Broadband Passive Frequency Doubler

Abstract

The present invention provides a broadband passive doubler, comprising: a double-sided microwave circuit board, a first input suspension microstrip line, a second input suspension microstrip line, an input short-circuit line, a diode bridge stack, a first output suspension microstrip line, a second output suspension microstrip line, a first output short-circuit line and a second output short-circuit line; the first input suspension microstrip line and the first output suspension microstrip line are arranged on the front side of the double-sided microwave circuit board and connected to the diode bridge stack; the second input suspension microstrip line and the second output suspension microstrip line are arranged on the reverse side of the double-sided microwave circuit board and connected to the diode bridge stack; the diode bridge stack runs through the double-sided microwave circuit board; the input short-circuit line, the first output short-circuit line and the second output short-circuit line are all connected to the diode bridge stack, so as to better match the input and output suspension strip lines with the diode bridge stack. The broadband passive doubler provided by the present invention has a small size, low frequency multiplication loss and a wide operating frequency bandwidth.

Description

Technical Field

[0001] The invention belongs to the technical field of frequency multipliers, and more specifically, relates to a broadband passive doubler. Background Art

[0002] Broadband and low frequency doubling loss are requirements for practical microwave doublers. To achieve this requirement, a double-balanced passive frequency doubling circuit is usually used. In the design of double-balanced passive frequency doubling circuits, the prior art has a method of using a cosine gradient method to implement input and output microstrip baluns, but the volume of the input and output microstrip baluns designed by this method is relatively large; there is also a spiral balun structure design in the prior art. Although the doubler implemented by this design method is small in size, the frequency doubling efficiency is low and the operating frequency bandwidth is relatively narrow.

[0003] Therefore, how to realize an ultra-wideband, low frequency doubling loss, and small-sized frequency doubler has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] The object of the present invention is to provide a broadband passive frequency doubler, which has small size, low frequency doubling loss and wide operating frequency bandwidth.

[0005] To achieve the above object, the present invention provides a broadband passive doubler, the broadband passive doubler comprising:

[0006] A double-sided microwave circuit board, a first input suspension microstrip line, a second input suspension microstrip line, an input short-circuit line, a diode bridge stack, a first output suspension microstrip line, a second output suspension microstrip line, a first output short-circuit line, and a second output short-circuit line;

[0007] The first input suspension microstrip line and the first output suspension microstrip line are arranged on the front side of the double-sided microwave circuit board, the second input suspension microstrip line and the second output suspension microstrip line are arranged on the reverse side of the double-sided microwave circuit board, and the diode bridge stack is arranged at a preset window position of the double-sided microwave circuit board, and runs through the double-sided microwave circuit board;

[0008] The first end of the first input suspension microstrip line is grounded, and the first end of the second input suspension microstrip line is the input end of the broadband passive doubler; the second end of the first input suspension microstrip line is connected to the first end of the diode bridge stack, the second end of the second input suspension microstrip line is connected to the second end of the diode bridge stack, the third end of the diode bridge stack is connected to the first end of the first output suspension microstrip line, and the fourth end of the diode bridge stack is connected to the first end of the second output suspension microstrip line; the second end of the first output suspension microstrip line is grounded, and the second end of the second output suspension microstrip line is the output end of the broadband passive doubler;

[0009] The first end of the input short-circuit line is grounded, and the second end is connected to the first end of the diode bridge stack; or the first end of the input short-circuit line is grounded, and the second end is connected to the second end of the diode bridge stack;

[0010] The first end of the first output short-circuit line is grounded, and the second end is connected to the third end of the diode bridge stack; the first end of the second output short-circuit line is grounded, and the second end is connected to the fourth end of the diode bridge stack.

[0011] Optionally, the broadband passive doubler further comprises a box body, an input radio frequency insulator, and an output radio frequency insulator;

[0012] The double-sided microwave circuit board, the input RF insulator and the output RF insulator are sintered on the box body, the input RF insulator is connected to the first end of the second input suspension microstrip line, and the output RF insulator is connected to the second end of the second output suspension microstrip line.

[0013] Optionally, the broadband passive doubler further includes a first SMA connector and a second SMA connector;

[0014] The first SMA connector is connected to the input RF insulator, and the second SMA connector is connected to the output RF insulator;

[0015] The first SMA connector and the second SMA connector are fixed to the box body by cross screws.

