180-degree phase shifter and digital control phase shift link

Abstract

The invention relates to a 180-degree phase shifter and a digital control phase shift link, the 180-degree phase shifter adopts a differential circuit structure, and the differential circuit structure comprises a first branch and a second branch; the first branch is divided into a first sub-branch and a second sub-branch, the second branch is divided into a third sub-branch and a fourth sub-branch, the first sub-branch is provided with a first amplifier, the second sub-branch is provided with a second amplifier, the third sub-branch is provided with a third amplifier, and the fourth sub-branch is provided with a fourth amplifier. A fourth amplifier is arranged on the fourth sub-branch; the output end of the first amplifier and the output end of the third amplifier are connected to serve as the output of the first branch, and the output end of the second amplifier and the output end of the fourth amplifier are connected to serve as the output of the second branch; and the first amplifier, the second amplifier, the third amplifier and the fourth amplifier have the same structure.

Description

Technical Field

[0001] The invention relates to the technical field of electronic circuit design, in particular to a 180° phase shifter and a digital controlled phase shift link. Background Art

[0002] As a new generation of wireless communication technology, phased array technology is widely used in satellite communications, navigation, radar, security and other fields because it can greatly improve the system's communication capacity, data transmission rate, anti-interference ability and transmission distance of wireless signals.

[0003] Phased array technology is often used in phased array antenna systems. Each antenna unit in the system transmits microwave signals of the same frequency. By adjusting the phase and amplitude of the microwave signals transmitted on different antennas, the signal can obtain a higher gain in the target beam direction and accurately point to the target. In order to achieve the above beamforming function, phase shifters are indispensable, and their performance directly affects the beam scanning quality of the phased array antenna system. Therefore, the research on high-performance and miniaturized phase shifters is of great significance that cannot be ignored.

[0004] Digitally controlled phase shifters are generally composed of multiple standard phase shift units such as 5.625°, 11.25°, 22.5°, 45°, 90° and 180° connected in series to achieve a phase shift range of 0°-360°. In the design of broadband phase shifters, it is necessary to ensure that the in-band phase shift of each standard phase shift unit is sufficiently flat and the additional attenuation is as small as possible, so that the overall performance of the cascaded phase shifter can reach the best. However, with the increase in the phase shift amount of the standard phase shift unit, the difficulty of implementing the standard phase shift unit gradually increases, especially the 180° standard phase shift unit. The 180° phase shift unit currently uses a switching high- and low-pass network design. Due to the extreme values ​​of the inductance and capacitance used in the high- and low-pass network, the 180° phase shift unit has a relatively large insertion loss and poor phase shift accuracy, which affects the overall performance of the phase shifter. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a 180° phase shifter and a digitally controlled phase shift link, which can improve the phase shift accuracy.

[0006] The technical solution adopted by the present invention to solve its technical problem is: providing a 180° phase shifter, adopting a differential circuit structure, the differential circuit structure includes a first branch and a second branch; the first branch is divided into a first sub-branch and a second sub-branch, the second branch is divided into a third sub-branch and a fourth sub-branch, the first sub-branch is provided with a first amplifier, the second sub-branch is provided with a second amplifier, the third sub-branch is provided with a third amplifier, and the fourth sub-branch is provided with a fourth amplifier; the output end of the first amplifier is connected to the output end of the third amplifier as the output of the first branch, the output end of the second amplifier is connected to the output end of the fourth amplifier as the output of the second branch; the structures of the first amplifier, the second amplifier, the third amplifier and the fourth amplifier are the same.

[0007] The input end of the differential circuit structure is provided with an input matching network, and the output end is provided with an output matching network.

[0008] The input matching network adopts a first transformer, the first end of the secondary coil of the first transformer is connected to the input end of the first branch, the second end of the secondary coil of the first transformer is connected to the input end of the second branch; the middle tap of the secondary coil of the first transformer is grounded.

[0009] The output matching network adopts a second transformer, the first end of the primary coil of the second transformer is connected to the output end of the first branch, and the second end of the primary coil of the second transformer is connected to the output end of the second branch; the middle tap supply voltage of the primary coil of the second transformer.

