Rapid design method of ultra-wideband microstrip equalizer

Abstract

The invention discloses a rapid design method of an ultra wide band micro-strip equalizer. The functional requirements of ultra wide band and miniaturization are realized by using a lambda / 4 stepped impedance resonance unit; a design method of combining ADS schematic diagram simulation and HFSS three-dimensional simulation is used, and mutual influence between resonance units in a three-dimensional space is reduced by reducing a coupling coefficient K between adjacent resonance units in an ADS schematic diagram simulation stage; in order to meet millimeter wave frequency band use and achieve simulation accuracy, the dielectric substrate is made of a ceramic filling reinforcing material, the loading resistor is a thin-film resistor, and a planar resistor burying process is adopted. The space coupling influence between the resonance units is considered, when the ADS schematic diagram is imported into HFSS three-dimensional simulation after simulation optimization, the design requirement can be met only by trimming the resistance and local parameters, the problem that the optimization time is slow when three-dimensional simulation software is used for multi-parameter simulation design currently is solved, and the development time is effectively saved.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave passive devices, and in particular to a fast design method for an ultra-wideband microstrip equalizer. Background Art

[0002] Microwave broadband transceivers are widely used in fields such as electronic countermeasures and phased array radar. As the bandwidth of modern RF microwave communication systems continues to increase, signal amplitude distortion may occur during transmission. To ensure transmission quality, this distortion must be limited, and gain equalization networks are typically used to correct it. Common gain equalization curves are inverted bell and diagonal. Gain equalizers primarily come in lumped circuit, coaxial, waveguide, and transmission line types. Lumped circuit equalizers offer the advantages of small size and low cost, but operate at low frequencies. Waveguide and coaxial equalizers, which use cavity structures, offer advantages such as high power handling and tunability. However, their complex structure, large size, heavy weight, and expensive processing hinder miniaturization. Transmission line equalizers are widely used in microwave circuits due to their small size, light weight, and ease of integration into RF circuit boards. The propagation characteristics of RF signals within a channel are characterized by increasing attenuation with increasing frequency, and this attenuation is particularly severe in the millimeter wave band. Therefore, the development of high-quality, ultra-wideband equalizers is highly significant.

[0003] The design of ultra-wideband microstrip equalizers has the following difficulties: First, the traditional transmission line equalizer uses a λ / 2 short-circuit line and a λ / 4 open-circuit line as resonant units, and mainly modulates the operating frequency by controlling the length of the resonant unit. The bandwidth of a single resonant unit is limited, and more branches need to be cascaded to meet the design requirements, resulting in a larger size of the equalizer, which is not conducive to the integrated design of the microwave system. Therefore, it is necessary to select a suitable resonant unit and control the physical properties of the resonant unit to broaden the operating bandwidth and equalization amount; on the other hand, as the number of branches increases, the parameters during simulation will also increase exponentially, which will consume a lot of design time in three-dimensional simulation design and increase the design difficulty of the microstrip equalizer. Summary of the Invention

[0004] In view of the difficulties faced in designing an ultra-wideband equalizer, the present invention aims to provide a fast design method for an ultra-wideband microstrip equalizer.

[0005] The technical solution to implement the present invention is: a rapid design method for an ultra-wideband microstrip equalizer, the steps of which are as follows:

[0006] S1: Determine the resonant unit of the microstrip equalizer based on the size restrictions, frequency range, and functional requirements of the ultra-wideband microstrip equalizer in the radio frequency link, and proceed to step S2.

[0007] S2: According to the functional requirements of the ultra-wideband microstrip equalizer in the radio frequency link for operating in the millimeter wave frequency band, the dielectric substrate and loading resistor of the microstrip equalizer are determined, and the process proceeds to step S3.

[0008] S3: Design the circuit based on the functional requirements of the ultra-wideband microstrip equalizer in the RF link:

[0009] The circuit of the ultra-wideband microstrip equalizer includes a main transmission line, a loading resistor, a SIR step impedance resonance unit, and a dielectric substrate.

[0010] The main transmission line includes an input 50-ohm transmission line, an output 50-ohm transmission line, an input matching transmission line, an output matching transmission line, a first-stage matching transmission line, a second-stage matching transmission line, and a third-stage matching transmission line. The input matching transmission line and the output matching transmission line are connected to the input 50-ohm transmission line and the output 50-ohm transmission line to perform input and output matching and ensure input and output standing wave indicators.