[0016] Optionally, the diode bridge stack includes a first diode, a second diode, a third diode and a fourth diode;

[0017] The anode terminal of the first diode is the first terminal of the diode bridge stack, the cathode terminal of the first diode is the third terminal of the diode bridge stack, the anode terminal of the third diode is the fourth terminal of the diode bridge stack, and the cathode terminal of the third diode is the second terminal of the diode bridge stack;

[0018] The cathode terminal of the first diode is connected to the cathode terminal of the second diode, the anode terminal of the second diode is connected to the cathode terminal of the third diode, the anode terminal of the third diode is connected to the anode terminal of the fourth diode, and the cathode terminal of the fourth diode is connected to the anode terminal of the first diode.

[0019] Optionally, the first diode, the second diode, the third diode, and the fourth diode are silicon Schottky low-barrier diodes.

[0020] Optionally, the plane formed by the diodes in the diode bridge stack is perpendicular to the plane where the double-sided microwave circuit board is located.

[0021] Optionally, a first metallized hole is provided at the first end of the input short-circuit line, and the input short-circuit line is grounded through the first metallized hole;

[0022] A second metallized hole is provided at the first end of the first output short-circuit line, and the first output short-circuit line is grounded through the second metallized hole;

[0023] A third metallized hole is disposed at the first end of the second output short-circuit line, and the second output short-circuit line is grounded through the third metallized hole.

[0024] Optionally, the diameters of the first metallized hole, the second metallized hole, and the third metallized hole are 0.5 mm.

[0025] Optionally, the double-sided microwave circuit board is a low dielectric constant double-sided microwave circuit board.

[0026] Optionally, the dielectric constant of the double-sided microwave circuit board is 2.2.

[0027] The beneficial effect of the broadband passive doubler provided by the present invention is that the embodiment of the present invention designs the broadband passive doubler by setting a suspension strip line on the front and back sides of the double-sided microwave circuit board. In order to make the input and output suspension strip lines better match the diode bridge stack, the embodiment of the present invention sets a short circuit line at the signal output end of the input suspension strip line (that is, the second end of the first input suspension strip line and the second end of the second input suspension strip line) and the signal input end of the output suspension strip line (that is, the first end of the first output suspension strip line and the first end of the second output suspension strip line). Based on the structure of the broadband passive doubler provided by the present invention, the thickness of the double-sided microwave circuit board and the width of the suspension strip lines on the front and back sides of the double-sided microwave circuit board can be obtained by simulation calculation, which can not only ensure the small size of the broadband passive doubler, but also effectively reduce the frequency doubling loss of the broadband passive doubler, so that the broadband passive doubler has a wider working frequency bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the front structure of a broadband passive doubler provided by an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of the reverse structure of a broadband passive doubler provided in one embodiment of the present invention;

[0031] Figure 3 A circuit schematic diagram of a broadband passive doubler provided by an embodiment of the present invention;

[0032] Figure 4 A graph showing the relationship between the output signal frequency and the frequency doubling loss provided by an embodiment of the present invention;

[0033] Figure 5 A cross-sectional schematic diagram of a suspended strip line and a double-sided microwave circuit board provided in one embodiment of the present invention;

[0034] Figure 6 A schematic diagram of the front structure of a broadband passive frequency doubler provided by another embodiment of the present invention;

[0035] Figure 7 A schematic diagram of leads of a diode bridge stack provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] Please refer to Figure 1 and Figure 2 , Figure 1 A schematic diagram of the front structure of a broadband passive doubler provided in one embodiment of the present invention. Figure 2 The schematic diagram of the reverse structure of a broadband passive doubler provided by an embodiment of the present invention includes: a double-sided microwave circuit board 12, a first input suspension microstrip line 1, a second input suspension microstrip line 17, an input short-circuit line 7, a diode bridge stack 19, a first output suspension microstrip line 10, a second output suspension microstrip line 20, a first output short-circuit line 5, and a second output short-circuit line 9.

[0038] The first input suspension microstrip line 1 and the first output suspension microstrip line 10 are arranged on the front side of the double-sided microwave circuit board 12, the second input suspension microstrip line 17 and the second output suspension microstrip line 20 are arranged on the back side of the double-sided microwave circuit board 12, and the diode bridge stack 19 is arranged at a preset window position of the double-sided microwave circuit board 12, running through the double-sided microwave circuit board 12.

[0039] The first end of the first input suspension microstrip line 1 is grounded, and the first end of the second input suspension microstrip line 17 is the input end of the broadband passive doubler. The second end of the first input suspension microstrip line 1 is connected to the first end of the diode bridge stack 19, the second end of the second input suspension microstrip line 17 is connected to the second end of the diode bridge stack 19, the third end of the diode bridge stack 19 is connected to the first end of the first output suspension microstrip line 10, and the fourth end of the diode bridge stack is connected to the first end of the second output suspension microstrip line 20. The second end of the first output suspension microstrip line 10 is grounded, and the second end of the second output suspension microstrip line 20 is the output end of the broadband passive doubler.

