A co-transmission line numerically controlled phase shifter based on a PI-type structure

Abstract

A co-transmission line numerically controlled phase shifter based on a PI structure, from top to bottom, includes a microstrip structure, a dielectric substrate and a metal floor. The microstrip structure includes a main transmission line and N pairs of open-circuit loaded lines of N phase shifters. Each pair of open-circuit loaded lines consists of two symmetric open-circuit loaded lines. Each open-circuit loaded line is connected to the main transmission line through a PIN diode switch. In the open-circuit loaded lines, two PIN diode switches for the same phase shift state control are controlled by the same control signal. When two open-circuit loaded lines controlled by the same control signal are loaded onto the main transmission line, that is, a phase shift state, the main transmission line is reused by multiple pairs of open-circuit loaded lines, having the function of single circuit and multiple phase shifts. Compared with traditional numerically controlled phase shifters, this phase shifter has the advantages of low insertion loss, small size, compact structure and easy processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic and electrical components, relates to the design of phase shifters, and particularly relates to a co-transmission line numerically controlled phase shifter based on a PI-type structure. Background Art

[0002] With the rapid development of information transmission and sensing technologies, the performance requirements for phased array systems are also getting higher and higher. The phased array system has replaced the traditional mechanical radar and antenna systems with its advantages such as flexibility, rapidity, and accuracy, and is widely used in the fields of military, aerospace, vehicle-mounted radar, wireless communication, etc. As an important part of the phase control unit, the performance of the phase shifter determines the performance of the entire system. In a phased array system, a large number of phase shifters are required. Therefore, compact size, low insertion loss, and low power consumption have become the key design requirements for phase shifters. Traditional numerically controlled phase shifters are designed based on individual phase shifter units and then cascaded, which increases the size of the phase shifter and deteriorates the insertion loss performance to a certain extent, thus damaging the overall dynamic range of the communication system. Therefore, designing phase shifters with low cost, high compactness, and low insertion loss has become an important research hotspot. The inverted E-type single-circuit multi-bit phase shifter based on the main transmission line sharing strategy proposed in the patent document CN 112768853 B requires 3 loading stubs for each phase shift state, which increases the insertion loss and size of the device to a certain extent. Summary of the Invention

[0003] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a co-transmission line numerically controlled phase shifter based on a PI-type structure, in which multiple phase shift units share one main transmission line to realize the function of multi-phase shift in a single circuit, so as to solve the problems of many phase shift units, large insertion loss, high power consumption, etc. existing in the existing phase shifters.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A co-transmission line numerically controlled phase shifter based on a PI-type structure, which includes a microstrip structure, a dielectric substrate, and a metal floor from top to bottom, wherein:

[0006] The microstrip structure includes one main transmission line and N pairs of open-circuit loading lines of N phase shifters. Each pair of open-circuit loading lines consists of two symmetric open-circuit loading lines, and each open-circuit loading line is connected to the main transmission line through a PIN diode switch; the input end of the main transmission line is the input port of the numerically controlled phase shifter, and the output end of the main transmission line is the output port of the numerically controlled phase shifter;

[0007] The N-bit phase shifter has N phase shift states; in the open-circuit loaded line, the two PIN diode switches for the same phase shift state control are controlled by the same control signal. When the two sections of the open-circuit loaded line controlled by the same control signal are loaded onto the main transmission line, that is, one phase shift state, the main transmission line is reused by multiple pairs of open-circuit loaded lines; when all PIN diode switches are in the off state, the circuit behaves as an ideal transmission line, that is, the non-phase shift state.

[0008] In one embodiment, the microstrip structure is printed on the upper surface of the dielectric substrate, and the metal floor is attached to the lower surface of the dielectric substrate.

[0009] In one embodiment, each section of the open-circuit loaded line is connected to the same side of the main transmission line, and the length direction of the open-circuit loaded line is perpendicular to the length direction of the main transmission line.

[0010] In one embodiment, the N pairs of open-circuit loaded lines are divided into two parts, each part includes N sections of open-circuit loaded lines, and each section of the open-circuit loaded line in the first part forms a pair of symmetric open-circuit loaded lines with one of the sections of the open-circuit loaded line in the second part.

[0011] In one embodiment, along the length direction of the main transmission line, the i-th section of the open-circuit loaded line in the first part forms a pair of symmetric open-circuit loaded lines with the i-th section of the open-circuit loaded line in the second part, where 1 ≤ i ≤ N.

