A substrate integrated waveguide electrically tunable notch equalizer based on varactor and PIN diode

Abstract

The application belongs to the microwave and millimeter wave technology and particularly relates to a substrate integrated waveguide electrically tunable concave type equalizer based on a varactor diode and a PIN diode, which comprises an SIW body, a gradually changing transition line and a 50Ω microstrip line. A rectangular area is arranged on the SIW body, four edges of the rectangular area adopt a groove structure, a plurality of resonance units are arranged on the grooves along two opposite long edges of the rectangular area at equal intervals, and capacitors are arranged on the grooves along two opposite wide edges of the rectangular area at equal intervals, so that the insertion loss at different frequencies is compensated to different degrees to realize the equalization effect. In the resonance unit, two chip capacitors introduced in the first adjusting structure cooperate with gold wires or inductors to realize the direct current blocking and alternating, PIN diodes introduced in the second adjusting structure replace microwave resistors to control the depth of the concave pits, and a reverse direct current voltage is applied to the varactor diode in the third adjusting structure to change the capacitance value of the varactor diode, so that the frequency of the concave pits is changed.

Description

Technical Field

[0001] This invention is based on microwave and millimeter-wave technology and studies an electrically adjustable pit type equalizer based on a substrate integrated waveguide (SIW) and a varactor diode and a PIN diode. Background Technology

[0002] SIW can realize the transmission characteristics of traditional metal waveguides on dielectric substrates, combining the advantages of rectangular waveguides and microwave planar circuits. These advantages include low radiation, low insertion loss, high Q value, high power capacity, miniaturization, and ease of integration, while remaining compatible with existing PCB manufacturing processes. Equalizers are one of the fundamental components of microwave and millimeter-wave circuits and systems. They are electronic devices that can individually adjust the amplitude of electrical signals of various frequency components to compensate for inconsistencies in the nonlinear gain response of components, thereby producing a flatter output power. Sometimes the circuit response curve is "bell-shaped," requiring an additional "inverted bell-shaped" (dimpled) equalization curve.

[0003] The following are the main reports on pit-type equalizers currently operating in the microwave band:

[0004] S. Tang et al. proposed a compact microstrip equalizer based on a spiral resonator structure. Employing a spiral resonator with thin-film resistors, it allows for frequency and attenuation adjustment and provides a parabolic attenuation curve to compensate for the nonlinear gain of the traveling wave tube. This equalizer operates in the 4-8 GHz range, with a minimum insertion loss of less than 1.5 dB, an equalization value of approximately 7 dB, and a maximum input and return loss of approximately -14 dB. See S. Tang, Y. Zhang and J. Zhang, "A novel compact size microstrip equalizer based on spiral resonators," 2010 International Conference on Microwave and Millimeter Wave Technology, Chengdu, China, 2010, pp. 730-733, doi:10.1109 / ICMMT.2010.5525046.

[0005] P. Zhou et al. proposed a broadband microwave gain equalizer using a thin-film resistor-terminated open-circuit resonator. By changing the electrical length of the main transmission line, the return loss is improved, and the bell-shaped performance of the resonant circuit unit can eliminate the non-uniform gain fluctuations of the traveling wave tube. This equalizer operates in the 6-18 GHz range, with a minimum insertion loss of approximately 4.3 dB, a maximum insertion loss of 12.8 dB, an input return loss of less than -15 dB, and an output return loss of less than -12.4 dB. See P. Zhou, X. Xie, J. Xie and J. Li, "A new research of broadband microwave gain equalizer," The 2012 International Workshop on Microwave and Millimeter Wave Circuits and System Technology, Chengdu, China, 2012, pp. 1-4, doi:10.1109 / MMWCST.2012.6238117.

[0006] J. Li et al. proposed a microstrip power equalizer based on a branched resonator load resistor. This equalizer employs multiple resonant branches to achieve equalization functionality, utilizing microstrip lines and resistors to form a loss network. The frequency and equalization value can be adjusted by changing its size and resistance. The equalizer operates in the 6-18 GHz range, with a minimum insertion loss of 3 dB, a maximum insertion loss of 12 dB, an equalization value of approximately 10 dB, and input and output return losses less than -15 dB. See J. Li, B. Yan and Y. Zhang, "Design of a microwave power equalizer," 2011 IEEE International Conference on Microwave Technology & Computational Electromagnetics, Beijing, China, 2011, pp. 145-147, doi:10.1109 / ICMTCE.2011.5915185.

