CN201623242U - Microwave and millimeter wave multi-drop load line phase shifter - Google Patents

Abstract

The utility model belongs to the technical field of microwave and millimeter waves, and in particular relates to the manufacture of microwave and millimeter wave phase shifters. The phase shifter at least includes a multi-branch parallel microstrip transmission line structural unit, which is a microstrip transmission line engraved on a printed circuit board and connected with multiple stubs in parallel, which consists of a transmission main line, an input terminal, The output terminal, parallel transmission branch lines and grounding short-circuit nails are formed. Each transmission branch line is cut off at one-eighth wavelength from the main line, and a PIN switch for controlling the electromagnetic wave phase of the transmission line unit is installed at the cut-off point; the length of the transmission main line is 1/4 One wavelength, the width of which is 0.2-2mm, the length of the transmission branch line is three-eighths wavelength, the width is 0.2-1mm, the distance between adjacent transmission branches is 1/4 wavelength, and the two ends of the transmission main line are respectively the input end of the transmission line and the output. The phase shifter can be cascaded into a multi-bit microwave and millimeter wave digital phase shifter, which has the advantages of small loss, small size, simple structure, and easy manufacture, and has advantages in application in radar and phased array antennas.

Description

Microwave and millimeter wave multi-drop load line phase shifter

technical field

The utility model belongs to the technical field of microwave and millimeter waves, and in particular relates to the manufacture of microwave and millimeter wave phase shifters.

Background technique

Microwave and millimeter wave phase shifters have applications in various fields, such as radar systems, satellite communication systems and phased array antenna arrays. There are many types of phase shifters. According to the materials used, there are generally five categories: ferrite phase shifters, ferroelectric phase shifters, semiconductor diode phase shifters, gallium arsenide MMIC phase shifters and MEMS phase shifters. phase device.

In 1991, Artech house published "Microwave and Millimeter Wave Phase Shifters". The first volume of the book, Dielectric and Ferrite Phase Shifters, introduced the main types, design, production and application of ferrite phase shifters in detail. The ferrite phase shifter mainly uses an external magnetic field to change the magnetic permeability of the ferrite in the waveguide, thereby changing the phase velocity of the electromagnetic wave to obtain different phase shifts. Its advantages are: broadband and large power capacity; its disadvantages are: large volume, large loss, slow switching speed, and it is difficult to meet the requirements of mobile communication.

In 2000, Kozyre et al published the paper "Application of Ferroelectrics in Phase Shifters Design" at the IEEE International Conference on Microwave Theory and Technology ("Application of Ferroelectrics in Phase Shifters Design", A.Kozyrev, V.Osadchy, A.Pavlov , L. Sengupta, 2000IEEE MTT-S Digest.P1355-1358). The ferroelectric phase shifter mainly changes the dielectric coefficient of the medium by changing the magnitude of the DC bias applied to the ferroelectric medium, thereby changing the phase velocity of the microwave and millimeter wave signals to achieve the purpose of phase shifting. Its advantages are: simple structure, small size, light weight, small loss, and fast response; the disadvantage is: small power capacity

In 1976, Chapter 8 Microstrip Solid Control Circuits in the book "Microstrip Circuits" written by the Microstrip Circuit Writing Group of Tsinghua University introduced in detail the switch line phase shifter, loaded line phase shifter, and reflective phase shifter. The basic principles and design methods of several phase shifters based on semiconductor PIN diodes. No matter which structure is adopted, the principle of the PIN diode-based phase shifter is to use the two different switching states of the PIN diode when it is forward-biased and reverse-biased, so that a transmission line is turned on or off to achieve phase shifting. Its advantages: small size, easy to use digital signal control, fast response speed; disadvantages: large power consumption, relatively small power capacity.

In June 2009, Zhu Qi and others published the paper "Design of High Power Capacity Phase Shifter with CompositeRight Left-Handed Transmission Line" on IEEE AP-S This kind of phase shifter also uses PIN diodes as switches for phase shift control, but it is different from traditional PIN diode phase shifters. A part of the entire phase shifter current flows, so its power capacity can be greatly improved. Its advantages are: small size, small insertion loss, and large power capacity; the disadvantage is: it is difficult to achieve a large phase shift.