[0011] The first, second, and third interstage matching transmission lines isolate the resonant units to avoid coupling effects and expand bandwidth. The first loading resistor is connected to the first resonant unit, the second loading resistor is connected to the second resonant unit, the third loading resistor is connected to the third resonant unit, and the fourth loading resistor is connected to the fourth resonant unit. The process then proceeds to step S4.

[0012] S4: Determine the circuit form of the ultra-wideband microstrip equalizer based on the operating frequency range and the equalization amount, and proceed to step S5.

[0013] S5: Calculate the initial sizes of the first resonance unit, the second resonance unit, the third resonance unit, and the fourth resonance unit, and proceed to step S6.

[0014] S6: Calculate the initial sizes of the input matching transmission line, the output matching transmission line, the first inter-stage matching transmission line, the second inter-stage matching transmission line, and the third inter-stage matching transmission line, and proceed to step S7.

[0015] S7: The initial values ​​of the first thin-film resistor, the second thin-film resistor, the third thin-film resistor, and the fourth thin-film resistor are all set to 50 ohms, and the process proceeds to step S8.

[0016] S8: Optimize the simulation using a computer optimization method based on the equilibrium curve index and proceed to step S9.

[0017] S9: Import the ADS simulation model parameters that meet the equalization curve into HFSS, verify the equalization target, fine-tune the resistor size, and complete the ultra-wideband microstrip equalizer design.

[0018] Compared with the prior art, the present invention has the following significant advantages:

[0019] (1) The use of a λ / 4 step impedance (SIR) resonant unit can effectively achieve the functional requirements of ultra-wideband and high equalization.

[0020] (2) During the ADS schematic simulation stage, the mutual influence of resonant units in the three-dimensional space is reduced by reducing the coupling coefficient K between adjacent resonant units; when the ADS schematic simulation is optimized and imported into the HFSS three-dimensional simulation, only the three-dimensional simulation software needs to be used to optimize and fine-tune the resistance and local parameters to meet the design requirements, avoiding the current problem of slow optimization time when using three-dimensional simulation software for multi-parameter simulation design, and effectively saving development time.

[0021] (3) The dielectric substrate of the microstrip equalizer adopts ceramic filling reinforcement material, which can meet the working requirements of the millimeter wave frequency band. The loading resistor is a thin film resistor, which adopts a planar buried resistor process. The thin film resistor is a resistor whose resistance value is controlled by controlling the surface length L and width W of the resistor after determining the surface PCB buried resistor resistivity. This is consistent with the principle of setting impedance boundary conditions in the design software HFSS used in the present invention, which is conducive to the accuracy of simulation design. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of a λ / 4 step impedance (SIR) resonance unit.

[0023] Figure 2 Schematic diagram of the design process of ultra-wideband microstrip equalizer.

[0024] Figure 3 This is the circuit diagram of the ultra-wideband equalizer.

[0025] Figure 4 Optimizing simulation flow chart for ultra-wideband equalizer.

[0026] Figure 5 Schematic diagram of parallel coupled microstrip lines.

[0027] Figure 6 S for ADS schematic simulation and HFSS 3D simulation 21 Curve comparison chart.

[0028] Figure 7 S for ADS schematic simulation and HFSS 3D simulation 11 Curve comparison chart. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The technical solutions between the various embodiments of the present invention can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The following will further introduce the specific implementation methods, as well as the technical difficulties and inventive points of this invention in combination with this design example.

[0032] Combine Figures 1 to 7 The rapid design method of an ultra-wideband microstrip equalizer according to the present invention comprises the following steps:

[0033] S1: Based on the size restrictions, frequency range, and functional requirements for the ultra-wideband microstrip equalizer in the RF link, determine the resonant unit of the microstrip equalizer as follows:

[0034] Design using a λ / 4 step impedance (SIR) resonant unit, such as Figure 1 As shown, the input impedance Z of the resonant unit transmission line in It can be expressed as follows:

[0035]

[0036] In the above formula, j is the imaginary part, Z1 is the characteristic impedance of the low-resistance line, Z2 is the characteristic impedance of the high-resistance line, θ1 is the electrical length of the low-resistance line, and θ2 is the electrical length of the high-resistance line.