[0010] The first amplifier, the second amplifier, the third amplifier and the fourth amplifier may be a common-source amplifier structure, a common-gate amplifier structure or a common-source and common-gate amplifier structure.

[0011] The first amplifier, the second amplifier, the third amplifier and the fourth amplifier may be a common-emitter amplifier structure, a common-base amplifier structure or a common-emitter-cascode amplifier structure.

[0012] The technical solution adopted by the present invention to solve its technical problem is: providing a digital controlled phase shift link, including a cascaded driving amplifier, a 5.625° phase shifter, an 11.25° phase shifter, a 22.5° phase shifter, a 45° phase shifter and a 90° phase shifter, wherein the driving amplifier includes a plurality of cascaded driving amplification units, and any one of the plurality of cascaded driving amplification units adopts the above-mentioned 180° phase shifter.

[0013] Beneficial Effects

[0014] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: the present invention utilizes the characteristic that the signals of the two branches in the differential circuit naturally have a 180° phase difference, and realizes a 180° phase shift by selecting the output paths of different branches at the output end. This method can improve the phase shift accuracy and additional attenuation performance of the 180° phase shifter, and the implementation method is relatively convenient. At the same time, in the link design, the 180° phase shifter can be absorbed into the amplifier design. Compared with the conventional amplitude and phase control system, there is no need to increase the digital control bit, and at the same time, the insertion loss of a 180° phase shift unit is saved, which reduces the amplifier pressure and can also reduce the chip area. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a reference state schematic diagram of a 180° phase shifter in accordance with a first embodiment of the present invention;

[0016] Figure 2 1 is a schematic diagram of a phase shift state of a 180° phase shifter according to a first embodiment of the present invention;

[0017] Figure 3 is a schematic diagram of a 180° phase shifter with differential input in a first embodiment of the present invention;

[0018] Figure 4 is a schematic diagram of a 180° phase shifter with a single-ended input in a first embodiment of the present invention;

[0019] Figure 5 It is a schematic structural diagram of a digitally controlled phase-shift link according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0021] The first embodiment of the present invention relates to a 180° phase shifter, which adopts a differential circuit structure. The 180° phase shifter has two working states: a reference state and a phase shift state. The reference state is Figure 1 As shown, the phase shift state is Figure 2As shown. The differential circuit structure includes a first branch (i.e., P branch) and a second branch (i.e., N branch); the P branch is divided into a first sub-branch and a second sub-branch, and the N branch is divided into a third sub-branch and a fourth sub-branch. The first sub-branch is provided with a first amplifier AMP1, the second sub-branch is provided with a second amplifier AMP2, the third sub-branch is provided with a third amplifier AMP3, and the fourth sub-branch is provided with a fourth amplifier AMP4; the output end of the first amplifier AMP1 is connected to the output end of the third amplifier AMP3 as the output of the P branch, and the output end of the second amplifier AMP2 is connected to the output end of the fourth amplifier AMP4 as the output of the N branch; the first amplifier AMP1, the second amplifier AMP2, the third amplifier AMP3 and the fourth amplifier AMP4 have the same structure.

[0022] This embodiment realizes the switching between the reference state and the phase shift state of the 180° phase shifter by controlling the input of the bias control terminal Bias1 of the first amplifier AMP1, the bias control terminal Bias2 of the second amplifier AMP2, the bias control terminal Bias3 of the third amplifier AMP3 and the bias control terminal Bias4 of the fourth amplifier AMP4. When the input of the bias control terminal Bias1 of the first amplifier AMP1 and the bias control terminal Bias4 of the fourth amplifier AMP4 is the bias voltage in the normal working state, and the input of the bias control terminal Bias2 of the second amplifier AMP2 and the bias control terminal Bias3 of the third amplifier AMP3 is 0, the 180° phase shifter is in the reference state; when the input of the bias control terminal Bias2 of the second amplifier AMP2 and the bias control terminal Bias3 of the third amplifier AMP3 is the bias voltage in the normal working state, and the input of the bias control terminal Bias1 of the first amplifier AMP1 and the bias control terminal Bias4 of the fourth amplifier AMP4 is 0, the 180° phase shifter is in the phase shift state. Because the P branch and N branch in the differential structure naturally have a 180° phase difference, the devices in the circuit are the same, and the two working states only change the mapping relationship from the input to the output, so accurate 180° phase shift can be achieved with less additional attenuation.