In May 2001, Ellinger et al. published the paper "Compact Reflective-TypePhase-Shifter MMIC for C-Band Using Lumped Element Coupler" on IEEE Transaction on MTT. a Lumped-Element Coupler" Frank Ellinger, Rolf Vogt, Werner Bechtold, IEEE Transaction on Microwave Theory and Techniques, VOL.49, NO.5, MAY 2001). The phase shifter based on gallium arsenide MMIC technology mainly adopts a reflective structure, and the reflection coefficient of different phases is obtained by selecting different reflection terminals, so as to realize the phase shift. Its advantages are: small size, mature manufacturing process, and fast response speed; the disadvantages are: large insertion loss and small power capacity.

In June 2002, Rebeiz et al published the paper "RF MEMS phase shifters: design and applications" on IEEE Microwave ("RF MEMS phase shifters: design and applications" Rebeiz G.M, Guan-Leng Tan, Hayden J.S, Microwave Magazine , IEEE Volume 3, Issue 2, June 2002 Page(s): 72-81). The MEMS phase shifter uses the MEMS radio frequency switch to change the size of the load capacitance connected in parallel between the central conduction band of the transmission line and the ground, so as to realize the change of the equivalent line capacitance of the entire structure, and then change the phase speed of the microwave signal passing through to realize the shift. Mutually. Its advantages are: small loss, large power capacity; disadvantages: slow switching speed, low reliability, and short service life.

The above literature shows that although ferrite phase shifters and MEMS phase shifters have large power capacity, their switching speed is slow; ferroelectric material phase shifters, semiconductor diode phase shifters, and gallium arsenide MMIC The speed is fast, but generally the power capacity is small; while the hybrid left-handed transmission line phase shifter is small in size, fast in switching speed, and large in power capacity, but it is difficult to achieve a large phase shift.

Contents of the invention

The technical purpose of this utility model is to provide a compact planar microwave and millimeter wave phase shifter with a microstrip transmission line structure, so as to overcome the existing microwave and millimeter wave phase shifters such as large volume and large loss, and realize large The phase shift amount is difficult and other disadvantages.

The technical solution of the utility model is as follows:

The microwave and millimeter wave multi-branch load line phase shifter of the present utility model comprises at least one multi-branch parallel microstrip transmission line structural unit, which is characterized in that each multi-branch parallel microstrip transmission line structural unit is engraved A microstrip transmission line with multiple stubs connected in parallel on a printed circuit board (PCB). It is cut off at one-eighth wavelength from the main line, and a PIN switch is installed at the cut-off place to control the electromagnetic wave phase of the transmission line unit; among them, the length of the main transmission line is one-quarter wavelength, the width of the main line is 0.2-2mm, and the length of the branch line is eight Three-thirds wavelength, the width is 0.2 ~ 1mm, the distance between adjacent transmission branch lines is one-quarter wavelength, the two ends of the transmission main line are the input end and the output end of the transmission line respectively, and the impedance of the input and output ends is 50 ohms. The grounding short-circuit nail is realized by using the existing via technology to connect a short-circuit piece to the ground of the third layer of the PCB, and the short-circuit piece is located on the left or right side of the transmission main line. The upper and lower layers of the PCB are conductor copper with a thickness of 0.004 mm, and the middle layer is a dielectric substrate with a dielectric constant of 1.07-13.6.

In the above-mentioned multi-branch load line phase shifter, the parallel transmission branch lines can be four straight or U-shaped stub lines, which are located on both sides of the transmission main line and distributed symmetrically, with two on each side to form four stub lines Load line phase shifter; the parallel transmission branch line can also be two straight or U-shaped stub lines, which are located on the same side of the transmission main line to form a double-branch load line phase shifter; it can also be used according to different It is required to cascade two or more multi-branch microstrip transmission line structural units in parallel to become a multi-bit microwave and millimeter wave digital phase shifter.