[0037] When the series resonance occurs, set Z i =0, then:

[0038] Z1-Z2tanθ1tanθ2=0 (2)

[0039] so:

[0040]

[0041] When the ratio R Z >1 and 0<θ1+θ2<π / 2, SIR achieves the minimum length; when the ratio R Z <1 and π / 2<θ1+θ2<π, SIR achieves maximum length, and at this time it satisfies

[0042]

[0043] According to formula (1) to formula (4), R Z The bigger the better, but R Z Too large will result in the size of SIR being too small and finally unable to be processed in practice. Z The selection must be reasonable.

[0044] Go to step S2.

[0045] S2: Based on the functional requirements of the ultra-wideband microstrip equalizer in the RF link to meet the millimeter wave frequency band, determine the dielectric substrate and loading resistor of the microstrip equalizer as follows:

[0046] The dielectric substrate used is a ceramic filler reinforcement material, model Taconic TSM-DS3, with a dielectric constant of ε r The dielectric plate thickness is 0.254 mm, meeting millimeter-wave frequency band requirements. The microstrip equalizer loading resistor is a thin-film resistor, using a planar embedded resistor process. This thin-film resistor is a resistor whose resistance is controlled by controlling the surface length L and width W of the resistor after determining the surface PCB embedded resistor resistivity. This is consistent with the principle of setting impedance boundary conditions in the design software HFSS used in this invention, facilitating simulation design accuracy.

[0047] Go to step S3.

[0048] S3: Based on the functional requirements of the ultra-wideband microstrip equalizer in the RF link, the circuit is designed using professional electromagnetic simulation software ADS and HFSS. The principle block diagram is as follows: Figure 2 As shown, the details are as follows:

[0049] Based on the equalizer design indicators, the initial dimensions of each part of the microstrip line equalizer are first calculated; the calculated parameters are used to build a model in the ADS schematic and optimize the simulation; then the original parameters of the ultra-wideband microstrip equalizer in the ADS schematic are imported into HFSS for three-dimensional simulation to ensure simulation accuracy; the dimensions of the ultra-wideband microstrip equalizer are fine-tuned and optimized to complete the design.

[0050] Go to step S4.

[0051] S4: According to the operating frequency range and the amount of equalization, determine the circuit form of the ultra-wideband microstrip equalizer, such as Figure 3 As shown, the details are as follows:

[0052] The circuit of the ultra-wideband microstrip equalizer includes a main transmission line, loading resistors, a SIR step impedance resonant unit, and a dielectric substrate. The main transmission line includes an input 50-ohm transmission line 1, an output 50-ohm transmission line 15, an input matching transmission line 2, an output matching transmission line 14, a first interstage matching transmission line 5, a second interstage matching transmission line 8, and a third interstage matching transmission line 11. The input matching transmission line 2 and the output matching transmission line 14 are connected to the input 50-ohm transmission line 1 and the output 50-ohm transmission line 15 to perform input and output matching and ensure input and output standing wave performance. The interstage matching lines, the first interstage matching transmission line 5, the second interstage matching transmission line 8, and the third interstage matching transmission line 11, isolate the various resonant units to avoid coupling effects and expand bandwidth. The first loading resistor 3 is connected to the first resonant unit 4, the second loading resistor 6 is connected to the second resonant unit 7, the third loading resistor 10 is connected to the third resonant unit 9, and the fourth loading resistor 13 is connected to the fourth resonant unit 7. The first loading resistor 3 and the fourth loading resistor 13, the second loading resistor 6 and the third loading resistor 10 have the same size and resistance value; the first resonant unit 4 and the fourth resonant unit 7, the second resonant unit 7, and the third resonant unit 9 have the same size; the ultra-wideband equalizer is a symmetrical reciprocal structure, so the input and output of the ultra-wideband microstrip equalizer can be used reversely.

[0053] Go to step S5.

[0054] S5: Calculate the initial sizes of the first resonant unit 4, the second resonant unit 7, the third resonant unit 9, and the fourth resonant unit 7, as follows:

[0055] Considering the rationality of size, according to formula (1)-formula (3), select R Z =3 / 5, and let Z1 in SIR = 50, substitute into formula (3) and formula (4), and calculate Z2 to be 30 ohms. The electrical lengths θ1 and θ2 of the SIR high and low resistance lines are 1.03 radians, which is converted into an angle of 59 degrees. Calculate the width W1 and physical length l1 of the SIR branch low resistance line Z1 at the lowest frequency in the working frequency band, as well as the width W1 and physical length l1 of the SIR branch high resistance line Z2. The initial dimensions of the multiple resonant units remain consistent for subsequent computer optimization.

