CN110752426A

CN110752426A - Substrate integrated waveguide equalizer

Info

Publication number: CN110752426A
Application number: CN201910977726.3A
Authority: CN
Inventors: 彭浩; 吴源浩; 赵发举; 刘宇; 周翼鸿; 杨涛
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2020-02-04
Anticipated expiration: 2039-10-15
Also published as: CN110752426B

Abstract

The invention relates to a microwave circuit technology, in particular to a substrate integrated waveguide equalizer. The invention separates 2 grooves penetrating through the metal layer at equal distance along the electromagnetic wave transmission direction in the SIW body, and introduces energy consumption elements, namely resistance films, into the grooves, thereby increasing the loss on the transmission channel. When electromagnetic wave is in SIW body with TE_1.0When the mode is transmitted, the surface resistance film is placed to transmit TE_1.0The mode simultaneously attenuates the signal to a certain degree, and the attenuation is closely related to the working frequency. The SIW body sidewall portion sheet resistance can be divided into two parts: region one and region two and region three. In the area one: the insertion loss difference between the high and low frequency points increases with increasing k. In region two and region three: the insertion loss difference between the high and low frequency points becomes smaller as k increases. The SIW equalizer structure of the invention can be used in microwave and millimeter wave circuits and systems to perform different attenuations on signals with different frequencies.

Description

Substrate integrated waveguide equalizer

Technical Field

The invention relates to a microwave technology, in particular to a Substrate Integrated Waveguide (SIW) equalizer.

Background

Substrate Integrated Waveguide (SIW) has been widely used in microwave and millimeter wave circuits as a new transmission line structure, and has the advantages of low loss, good microwave performance, easy integration, etc.

Equalizers are an important component of radio frequency, microwave and millimeter wave circuits and systems. For most active and passive devices or circuits, the trend of gain drop or the trend of insertion loss increase is objective as the frequency increases. Existing equalizer theory is mainly based on resonant circuits, which means that the equalizer design method and process is similar to filter design. In this patent, a new type of SIW based equalizer will be proposed.

To our knowledge, there are two main types of existing equalizers: passive/active equalizers for high-speed digital signal transmission and passive equalizers for the microwave and millimeter wave frequency bands.

For equalizers used for high speed digital signal transmission, all start frequency points are dc, and a higher insertion loss or lower gain will be obtained at the lower end of the frequency. The main reports are as follows:

researchers Yujeong Shim et al used a defected ground stub structure to make a broadband passive equalizer for high-speed data transmission, which used a 60 cm transmission line on a printed circuit board and the transmission data rate reached 8 Gbps. See documents y.shim, w.lee, e.song, j.cho, and j.kim, "a compact and with-tape developer design using a stub with a fed ground structure for a highmeasured data transmission," IEEE Microwave Wireless Components Letters, vol.20, No.5, pp.256-258, may 2010.2010.

Researchers s.m.wu et al have made a broadband passive equalizer that is also applicable to high-speed data transmission using open stubs, and have compensated the frequency-dependent channel loss of long transmission paths by combining a section of open stub with a conventional RL (resistive-inductive) type passive equalizer, making the frequency response of the channel flatter and the bandwidth wider. See documents s.m.wu, s.h.huang, h.y.wang, c.t.chiu, c.p.hung, c.w.kuo and c.c.wang, "Enhanced passive equivalent using open-stub structure," Electronics Letters, vol.49, No.24, pp.1528-1529, nov.2013.

The theoretical analysis and design flow of the existing passive equalizer for microwave frequency band is very similar to the filter design in the resonant circuit. The main reports are as follows:

researchers Peihan Zhou et al have proposed a new equalizer concept by replacing the chip resistor with a thin film resistor. By varying the electrical length of the main transmission line within a certain range, return loss is significantly improved with small variations in transmission parameters. See documents p.h.zhou, x.q.xie, j.xie, j.li, "new research of branched Microwave gain equalizer", 2012International work kshop on Microwave and millimeter Wave Circuits and System Technology, Chengdu, China, apr.2012, pp.1-4.

Wang et al have proposed a wideband microwave gain equalizer for microstrip circuits that uses open-circuited Stepped Impedance Resonators (SIRs) to add tuning parameters, making the equalization curve simpler and making matching easier with a simple topology of the gain equalizer. See documents H.Wang, B.Yan, Z.Wang, and R.xu, "A broadband and microwave gain equalizer", Progress in electromagnetic Research Letters, vol.33, pp.63-72,2012.

The design theory and design flow of the microwave frequency band equalizer reported in the above reference are similar to the design of the filter, and the working frequency and bandwidth need to be improved. SIW-based equalizers are not commonly reported, and SIW equalizers used in the millimeter wave band have not been reported. The invention provides a millimeter wave equalizer based on SIW.