其中

为所要求的移相器的移相量，Z₀为输入输出端阻抗。支线的特性阻抗由支线结构决定，对于四支节负载线移相器，可令位于主线同侧的其中一对支节的特性阻抗等于输入端的特性阻抗，另一对支节的特性阻抗Z₀₂可由式

得到；对于双支节负载线移相器，两个支节的特性阻抗均等于输入端的特性阻抗。微带线宽度W可以利用以下计算公式得到：In actual use, it is usually first to determine the working frequency band and center frequency according to the needs of the use, and then, according to the characteristic impedance, use the relevant formulas in the prior art (see "Microwave Engineering", David M. Pozar, Publishing House of Electronics Industry, 2006) to calculate the width of the input terminal, output terminal, main line and branch line. The characteristic impedance Z ₀₁ of the main line is obtained by the following formula:

in

It is the phase shift amount of the required phase shifter, and Z ₀ is the impedance of the input and output terminals. The characteristic impedance of the branch line is determined by the structure of the branch line. For the four-branch load line phase shifter, the characteristic impedance of one pair of branch nodes located on the same side of the main line can be equal to the characteristic impedance of the input end, and the characteristic impedance of the other pair of branch nodes is Z ₀₂ by formula

Obtained; for the double branch load line phase shifter, the characteristic impedance of the two branches is equal to the characteristic impedance of the input terminal. The width W of the microstrip line can be obtained using the following formula:

$W=\left\{\begin{array}{cc}\frac{8{\mathrm{de}}^A}{e^{2A}-2},& W/d<2\\ \frac{2d}{\mathrm{\&pi;}}[B-1-\ln (2B-1)+\frac{{\mathrm{\&epsiv;}}_r-1}{2{\mathrm{\&epsiv;}}_r}\{\ln (B-1)+0.39-\frac{0.61}{{\mathrm{\&epsiv;}}_r}\left\}\right],& W/d>2\end{array}\right.,$ in, $A=\frac{Z}{60}\sqrt{\frac{{\mathrm{\&epsiv;}}_r+1}{2}}+\frac{{\mathrm{\&epsiv;}}_r-1}{{\mathrm{\&epsiv;}}_r+1}(0.23+\frac{0.11}{{\mathrm{\&epsiv;}}_r}),$ $B=\frac{377\mathrm{\&pi;}}{2Z\sqrt{{\mathrm{\&epsiv;}}_r}},$ d is the thickness of the dielectric substrate, ε _r is the dielectric constant of the dielectric substrate, e=2.718281828 is the natural logarithm, and Z is the characteristic impedance of the transmission line to be obtained. Since there are two situations of W/d, one of them must be selected first when calculating In this case, a hypothetical calculation should be carried out. After the calculation, it should be verified according to the conditions. If there is a contradiction, another formula should be used for calculation.

The microwave and millimeter wave multi-branch load line phase shifter in the utility model is formed by connecting a plurality of stub lines in parallel on the transmission line unit. According to the transmission line theory, the voltage and current on the transmission line are composed of incident waves and reflected waves. The smaller the reflected wave intensity is, the smaller the standing wave ratio of the transmission line is, and the smaller the energy loss of the transmission line is. In the utility model, the distance between the adjacent transmission branch lines on the same side of the main line on the phase shifter is a quarter wavelength, and the wave path difference of the electromagnetic wave reflected back through the adjacent transmission branch lines is half a wavelength, so that the reflected wave The phase shifter is weakened after being superimposed, so the loss of the phase shifter is small. At the same time, the phase shifter also has many other advantages, such as small size, flexible structure, easy to manufacture, and can be designed according to different frequency bands and phase shift requirements, which can effectively overcome the large volume and large loss of traditional phase shifters, and realize large The disadvantage that the phase shift is relatively difficult has great advantages in the application of radar and phased array antennas.

Further description will be made below through embodiments and accompanying drawings.

Description of drawings

FIG. 1 is a structural schematic diagram of an embodiment of the four-branch load line phase shifter of the present invention.

Fig. 2 is a view along the direction A of Fig. 1 .

Fig. 3 is a graph of the phase shift degrees of the four-branch load line phase shifter in Embodiment 1 of the present utility model. Wherein, the abscissa represents the frequency, and the ordinate represents the degree of phase shift. The coordinate names in Figure 8 below are the same.