[0040] The first end of the input short-circuit line 7 is grounded, and the second end is connected to the first end of the diode bridge stack 19 . Or the first end of the input short-circuit line 7 is grounded, and the second end is connected to the second end of the diode bridge stack 19 .

[0041] The first end of the first output short-circuit line 5 is grounded, and the second end is connected to the third end of the diode bridge stack 19. The first end of the second output short-circuit line 9 is grounded, and the second end is connected to the fourth end of the diode bridge stack 19.

[0042] In this embodiment, the circuit schematic diagram of the broadband passive doubler is as follows: Figure 3 As shown, L41 corresponds to the first input suspension microstrip line 1, L42 corresponds to the second input suspension microstrip line, L3 corresponds to the input short-circuit line 7, the bridge stack composed of D1, D2, D3, and D4 corresponds to the diode bridge stack 19, L5 corresponds to the first output short-circuit line 5, L2 corresponds to the second output short-circuit line 9, L11 corresponds to the first output suspension microstrip line 10, and L12 corresponds to the second output suspension microstrip line.

[0043] In this embodiment, the impedance matching is performed by using the width coupling of the suspended strip line to achieve broadband frequency doubling, wherein the dielectric constant of the double-sided microwave circuit board 12 can be 2.2 and the thickness can be 0.13 mm. The passive structure provided in the embodiment of the present invention can be subjected to electromagnetic simulation, and the overall circuit is simulated by the actual circuit and the circuit schematic diagram. The output power simulation of the circuit is as follows: Figure 4 As shown, in the frequency range of 2 to 22 GHz, the frequency doubling loss is less than -11 dB.

[0044] In this embodiment, the relative positions of the suspension strip line and the double-sided microwave circuit board are as follows: Figure 5 As shown, Figure 5 The cross-sectional diagram of the suspension strip line and the double-sided microwave circuit board is shown in FIG. 1 , wherein the front suspension strip line in this embodiment refers to the first input suspension strip line 1 and the second input suspension strip line 17 , and the back suspension strip line refers to the first output suspension strip line 10 and the second output suspension strip line 20 .

[0045] From the above description, it can be known that the embodiment of the present invention designs a broadband passive doubler by setting a suspension strip line on the front and back sides of a double-sided microwave circuit board. In order to make the input and output suspension strip lines better match the diode bridge stack, the embodiment of the present invention sets a short circuit line at the signal output end of the input suspension strip line (that is, the second end of the first input suspension strip line and the second end of the second input suspension strip line) and the signal input end of the output suspension strip line (that is, the first end of the first output suspension strip line and the first end of the second output suspension strip line). On the basis of the broadband passive doubler structure provided by the present invention, the thickness of the double-sided microwave circuit board and the width of the suspension strip lines on the front and back sides of the double-sided microwave circuit board can be obtained by simulation calculation, which can not only ensure the small size of the broadband passive doubler, but also effectively reduce the frequency doubling loss of the broadband passive doubler, so that the broadband passive doubler has a wider operating frequency bandwidth.

[0046] Optionally, refer to Figure 2 by Figure 7 As a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the broadband passive doubler also includes a box body 13, an input radio frequency insulator 11, and an output radio frequency insulator 21.

[0047] The double-sided microwave circuit board 12 , the input RF insulator 11 , and the output RF insulator 21 are sintered on the box body. The input RF insulator 11 is connected to the first end of the second input suspension microstrip line 17 , and the output RF insulator 21 is connected to the second end of the second output suspension microstrip line 20 .

[0048] In this embodiment, the box body 13 is a brass box body with a nickel-plated surface, and the double-sided microwave circuit board 12, the input radio frequency insulator 11, and the output radio frequency insulator 21 are sintered on the box body by 179° C. solder paste.

[0049] Optionally, as a specific implementation of the broadband passive frequency doubler provided in an embodiment of the present invention, the broadband passive frequency doubler further includes a first SMA connector and a second SMA connector.

[0050] The first SMA connector is connected to the input radio frequency insulator, and the second SMA connector is connected to the output radio frequency insulator. The first SMA connector and the second SMA connector are fixed to the box body by cross screws 15.

[0051] In this embodiment, the first SMA connector and the second SMA connector are both detachable SMA connectors. Figure 2 , Figure 2 16 in the middle is a detachable SMA connector.

[0052] Optionally, refer to Figures 1 to 3As a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the diode bridge stack 19 includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4.