[0007] In practical applications of microwave and millimeter-wave circuits, the required equalization level is often difficult to predict accurately in advance. Therefore, it is crucial that the designed equalizer can dynamically adjust the equalization level within a certain range. Existing equalization technologies mainly suffer from the following problems: First, the first equalizer operates at a relatively low frequency (not exceeding 8GHz), and the latter two are limited to 6-18GHz. For higher frequency ranges such as the millimeter-wave band, dynamic adjustment of the equalization level is not possible. Second, the equalization level of all three equalizers is fixed and cannot be electrically adjusted. Therefore, designing an equalizer with a higher operating frequency and flexible dynamic electronic tuning, while ensuring good equalization performance, is a key direction for equalizer development. Summary of the Invention

[0008] In view of this, the present invention proposes a substrate-integrated waveguide modulated pit equalizer based on varactor diodes and PIN diodes. This equalizer utilizes the characteristic that varactor diodes exhibit different capacitance values ​​under different voltages and the characteristic that PIN diodes exhibit different impedance values ​​under different voltages (replacing microwave resistors). The center frequency of the pit is changed by adjusting the voltage of the varactor diode, and the depth of the pit is changed by adjusting the voltage of the PIN diode.

[0009] The technical solution of the present invention is as follows:

[0010] A substrate-integrated waveguide modulated pit equalizer based on varactor diodes and PIN diodes includes a SIW body, a gradient transition line, and a 50Ω microstrip line.

[0011] The SIW body has a 50Ω microstrip line at each end, and the 50Ω microstrip line is connected to the SIW body through a gradient transition line.

[0012] The SIW body has multiple first metallized vias, multiple second metallized vias, a rectangular region, and electronic components. The first metallized vias are arranged in a row at equal intervals along one long side of the SIW body, and the second metallized vias are arranged in a row at equal intervals along the other long side of the SIW body. The rectangular region is located between the two rows of metallized vias and at the center of the SIW body, with its center point coinciding with the center point of the SIW body. Its long and wide sides are parallel to the long and wide sides of the SIW body, respectively, forming a rectangular region with four groove structures on each side. The electronic components are located on the grooves and consist of multiple resonant units and multiple capacitors. The multiple resonant units are respectively... The capacitors are evenly spaced on the two opposite long side grooves forming the rectangular area. Each resonant unit has the same structure, consisting of a first adjustment structure, a second adjustment structure, and a third adjustment structure connected in parallel. The first adjustment structure consists of two chip capacitors and a connecting structure. The two chip capacitors are the first chip capacitor and the second chip capacitor. The connecting structure is located above the first chip capacitor and the second chip capacitor and together with the first chip capacitor and the second chip capacitor, forms a Π-shaped structure. The second adjustment structure consists of a third chip capacitor and a PIN diode connected in series with the third chip capacitor. The third adjustment structure is composed of a varactor diode. Multiple capacitors are evenly spaced on the two opposite wide side grooves forming the rectangular area.

[0013] Furthermore, the connection structure in the first adjustment structure is selected from inductors or gold wires according to the application frequency band.

[0014] Furthermore, a third metallized via is introduced on each side of the junction between the gradient transition line and the wide edge of the SIW body to precisely match the SIW body with the 50Ω microstrip line; there are a total of 4 third metallized vias at both ends of the SIW body.

[0015] Furthermore, the center distance between the first metallized via and the second metallized via is W. p The center-to-center distance between two adjacent first metallized vias and the center-to-center distance between two adjacent second metallized vias are both svp.

[0016] Furthermore, the gradient transition line is located in the center of the wide side of the SIW body, and its length is L. t The length of the connecting side with the wide side of the SIW body is W. t The width of the 50Ω microstrip line is W.

[0017] Furthermore, the length of the long side of the SIW body is L. s The length of the wider side is Ws; the diameters of the first and second metallized vias are both dvp; the distance between the third metallized via and the first or second adjacent first metallized via on the same side along the electromagnetic wave propagation direction is L. xThe distance L between the third metallized via and the adjacent first or second metallized via on the same side, perpendicular to the electromagnetic wave propagation direction. y .