Disclosure of Invention

To address the above-mentioned problems or deficiencies, the present invention provides a Substrate Integrated Waveguide (SIW) equalizer for compensating for amplitude mismatch between devices and circuits operating in the millimeter wave band.

The substrate integrated waveguide equalizer is realized on a ceramic substrate and comprises an SIW body and a surface resistance film, wherein the SIW body is connected with a 50 omega microstrip line through a gradient line.

The width and side length of the SIW body is W_s(i.e., the distance between two rows of metallized vias) and a long side length of L_sThe length of the connecting edge of the gradual change line and the wide edge of the SIW body is W_tAnd two sides of the connecting edge are respectively introduced with a matching metalized through hole, 2 matching metalized through holes on the same side and the center line of the wide edge of the SIW body form axial symmetry, one end of the connecting edge is provided with 2 matching metalized through holes, and the two ends of the connecting edge are 4 in total.

The SIW body is provided with 2 grooves penetrating through a metal layer on the surface of the SIW body and used for placing surface resistance films, the surface resistance films are adaptive to the sizes of the grooves, and the 2 grooves form mirror images about the central line of the wide side of the SIW body.

The grooves are formed by a rectangle in the middle and isosceles triangles with the rectangular wide side as the bottom at two ends, the vertex connecting line of the two isosceles triangles is parallel to the central line of the wide side of the SIW body, the 2 grooves form mirror images relative to the central line of the wide side of the SIW body, and the physical centers of the two grooves, namely the centers of the rectangles, are positioned on the central line of the long side of the SIW body. The length of the long side (the side parallel to the propagation direction of the electromagnetic wave) of the rectangle is L_srThe length of the wide side of the rectangle is W_sr(W_sr<W_s/2), the heights of both triangles are L_srt(L_sr+2*L_srt<L_s) The connection lines of the vertexes of the isosceles triangles in the two grooves are separated by del (del)<W_s) The surface resistances in the respective grooves are set to be uniform and are set to be 50 Ω/square resistance.

L_tIn order to change the line length, dvp is the diameter of the metalized through hole, svp is the center hole distance of the adjacent metalized through holes in the same row, and W_sIs the distance of two rows of metallized through holes, L_xThe distance of the center of the metalized through hole for matching corresponds to the distance of the wide side of the SIW body.

The working principle of the equalizer in the invention is as follows: electromagnetic waves in the SIW body with TE_1.0The modes are propagated, and the front side and the back side in the transmission structure are covered by the metal layer to restrain the propagation boundary of the electromagnetic wave. In the conventional SIW structure, the first substrate,the loss is mostly from the dielectric loss of the dielectric substrate itself. To increase the losses in the propagation path, we introduce the energy consuming element, the resistive film. When electromagnetic wave is in SIW body with TE_1.0When the mode is transmitted, the surface resistance film is placed in the two slot lines, so that TE can be transmitted_1.0The mode simultaneously attenuates the signal to a certain degree, and the attenuation is closely related to the working frequency.

In summary, the present invention provides a new SIW equalizer structure, which can be used in microwave and millimeter wave circuits and systems to perform different attenuations on signals with different frequencies.

Drawings

Fig. 1 is a top view of an example equalizer structure of the present invention.

Fig. 2 is a block resistance region of an example equalizer of the present invention.

Fig. 3 is a resistive area division of the sidewalls of RW in accordance with an example embodiment of the present invention.

FIG. 4 is a graph of simulated normalized attenuation values for the differences between k and k + Δ k according to an embodiment of the present invention.

FIG. 5 is a 3dB simulation of the S-parameter curve of an example of the present invention.

FIG. 6 is a 6dB simulation of the S-parameter curve of an example of the present invention.

FIG. 7 is a 10dB simulation of the S-parameter curve of an example of the present invention.

Reference numerals: the SIW equalizer comprises a SIW equalizer body-1, a slot line-2, a metalized through hole-3, a gradient line-4, a matching metalized through hole-5 and a microstrip line-6.

Detailed Description

The invention is described in further detail below with reference to the figures and examples.

Since the EM field distribution characteristics in SIW and Rectangular Waveguide (RW) are similar, the equalizer in RW was first analyzed for simplicity. The distribution of the surface resistance of the side wall part of the equalizer body is shown in fig. 3 and can be divided into two parts: region one and region two and region three.