[0053] The anode end of the first diode D1 is the first end of the diode bridge stack 19 , the cathode end of the first diode D1 is the third end of the diode bridge stack 19 , the anode end of the third diode D3 is the fourth end of the diode bridge stack 19 , and the cathode end of the third diode D3 is the second end of the diode bridge stack 19 .

[0054] The cathode terminal of the first diode D1 is connected to the cathode terminal of the second diode D2, the anode terminal of the second diode D2 is connected to the cathode terminal of the third diode D3, the anode terminal of the third diode D3 is connected to the anode terminal of the fourth diode D4, and the cathode terminal of the fourth diode D4 is connected to the anode terminal of the first diode D1.

[0055] Optionally, as a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the first diode, the second diode, the third diode, and the fourth diode are silicon Schottky low-barrier diodes.

[0056] The diode parallel capacitance CP in the silicon Schottky low-barrier diode bridge is 0.08pF, the on-resistance RD is less than 15Ω, the barrier voltage is less than 0.35V, and it can work in the Ka band. Therefore, the embodiment of the present invention adopts a silicon Schottky low-barrier diode bridge tube stack, which has a compact appearance and can reduce the volume of the broadband passive doubler.

[0057] Optionally, as a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the plane formed by the diodes in the diode bridge stack is perpendicular to the plane where the double-sided microwave circuit board is located.

[0058] In this embodiment, the diode bridge stack can be vertically welded on the double-sided microwave circuit board. The three-dimensional assembly of the diode bridge stack can effectively reduce the parasitic constant between the bridge stack and its matching circuit, thereby reducing the loss.

[0059] Based on the above embodiment, the method for manufacturing the broadband passive doubler may be:

[0060] 1) A window is opened at position D1 of the processed double-sided microwave circuit board 12 according to the shape and size of the bridge stack. 8 is the position of the window, and the area is about 0.6×1.6mm 2 The double-sided microwave circuit board 12 with windows opened, together with the input RF insulator 11 and the output RF insulator 21 are sintered on the nickel-plated brass box body 13 with 179°C solder paste, and the detachable SMA connector 16 is fixed on the box body 13 with M2×5 pan head screws 15.

[0061] 2) The diode bridge stack 19 is vertically soldered on the double-sided microwave circuit board 12 .

[0062] In this embodiment, please refer to Figure 1 and Figure 7 , a flag 3 can be set on the diode bridge stack 19, and the flag 3 is used to identify each port of the diode bridge stack. In this embodiment, each port is led out in the form of a lead, wherein the flag 3 corresponds to the first lead 2, that is, the first port of the diode bridge stack 19, and the second lead 6 corresponds to the third port of the diode bridge stack 19 in a counterclockwise direction, the third lead 18 corresponds to the second port of the diode bridge stack 19, and the fourth lead 14 corresponds to the fourth port of the diode bridge stack 19. On this basis, the method of welding the diode bridge stack 19 to the double-sided microwave circuit board 12 can be:

[0063] Place the box body manufactured according to step 1) on the table with the front side facing up, then weld the first lead 2 in the counterclockwise direction at the marked position 3 on the diode bridge stack 19 to the first input suspension strip line 1 as short as possible after forming, and then weld the second lead 6 in the counterclockwise direction to the first output suspension strip line 10 as short as possible after forming; then place the completed box body on the table with the back side facing up, weld the third lead 18 in the counterclockwise direction at the marked position 3 on the diode bridge stack 19 to the first output suspension strip line 17 as short as possible after forming, and weld the fourth lead 14 in the counterclockwise direction to the second output suspension strip line 20 as short as possible after forming, and the diode bridge stack 19 is welded.

[0064] Optionally, refer to Figure 1 As a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, a first end of the input short-circuit line 7 is provided with a first metallized hole, and the input short-circuit line 7 is grounded through the first metallized hole.

[0065] A second metallized hole 4 is provided at the first end of the first output short circuit line 5, and the first output short circuit line 5 is grounded through the second metallized hole 4. A third metallized hole is provided at the first end of the second output short circuit line 9, and the second output short circuit line 9 is grounded through the third metallized hole.

[0066] Optionally, as a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the apertures of the first metallized hole, the second metallized hole, and the third metallized hole are 0.5 mm.

[0067] Optionally, as a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the double-sided microwave circuit board is a low dielectric constant double-sided microwave circuit board.

[0068] Optionally, as a specific implementation of the broadband passive doubler provided in an embodiment of the present invention, the dielectric constant of the double-sided microwave circuit board is 2.2.