[0018] Furthermore, the width of the rectangular region is d, and the length of the long side of the rectangular region is L. r The spacing between the varactor diodes in two adjacent resonant units along the longer side of the rectangular region is S. r1 The spacing between the PIN diodes in two adjacent resonant unit structures is S. r2 .

[0019] Furthermore, the capacitors equally spaced on the two opposite wide-side grooves forming the rectangular region are 100pF capacitors, and the spacing between two adjacent 100pF capacitors is S. c .

[0020] The working principle of the electronically tunable equalizer of this invention is: electromagnetic waves in the SIW body are in the form of TE 10 The pattern propagates, and the metal layers covering the front and back sides of the equalizer structure, as well as the two rows of metallized vias in the SIW body, are used to constrain the propagation boundary of the electromagnetic wave. The two chip capacitors introduced in the first adjustment structure, in conjunction with gold wires or inductors, achieve DC blocking and AC passing. The PIN diodes introduced in the second adjustment structure replace microwave resistors to control the depth of the pit. The frequency of the pit is changed by applying a reverse DC voltage to the varactor diode in the third adjustment structure to change its capacitance value.

[0021] In the equalizer structure, the varactor diode acts as capacitor C, the PIN diode acts as resistor R (the PIN diode can be considered equivalent to a resistor under forward bias), and the inductor L together form an RLC parallel resonant circuit. The admittance of the parallel resonant circuit is: The resonant angular frequency is: By applying voltages across the varactor diode and the PIN diode, the capacitance and microwave resistance values ​​in the circuit can be changed, respectively. Increasing the microwave resistance increases the total impedance at circuit resonance, leading to increased circuit losses and consequently affecting S. 21 The depth of the curve's indentation increases; the increase in capacitance causes the circuit's resonant angular frequency to decrease, corresponding to S... 21 The center frequency of the curve's dimple decreases. In summary, the substrate-integrated waveguide modulation dimple-type equalizer of this invention can theoretically achieve electrical tuning of the equalization frequency and attenuation within the same band.

[0022] The substrate-integrated waveguide modulation pit type equalizer of the present invention can be applied to microwave and millimeter-wave circuits and systems to compensate for the insertion loss of devices at different frequencies to achieve equalization. The center frequency of the pit is changed by adjusting the voltage of the varactor diode, and the depth of the pit is changed by adjusting the voltage of the PIN diode. Attached Figure Description

[0023] Figure 1 This is a top view of the structure of a Ku-band equalizer;

[0024] Figure 2 This is a schematic diagram of the components and structure of a Ku-band equalizer;

[0025] Figure 3 This is a top view of the Ka-band equalizer.

[0026] Figure 4 This is a schematic diagram of the components and structure of a Ka-band equalizer;

[0027] Figure 5 These are the overall physical diagram and a partial enlarged view of the equalizer operating in the Ku band. (a) is the overall physical diagram, and (b) is a partial enlarged view of the parallel structure of the inductor (including the chip capacitor), PIN diode, and varactor diode.

[0028] Figure 6 These are the overall physical diagram and a partial enlarged view of the Ka-band equalizer, where (a) is the overall physical diagram and (b) is a partial enlarged view of the parallel structure of the inductor (including the chip capacitor) with the PIN diode and varactor diode.

[0029] Figure 7 S obtained by varying the capacitance under different resistance values ​​in a Ku-band equalizer 21 With S 11 The simulation results are shown in the figure, where (a) is a resistance of 25Ω, (b) is a resistance of 50Ω, and (c) is a resistance of 75Ω.

[0030] Figure 8 Simulated values ​​of equalization output of a Ku-band equalizer with different capacitors and resistors;

[0031] Figure 9 It is a Ku-band equalizer, V c =V p Time (i.e., ΔV) pin =0), S under different voltage conditions 21 With S 11 Test results (TRL-calibrated deembedding);

[0032] Figure 10 When operating in a Ku-band equalizer, V at different frequencies / with the same insertion loss c V p S 21 and S 11The test results (TRL calibration de-embedding) are shown, where (a) is insertion loss -10dB, (b) is insertion loss -15dB, (c) is insertion loss -20dB, (d) is insertion loss -25dB, and (e) is insertion loss -30dB.