Fig. 4 is a schematic diagram of the voltage standing wave ratio when the upper pair of switches of the four-branch load line phase shifter in embodiment 1 of the present invention are turned off and the lower pair of switches are closed, wherein the abscissa represents the frequency, and the ordinate represents the voltage standing wave ratio. Bobbi. The coordinate names in Figure 5, Figure 9, and Figure 10 below are the same.

Fig. 5 is a graph of voltage standing wave ratio when the lower pair of switches of the four-branch load line phase shifter in Embodiment 1 of the present utility model are turned off and the upper pair of switches are turned on.

Fig. 6 is a structural schematic diagram of another embodiment of the double-branch load line phase shifter described in the present invention

FIG. 7 is a view taken along direction B of FIG. 6 .

Fig. 8 is a schematic diagram of the phase shift degree of the double-branch load line phase shifter in Embodiment 3 of the present invention.

Fig. 9 is a schematic diagram of the voltage standing wave ratio when the switch of the phase shifter of the double-branch load line in Embodiment 3 of the present invention is turned off.

Fig. 10 is a schematic diagram of the voltage standing wave ratio when the switch of the dual-branch load line phase shifter in Embodiment 3 of the present invention is closed.

Detailed ways

Example 1

Referring to Figures 1 and 2, the multi-branch parallel microstrip transmission line structural unit is set on a square PCB board 1. The PCB board is composed of upper and lower layers of metal copper and a dielectric substrate in the middle. The upper layer of metal copper is used to form a transmission line. line, the underlying metal forms the ground for the transmission line. The transmission main line 7 is linear and located in the middle of the square PCB board 1. The four transmission branch lines 2 are also linear and connected in parallel on both sides of the transmission main line; connected. Input and output ports 4 and 5 are respectively provided at both ends of the transmission main line 7; a PIN switch 6 for controlling the phase shifter is respectively provided on the four parallel transmission branch lines. In this embodiment, the thickness of copper on the PCB board and the lower conductor is 0.004 mm, the thickness of the intermediate dielectric substrate (Rogers RT/duroid 6006) is 0.254 mm, and the dielectric constant is 6.15. The main transmission line has a length of 3.1mm and a width of 0.29mm. The length of the pair of transmission branches on the left is 5.28mm, the width is 0.18mm, and the distance between the two lines is 3.1mm; the length of the pair of transmission branches on the right is 5.13mm, the width is 0.28mm, and the distance between the two lines is 2.9mm. Install two pairs of PIN switches at the symmetrical positions of the two pairs of transmission branch lines. The distances between them and the main line are 1.71mm (left side) and 1.73mm (right side) respectively. The size of the switches is 0.35mm×0.35mm×0.13mm. The input and output line width is 0.28mm. There is a short circuit piece with a size of 0.5mm×0.5mm on the left side of the main line. The distance between the center of the short circuit piece and the side of the transmission main line is 0.35mm, and the distance between the two transmission branch lines on the same side is equal. The short circuit piece passes through One short-circuit nail (solid cylindrical metal copper, radius 0.1mm, height 0.254mm) is connected to the ground wire of the lower layer, the short-circuit nail passes through the dielectric layer vertically, and the projection of the short-circuit nail on the upper metal surface is a circle, and the outermost part of the circle is connected to the The distance between the borders of the shorts is 0.15 mm.

The four-node load line phase shifter of this embodiment is simulated and tested with ie3d software, and the results are shown in Fig. 3, Fig. 4 and Fig. 5. It can be seen from the figure that the VSWR of the phase shifter is less than 1.3 when the switch is opened and closed. The electrical properties that can be realized in this embodiment are: a center frequency of 10.8 GHz, a working bandwidth of 1 GHz, and a phase shift of 22.5° when the states of the two pairs of switches change simultaneously.

Example 2

The characteristics of the PCB used in Embodiment 2 are the same as those in Embodiment 1, and the structural unit of the microstrip transmission line with multiple branches connected in parallel is also the same as in Embodiment 1. The specific dimensions of this embodiment are as follows: the length of the transmission main line is 2.5mm, and the width is 0.32mm. Two identical transmission branch lines are connected in parallel on the left and right sides of the transmission main line. The length of the left pair of transmission branch lines is 5.26mm, the width is 0.41mm, and the spacing is 2.3mm; the length of the right pair of transmission branch lines is 5.58mm, and the width is 0.19mm, and the spacing is 2.5mm. Two pairs of PIN switches are installed on the symmetrical positions of the two pairs of transmission branch lines, and the distances between them and the main line are 1.64mm (left side) and 1.73mm (right side) respectively, and the switches used are the same as those in Embodiment 1. The input and output ports are respectively located at both ends of the main line, and the line width is 0.28mm.