[0012] In one embodiment, the sections of the open-circuit loaded line in the first part are equally spaced, and the S-parameter adjustment of the phase shift state is achieved by adjusting the spacing of the sections of the open-circuit loaded line in the second part.

[0013] In one embodiment, the main transmission line is a 50Ω main transmission line.

[0014] In one embodiment, N = 4, and there are four phase shift states of 45°, 22.5°, 11.25°, and 5.625°.

[0015] In one embodiment, the voltage signal for controlling the on / off of the PIN diode switch is provided and controlled by the FPGA module.

[0016] Compared with the prior art, the beneficial effects of the present invention are: based on the PI-type structure, multiple phase shift amounts use a common transmission line, reducing the number of separate reference microstrip lines corresponding to each phase state, and realizing multiple phase shift states with one phase shift circuit, effectively reducing the size and loss of the phase shifter.

[0017] The present invention relates to a numerically controlled phase shifter based on a co - transmission line of a PI - type structure. Whether an open - circuit loaded line is connected to the main transmission line is controlled by the on - off of PIN diode switches connected in parallel to the main transmission line. Each phase - shifted state of the phase shifter exists independently. The two loaded lines in each phase - shifted state are controlled by two corresponding PIN diode switches to be connected to the main transmission line, and switches with the same phase shift amount use one control signal. The main transmission line is used multiple times, avoiding the need for a dedicated main transmission line for each phase shift amount and reducing the circuit size. At the same time, since the PIN diode switches are not connected in series in the circuit and the required number is reduced, the phase shifter achieves low insertion loss and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the present invention.

[0019] Figures 2(a) to 2(e) It is an S - parameter diagram of the present invention in five states.

[0020] Figure 3 It is a phase - shift amount diagram of the present invention.

[0021] Figure 4 It is a phase - error diagram of the present invention in four phase - shifted states. DETAILED DESCRIPTION OF THE INVENTION

[0022] In order to make the objectives, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but it shall not be used as a basis for any limitation to the present invention.

[0023] A numerically controlled phase shifter based on a co - transmission line of a "PI - type (i.e., π - shaped)" structure according to the present invention includes a microstrip structure, a dielectric substrate, and a metal floor from top to bottom. The microstrip structure is printed on the upper surface of the dielectric substrate, and the metal floor is attached to the bottom surface of the dielectric substrate.

[0024] The microstrip structure of the present invention includes a main transmission line and N pairs of open - circuit loaded lines of an N - bit phase shifter. Each pair of open - circuit loaded lines consists of two symmetric open - circuit loaded lines. Each open - circuit loaded line is connected to the main transmission line through a PIN diode switch. The input end of the main transmission line is the input port of the numerically controlled phase shifter, and the output end of the main transmission line is the output port of the numerically controlled phase shifter.

[0025] Obviously, an N-bit phase shifter has N phase shift states. Among the open-circuit loaded lines, the two PIN diode switches used for controlling the same phase shift state are controlled by the same control signal. Whether the open-circuit loaded lines of each phase shift state are connected is achieved by the on / off of the switches. When all PIN diode switches are in the off state, the circuit behaves as an ideal transmission line, i.e., the non-phase shift state. When two open-circuit loaded lines controlled by the same control signal are loaded onto the main transmission line, a phase shift state is obtained. For the N phase shift states of the phase shifter, only two open-circuit loaded lines are connected to the main transmission line for each phase shift amount, and the main transmission line is reused by multiple pairs of open-circuit loaded lines, avoiding the need for the main transmission line for each phase state, thereby reducing the insertion loss. In the present invention, multiple phase shift states share one main transmission line, having the function of single-circuit multi-phase shift. Compared with the traditional numerically controlled phase shifter, this phase shifter has the advantages of low insertion loss, small size, compact structure, and easy processing. Moreover, the length of the main transmission line can be freely selected, and the distance between the two loading stubs is no longer fixed at 1 / 4 wavelength, so that the overall structure of the phase shifter is compact.

[0026] Reference Figure 1 , in this embodiment, for the convenience of description, take N = 4. The microstrip structure consists of: a main transmission line 1, 8 PIN diode switches 2 connected in parallel to the main transmission line 1, and 8 open-circuit loaded lines respectively controlled by each PIN diode switch 2.

[0027] In the embodiment of the present invention, the dielectric substrate uses Rogers4003C with a thickness of 20 mil and a dielectric constant of 3.55, and the thickness of the metal floor is 0.15 mil. The PIN diode switch 2 uses the PIN diode of Infineon bar64-02v. The main transmission line 1 is a 50Ω main transmission line.

