WO2017091944A1

WO2017091944A1 - Microstrip switch type phase shifter and phase shift module adopting same

Info

Publication number: WO2017091944A1
Application number: PCT/CN2015/095983
Authority: WO
Inventors: 李志强; 黄健欧; 张海英
Original assignee: 中国科学院微电子研究所
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2017-06-08

Abstract

Provided are a microstrip switch type phase shifter and a phase shift module adopting same. The microstrip switch type phase shifter comprises: a reference branch circuit, a phase shift branch circuit, a first path selection switch and a second path selection switch, wherein the reference branch circuit comprises a first microstrip transmission line; the phase shift branch circuit comprises a second microstrip transmission line and a third microstrip transmission line which are connected in series, and a fourth microstrip transmission line connected between a node between the second and third microstrip transmission lines and a ground level; and a front end of the first path selection switch is connected to a signal input end, a rear end of the second path selection switch is connected to a signal output end, and the two are simultaneously connected to the reference branch circuit and the phase shift branch circuit under control. In the present invention, continuous microstrip lines and a simple topology structure are adopted, and parasitic parameters caused by discontinuity of microstrip lines are reduced. The present invention can be applied to a high-frequency scenario, and at the same time, upon simulation and experiment, it is proved that the phase shifter has a very flat phase shifting characteristic nearby a central frequency and the phase shift precision is high.

Description

Microstrip switch type phase shifter and phase shifting module using same

Technical field

The invention relates to the field of microwave technology, in particular to a microstrip switch type phase shifter and a phase shifting module using the same.

Background technique

With the popularity of a large number of smart terminals such as smartphones and tablets, the demand for high-speed mobile data services is increasing day by day. With the current growth rate of communication capacity demand, it is expected that the total mobile data volume will increase by a thousand times by 2020, which poses a serious challenge to the next generation mobile communication system. Compared with the increasingly depleted spectrum below 3 GHz, the millimeter-wave band has a very rich spectrum of resources to meet the needs of future high-speed broadband mobile communications. In addition, in the millimeter wave band, space division multiple access and beam combination can be combined with time division or frequency division multiple access technology to greatly improve system capacity and spectrum utilization, and can meet people's demand for high speed data services. Therefore, the biggest difference between the future 5G system and 4G is likely to be that the 5G will use the higher frequency millimeter wave band, and the beam-adjustable phased array antenna with good directionality is used at both the receiving and transmitting ends. The backbone network will use millimeter-wave wireless connectivity, which will enable 5G systems to have lower power consumption, lower call drop rates and higher bit rates. Due to its great potential, millimeter wave mobile communication has become a hot spot of current research and has very good prospects.

The phased array transceiver is a key component in the millimeter wave mobile communication system, and the phase shifter is an important circuit module in the phased array transceiver, and is also one of the design difficulties of the entire transceiver. Phase shifters for millimeter wave mobile communication systems have the following difficulties:

1. High frequency (near 30GHz or higher);

2. High phase shift accuracy;

3, low cost, phased array transceivers need a large number of phase shifters, if the price of the phase shifter will make the communication equipment expensive, and this is unacceptable for civilian mobile communications.

At present, the industry urgently needs to develop a phase shifter with high frequency, high phase shift accuracy and low cost to meet the needs of millimeter wave mobile communication.

Summary of the invention

(1) Technical problems to be solved

In view of the above technical problems, the present invention provides a microstrip switch type phase shifter and an application thereof Phase shifting module to meet the needs of millimeter wave mobile communication systems for phase shifters with high frequency, high phase shift accuracy and low cost.

(2) Technical plan

According to an aspect of the invention, a microstrip switch type phase shifter is provided. The microstrip switch type phase shifter comprises: a reference branch circuit, a phase shift branch circuit, a first path selection switch S1 and a second path selection switch S2, wherein: the reference branch circuit comprises: a first microstrip transmission line L1; a phase shift branch The circuit includes: a second microstrip transmission line L2 and a third microstrip transmission line L3 connected in series, and a fourth microstrip transmission line L4 connected between the node A and the ground level therebetween; the first path selection switch S1 The front end is connected to the signal input end, and the rear end of the second path selection switch S2 is connected to the signal output end, and both are controlled to be simultaneously connected to the reference branch circuit and the phase shift branch circuit.

According to another aspect of the invention, a phase shifting module is also provided. The phase shifting module comprises: a power splitter, which divides the signal into N channels; N phase shifter strings, the front end of each phase shifter string is connected to one output of the power splitter, and the end thereof is used as an output of the phase shifting module Where N ≥ 2; wherein each of the N phase shifter strings includes M microstrip switching type phase shifters as described above, M ≥ 1.