[0033] Figure 11 It is a Ku-band equalizer, V at each resonant frequency c ΔV p S 21 and S 11 Test results (V per image) c (Fixed, and TRL calibration de-embedded), where (a) is the resonant frequency 13 GHz, (b) is the resonant frequency 14 GHz, (c) is the resonant frequency 15 GHz, (d) is the resonant frequency 16 GHz, (e) is the resonant frequency 17 GHz, and (f) is the resonant frequency 18 GHz.

[0034] Figure 12 It is a Ku-band equalizer with different ΔV. p The obtained equalization quantity test results (TRL-calibrated deembedding); Figure 13 The S is obtained by varying the capacitance under different resistance values ​​of a Ka-band equalizer. 21 With S 11 The simulation results are shown in the figure, where (a) is a resistance of 25Ω, (b) is a resistance of 50Ω, and (c) is a resistance of 75Ω.

[0035] Figure 14 Simulation diagram of the equalization output of a Ka-band equalizer under different capacitors and resistors;

[0036] Figure 15 It is a Ka-band equalizer, V c =V p Time (i.e., ΔV) pin =0), S under different voltage conditions 21 With S 22 Test results (TRL-calibrated deembedding);

[0037] Figure 16 It operates as a Ka-band equalizer. At different frequencies / with the same insertion loss, V c V p S 21 and S 11 The test results (TRL calibration de-embedding) are shown, where (a) is insertion loss -15dB, (b) is insertion loss -20dB, (c) is insertion loss -25dB, (d) is insertion loss -30dB, (e) is insertion loss -35dB, and (f) is insertion loss -40dB.

[0038] Figure 17 It is a Ka-band equalizer, V at each resonant frequency c ΔV p S 21 and S 11 Test results (V per image) c (Fixed, and TRL calibration de-embedded), where (a) is a resonant frequency of 27 GHz, (b) is a resonant frequency of 29 GHz, (c) is a resonant frequency of 31 GHz, (d) is a resonant frequency of 33 GHz, (e) is a resonant frequency of 35 GHz, and (f) is a resonant frequency of 36.8 GHz.

[0039] Figure 18 It is a Ka-band equalizer with different ΔV. p The obtained equalization quantity test results (TRL-calibrated deembedding);

[0040] Reference numerals: SIW body-1, gradient transition line-2, first metallized through hole-3, rectangular groove-4, third metallized through hole-5. Detailed Implementation

[0041] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0042] This invention provides a substrate-integrated waveguide modulated pit equalizer based on varactor diodes and PIN diodes, comprising a SIW body, a gradient transition line, and a 50Ω microstrip line. Both sides of the SIW body are coated with a layer of copper foil, and each end has a 50Ω microstrip line connected to the SIW body via the gradient transition line. Utilizing the characteristics of varactor diodes exhibiting different capacitance values ​​under different voltages and PIN diodes exhibiting different impedance values ​​under different voltages, the center frequency of the pit is changed by adjusting the voltage of the varactor diode, and the pit depth is changed by adjusting the voltage of the PIN diode. Based on this, two substrate-integrated waveguide modulated pit equalizers based on varactor diodes and PIN diodes were designed, one of which operates in the Ku band. A physical diagram is shown below. Figure 5 (a) and Figure 5 As shown in (b), another model operates in the Ka band, physical object Figure 6 (a) and Figure 6 As shown in (b).

[0043] Example 1

[0044] The substrate-integrated waveguide modulation pit type equalizer in this embodiment operates in the Ku band. For example... Figure 1As shown, the SIW body has multiple first metallized vias, multiple second metallized vias, a rectangular region, and electronic components. The multiple first metallized vias are arranged in a row at equal intervals along one of the long sides of the SIW body. The multiple second metallized vias are arranged in a row at equal intervals along the other long side of the SIW body. The rectangular region is located between the two rows of metallized vias and at the center of the SIW body, with its center point coinciding with the center point of the SIW body. Its long and wide sides are parallel to the long and wide sides of the SIW body, respectively, and all four sides of the rectangular region are groove structures.

