0.1 mm, the line width w0 = 0.4 mm ± 0.1 mm, the gap g0 = 0.2 mm ± 0.1 mm; the period of the meander line dual-conductor miniaturized SSPPs unit (1) is p = 4.6 mm ± 1 mm; the depth The width of the corrugated metal strip of the trapezoidal corrugated groove line (4) with a gradual change in degree is h1=1.8±0.1mm, h2=3.33±0.1mm, h3=3.93±0.1mm, h4=5.46±0.1mm, h5=6.06±0.1mm, h6=7.6±0.1mm, and the length is l2=2.6mm±0.1mm. The width of the rectangular metal strip (5) is w3=1.8mm±0.1mm, and the length is l3=4.6mm±0.1mm. When the meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention is actually applied, according to different communication occasions and application requirements, by matching and selecting the number N of the meander line dual-conductor miniaturized SSPPs units 1, the meander line width, the gap, the surface current path length and other parameters, different rectangular coefficients, insertion losses and transmission cut-off frequencies within the filter band are controlled to meet different application requirements.

[0031] Reference Figure 2The meander line dual-conductor miniaturized SSPPs bandpass filter of the present invention is applied to a broadband wireless communication system receiver. The main structure of the receiver includes a broadband antenna 7, which is sequentially connected to a broadband low-noise amplifier 1 8, a gain amplifier 2 9, a meander line dual-conductor miniaturized SSPPs bandpass filter 10, a down-conversion circuit 11, an intermediate frequency filter 12, a gain amplifier 3 13 and an A / D converter 17. The A / D converter 17 is simultaneously connected to a microprocessor 18 and a memory 20 through a related channel 19; in addition, a reference crystal oscillator 14 is connected to the down-conversion circuit 11 (another input end) through a frequency synthesizer 15, and the gain amplifier 3 13 is connected to an AGC module 16.

[0032] The above-mentioned broadband antenna 7 and broadband low noise amplifier 8 together constitute an antenna unit;

[0033] The above-mentioned gain amplifier 2 9, meander line dual conductor miniaturized SSPPs bandpass filter 10, down-conversion circuit 11, intermediate frequency filter 12, gain amplifier 3 13, reference crystal oscillator 14, frequency synthesizer 15 and AGC module 16 together constitute a down-conversion circuit unit;

[0034] The above-mentioned A / D converter 17, microprocessor 18, relevant channel 19 and memory 20 together constitute a baseband signal processing unit.

[0035] The broadband low noise amplifier 1 8 uses an LNA module QPL9503 from Qorvo, the gain amplifier 2 9 and the gain amplifier 13 use ERA-3SM+ from Mini_circuit, and the intermediate frequency filter 12 uses SXBP-29+ from Mini_circuit.

[0036] The down-conversion circuit 11 uses LTC5555 from Analog.

[0037] The baseband signal processing unit uses the FMCJ457 analog digital acquisition board and KC705EFPGA baseband processing card from Beijing Taisu Technology Co., Ltd.

[0038] The above-mentioned circuit modules or units are all system circuits, and other relevant specific models can also be selected for combination design according to different application requirements.

[0039] The specific parameter settings of the meander line dual-conductor miniaturized SSPPs bandpass filter in this embodiment are: the width of the rectangular metal strip (3) is h = 0.6 ± 0.1 mm, the length l1 = 1 mm ± 0.1 mm, the meander line (2) groove depth h0 = 3.5 mm ± 0.1 mm, the line width w0 = 0.4 mm ± 0.1 mm, the gap g0 = 0.2 mm ± 0.1 mm; the period of the meander line dual-conductor miniaturized SSPPs unit (1) is p = 4.6 mm ± 1 mm; The corrugated metal strip of the depth-gradient trapezoidal corrugated groove line (4) has a width of h1=1.8±0.1mm, h2=3.33±0.1mm, h3=3.93±0.1mm, h4=5.46±0.1mm, h5=6.06±0.1mm, h6=7.6±0.1mm, and a length of l2=2.6mm±0.1mm. The rectangular metal strip II (5) has a width of w3=1.8mm±0.1mm and a length of l3=4.6mm±0.1mm. The input and output coaxial connecting lines are connected to the 50-ohm TEM transmission line 6. The upper edge cutoff frequency of the meander line dual-conductor miniaturized SSPPs bandpass filter proposed by the present invention is 1.5 GHz, the lower edge cutoff frequency is 3.5 GHz, and its 3dB bandwidth covers from 2.21 GHz to 2.87 GHz, i.e. 660 MHz; its 3dB bandwidth passband ripple is less than 0.15 dB, and the passband is flat; the reflection coefficient in the passband is less than -16.6 dB. The stopband suppression capability above the cutoff frequency is better than -53 dB, which can effectively suppress out-of-band interference.

[0040] When the system is working, first, the broadband antenna 7 receives weak electromagnetic signals, and then the signal power is amplified to the required level through the broadband low noise amplifier 1 8 and the gain amplifier 2 9, and then sent to the meander line dual conductor miniaturized SSPPs bandpass filter 10. The meander line dual conductor miniaturized SSPPs bandpass filter 10 filters out the out-of-band interference signal for the amplitude-frequency response within the system wide frequency band, and then enters the down-conversion circuit 11. At the same time, the signal of the reference crystal oscillator 14 (TCXO) also enters the down-conversion circuit 11 through the frequency synthesizer 15; then, according to different application requirements, the broadband RF signal is down-converted to the intermediate frequency through the down-conversion circuit 11, and then sent to the final baseband signal processing unit through the self-circulating loop of the intermediate frequency filter 12 and the gain amplifier 3 13, and the baseband signal processing unit completes the processing of the baseband signal.