(3) Beneficial effects

It can be seen from the above technical solutions that the microstrip switch type phase shifter of the present invention and the phase shifting module using the same have the following beneficial effects:

(1) The use of continuous microstrip lines and simple topologies reduces the parasitic parameters introduced due to discontinuities in the microstrip lines, such as bending and width variations, enabling the microstrip switching phase shifter to be applied to high Frequency scene;

(2) It is proved by simulation and experiment that there is very flat phase shift characteristic near the center frequency, and the phase shift precision is high;

(3) The structure is simple, the manufacturing is easy, and the cost is low, which is very suitable for civil communication.

DRAWINGS

1 is a schematic structural view of a microstrip switch type phase shifter according to a first embodiment of the present invention;

2A-2D are schematic structural views of a phase shifting module according to a second embodiment of the present invention;

3 is a schematic structural view of a phase shifting module according to a third embodiment of the present invention.

detailed description

In the microstrip switch type phase shifter of the present invention, different signal paths can be selected through switches, so that The desired relative phase shift is obtained between the different outputs of the phase shifter.

The present invention will be further described in detail below with reference to the specific embodiments of the invention.

In a first exemplary embodiment of the present invention, a microstrip switching type phase shifter for millimeter wave mobile communication is provided. As shown in FIG. 1, the microstrip switch type phase shifter of this embodiment includes: a first path selection switch S1, a second path selection switch S2, a reference branch circuit, and a phase shift branch circuit. The first path selection switch S1 and the second path selection switch S2 cooperate to select one of the reference branch circuit and the phase shift branch circuit as the signal transmission path.

Referring to FIG. 1, the reference branch circuit includes a first microstrip transmission line L1. The phase shifting branch circuit includes: a second microstrip transmission line L2, a third microstrip transmission line L3, and a fourth microstrip transmission line L4, wherein the second microstrip transmission line L2 and the third microstrip transmission line L3 are connected in series, and the fourth microstrip transmission line L4 Connected between node A and ground level between the second microstrip transmission line and the third microstrip transmission line.

In the reference branch circuit, the characteristic impedance of the first microstrip transmission line L1 and the system characteristic impedance are the same as Z ₀ ; the electrical length is θ _r at the center frequency ω ₀ . Here, the characteristic impedance refers to the input or output impedance of other devices connected to the microstrip switching type phase shifter, and the center frequency ω ₀ is the operating frequency band given by the microstrip switching type phase shifter at the design stage. Center frequency.

In the phase shifting branch circuit, the characteristic impedances of the second microstrip transmission line L2 and the third microstrip transmission line L3 are both Z ₂ , and the characteristic impedance of the fourth microstrip transmission line L4 is Z ₁ . The second microstrip transmission line L2, the third microstrip transmission line L3, and the fourth microstrip transmission line L4 have an electrical length of 90° at the center frequency ω ₀ .

In this embodiment, the four microstrip transmission lines L1 to L4 are continuous transmission lines having a constant width extending in one direction, and the parasitic parameters introduced due to discontinuity of the microstrip line, such as bending, width variation, etc., are reduced. The microstrip switch type phase shifter of this embodiment can be applied to a high frequency scene.

Similarly, referring to FIG. 1, the front end of the first path selection switch S1 is connected to the signal input end (IN), and the rear end of the second path selection switch S2 is connected to the signal output end (OUT), after the first path selection switch S1. The front ends of the end and second path selection switches S2 are controlled to be simultaneously connected to the reference branch circuit and the phase shift branch circuit.

It can be seen from the above structure that the microstrip switch type phase shifter of the present embodiment has a simple structure, is easy to manufacture, and has low cost, and is therefore very suitable for civil communication.

The first path selection switch S1 and the second path selection switch S2 are single-pole double-throw switches, and the two work in cooperation for selecting a signal transmission path. The signal has different insertion phases through the reference branch circuit and the phase shift branch circuit, and the phase difference between the two is the relative phase shift. The insertion phase of the phase shifting branch circuit at the center frequency ω ₀ is fixed to -π, independent of Z ₁ and Z ₂ , thus changing the electrical length θ _r of the first microstrip transmission line L1 in the reference branch circuit at the center frequency ω ₀ Obtain the required relative phase shift. Also, changing the values of Z ₁ and Z ₂ can change the relative phase shift as a function of frequency. The calculation method of each parameter in the microstrip switch type phase shifter of this embodiment is as follows:

The insertion phase of the phase shift branch circuit can be calculated using the transfer matrix:

among them:

To normalize the frequency,

with

To normalize the characteristic impedance,

It can be seen from (1) that the phase of the phase shifting branch circuit is -π at the center frequency.