[0045] The SIW body has a long side length of Ls and a wide side length of Ws. The center distance between the first metallized via and the second metallized via is W. p The center-to-center distance between two adjacent first metallized vias and the center-to-center distance between two adjacent second metallized vias are both svp. The diameters of the first and second metallized vias are the same, both dvp. The gradient transition line is located in the center of the wide side of the SIW body, and its length is L. t The length of the connecting side with the wide side of the SIW body is W. t The width of the 50Ω microstrip line is W. A third metallized via is introduced on each side of the junction between the gradient transition line and the wide side of the SIW body. These third metallized vias are used for precise matching between the SIW body and the 50Ω microstrip line. There are a total of four third metallized vias at both ends of the SIW body, and the two matching vias on the same end of the SIW body are axially symmetrical about the line connecting the centers of the two wide sides of the SIW body. The distance between the third metallized via and the first adjacent metallized via on the same side along the longitudinal width of the SIW body (in the direction of electromagnetic wave propagation) is L. y The distance between the matching metallized via and the adjacent metallized via on the same side along the long side of the SIW body (perpendicular to the direction of electromagnetic wave propagation) is L. x .

[0046] The electronic component, mounted on the groove, comprises multiple resonant units and multiple 100pF capacitors. The resonant units are equally spaced along the two opposite long sides constituting the rectangular region, as shown in the specific arrangement. Figure 2 As shown:

[0047] This embodiment contains 12 resonant units. Six resonant units are evenly spaced along each of the two opposite long sides of the rectangular area. Each resonant unit has the same structure, consisting of a first adjustment structure, a second adjustment structure, and a third adjustment structure connected in parallel. The first adjustment structure comprises a PCB board, two chip capacitors, and an inductor. The two chip capacitors, designated as the first and second chip capacitors respectively, act as DC blocking capacitors and are mounted on the PCB board. The inductor is positioned above the first and second chip capacitors, forming a near-Π-shaped structure together with them. The selected inductor is packaged in 01005 and is model LQP02TN0N3B02D. The first and second chip capacitors are model SK00C101M11A6. During assembly, the two chip capacitors are assembled first, followed by the assembly of an inductor onto the plates of these two chip capacitors. The second adjustment structure consists of a third chip capacitor, a PIN diode connected in series with the third chip capacitor, and a third ceramic grounding block. The PIN diode is model MADP-000907-14020P, the third chip capacitor is model C5B2010W101M, and the ceramic grounding block is model MB(0.35)N(0.28)(0.20). During assembly, the third chip capacitor and the ceramic grounding block are assembled first, and then the PIN diode is assembled onto their plates. The third adjustment structure is composed of a varactor diode, model MAVR-000120-14110P, which is directly connected across the two sides of the SIW slot. The spacing between the varactor diodes in two adjacent resonant units on the long side of the rectangular area is S. r1 The spacing between the PIN diodes in two adjacent resonant unit structures is S. r2 Multiple 100pF capacitors are evenly spaced along the two opposite wide sides of a rectangular area. These 100pF capacitors are used for microwave signal transmission. In this embodiment, there are 6 100pF capacitors per width of the rectangular area, and a total of 12 100pF capacitors are arranged along the two opposite wide sides. The spacing between two adjacent 100pF capacitors is S. c To facilitate later assembly, components such as chip capacitors, grounding blocks, PIN diodes, and varactor diodes are marked with a silkscreen layer around the rectangular slot to determine the position of each component.

[0048] In this embodiment, the SIW equalizer operating in the Ku band is implemented using a Rogers 5880 dielectric substrate with a thickness of 0.254 mm, a dielectric constant of 2.2, a tangent loss of 0.0009, and a copper thickness of 18 μm (1 / 2 oz). The front and back metal layers are gold-plated, resulting in a final thickness of 40 μm. After simulation and optimization using the electromagnetic simulation software Ansoft HFSS, the optimal parameter dimensions were obtained, as shown in Table 1.

[0049] Table 1

[0050]

[0051] In Ansoft HFSS, the capacitance value of the varactor diode was set to `cap`, with a range of 0.25pF to 0.45pF. Simulations were performed in 0.05pF increments. Data sets of 0.25, 0.30, 0.35, 0.40, and 0.45pF were selected to illustrate the simulation results. 21 and S 11 The curves showing the changes in resistance (res) of the PIN diode and capacitance (cap) of the varactor diode are as follows: [Image of S-parameter simulation curves and equalization curves]. Figure 7 (a) to Figure 7 (c) and Figure 8 As shown in the simulation results, both the pit depth and the pit center frequency can be adjusted; the resistance value adjusts the pit depth, and the capacitance value adjusts the pit center frequency. The pit center frequency can be freely adjusted within the range of 12GHz-18GHz.