[0028] The open-circuit loaded lines of the four phase shift states are distributed on the same side of the main transmission line 1. The 4 pairs of open-circuit loaded lines are divided into two parts, each part includes 4 open-circuit loaded lines. Each open-circuit loaded line in the first part and one of the open-circuit loaded lines in the second part form a pair of symmetric open-circuit loaded lines. Preferably, along the length direction of the main transmission line, the i-th open-circuit loaded line in the first part and the i-th open-circuit loaded line in the second part form a pair of symmetric open-circuit loaded lines, 1 ≤ i ≤ N.

[0029] In this embodiment, that is: the first open-circuit loaded line A31, the second open-circuit loaded line A41, the third open-circuit loaded line A51, the fourth open-circuit loaded line A61 are the first part, and the first open-circuit loaded line B32, the second open-circuit loaded line B42, the third open-circuit loaded line B52, the fourth open-circuit loaded line B62 are the second part. Among them:

[0030] The first open-circuit loaded line A31 and the first open-circuit loaded line B32 form a pair of symmetric open-circuit loaded lines;

[0031] The second open-circuit loading line A41 and the second open-circuit loading line B42 form a pair of symmetric open-circuit loading lines;

[0032] The third open-circuit loading line A51 and the third open-circuit loading line B52 form a pair of symmetric open-circuit loading lines;

[0033] The fourth open-circuit loading line A61 and the fourth open-circuit loading line B62 form a pair of symmetric open-circuit loading lines.

[0034] In the embodiment of the present invention, other structural dimensions are shown in Table 1:

[0035] Table 1

[0036] Structure L W <![CDATA[L0]]> <![CDATA[W0]]> <![CDATA[L1]]> <![CDATA[L2]]> Dimensions (mm) 23 22 23 1.13 11.65 4.5 Structure <![CDATA[L3]]> <![CDATA[L4]]> <![CDATA[W1]]> <![CDATA[W2]]> <![CDATA[W3]]> <![CDATA[W4]]> Dimensions (mm) 3.3 1.8 0.5 1.5 1 1

[0037] Wherein: L is the length of the dielectric substrate, W is the width of the dielectric substrate, L0 is the length of the main transmission line 1, W0 is the width of the main transmission line 1, L1 is the length of the first open-circuit loading line A31 and the first open-circuit loading line B32, W1 is the width of the first open-circuit loading line A31 and the first open-circuit loading line B32, L2 is the length of the second open-circuit loading line A41 and the second open-circuit loading line B42, W2 is the width of the second open-circuit loading line A41 and the second open-circuit loading line B42, L3 is the length of the third open-circuit loading line A51 and the third open-circuit loading line B52, W3 is the width of the third open-circuit loading line A51 and the third open-circuit loading line B52, L4 is the length of the fourth open-circuit loading line A61 and the fourth open-circuit loading line B62, and W4 is the width of the fourth open-circuit loading line A61 and the fourth open-circuit loading line B62.

[0038] In the figure, each open-circuit loading line is connected to the same side of the main transmission line 1, and the length direction of each open-circuit loading line is perpendicular to the length direction of the main transmission line 1.

[0039] In this embodiment, the phase shifter has a total of four phase shift states, and each phase shift state needs to be realized by connecting two identical open-circuit loading lines. The first open-circuit loading line A31 and the first open-circuit loading line B32 are open-circuit loading lines with a phase shift amount of 45°; the second open-circuit loading line A41 and the second open-circuit loading line B42 are open-circuit loading lines with a phase shift amount of 22.5°; the third open-circuit loading line A51 and the third open-circuit loading line B52 are open-circuit loading lines with a phase shift amount of 11.25°; the fourth open-circuit loading line A61 and the fourth open-circuit loading line B62 are open-circuit loading lines with a phase shift amount of 5.625°. The PIN diode switches of the two open-circuit loading lines controlling the same phase shift amount are controlled by the same control signal. Therefore, there are a total of 4 control voltages, namely V1, V2, V3, and V4, in this embodiment.

[0040] In the present invention, the open-circuit loaded lines of each segment in the first part are equally spaced. By adjusting the spacing of the open-circuit loaded lines of each segment in the second part, the S-parameter adjustment of the phase shift state can be achieved.

[0041] In this embodiment, the first open-circuit loaded line A31, the second open-circuit loaded line A41, the third open-circuit loaded line A51, and the fourth open-circuit loaded line A61 are equally spaced. The spacing of the first open-circuit loaded line B32, the second open-circuit loaded line B42, the third open-circuit loaded line B52, and the fourth open-circuit loaded line B62 is appropriately adjusted to optimize the S-parameters of the phase shift state.