[0041] Reference Figure 3 , is the frequency response characteristic curve of the meander line dual-conductor miniaturized SSPPs bandpass filter according to the embodiment of the present invention, Figure 3It can be seen that the lower edge cutoff frequency of the meander line dual-conductor miniaturized SSPPs bandpass filter is 1.5GHz, the upper edge cutoff frequency is 3.5GHz, and its 3dB bandwidth covers from 2.21GHz to 2.87GHz, that is, 660MHz; its 3dB bandwidth passband ripple is less than 0.15dB, and the reflection coefficient in the passband is less than -16.6dB. The stopband suppression capability above the cutoff frequency is better than -53dB, which can effectively suppress out-of-band interference.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any equivalent structural changes made using the contents of the description and drawings of the present invention should be included in the patent protection scope of the invention.

Claims

1. A meander line dual-conductor miniaturized SSPPs transmission line, characterized by: The meander line dual-conductor miniaturized SSPPs transmission line is composed of a cascade of meander line dual-conductor miniaturized SSPPs units (1), wherein the meander line dual-conductor miniaturized SSPPs unit (1) is composed of a meander line (2), a rectangular metal strip (3) and a rectangular waveguide, wherein two rectangular metal strips (3) are arranged in parallel at both ends of the meander line (2), and the rectangular waveguide is arranged on the lower side of a dielectric substrate.

2. A bandpass filter using the meander line dual-conductor miniaturized SSPPs transmission line as claimed in claim 1, characterized in that: Momentum matching converters are respectively arranged at both ends of a meander line dual-conductor miniaturized SSPPs transmission line, and the meander line dual-conductor miniaturized SSPPs transmission line is connected to the momentum matching converter via a TEM transmission line; the momentum matching converter is composed of a depth-gradient trapezoidal corrugated groove (4) and a second rectangular metal strip (5), and two ends of the depth-gradient trapezoidal corrugated groove line (4) are respectively provided with a second rectangular metal strip (5) with different widths, and the depth-gradient trapezoidal corrugated groove line (4) gradually converts the second rectangular metal strip (5) into a 50-ohm TEM transmission line (6) to achieve momentum matching, and realizes conversion between a TEM mode and a TM mode.

3. The meander line dual-conductor miniaturized SSPPs bandpass filter according to claim 2, characterized in that: The bend line (2) is formed by two open-circuit bend lines embedded in each other; the position of the high-pass cutoff frequency of the filter is controlled by setting the groove depth of the bend line (2) and the gap between the mutually embedded parts; and the position of the low-pass cutoff frequency of the filter is controlled by setting the groove depth of the bend line (2) and the width of the bend line.

4. The meander line dual-conductor miniaturized SSPPs bandpass filter according to claim 3, characterized in that: The depth of the gradually varying trapezoidal corrugated groove line (4) increases linearly for multiple times, from 0 to the groove depth value of the meander line dual-conductor miniaturized SSPPs unit (1).

5. The meander line dual-conductor miniaturized SSPPs bandpass filter according to claim 4, characterized in that: In the miniaturized SSPPs transmission line, the number of meander line dual-conductor miniaturized SSPPs units (1) is set between one and infinity.

6. The meander line dual-conductor miniaturized SSPPs bandpass filter according to claim 5, characterized in that: The number of times the depth of the trapezoidal corrugation groove increases linearly is three times; the number of the meander line double-conductor miniaturized SSPPs units (1) is four.

7. The meander line dual-conductor miniaturized SSPPs bandpass filter according to claim 6, characterized in that: The number of the meander line dual-conductor miniaturized SSPPs units (1) is set according to actual usage, and the number is ≥1.

8. The meander line dual-conductor miniaturized SSPPs bandpass filter according to claim 7, characterized in that: The rectangular metal strip (3) has a width of h = 0.6 ± 0.1 mm, a length of l1 = 1 mm ± 0.1 mm, a bend line (2) groove depth h0 = 3.5 mm ± 0.1 mm, a line width w0 = 0.4 mm ± 0.1 mm, and a gap g0 = 0.2 mm ± 0.1 mm; the period of the bend line dual-conductor miniaturized SSPPs unit (1) is p = 4.6 mm ± 1 mm; the corrugation of the depth-gradient trapezoidal corrugated groove line (4) is The width of the metal strip is h1 = 1.8 ± 0.1 mm, h2 = 3.33 ± 0.1 mm, h3 = 3.93 ± 0.1 mm, h4 = 5.46 ± 0.1 mm, h5 = 6.06 ± 0.1 mm, h6 = 7.6 ± 0.1 mm, and the length is l2 = 2.6 mm ± 0.1 mm. The width of the rectangular metal strip 2 (5) is w3 = 1.8 mm ± 0.1 mm, and the length is l3 = 4.6 mm ± 0.1 mm.

Images