[0052] Based on the above theories and ideas, the relevant PCB and structural components were fabricated to assemble the actual circuit. In actual testing, after TRL calibration and de-embedding, a reverse DC voltage of 0V-16V was set on the varactor diode, and the actual voltage applied to the PIN diode was the differential voltage ΔV. p (The difference between the forward bias voltage applied to the PIN diode outside the groove and the voltage on the rectangular area plate inside the groove), tested in 0.1V steps, and the obtained data was processed as follows: First, at V c =V p At that time, several sets of data (3, 4, 4.8, 5.9, 7.2, 8.7, 10.5, 12.6, 15, 16 V) were selected to plot the isovoltage S-parameter curves as follows: Figure 9 As shown, the dynamic adjustability of the center frequency of the pit within the frequency band can be intuitively observed. Then, the value of V is determined at different frequencies / with the same insertion loss (-10dB, -15dB, ... -30dB). c V p S 21 and S 11 The test results are as follows Figure 10 (a) to Figure 10 As shown in (e), the dynamic adjustability of the pit depth within the frequency band can be visually observed. Finally, the V value at each resonant frequency is determined. c ΔV p S 21 and S 11 The test results are as follows Figure 11 As shown. Figure 11 It is a Ku-band equalizer, V at each resonant frequency c ΔV p S 21 and S11 Test results (V per image) c Fixed, and TRL calibration de-embedded), where (a) is the resonant frequency of 13 GHz, (b) is the resonant frequency of 14 GHz, (c) is the resonant frequency of 15 GHz, (d) is the resonant frequency of 16 GHz, (e) is the resonant frequency of 17 GHz, and (f) is the resonant frequency of 18 GHz; for Figure 11 (a) to Figure 11 The changes in the equilibrium values ​​of the selected test groups in (f) were statistically analyzed and plotted in Table 2. Combined with... Figure 11 (a) to Figure 11 (f) and Table 2, in V c When the resonant frequency remains constant, the change in ΔV within a certain range p This allows the equalization amount (dimple depth) to be changed within a corresponding range. Furthermore, to more significantly observe the measured results, this embodiment modulates the value at each resonant frequency (V0). c (Closely related to the resonant frequency), changing ΔV p The curves plotted from the obtained equilibrium values ​​are as follows: Figure 12 As shown. By Figure 12 It can be seen that at different frequencies, as ΔV p As the gain increases, the equalizer's overall equalization value shows a decreasing trend. This embodiment can achieve amplitude equalization of the bell-shaped gain curve.

[0053] Table 2

[0054]

[0055]

[0056] Example 2

[0057] The substrate-integrated waveguide modulation pit equalizer in this embodiment operates in the Ka band, such as... Figure 3 As shown, the overall structural design of the equalizer operating in the Ka band is basically the same as that of the Ku band equalizer, and the names used to label the dimensions of each part are also interchangeable. The only difference compared to the Ku band equalizer lies in the electronic components mounted on the recess, specifically, as... Figure 4 As shown:

[0058] In the first adjustment structure, the inductor is replaced with a 25µm gold wire, bonded to the edge; it is connected in series with the first and second chip capacitors. During assembly, the first and second chip capacitors are assembled first, and then two gold wires are bonded to connect the plates of the first and second chip capacitors; the remaining two parts are consistent with the Ku-band design. The spacing between the varactor diodes in two adjacent units on the long side is S. r1 The spacing between the PIN diodes is S r2Four 100pF capacitors (package 01005) are mounted on one wide side, with a spacing of S between adjacent capacitors. c The 100pF capacitors are used for signal flow and are also arranged at equal intervals, with the outermost capacitors on both sides aligned with the edges.