Assume

For the relative phase shift required at the center frequency ω ₀ , then refer to the electrical length of the first microstrip transmission line L1 in the branch circuit

Further referring to the insertion phase of the branch circuit is:

Relative phase shift can be obtained from (1) and (2)

Expression:

In order to get the smallest phase error near the center frequency,

The following system of equations should be met:

Where n=1, 2... and as large as possible.

with

It can be obtained by solving the equations (4). When n=1:

due to

Then there is

Another cause

Therefore, the restrictions can be simplified to:

When n=2, (4) is always true, so consider the case when n=3:

Lianli (5), (6) and (7) can solve

with

When n=4, (4) is also always true, that is, n in (4) can take up to 4, and thus is solved by the above method.

with

The relative phase shift can be made to have a zero derivative of the frequency up to the fourth order at the center frequency, that is, the relative phase shift is very flat near the center frequency, and the solution is the optimal solution for the embodiment, and the microstrip corresponding to the solution Switching phase shifters are ideal for high frequency applications.

So far, the microstrip switch type phase shifter of the first embodiment of the present invention has been completed.

In a second exemplary embodiment of the invention, a phase shifting module is proposed. As shown in FIGS. 2A to 2D, the phase shifting module includes a power splitter and two phase shifters, a first phase shifter PS1 and a second phase shifter PS2, which are given in the first embodiment. The relative phase shifts required by the two phase shifter units PS1 and PS2 at the center frequency ω ₀ are also φ ₁ .

When the phase shifting module is in operation, the signal is divided into two paths by the power splitter, and is input to the first phase shifter PS1 and the second phase shifter PS2, respectively. The following are the four working states of the phase shifting module:

State 1:

Referring to FIG. 2A, in the first phase shifter PS1, the first path selection switch S1 and the second path selection switch S2 are both connected to the reference branch circuit, that is, the reference branch circuit is selected as a signal transmission path, and the first path signal is output. In the second phase shifter PS2, the first path selection switch S1 and the second path selection switch S2 are both connected to the phase shift branch circuit, that is, the phase shift branch circuit is selected as the signal transmission path, and the second signal is output; The required phase difference between the one signal and the second signal

State 2:

Referring to FIG. 2B, in the first phase shifter PS1, a phase shifting branch circuit is selected as a signal transmission path, which outputs a first path signal; and in a second phase shifter PS2, a reference branch circuit is selected as a signal transmission path. Outputting a second signal; a desired phase difference is generated between the first signal and the second signal

As shown in Figure 2B.

State 3:

Referring to FIG. 2C, in the first phase shifter PS1, a phase shift branch circuit is selected as a signal transmission path, which outputs a first path signal; and in a second phase shifter PS2, a phase shift branch circuit is selected as a signal transmission path. It outputs a second signal; a desired phase difference of 0 is generated between the first signal and the second signal.

State 4:

Referring to FIG. 2D, in the first phase shifter PS1, a reference branch circuit is selected as a signal transmission path, which outputs a first path signal; in the second phase shifter PS2, a reference branch circuit is selected as a signal transmission path, and an output thereof is selected. The second signal; the required phase difference 0 is generated between the first signal and the second signal.

It should be noted that the characteristic impedance of the reference branch circuit in the first phase shifter and the second phase shifter is consistent with the characteristic impedance of the power splitter, that is, the system characteristic impedance. For details of the first phase shifter and the second phase shifter, reference may be made to the related description of the first embodiment, and the description thereof will not be repeated here.

So far, the phase shifting module of the second embodiment of the present invention has been introduced.

In a third exemplary embodiment of the invention, a phase shifting module is proposed. As shown in FIG. 3, the phase shifting module includes: a power splitter and four phase shifters given in the first embodiment - a first phase shifter PS1, a second phase shifter PS2, and a third phase shifter PS3. And a fourth phase shifter PS4. Wherein, the first phase shifter PS1 and the second phase shifter PS2 are identical, and their relative phase shifts at the center frequency ω ₀ are

The two form a first phase shifter string; the third phase shifter PS3 and the fourth phase shifter PS4 are identical, and their relative phase shifts at the center frequency ω ₀ are

Both form a second phase shifter string. The front end of the two phase shifter strings is connected to the two outputs of the power splitter, and the back end is respectively used as an output end of the phase shifting module.

In the phase shifting module, the signal is divided into two paths by a power splitter, and different phase paths are selected by the switches to realize multiple phase differences between the two outputs. The specific working modes are as follows:

The phase difference between the output 1 and the output 2 is the difference between the phase of the output 2 minus the phase of the output 1.

It should be noted that the characteristic impedance of the reference branch circuit in the four phase shifters is consistent with the characteristic impedance of the power divider, that is, the system characteristic impedance. For details of the phase shifters, reference may be made to the related description of the first embodiment, and the description thereof will not be repeated here.

