A passive-active hybrid circuit capable of reconfiguring four microwave functions

Abstract

The application discloses a passive and active hybrid circuit capable of reconstructing four microwave functions, wherein the resistance, the capacitance and the transistor of the upper layer are reasonably placed on the microstrip line, and are made on the upper surface of the intermediate dielectric layer together with the PIN diode; the lower surface of the dielectric layer is connected with the metal grounding surface, and the size of the metal grounding surface is completely consistent with the size of the lower surface of the dielectric layer. Through the control of the forward and reverse voltage of the PIN diode, the conduction and the disconnection of the diode can be realized, the on-off of the microstrip circuit can be realized, and the function reconstruction of the device can be realized; the function reconstruction device comprises four functions, which are respectively an antenna, a filter, a power amplifier and a mixer, and the filter is a 3-order band-pass filter; the function reconstruction device has the advantages of compact structure, high port multiplexing rate, wide application range, high integration degree, quick switching among the four functions, and independent working in time-sharing mode without affecting each other.

Description

Technical Field

[0001] This invention relates to the field of reconfigurable circuit technology, and in particular to a passive-active hybrid circuit capable of reconfiguring four microwave functions. Background Technology

[0002] With the development of wireless communication technology, microwave devices with various functions have emerged one after another, and spectrum resources are being utilized more and more fully. Generally speaking, different circuit functions and operating frequency bands often require multiple different microwave devices to realize. Due to the single function of general microwave devices, the application scenarios are very limited. Functionally reconfigurable microwave devices integrate the different functions of multiple devices into one device, and can be used in various different application scenarios through function switching, thus greatly expanding the application range of a single microwave device. In recent years, some scholars have been studying functionally reconfigurable microwave devices, but the existing functionally reconfigurable devices have the following problems: (1) lack of reconfigurability for active circuits (2) low port reuse rate (3) no research on passive-active hybrid circuit reconfiguration technology (4) insufficient function switching speed. Summary of the Invention

[0003] The present invention aims to overcome the lack of reconfigurability of active circuits in the prior art and the absence of reconfiguration technology for passive-active hybrid circuits, and provides a passive-active hybrid circuit that can reconfigure four microwave functions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A reconfigurable passive-active hybrid circuit with four microwave functions includes a hybrid circuit mounted on a circuit board. The circuit board consists of a three-layer structure (upper, middle, and lower), with the hybrid circuit located on the upper layer and a metal ground plane on the lower layer. The hybrid circuit includes four operating modes: antenna mode, filter mode, power amplifier mode, and mixer mode. This invention provides a reconfigurable passive-active hybrid circuit with four microwave functions, achieving integrated active and passive microwave functionality. This reconfigurable circuit combines the functions of an antenna, filter, power amplifier, and mixer into one unit. The filter is a third-order bandpass filter, the antenna is a microstrip monopole antenna, the power amplifier is a broadband power amplifier, and the mixer is an active downconverter. Each function can operate independently and in a time-division multiplexing manner without interference.

[0006] In a preferred embodiment of the present invention, the hybrid circuit has three ports: Port1, Port2, and Port3. The hybrid circuit also includes several PIN diodes, several microstrip lines, resistors, capacitors, transistors, and switches. The PIN diodes include a first PIN diode to a fifth PIN diode. Different operating modes are switched by controlling the on / off state of these PIN diodes. The present invention, by controlling the forward and reverse voltages of the PIN diodes, can realize the conduction and disconnection of the diodes, thereby realizing the on / off state of the microstrip circuit and achieving functional reconfigurability of the device.