[0059] The use of gold wire instead of inductors is explained as follows: According to relevant research, the highest self-resonant frequency of commercially available inductors is 20GHz. If the circuit operating frequency exceeds 20GHz, the inductor loses its inductive characteristics and becomes a capacitive device. In equalizers operating in the Ku-band (12GHz-18GHz), inductors function normally; however, in equalizers operating in the Ka-band (26GHz-40GHz), the inductor's maximum self-resonant frequency is exceeded. Based on practical engineering experience, gold wire is used to achieve the inductor function. In actual testing, to obtain a wider frequency range for the equalizer, two gold wires are usually connected in parallel to achieve a smaller inductance.

[0060] In this embodiment, the SIW equalizer operates in the Ka-band. The substrate is Rogers 5880, 0.254 mm thick, with a dielectric constant of 2.2, a tangent loss of 0.0009, and a copper thickness of 18 μm (1 / 2 oz). Both sides are gold-plated, resulting in a final thickness of 40 μm. After simulation and optimization using Ansoft HFSS electromagnetic simulation software, the optimal parameter dimensions were obtained, as shown in Table 3.

[0061] Table 3

[0062]

[0063] In Ansoft HFSS, the capacitance value of the varactor diode was set to `cap`, with a range of 0.08 pF to 0.14 pF, and simulations were performed in 0.02 pF increments. From all the obtained data, the sets of data at 0.08, 0.10, 0.12, and 0.14 pF were selected to display the variation curves of S21 and S11 in the simulation results. The S-parameter simulation curves and equalization curves of the varactor diode with varying capacitance are shown below. Figure 13 (a) to Figure 13 (c) and Figure 14 As shown. From Figure 13 (a) to Figure 13 (c) and Figure 14 The simulation results show that both the pit depth and the pit center frequency can be adjusted; the resistance value adjusts the pit depth, and the capacitance value adjusts the pit center frequency, which can be freely adjusted within the range of 26GHz-40GHz.

[0064] Based on the above theories and ideas, the relevant PCB and structural components were fabricated to assemble the actual circuit. In the actual testing phase, after TRL calibration and de-embedding, a reverse DC voltage of 0V-17.2V was set on the varactor diode, and the actual voltage applied to the PIN diode was the differential voltage ΔV. p (The difference between the forward bias voltage applied to the PIN diode outside the groove and the voltage on the rectangular area plate inside the groove), tested in 0.1V steps, and the obtained data was processed as follows. First, at V c =V p At that time, several sets of data were selected: 1, 1.5, 2, 3.18, 4.25, 5.57, 7.84, 12.13, and 17.2 (V) to plot the isovoltage S-parameter curves as follows: Figure 15 As shown. By Figure 15 This visually demonstrates the dynamic adjustability of the center frequency of the pit within the frequency band. Find the value of V at different frequencies / with the same insertion loss (-15dB, -20dB, ... -40dB). c V p S 21 and S 11 The test results are as follows Figure 16 (a) to Figure 16 As shown in (f). From Figure 16 (a) to Figure 16 In (f), the dynamic adjustability of the pit depth within the frequency band can be clearly seen. V at each resonant frequency c ΔV p S 21 and S 11 The test results are as follows Figure 17 (a) to Figure 17 As shown in (f). This embodiment will Figure 17 (a) to Figure 17 Table 4 shows the changes in the equilibrium values ​​of the selected test groups in (f). Combined with... Figure 17 (a) to Figure 17 (f) and Table 4 show that in V c When the resonant frequency remains constant, the change in ΔV within a certain range p This allows the equalization amount (dimple depth) to be changed within a corresponding range. Furthermore, to more significantly observe the measured results, we measured the values ​​at various resonant frequencies (V0). c (Closely related to the resonant frequency), changing ΔV p The equilibrium values ​​are statistically analyzed and plotted as a curve, as shown below. Figure 18 As shown. By Figure 18 It can be seen that at different frequencies, as ΔV p As the gain increases, the equalizer's overall equalization value shows a decreasing trend. This embodiment can achieve amplitude equalization of the bell-shaped gain curve.

[0065] Table 4

[0066]

[0067] The simulation and experimental results above show that at the resonant frequency, most of the current flows through the resistor, resulting in significant signal loss near this frequency. This creates the "pit" characteristic on the equalizer's gain curve. Due to the electrically adjustable characteristics of the PIN diode and varactor diode, the pit depth and center frequency can be controlled by changing the voltage. In summary, this equalizer has wider adjustability and adaptability, and can better achieve amplitude equalization of the bell-shaped gain curve, resulting in a flatter overall output.