[0069] From the above description, it can be seen that the suspended stripline balun and its matching circuit (3-segment short-circuit line) made of a double-sided microwave circuit board with a low dielectric constant in the embodiment of the present invention effectively reduce the frequency multiplication loss of the frequency doubler, and the three-dimensional assembly method of the diode bridge stack reduces the parasitic constant between the bridge stack and the matching circuit. Various indicators are better than those of doublers using other structures.

[0070] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A broadband passive doubler, characterized in that: include: A double-sided microwave circuit board, a first input suspension microstrip line, a second input suspension microstrip line, an input short-circuit line, a diode bridge stack, a first output suspension microstrip line, a second output suspension microstrip line, a first output short-circuit line, and a second output short-circuit line; The first input suspension microstrip line and the first output suspension microstrip line are arranged on the front side of the double-sided microwave circuit board, the second input suspension microstrip line and the second output suspension microstrip line are arranged on the reverse side of the double-sided microwave circuit board, and the diode bridge stack is arranged at a preset window position of the double-sided microwave circuit board, and runs through the double-sided microwave circuit board; The first end of the first input suspension microstrip line is grounded, and the first end of the second input suspension microstrip line is the input end of the broadband passive doubler; the second end of the first input suspension microstrip line is connected to the first end of the diode bridge stack, the second end of the second input suspension microstrip line is connected to the second end of the diode bridge stack, the third end of the diode bridge stack is connected to the first end of the first output suspension microstrip line, and the fourth end of the diode bridge stack is connected to the first end of the second output suspension microstrip line; the second end of the first output suspension microstrip line is grounded, and the second end of the second output suspension microstrip line is the output end of the broadband passive doubler; The first end of the input short-circuit line is grounded, and the second end is connected to the first end of the diode bridge stack; or the first end of the input short-circuit line is grounded, and the second end is connected to the second end of the diode bridge stack; The first end of the first output short-circuit line is grounded, and the second end is connected to the third end of the diode bridge stack; the first end of the second output short-circuit line is grounded, and the second end is connected to the fourth end of the diode bridge stack.

2. The broadband passive doubler as claimed in claim 1, characterized in that: It also includes a box body, an input radio frequency insulator, and an output radio frequency insulator; The double-sided microwave circuit board, the input RF insulator and the output RF insulator are sintered on the box body, the input RF insulator is connected to the first end of the second input suspension microstrip line, and the output RF insulator is connected to the second end of the second output suspension microstrip line.

3. The broadband passive doubler as claimed in claim 2, characterized in that: Also included is a first SMA connector and a second SMA connector; The first SMA connector is connected to the input RF insulator, and the second SMA connector is connected to the output RF insulator; The first SMA connector and the second SMA connector are fixed to the box body by cross screws.

4. The broadband passive doubler as claimed in claim 1, characterized in that: The diode bridge stack includes a first diode, a second diode, a third diode and a fourth diode; The anode terminal of the first diode is the first terminal of the diode bridge stack, the cathode terminal of the first diode is the third terminal of the diode bridge stack, the anode terminal of the third diode is the fourth terminal of the diode bridge stack, and the cathode terminal of the third diode is the second terminal of the diode bridge stack; The cathode terminal of the first diode is connected to the cathode terminal of the second diode, the anode terminal of the second diode is connected to the cathode terminal of the third diode, the anode terminal of the third diode is connected to the anode terminal of the fourth diode, and the cathode terminal of the fourth diode is connected to the anode terminal of the first diode.

5. The broadband passive doubler as claimed in claim 4, characterized in that: The first diode, the second diode, the third diode and the fourth diode are silicon Schottky low barrier diodes.

6. The broadband passive doubler as claimed in claim 1, characterized in that: The plane formed by the diodes in the diode bridge stack is perpendicular to the plane where the double-sided microwave circuit board is located.

7. The broadband passive doubler as claimed in claim 1, characterized in that: A first metallized hole is provided at the first end of the input short-circuit line, and the input short-circuit line is grounded through the first metallized hole; A second metallized hole is provided at the first end of the first output short-circuit line, and the first output short-circuit line is grounded through the second metallized hole; A third metallized hole is disposed at the first end of the second output short-circuit line, and the second output short-circuit line is grounded through the third metallized hole.

8. The broadband passive doubler as claimed in claim 7, characterized in that: The diameters of the first metallized hole, the second metallized hole, and the third metallized hole are 0.5 mm.

9. The broadband passive doubler as claimed in claim 1, characterized in that: The double-sided microwave circuit board is a low dielectric constant double-sided microwave circuit board.

10. The broadband passive doubler as claimed in claim 9, characterized in that: The dielectric constant of the double-sided microwave circuit board is 2.2.

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