[0007] As a preferred embodiment of the present invention, the hybrid circuit is specifically configured as follows: Port 1 is connected to one end of the sixth microstrip line and one end of the ninth microstrip line via a first microstrip line; Port 2 is connected to the positive terminal of the first PIN diode and the other end of the sixth microstrip line via a second microstrip line; Port 3 is connected to a single-pole three-throw switch via a thirty-first microstrip line; the negative terminal of the first PIN diode is connected to one end of the seventh microstrip line and the positive terminal of the second PIN diode via a third microstrip line; and the negative terminal of the second PIN diode is connected to the first microstrip line and the other end of the sixth microstrip line via a fourth microstrip line. One end of the fifth microstrip line is connected to one end of the eighth microstrip line. The other end of the ninth microstrip line is connected to the other end of the seventh microstrip line and one end of the tenth microstrip line. The other end of the tenth microstrip line is connected to the other end of the eighth microstrip line and one end of the eleventh microstrip line. The eleventh microstrip line is connected to the positive terminals of the third and fourth PIN diodes. The negative terminal of the third PIN diode is connected to one end of the first DC blocking capacitor through the thirteenth microstrip line. The other end of the first DC blocking capacitor is connected sequentially through the fourteenth, fifteenth, and sixteenth microstrip lines. One end of the 17th microstrip line, one end of the first resistor, and one end of the first capacitor are connected. The negative terminal of the fourth PIN diode is connected to one end of the 29th microstrip line and one end of the 30th microstrip line via the 12th microstrip line. The other end of the 30th microstrip line is connected to a single-pole three-throw switch. One end of the 18th microstrip line is connected to the other end of the first resistor and the other end of the first capacitor. The other end of the 18th microstrip line is connected to one end of the 21st microstrip line via a transistor. The 18th microstrip line is also connected to the 19th microstrip line via an inductor. The other end of the 21st microstrip line is connected to a second DC blocking transistor. A capacitor is connected to one end of the 22nd microstrip line. The 21st microstrip line is also connected to the 20th microstrip line via an inductor. The other end of the 22nd microstrip line is connected to the positive terminal of the 5th PIN diode and one end of the 25th microstrip line. The negative terminal of the 5th PIN diode is connected to a single-pole triple-throw switch via the 23rd and 24th microstrip lines. The other end of the 25th microstrip line is connected to one end of the 26th microstrip line via a capacitor-inductor filter. The other end of the 26th microstrip line is connected to a single-pole triple-throw switch via the 27th and 28th microstrip lines. This invention's reconfigurable passive-active hybrid circuit with four microwave functions includes four functions: antenna, filter, power amplifier, and mixer. The filter is a 3rd-order bandpass filter, the antenna is a microstrip monopole antenna, the power amplifier is a broadband power amplifier, and the mixer is an active downconverter. This reconfigurable device has a compact structure, high port reuse rate, wide application range, and high integration. The four functions can be quickly switched and can operate independently in a time-division multiplexing manner without interference.

[0008] As a preferred embodiment of the present invention, when the hybrid circuit operates in antenna mode, the first PIN diode, the second PIN diode, the third PIN diode, the fourth PIN diode, and the fifth PIN diode are all disconnected, and the single-pole triple-throw switch turns on the 31st microstrip line and the 30th microstrip line, and the 12th microstrip line, the 29th microstrip line, the 30th microstrip line, and the 31st microstrip line are operational.

[0009] In a preferred embodiment of the present invention, when the hybrid circuit operates in filter mode, the fourth PIN diode is turned on, and the first, second, third, and fifth PIN diodes are turned off. The single-pole triple-throw switch turns on the thirty-first and thirtieth microstrip lines, and the first, second, third, fourth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirtieth, and thirty-first microstrip lines are operational.

[0010] In a preferred embodiment of the present invention, when the hybrid circuit operates in power amplifier mode, the third PIN diode and the fifth PIN diode are turned on, while the first PIN diode, the second PIN diode, and the fourth PIN diode are turned off. The single-pole triple-throw switch turns on the thirty-first microstrip line and the twenty-fourth microstrip line. The first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the sixth microstrip line, the seventh microstrip line, the eighth microstrip line, the ninth microstrip line, the tenth microstrip line, the eleventh microstrip line, the thirteenth microstrip line, the first DC blocking capacitor, the fourteenth microstrip line, the fifteenth microstrip line, the sixteenth microstrip line, the seventeenth microstrip line, the first resistor, the first capacitor, the eighteenth microstrip line, the nineteenth microstrip line, the twentieth microstrip line, the inductor, the transistor, the twenty-first microstrip line, the second DC blocking capacitor, the twenty-second microstrip line, the twenty-third microstrip line, the twenty-fourth microstrip line, the twenty-fifth microstrip line, the capacitor-inductor filter, and the thirty-first microstrip line are all operational.