Claims

1. A substrate-integrated waveguide modulated pit equalizer based on varactor diodes and PIN diodes, comprising a SIW body, a gradient transition line, and a 50Ω microstrip line; each end of the SIW body is provided with a 50Ω impedance microstrip line, and the 50Ω impedance microstrip line is connected to the SIW body through the gradient transition line, characterized in that: The SIW body is provided with multiple first metallized through holes, multiple second metallized through holes, a rectangular area, and electronic components; Multiple first metallized vias are arranged in a row at equal intervals along one of the long sides of the SIW body, and multiple second metallized vias are arranged in a row at equal intervals along the other long side of the SIW body. The rectangular area is located between two rows of metallized through holes and at the center of the SIW body. Its center point coincides with the center point of the SIW body. Its long side and wide side are parallel to the long side and wide side of the SIW body, respectively. All four sides of the rectangular area are groove structures. The electronic component is disposed on the groove and consists of multiple resonant units and multiple capacitors. The multiple resonant units are respectively disposed at equal intervals on the two opposite long side grooves forming the rectangular region. Each resonant unit has the same structure, consisting of a first adjustment structure, a second adjustment structure, and a third adjustment structure arranged in parallel. The first adjustment structure consists of two chip capacitors and a connecting structure. The two chip capacitors are the first chip capacitor and the second chip capacitor, respectively. The connecting structure is located above the first chip capacitor and the second chip capacitor, and together with the first chip capacitor and the second chip capacitor, they form a "Π"-shaped structure. The second adjustment structure consists of a third chip capacitor and a PIN diode connected in series with the third chip capacitor. The third adjustment structure is composed of a varactor diode. Multiple capacitors are equally spaced on the two opposite wide-side grooves forming the rectangular area.

2. The substrate-integrated waveguide modulation pit type equalizer based on varactor diodes and PIN diodes according to claim 1, characterized in that: The connection structure in the first adjustment structure is selected from inductors or gold wires according to the application frequency band.

3. The substrate-integrated waveguide modulation pit type equalizer based on varactor diodes and PIN diodes according to claim 1, characterized in that: A third metallized via is introduced on each side of the junction between the gradient transition line and the wide edge of the SIW body to precisely match the SIW body with the 50Ω microstrip line; there are a total of 4 third metallized vias at both ends of the SIW body.

4. A substrate-integrated waveguide modulation pit-type equalizer based on varactor diodes and PIN diodes according to claim 1, characterized in that: The center distance between the first metallized via and the second metallized via is W. p The center-to-center distance between two adjacent first metallized vias and the center-to-center distance between two adjacent second metallized vias are both svp.

5. A substrate-integrated waveguide modulation pit-type equalizer based on varactor diodes and PIN diodes according to claim 1, characterized in that: The gradient transition line is located in the center of the wide side of the SIW body, and its length is L. t The length of the connecting side with the wide side of the SIW body is W. t The width of the 50Ω impedance microstrip line is W.

6. A substrate-integrated waveguide modulation pit-type equalizer based on varactor diodes and PIN diodes according to claim 3, characterized in that: The length of the long side of the SIW body is L. s The length of the wider side is Ws; the diameters of the first and second metallized vias are both dvp; the distance between the third metallized via and the first or second adjacent first metallized via on the same side along the electromagnetic wave propagation direction is L. x The distance L between the third metallized via and the adjacent first or second metallized via on the same side, perpendicular to the electromagnetic wave propagation direction. y .

7. A substrate-integrated waveguide modulation pit-type equalizer based on varactor diodes and PIN diodes according to claim 1, characterized in that: The width of the rectangular region is d, and the length of the long side is L. r The spacing between the varactor diodes in two adjacent resonant units along the longer side of the rectangular region is S. r1 The spacing between the PIN diodes in two adjacent resonant unit structures is S. r2 .

8. A substrate-integrated waveguide modulation pit-type equalizer based on varactor diodes and PIN diodes according to claim 1, characterized in that: The capacitors, 100pF, are equally spaced and positioned on the two opposite wide-side grooves forming the rectangular region, with a spacing of S between adjacent 100pF capacitors. c .

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