[0056] Go to step S6.

[0057] S6: Calculate the initial dimensions of the input matching transmission line 2, the output matching transmission line 14, the first inter-stage matching transmission line 5, the second inter-stage matching transmission line 8, and the third inter-stage matching transmission line 11, as follows:

[0058] The input and output matching of the microstrip equalizer also uses SIR stepped impedance lines. The high-impedance line width and the low-impedance line width are both set to 50 ohms, and the physical length is λ / 8 of the lowest frequency wavelength in the operating frequency band. The inter-stage matching microstrip lines connecting the resonant branches are the same as the input and output matching lines. The initial setting is 50 ohms and the physical length is λ / 8 to facilitate subsequent simulation optimization.

[0059] Go to step S7.

[0060] S7: The initial values ​​of the first thin-film resistor 3, the second thin-film resistor 6, the third thin-film resistor 10, and the fourth thin-film resistor 13 are all set to 50 ohms, and the process proceeds to step S8.

[0061] S8: According to the equilibrium curve index, use computer optimization method to optimize the simulation, and optimize the block diagram as follows Figure 4 As shown, the details are as follows:

[0062] When using ADS schematic simulation design, the real three-dimensional electromagnetic situation is not taken into account, and the simulation results are often inaccurate. It is necessary to accurately simulate in professional three-dimensional electromagnetic simulation software. When the SIR step impedance resonance unit selected in this example is used to implement the ultra-wideband equalizer design, as the branches of the resonance unit increase, if the model parameters of the schematic simulation are unreasonable, the schematic model parameters will have large errors when simulated in HFSS; at the same time, the three-dimensional simulation will face the problem of too many optimization parameters, resulting in an increase in design time. This embodiment takes into account the coupling effect of parallel coupled microstrip lines between adjacent resonant units. The schematic diagram of the principle of the parallel coupled microstrip line is shown in the figure below. Figure 5 By controlling the distance between adjacent resonant units, the coupling coefficient K between resonant units is reduced, thereby reducing the electromagnetic impact of the microstrip line in three dimensions. Because the coupling effect of parallel coupled microstrip lines is taken into account, this embodiment uses modeling in the ADS schematic diagram and uses optimization controls to complete simulation optimization. After achieving the expected performance, the schematic simulation dimension parameters are directly modeled in HFSS software. The simulation performance is basically consistent with the schematic simulation, and only fine-tuning of the resistor value is required to meet the design requirements.

[0063] The coupling strength of parallel coupled microstrip lines is expressed by the coupling coefficient K:

[0064]

[0065] Where, ε r is the dielectric constant of the dielectric plate, Z e represents the even-mode characteristic impedance and Z of the coupled microstrip line o represents the odd-mode characteristic impedance of the coupled microstrip line.

[0066] Even-mode characteristic impedance Z e for:

[0067]

[0068] Singular mode characteristic impedance Z o for:

[0069]

[0070] In the formula, K(k i ) is the coefficient k i is the first kind of complete elliptic integral modulo, i=1,2,3,4; k i ′ represents the same as k i The corresponding complementary modulus.

[0071] and:

[0072]

[0073] The coupling coefficient K between coupled microstrip lines can be calculated according to equations (5) to (12).

[0074] According to the function of the ultra-wideband microstrip equalizer, the optimization target is set, and the optimization control in the ADS schematic diagram is used to optimize the simulation. When the equalization target is achieved, the microstrip line width W and distance S data of the adjacent second resonant unit 7 and the third resonant unit 9 are extracted and substituted into formulas (5)-(12) to calculate the coupling coefficient K between the coupled microstrip lines at the highest frequency in the working frequency band. According to actual experience, if K≤5, the simulation parameters can be used to import into HFSS for three-dimensional simulation.

[0075] Go to step S9.

[0076] S9: Import the ADS simulation model parameters that meet the equalization curve into HFSS, verify the equalization target, fine-tune the resistor size, and complete the ultra-wideband microstrip equalizer design.