[0011] In a preferred embodiment of the present invention, when the hybrid circuit operates in mixer mode, the first PIN diode, the second PIN diode, and the third PIN diode are turned on, the fourth PIN diode and the fifth PIN diode are turned off, and the single-pole triple-throw switch turns on the thirty-first microstrip line and the twenty-eighth microstrip line. The first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the sixth microstrip line, the seventh microstrip line, the eighth microstrip line, the ninth microstrip line, the tenth microstrip line, the eleventh microstrip line, the thirteenth microstrip line, the first DC blocking capacitor, the fourteenth microstrip line, the fifteenth microstrip line, the sixteenth microstrip line, the seventeenth microstrip line, the first resistor, the first capacitor, the eighteenth microstrip line, the nineteenth microstrip line, the twentieth microstrip line, the inductor, the transistor, the twenty-first microstrip line, the second DC blocking capacitor, the twenty-second microstrip line, the twenty-fifth microstrip line, the capacitor-inductor filter, the twenty-sixth microstrip line, the twenty-seventh microstrip line, the twenty-eighth microstrip line, and the thirty-first microstrip line are operational.

[0012] In a preferred embodiment of the present invention, Port1, Port2, and Port3 are multiplexed. When the hybrid circuit operates in antenna mode, Port3 is the antenna receiving port; when the hybrid circuit operates in filter mode, Port1 is the input port and Port3 is the output port; when the hybrid circuit operates in power amplifier mode, Port1 is the RF signal input port and Port3 is the power amplifier output port; when the hybrid circuit operates in mixer mode, Port1 is the RF input port, Port2 is the local oscillator input port, and Port3 is the intermediate frequency output port. The present invention exhibits high reusability, demonstrating circuit multiplexing and port multiplexing, thus reducing circuit size and the number of ports.

[0013] As a preferred embodiment of the present invention, the middle layer of the circuit board is a dielectric layer, the dielectric substrate material is Rogers 4350 with a relative permittivity of 3.66, the dielectric substrate thickness is 0.762 mm, and the metal part is made of copper.

[0014] Therefore, the present invention has the following beneficial effects: (1) It realizes the active and passive hybrid integration of microwave functions. The reconfigurable circuit realizes the four functions of antenna, filter, power amplifier and mixer in one, and each function can work independently in time division without interfering with each other. (2) It has high reusability, presenting circuit reuse and port reuse, reducing the circuit size and the number of ports. Attached Figure Description

[0015] Figure 1 This is an overall circuit diagram of a passive-active hybrid circuit capable of reconfiguring four microwave functions according to the present invention.

[0016] Figure 2 This is a circuit structure diagram of the hybrid circuit of the present invention when it operates in antenna mode.

[0017] Figure 3 This is a circuit structure diagram of the hybrid circuit of the present invention when it operates in filter mode.

[0018] Figure 4 This is a circuit structure diagram of the hybrid circuit of the present invention when it operates in power amplifier mode.

[0019] Figure 5 This is a circuit structure diagram of the hybrid circuit of the present invention when it operates in mixer mode.

[0020] Figure 6 The S-parameter simulation diagram of the hybrid circuit of the present invention when operating in antenna mode.

[0021] Figure 7 Simulation diagram of the hybrid circuit of the present invention operating in filter mode.

[0022] Figure 8 The spectrum simulation diagram of the hybrid circuit of the present invention when operating in power amplifier mode.

[0023] Figure 9 The S-parameter simulation diagram of the hybrid circuit of the present invention when operating in power amplifier mode.

[0024] Figure 10 The spectrum simulation diagram of the hybrid circuit of the present invention when operating in mixer mode.