In addition, the present embodiment is described by using a 2-way phase shifter string, and each phase shifter string has two phase shifters as an example. However, in other embodiments of the present invention, the phase-shifting module may also be an N-way. The phase shifter string, each phase shifter string includes M serial phase shifters, and the end of the phase shifter string serves as an output of the phase shifting module. For the convenience of design, the mth phase shifter in the N phase shifter strings is generally designed to be the same phase shifter, m=1, 2, . . . , M. Among them, N≥2, M≥1.

So far, the phase shifting module of the third embodiment of the present invention has been introduced.

Heretofore, the present embodiment has been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the microstrip switch type phase shifter of the present invention.

It should be noted that the implementations that are not shown or described in the drawings or the text of the specification are all known to those of ordinary skill in the art and are not described in detail. In addition, the above definitions of the various elements and methods are not limited to the specific structures, shapes or manners mentioned in the embodiments, and those skilled in the art can simply modify or replace them, for example:

(1) Regarding the grounding manner of the fourth microstrip line L4, it may be grounded with a metal via, grounded with a gold wire, or the like;

(2) regarding the first path selection switch S1 and the second path selection switch S2, which may be a PIN diode switch or a transistor switch;

(3) The microstrip switching type phase shifter can be used in radar and other industries in addition to the field of millimeter wave mobile communication.

In summary, the present invention provides a microstrip switching type phase shifter that selects different signal paths through a switch to obtain a desired relative phase shift between different outputs of the phase shifter. The microstrip switching phase shifter is based on a microstrip line, is easy to manufacture, low in cost and simple in structure, and minimizes parasitic parameters at high frequencies; in addition, its relative phase shift has a frequency up to the fourth order at the center frequency. 0 derivative, which indicates that the relative phase shift is very flat near the center frequency, so it is very suitable for high frequency applications, and has good application value.

The specific embodiments of the present invention have been described in detail, and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A microstrip switching type phase shifter, comprising: a reference branch circuit, a phase shift branch circuit, a first path selection switch (S1) and a second path selection switch (S2), wherein:

The reference branch circuit includes: a first microstrip transmission line (L1);

The phase shifting branch circuit includes: a second microstrip transmission line (L2) and a third microstrip transmission line (L3) connected in series, and a fourth microstrip transmission line connected between the node A and the ground level therebetween (L4);

The front end of the first path selection switch (S1) is connected to the signal input end, and the rear end of the second path selection switch (S2) is connected to the signal output end, and the two are controlled to be simultaneously connected to the reference branch circuit and the phase shift branch Circuit.
The microstrip switch type phase shifter according to claim 1, wherein the first path selection switch (S1) and the second path selection switch (S2) are single pole double throw switches, and the two work together to One of the reference branch circuit and the phase shift branch circuit is selected as the signal transmission path.
The microstrip switching type phase shifter according to claim 2, wherein said first path selection switch (S1) and said second path selection switch (S2) are PIN diode switches or transistor switches.
The microstrip switching type phase shifter according to claim 1, wherein said first microstrip transmission line (L1), second microstrip transmission line (L2), third microstrip transmission line (L3), and fourth The microstrip transmission line (L4) is a continuous transmission line having a constant width extending in one direction.
The microstrip switching type phase shifter according to claim 4, wherein said first microstrip transmission line (L1), second microstrip transmission line (L2), third microstrip transmission line (L3), and fourth The microstrip transmission line (L4) satisfies:

among them,
The relative phase shift required at the center frequency ω 0 ;

with
To normalize the characteristic impedance, Z 1 is the characteristic impedance of the fourth microstrip transmission line (L4), Z 2 is the characteristic impedance of the second microstrip transmission line (L2) and the third microstrip transmission line (L3), and Z 0 is the system Characteristic impedance

The characteristic impedance of the first microstrip transmission line (L1) is the same as the system characteristic impedance, and the second microstrip transmission line (L2), the third microstrip transmission line (L3), and the fourth microstrip transmission line (L4) are electrically charged at the center frequency ω 0 . The length is 90°.
The microstrip switch type phase shifter according to any one of claims 1 to 5, wherein the fourth microstrip transmission line (L4) is connected to the ground via a metal via or a gold wire. Ground level.
A phase shifting module, comprising:

a power splitter that splits the signal into N ways;

N phase shifter strings, the front end of each phase shifter string is connected to one output of the power splitter, and the end thereof is used as an output of the phase shifting module, wherein N≥2;

Wherein, each of the N phase shifter strings includes M microstrip switch type phase shifters according to any one of claims 1 to 6 in series, M≥1.
The phase shifting module according to claim 7, wherein the mth microstrip switching type phase shifter of each of the N phase shifter strings is the same microstrip switching type phase shifting The relative phase shift at the center frequency ω 0 is the same, m = 1, 2, ..., M.