The four-branch load line phase shifter of this embodiment is simulated and tested with ie3d software, and the results show that the VSWR of the phase shifter is less than 1.38 when the switch is opened and closed. The electrical properties that can be realized in this embodiment are: a center frequency of 10.8 GHz, a working bandwidth of 1 GHz, and a phase shift of 45° when the states of the two pairs of switches change simultaneously.

Example 3

Referring to FIG. 6 and FIG. 7 , the characteristics of the PCB used in Embodiment 3 are the same as those in Embodiment 1. The multi-branched parallel microstrip transmission line structure unit is different from that in Embodiment 1. Two identical U-shaped transmission branch lines 2 are connected in parallel on the same side of the transmission main line 7, and the rest of the structure is the same as that of Embodiment 1. The specific dimensions of this embodiment are: the length of the main transmission line is 7.1 mm, and the width is 0.5 mm; the length of the transmission branch line is 15.3 mm, the width is 0.28 mm, and the distance between them is 7.1 mm. A pair of PIN switches are respectively installed at the symmetrical positions of the transmission branch lines, which are 5.5 mm away from the main line, and the switches used are the same as those in the first embodiment. The structure and arrangement of the grounding short-circuit nail are also the same as those in Embodiment 1. The input and output ports are respectively located at both ends of the main line, and the line width is 0.28mm.

Use ie3d software to simulate and test the dual-node load line phase shifter of this embodiment, and the results are shown in Fig. 8, Fig. 9 and Fig. 10 . It can be seen from the figure that the VSWR of the phase shifter is less than 1.5 when the switch is opened and closed. The electrical properties that can be realized in this embodiment are: a center frequency of 4 GHz, a working bandwidth of 0.4 GHz, and a phase shift of 90° when the two switch states change simultaneously.

Claims (5)

1. A microwave millimeter wave multi-node load line phase shifter at least comprises a multi-node parallel microstrip transmission line structure unit, and is characterized in that each multi-node parallel microstrip transmission line structure unit is a microstrip transmission line which is engraved on a printed circuit board and is connected with a plurality of stub lines in parallel, the microstrip transmission line is composed of a transmission main line, an input end, an output end, parallel transmission branch lines and a grounding short-circuit nail, each transmission branch line is cut off at a wavelength which is one eighth of the main line, and a PIN switch for controlling the electromagnetic wave phase of the transmission line unit is installed at the cut-off position; the length of the transmission main line is one quarter wavelength, the width of the transmission main line is 0.2-2 mm, the length of the transmission branch line is three-eighths wavelength, the width of the transmission branch line is 0.2-1 mm, the distance between adjacent transmission branch lines is one quarter wavelength, the two ends of the transmission main line are respectively an input end and an output end of the transmission line, and the impedance of the input end and the impedance of the output end are both 50 ohms.

2. The microwave and millimeter wave multi-stub load line phase shifter of claim 1, wherein the upper and lower layers of said printed circuit board are of conductive copper of 0.004mm thickness and the middle is a dielectric plate of 1.07-13.6 dielectric constant.

3. The microwave and millimeter wave multi-stub load line phase shifter of claim 1, wherein the parallel transmission branches are four straight or U-shaped stubs located on both sides of the transmission main line, symmetrically distributed, two on each side, to form a four-stub load line phase shifter.

4. The microwave and millimeter wave multi-stub load line phase shifter of claim 1, wherein the parallel transmission branch lines are two straight or U-shaped stub lines, which are located on the same side of the transmission main line, to form a dual-stub load line phase shifter.

5. The microwave millimeter wave multi-stub load line phase shifter according to claim 1, wherein the two or more multi-stub parallel microwave millimeter wave microstrip transmission line structure units are cascaded to form a multi-bit microwave millimeter wave digital phase shifter.

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