[0023] Figure 3The figure shows a schematic diagram of a 180° phase shifter with differential input, wherein the transformer TF1 is used as an input matching network (capacitors or inductors can be added at corresponding positions according to matching requirements) to match the input impedance of the 180° phase shifter to 100Ω, and the transformer TF2 is used as an output matching network (capacitors or inductors can be added at corresponding positions according to matching requirements) to match the output impedance of the 180° phase shifter to 100Ω. The input end of the first amplifier AMP1 and the input end of the second amplifier AMP2 are connected to the first end of the secondary coil of the transformer TF1, and the input end of the third amplifier AMP3 and the input end of the fourth amplifier AMP4 are connected to the second end of the secondary coil of the transformer TF1. The output end of the first amplifier AMP1 and the output end of the third amplifier AMP3 are connected to the first end of the primary coil of the transformer TF2, and the output end of the second amplifier AMP2 and the output end of the fourth amplifier AMP4 are connected to the second end of the primary coil of the transformer TF2. When the bias control terminal Bias1 of the first amplifier AMP1 and the bias control terminal Bias4 of the fourth amplifier AMP4 are inputted with the bias voltage in the normal working state, and the bias control terminal Bias2 of the second amplifier AMP2 and the bias control terminal Bias3 of the third amplifier AMP3 are inputted with 0, the 180° phase shifter is in the reference state; when the bias control terminal Bias2 of the second amplifier AMP2 and the bias control terminal Bias3 of the third amplifier AMP3 are inputted with the bias voltage in the normal working state, and the bias control terminal Bias1 of the first amplifier AMP1 and the bias control terminal Bias4 of the fourth amplifier AMP4 are inputted with 0, the 180° phase shifter is in the phase shift state. Because the P branch and the N branch in the differential structure naturally have a 180° phase difference, the devices in the circuit are the same, and the two working states only change the mapping relationship from the input end to the output end, so that accurate 180° phase shift can be achieved with less additional attenuation.

[0024] like Figure 4 As shown, the 180° phase shifter adopts a single-ended input form. Compared with the 180° phase shifter with differential input, the transformer TF1 not only needs to realize the impedance transformation function, but also needs to realize the single-ended to differential function. It should be noted that when the transformer TF1 is used as an input matching network (capacitors or inductors can be added at the corresponding positions according to matching requirements), the input impedance of the differential 180° phase shifter needs to be matched to 50Ω. Similarly, the transformer TF2 not only needs to realize the impedance transformation function, but also needs to realize the differential to single-ended function. It should be noted that when the transformer TF2 is used as an output matching network (capacitors or inductors can be added at the corresponding positions according to matching requirements), the output impedance of the differential 180° phase shifter needs to be matched to 50Ω.

[0025] It is worth mentioning that the transistor type used in the amplifier structure of the amplifier used in the 180° phase shifter of this embodiment can be a MOS tube or a BJT tube. When a MOS tube is used, the amplifier can adopt a common source structure, a common gate structure or a common source and common gate structure. When a BJT tube is used, the amplifier can adopt a common emitter structure, a common base structure or a common emitter and common base structure. It should be noted that no matter which structure is used, it is only necessary to ensure that the structure of the four amplifiers and the type of transistors used are exactly the same to implement this embodiment.