[0077] This embodiment provides a rapid design method for an ultra-wideband microstrip equalizer. The designed ultra-wideband equalizer example operates in the range of 20-40 GHz with an equalization amount of 7 dB and has a size of 7.4 mm*5.8 mm. Figure 6 and Figure 7 The comparison of ADS schematic simulation and HFSS 3D simulation results under the same parameters shows that the difference between the two simulation results is small, which can effectively verify the scientific nature of this example method.

[0078] The present invention proposes a rapid design method for an ultra-wideband microstrip equalizer, which has rapid simulation design and avoids the problem of slow optimization time during multi-parameter simulation using three-dimensional simulation software, thereby effectively saving development time.

Claims

1. A fast design method for an ultra-wideband microstrip equalizer, characterized in that: Here are the steps: S1: Determine the resonant unit of the microstrip equalizer based on the size restrictions, frequency range, and functional requirements of the ultra-wideband microstrip equalizer in the radio frequency link, and proceed to step S2; S2: Determine the dielectric substrate and loading resistor of the microstrip equalizer based on the functional requirements of the ultra-wideband microstrip equalizer in the radio frequency link to meet the millimeter wave frequency band, and then proceed to step S3; S3: Design the circuit based on the functional requirements of the ultra-wideband microstrip equalizer in the RF link: The circuit of the ultra-wideband microstrip equalizer includes a main transmission line, a loading resistor, a SIR step impedance resonance unit, and a dielectric substrate; The main transmission line includes an input 50-ohm transmission line (1), an output 50-ohm transmission line (15), an input matching transmission line (2), an output matching transmission line (14), a first inter-stage matching transmission line (5), a second inter-stage matching transmission line (8), and a third inter-stage matching transmission line (11); wherein the input matching transmission line (2) and the output matching transmission line (14) are connected to the input 50-ohm transmission line (1) and the output 50-ohm transmission line (15) to perform input and output matching and ensure input and output standing wave indicators; The inter-stage matching lines, namely the first inter-stage matching transmission line (5), the second inter-stage matching transmission line (8), and the third inter-stage matching transmission line (11), isolate the resonance units to avoid coupling effects and are used to expand bandwidth; the first loading resistor (3) is connected to the first resonance unit (4), the second loading resistor (6) is connected to the second resonance unit (7), the third loading resistor (10) is connected to the third resonance unit (9), and the fourth loading resistor (13) is connected to the fourth resonance unit (12), and the process proceeds to step S4; S4: Determine the circuit form of the ultra-wideband microstrip equalizer based on the operating frequency range and the equalization amount, and proceed to step S5; S5: Calculate the initial sizes of the first resonant unit (4), the second resonant unit (7), the third resonant unit (9), and the fourth resonant unit (12), and proceed to step S6; S6: Calculate the initial sizes of the input matching transmission line (2), the output matching transmission line (14), the first inter-stage matching transmission line (5), the second inter-stage matching transmission line (8), and the third inter-stage matching transmission line (11), and proceed to step S7; S7: The initial values ​​of the first thin film resistor (3), the second thin film resistor (6), the third thin film resistor (10), and the fourth thin film resistor (13) are all set to 50 ohms, and the process proceeds to step S8; S8: Optimize the simulation using a computer optimization method based on the equilibrium curve index, and proceed to step S9; S9: Import the ADS simulation model parameters that meet the equalization curve into HFSS, verify the equalization target, fine-tune the resistor size, and complete the ultra-wideband microstrip equalizer design.

2. The rapid design method of an ultra-wideband microstrip equalizer according to claim 1, characterized in that: In S1, the resonant unit of the microstrip equalizer is determined based on the size restrictions, frequency range, and functional requirements of the ultra-wideband microstrip equalizer in the RF link. The details are as follows: The design is performed using a λ / 4 step impedance resonant unit. The input impedance of the transmission line of the resonant unit is Z in It is expressed as follows: In the above formula, j is the imaginary part, Z1 is the characteristic impedance of the low-resistance line, Z2 is the characteristic impedance of the high-resistance line, θ1 is the electrical length of the low-resistance line, and θ2 is the electrical length of the high-resistance line; When the series resonance occurs, the characteristic impedance Z i =0, then: Z1-Z2tanθ1tanθ2=0 (2) so: When the ratio R Z >1 and 0<θ1+θ2<π / 2, SIR achieves the minimum length; when the ratio R Z <1 and π / 2<θ1+θ2<π, SIR achieves maximum length, and at this time it satisfies 3. The rapid design method of an ultra-wideband microstrip equalizer according to claim 1, characterized in that: In S2, based on the functional requirements of the ultra-wideband microstrip equalizer in the RF link to meet the millimeter wave frequency band, the dielectric substrate and loading resistor of the microstrip equalizer are determined as follows: The dielectric substrate used is a ceramic filler reinforcement material, model Taconic TSM-DS3, with a dielectric constant of ε r The thickness of the dielectric plate is 0.254 mm, which can meet the working requirements of the millimeter wave band; The loading resistor of the microstrip equalizer is a thin film resistor, which adopts a planar buried resistor process. The thin film resistor is a resistor whose resistance value is controlled by controlling the surface length L and width W of the resistor after determining the surface PCB buried resistor resistivity.