[0042] When V1 = V2 = V3 = V4 = 0, all PIN diode switches are turned off, and the circuit is equivalent to the main transmission line, that is, an ideal 50Ω transmission line. At this time, it is represented as the non-phase shift state, and the phase is Ψ0, where Ψ0 is the reference phase. When the control voltage V1 of the PIN diode switch 2 of the first open-circuit loaded line A31 and the first open-circuit loaded line B32 is 3V, only the first open-circuit loaded line A31 and the first open-circuit loaded line B32 are connected to the main transmission line 1. At this time, the phase difference between the circuit phase and the reference phase is Ψ1, and Ψ1 = 45°; when the control voltage V2 of the PIN diode switch 2 of the second open-circuit loaded line A41 and the second open-circuit loaded line B42 is 3V, only the second open-circuit loaded line A41 and the second open-circuit loaded line B42 are connected to the main transmission line 1. At this time, the phase difference between the circuit phase and the reference phase is Ψ2, and Ψ2 = 22.5°; when the control voltage V3 of the PIN diode switch 2 of the third open-circuit loaded line A51 and the third open-circuit loaded line B52 is 3V, only the third open-circuit loaded line A51 and the third open-circuit loaded line B52 are connected to the main transmission line 1. At this time, the phase difference between the circuit phase and the reference phase is Ψ3, and Ψ3 = 11.25°; when the control voltage V4 of the PIN diode switch 2 of the fourth open-circuit loaded line A61 and the fourth open-circuit loaded line B62 is 3V, only the fourth open-circuit loaded line A61 and the fourth open-circuit loaded line B62 are connected to the main transmission line 1. At this time, the phase difference between the circuit phase and the reference phase is Ψ4, and Ψ4 = 5.625°.

[0043] In this embodiment, the four voltage signals V1, V2, V3, and V4 that control the on / off of the PIN diode switches are provided and controlled by the FPGA module. When the "0000" instruction is input, V1, V2, V3, and V4 all exhibit low levels, and all switches are turned off at this time; when the "1000" instruction is input, V1 exhibits a high level, and V2, V3, and V4 all exhibit low levels. The PIN diode switches of the first open-circuit loading line A31 and the first open-circuit loading line B32 are turned on, and the rest are turned off. At this time, it is in a 45° phase shift state; when the "0100" instruction is input, V2 exhibits a high level, and V1, V3, and V4 all exhibit low levels. The PIN diode switches of the second open-circuit loading line A41 and the second open-circuit loading line B42 are turned on, and the rest are turned off. At this time, it is in a 22.5° phase shift state; when the "0010" instruction is input, V3 exhibits a high level, and V1, V2, and V4 all exhibit low levels. The PIN diode switches of the third open-circuit loading line A51 and the third open-circuit loading line B52 are turned on, and the rest are turned off. At this time, it is in an 11.25° phase shift state; when the "0001" instruction is input, V4 exhibits a high level, and V1, V2, and V3 all exhibit low levels. The PIN diode switches of the fourth open-circuit loading line A61 and the fourth open-circuit loading line B62 are turned on, and the rest are turned off. At this time, it is in a 5.625° phase shift state;

[0044] In this embodiment, a co-transmission line numerically controlled phase shifter based on the "PI-type" structure with a center frequency of 2.4 GHz is designed, and the designed bandwidth is 200 MHz.

[0045] The effects of the present invention can be further illustrated in combination with the simulation results:

[0046] Figure 2(a) is the S-parameter simulation diagram in the non-phase shift state where V1 = V2 = V3 = V4 = 0; Figure 2(b) is the S-parameter simulation diagram in the 45° phase shift state where V1 = 3V, V2 = V3 = V4 = 0; Figure 2(c) is the S-parameter simulation diagram in the 22.5° phase shift state where V2 = 3V, V1 = V3 = V4 = 0; Figure 2(d) is the S-parameter simulation diagram in the 11.25° phase shift state where V3 = 3V, V1 = V2 = V4 = 0; Figure 2(e) is the S-parameter simulation diagram in the 5.625° phase shift state where V4 = 3V, V1 = V2 = V3 = 0. The insertion losses of the five states at 2.4 GHz are 0.4 dB, 0.78 dB, 0.48 dB, and 0.43 dB respectively. The return losses of the four phase shift states in the 2.3 - 2.5 GHz frequency band are better than 16 dB. It can be seen that the co-transmission line numerically controlled phase shifter based on the "PI-type" structure can achieve lower insertion losses and better return losses.