[0026] The second embodiment of the present invention relates to a digital controlled phase shift link. In system design, since the insertion loss of the digital controlled phase shift link of the passive solution is relatively large, in order to prevent the gain, noise and linearity performance of the link from being seriously deteriorated, a driver amplifier (DA) must be added to the link for compensation. Figure 5 As shown in the upper part, in the conventional link design, the driving amplifier and the phase shifter are designed separately and then cascaded together. It is assumed that the driving amplifier is composed of a driving amplifier unit DA1, a driving amplifier unit DA2 and a driving amplifier unit DA3 in cascade, and the phase shifting system is composed of a 5.625° phase shifter, a 11.25° phase shifter, a 22.5° phase shifter, a 45° phase shifter, a 90° phase shifter and a 180° phase shifter in cascade. The 180° phase shifter based on the first embodiment of the present invention can be integrated into any one of the driving amplifier units in the driving amplifier, such as Figure 5 As shown in the lower part, this embodiment integrates it into the driving amplifier unit DA2. At this time, the output end of the driving amplifier unit DA1 is connected to the input end of the 180° phase shifter, and the transformer TF1 is the inter-stage matching network of the driving amplifier unit DA1 and the 180° phase shifter (capacitors or inductors can be added at the corresponding positions according to the matching requirements). The output end of the 180° phase shifter is connected to the input end of the driving amplifier unit DA3, and the transformer TF2 is the inter-stage matching network of the 180° phase shifter and the driving amplifier unit DA3 (capacitors or inductors can be added at the corresponding positions according to the matching requirements). Then the driving amplifier unit DA3 and the 5.625° phase shifter, 11.25° phase shifter, 22.5° phase shifter, 45° phase shifter, and 90° phase shifter are sequentially cascaded. Compared with the conventional link design, this embodiment does not need to increase the digital control bit, and at the same time saves the insertion loss of a 180° phase shifter, reduces the pressure on the driving amplifier, and can also reduce the chip area.

Claims

1. A 180° phase shifter, characterized in that: A differential circuit structure is adopted, the differential circuit structure includes a first branch and a second branch; the first branch is divided into a first sub-branch and a second sub-branch, the second branch is divided into a third sub-branch and a fourth sub-branch, the first sub-branch is provided with a first amplifier, the second sub-branch is provided with a second amplifier, the third sub-branch is provided with a third amplifier, and the fourth sub-branch is provided with a fourth amplifier; the output end of the first amplifier is connected to the output end of the third amplifier as the output of the first branch, and the output end of the second amplifier is connected to the output end of the fourth amplifier as the output of the second branch; The first amplifier, the second amplifier, the third amplifier and the fourth amplifier have the same structure.

2. The 180° phase shifter according to claim 1, characterized in that: The input end of the differential circuit structure is provided with an input matching network, and the output end is provided with an output matching network.

3. The 180° phase shifter according to claim 2, characterized in that: The input matching network adopts a first transformer, the first end of the secondary coil of the first transformer is connected to the input end of the first branch, the second end of the secondary coil of the first transformer is connected to the input end of the second branch; the middle tap of the secondary coil of the first transformer is grounded.

4. The 180° phase shifter according to claim 2, characterized in that: The output matching network adopts a second transformer, the first end of the primary coil of the second transformer is connected to the output end of the first branch, and the second end of the primary coil of the second transformer is connected to the output end of the second branch; the middle tap of the primary coil of the second transformer is connected to the supply voltage.

5. The 180° phase shifter according to claim 1, characterized in that: The first amplifier, the second amplifier, the third amplifier and the fourth amplifier are all of a common-source amplifier structure, a common-gate amplifier structure or a common-source and common-gate amplifier structure.

6. The 180° phase shifter according to claim 1, characterized in that: The first amplifier, the second amplifier, the third amplifier and the fourth amplifier are all common-emitter amplifier structures, common-base amplifier structures or common-emitter-cascode amplifier structures.

7. A digitally controlled phase shift link, characterized in that: It includes a cascaded driving amplifier, a 5.625° phase shifter, an 11.25° phase shifter, a 22.5° phase shifter, a 45° phase shifter and a 90° phase shifter, wherein the driving amplifier includes a plurality of cascaded driving amplifying units, and any one of the plurality of cascaded driving amplifying units adopts the 180° phase shifter as described in any one of claims 1-6.

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