The amplitude of the electric field is represented as propagating as a wave in the + z direction, with an attenuation constant of α in RW

E＝E₀e^-αz(1)

The transmission power can be expressed as

P＝P₀e^-2αz(2)

Power loss per unit length of

Wherein R is_s，R_s'，Js，

And

the surface resistance of the metal in RW, the surface resistance in the lossy material, the surface current density, the normal unit vector to the ideal conductor and surface resistance, and the magnetic field strength in RW are shown, respectively. To simplify the analysis, the surface resistance of the metal wall may be approximately equal to 0 Ω compared to the surface resistance of the lossy material.

Then, the user can use the device to perform the operation,

η,Z_TE,f_cis the inherent impedance of the SIW, the wave impedance of the transverse electric wave and the magnetic field, and the cut-off thereofFrequency.

Substituting formula (7) and formula (8) into formula (6)

Therefore, the damping constant α is given by

Let c be k · a (0 ≦ k ≦ 1), from equation (12), the attenuation constant α may be rewritten as

Let F equal to F_cF (0.5 < F < 0.85), and

from equation (13), the damping constant α can be simplified to

The simulation result of the different normalized attenuation values from k to k + Δ k is shown in fig. 4, and the surface resistance of the sidewall of the SIW body can be divided into two parts: region one and region two and region three. In the area one: the insertion loss difference between the high and low frequency points increases with increasing k. In region two and region three: the insertion loss difference between the high and low frequency points becomes smaller as k increases. Starting from the RW attenuation characteristic, the scaling factor k is selected to be about 0.8 and the surface resistance is placed in the second and third regions in order to achieve the maximum slope.

According to the SIW equalizer based on surface resistance type mentioned above, operating in Ka band, it is realized on ceramic substrate, its relative dielectric constant is 9.9, substrate thickness h is 0.254mm, and gold thickness is 7 μm. L is_yThe distance between the circle center of the metallized through hole for matching and the straight line where the circle center of the through hole of the corresponding side metallized through hole row is located.

After simulation and optimization are performed by electromagnetic simulation software Ansoft HFSS, the optimal parameter size is obtained, which is specifically shown in table 1:

TABLE 1

The simulation results of the equalization values of 3dB, 6dB and 10dB are shown in fig. 5, 6 and 7, respectively, and the specific analysis results are shown in table 2.

TABLE 2

Frequency range	Equalization value	Test results of S21	Error of the measurement
				26GHz-40GHz (Ka band)	3dB	2.8dB	0.2dB
26GHz-40GHz (Ka band)	6dB	5.6dB	0.4dB
				26GHz-40GHz (Ka band)	10dB	9dB	1dB

The test and simulation results are shown in fig. 5, 6 and 7, and the test results and the simulation results are better matched. The measured value is better than 18.8dB in the range of 23.9-40GHz, and the whole Ka wave band is covered. The equalization values of the SIW equalizer, which are defined as different values of transmission loss | S21| at the frequency points of 26Ghz and 40Ghz, are actually 2.8dB, 5.6dB and 9dB, respectively, and the equalization errors are 0.2dB, 0.4dB and 1dB, respectively, compared with the simulation results of 3dB, 6dB and 10 dB. Simulation results show that the SIW equalizer can perform different attenuations on signals with different frequencies, and the attenuation is smaller when the frequency is higher. The method can be used in microwave and millimeter wave circuits and systems to equalize the amplitude of signals.

Claims

1. A substrate integrated waveguide equalizer, characterized by: the SIW substrate is realized on a ceramic substrate and comprises an SIW body and a surface resistance film, wherein the SIW body is connected with a 50 omega microstrip line through a gradient line;

the width of the SIW body, i.e., the distance between two rows of metallized vias, is W_sLong side length of L_sThe length of the connecting edge of the gradual change line and the wide edge of the SIW body is W_tThe two ends of the connecting edge are respectively introduced with a metalized through hole for matching, 2 metalized through holes for matching on the same side are in axial symmetry with the center line of the wide edge of the SIW body, one end of the SIW body is provided with 2 metalized through holes for matching, and the two ends are 4 in total;

The groove is composed of a rectangle in the middle and isosceles triangles with the wide sides of the rectangle as the bottom at the two ends, and the two isosceles trianglesThe connecting line of the vertexes of the isosceles triangles is parallel to the central line of the wide side of the SIW body, and the physical centers of the two grooves, namely the centers of the rectangles, are positioned on the central line of the long side of the SIW body; the length of the long side of the rectangle is L_srThe length of the wide side of the rectangle is W_srThe heights of the two triangles are L_srtThe connecting lines of the vertexes of the isosceles triangles in the two grooves are separated by del, del<W_s，L_sr+2*L_srt<L_s，W_sr<W_sAnd/2, the surface resistance films in the grooves are uniformly arranged.

2. The substrate integrated waveguide equalizer of claim 1, wherein: the surface resistance film is 50 omega/square resistance.