[0047] As Figure 3 shown, it is the phase shift amount diagram of a co-transmission line numerically controlled phase shifter based on the "PI-type" structure in this embodiment. FromFigure 3 It can be seen that the phase shift errors of the four phase shift states of 45°, 22.5°, 11.25°, and 5.625° at a frequency of 2.4 GHz are -0.44°, -0.29°, 0.34°, and 0.405° respectively, and the overall absolute phase shift error is less than 0.5°.

[0048] Figure 4 Specifically, it shows the phase shift errors of four phase shift amounts. Within a 200 MHz bandwidth, the maximum absolute phase shift difference of 45° is 12.61°; the maximum absolute phase shift difference of 22.5° is 3.55°; the maximum absolute phase shift difference of 11.25° is 1.36°; the maximum absolute phase shift difference of 5.625° is 0.81°.

[0049] In summary, the phase shifter of the present invention realizes multiple phase shift states by sharing a main transmission line with multiple PI-type structures, and has the advantages of low insertion loss, small size, compact structure, easy processing, etc.

[0050] The above has introduced in detail a co-transmission line numerically controlled phase shifter based on a PI-type structure provided by the present invention, and elaborated and implemented the principle and implementation manner of the present invention with a detailed structural design. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A co - transmission - line numerically controlled phase shifter based on a PI - type structure, which includes a microstrip structure, a dielectric substrate, and a metal floor from top to bottom. It is characterized in that: The microstrip structure includes a main transmission line and N pairs of open - circuit loaded lines of N phase shifters. Each pair of open - circuit loaded lines consists of two symmetric open - circuit loaded lines. Each open - circuit loaded line is connected to the main transmission line through a PIN diode switch; the input end of the main transmission line is the input port of this numerically controlled phase shifter, and the output end of the main transmission line is the output port of this numerically controlled phase shifter. The N phase shifters have N phase - shift states; among the open - circuit loaded lines, the two PIN diode switches for controlling the same phase - shift state are controlled by the same control signal. When the two open - circuit loaded lines controlled by the same control signal are loaded onto the main transmission line, that is, one phase - shift state, the main transmission line is reused by multiple pairs of open - circuit loaded lines; when all PIN diode switches are in the off state, the circuit behaves as an ideal transmission line, that is, the non - phase - shift state.

2. The co - transmission - line numerically - controlled phase shifter based on the PI - type structure according to claim 1, characterized in that, The microstrip structure is printed on the upper surface of the dielectric substrate, and the metal floor is attached to the lower surface of the dielectric substrate.

3. The co-transmission line numerically controlled phase shifter based on the PI structure according to claim 1, wherein Each open - circuit loaded line is connected to the same side of the main transmission line, and the length direction of the open - circuit loaded line is perpendicular to the length direction of the main transmission line.

4. The co-transmission line numerically controlled phase shifter based on the PI-type structure according to claim 1, characterized in that The N pairs of open - circuit loaded lines are divided into two parts. Each part includes N open - circuit loaded lines. Each open - circuit loaded line in the first part forms a pair of symmetric open - circuit loaded lines with one of the open - circuit loaded lines in the second part.

5. The co-transmission line numerically controlled phase shifter based on the PI type structure according to claim 4, wherein Along the length direction of the main transmission line, the i - th open - circuit loaded line in the first part forms a pair of symmetric open - circuit loaded lines with the i - th open - circuit loaded line in the second part, where 1 ≤ i ≤ N.

6. The co-transmission line numerically controlled phase shifter based on the PI-type structure according to claim 4 or 5, characterized in that, The open - circuit loaded lines in the first part are equally spaced, and the S - parameter adjustment of the phase - shift state is achieved by adjusting the spacing of the open - circuit loaded lines in the second part.

7. The co-transmission line numerically controlled phase shifter based on the PI structure according to claim 1, characterized in that The main transmission line is a 50Ω main transmission line.

8. The co-transmission line numerically controlled phase shifter based on the PI-type structure according to claim 1 or 7, characterized in that The N = 4, and it has four phase - shift states of 45°, 22.5°, 11.25°, and 5.625°.

9. The co-transmission line numerically controlled phase shifter based on the PI-type structure according to claim 1, wherein The voltage signal for controlling the on - off of the PIN diode switch is provided and controlled by an FPGA module.

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