4. The rapid design method of an ultra-wideband microstrip equalizer according to claim 1, characterized in that: In S3, the first loading resistor (3) and the fourth loading resistor (13), the second loading resistor (6) and the third loading resistor (10) are of equal size and resistance value; the first resonant unit (4) and the fourth resonant unit (12), the second resonant unit (7) and the third resonant unit (9) are of equal size; and the ultra-wideband equalizer is a symmetrical reciprocal structure, and the input and output can be used in reverse.

5. The rapid design method of an ultra-wideband microstrip equalizer according to claim 1, wherein: In S5, the initial sizes of the first resonant unit (4), the second resonant unit (7), the third resonant unit (9), and the fourth resonant unit (12) are calculated as follows: Considering the rationality of size, according to formula (1)-formula (3), select R Z =3 / 5, and let Z1 in SIR = 50, substitute into formula (3) and formula (4), and calculate Z2 to be 30 ohms. The electrical lengths θ1 and θ2 of the SIR high and low resistance lines are 1.03 radians, which is converted into an angle of 59 degrees. Calculate the width W1 and physical length l1 of the SIR branch low resistance line Z1 at the lowest frequency in the working frequency band, as well as the width W1 and physical length l1 of the SIR branch high resistance line Z2. The initial sizes of the multiple resonant units remain consistent.

6. The rapid design method of an ultra-wideband microstrip equalizer according to claim 1, characterized in that: In S6, the initial sizes of the input matching transmission line (2), the output matching transmission line (14), the first inter-stage matching transmission line (5), the second inter-stage matching transmission line (8), and the third inter-stage matching transmission line (11) are calculated as follows: The input and output matching of the microstrip equalizer also uses SIR stepped impedance lines. The high-impedance line width and the low-impedance line width are both set to 50 ohms, and the physical length is λ / 8 of the lowest frequency wavelength in the operating frequency band. The inter-stage matching microstrip lines connecting the resonant branches are the same as the input and output matching lines, and are initially set to 50 ohms with a physical length of λ / 8.

7. The rapid design method for an ultra-wideband microstrip equalizer according to claim 1, wherein: In S8, the simulation is optimized using a computer optimization method based on the equilibrium curve indicators, as follows: Considering the coupling effect of parallel coupled microstrip lines between adjacent resonant units, the distance between adjacent resonant units is controlled to reduce the coupling coefficient K between the resonant units, thereby reducing the electromagnetic influence of the microstrip line in three-dimensional space; The coupling strength of parallel coupled microstrip lines is expressed by the coupling coefficient K: Where, ε r is the dielectric constant of the dielectric plate, Z e Z represents the even-mode characteristic impedance of the coupled microstrip line. o It represents the odd-mode characteristic impedance of the coupled microstrip line; Even-mode characteristic impedance Z of coupled microstrip lines e for: The odd-mode characteristic impedance Z of coupled microstrip lines o for: In the formula, K(k i ) is the coefficient k i is the first kind of complete elliptic integral modulo, i=1,2,3,4; k i ′ represents the same as k i The corresponding complementary modulus; and: Calculate the coupling coefficient K between the coupled microstrip lines according to equations (5) to (12); According to the function of the ultra-wideband microstrip equalizer, the optimization target is set, and the optimization control in the ADS schematic diagram is used to optimize the simulation. When the equalization target is achieved, the microstrip line width W and distance S data of the adjacent second resonant unit (7) and the third resonant unit (9) are extracted and substituted into formulas (5)-(12) to calculate the coupling coefficient K between the coupled microstrip lines at the highest frequency in the working frequency band. According to actual experience, if K≤5, the simulation parameters can be used to import into HFSS for three-dimensional simulation.

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