[0025] Figure 11 The S-parameter simulation diagram of the hybrid circuit of the present invention when operating in mixer mode.

[0026] In the diagram: 1. First microstrip line; 2. Second microstrip line; 3. First PIN diode; 4. Third microstrip line; 5. Second PIN diode; 6. Fourth microstrip line; 7. Fifth microstrip line; 8. Sixth microstrip line; 9. Seventh microstrip line; 10. Eighth microstrip line; 11. Ninth microstrip line; 12. Tenth microstrip line; 13. Eleventh microstrip line; 14. Third PIN diode; 15. Fourth PIN diode; 16. Twelfth microstrip line; 17. Thirteenth microstrip line; 18. First DC blocking capacitor; 19. Fourteenth microstrip line; 20. Fifteenth microstrip line; 21. Sixteenth microstrip line; 22. Seventeenth microstrip line; 23. ... 1. Resistor; 24. First capacitor; 25. Eighteenth microstrip line; 26. Nineteenth microstrip line; 27. Twentieth microstrip line; 28. Inductor; 29. ​​Transistor; 30. Twenty-first microstrip line; 31. Second DC blocking capacitor; 32. Twenty-second microstrip line; 33. Fifth PIN diode; 34. Twenty-third microstrip line; 35. Twenty-fourth microstrip line; 36. Twenty-fifth microstrip line; 37. Capacitor-inductor filter; 38. Twenty-sixth microstrip line; 39. Twenty-seventh microstrip line; 40. Twenty-eighth microstrip line; 41. Twenty-ninth microstrip line; 42. Thirtieth microstrip line; 43. Single-pole three-throw switch; 44. Thirty-first microstrip line. Detailed Implementation

[0027] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0028] Referring to the accompanying drawings, this invention discloses a passive-active hybrid circuit capable of reconfiguring four microwave functions, comprising an upper metal microstrip section, resistors, capacitors, transistors, and PIN diodes, a middle dielectric layer section, and a lower metal grounding section. The upper layer is fabricated on the upper surface of the dielectric layer, the lower layer overlaps with the lower surface of the dielectric layer, and the middle layer is the dielectric layer itself. The dielectric substrate material is Rogers 4350 with a relative permittivity of 3.66 and a thickness of 0.762 mm. The metal portion is made of copper. The circuit has three ports: Port1 and Port2 are located on the left side of the circuit, and Port3 is located on the right side. All three ports are connected to a 50-ohm microstrip line.

[0029] Figure 1 This is the overall circuit diagram of a functionally reconfigurable planar microwave passive-active circuit. The circuit structure can be controlled by switching the PIN diodes on and off, thus achieving functional reconfiguration. The hybrid functionally reconfigurable circuit of this invention can realize four functions: antenna, filter, power amplifier, and mixer. Figures 2-5 This is a circuit structure diagram when each function works independently. The bold part represents the structure in which each functional circuit participates in the operation when working independently. Figure 6 These are the results of antenna simulation. Figure 7 These are the results of the filter simulation. Figure 8and Figure 9 These are the results of the power amplifier simulation. Figure 10 and Figure 11 These are the results of mixer simulation.

[0030] like Figure 1As shown, a passive-active hybrid circuit capable of reconfiguring four microwave functions includes: a first microstrip line 1, a second microstrip line 2, a first PIN diode 3, a third microstrip line 4, a second PIN diode 5, a fourth microstrip line 6, a fifth microstrip line 7, a sixth microstrip line 8, a seventh microstrip line 9, an eighth microstrip line 10, a ninth microstrip line 11, a tenth microstrip line 12, an eleventh microstrip line 13, a third PIN diode 14, a fourth PIN diode 15, a twelfth microstrip line 16, a thirteenth microstrip line 17, a first DC blocking capacitor 18, a fourteenth microstrip line 19, a fifteenth microstrip line 20, a sixteenth microstrip line 21, and a tenth microstrip line 22. 22. Microstrip line 7, 23. First resistor, 24. First capacitor, 25. Eighteenth microstrip line, 26. Nineteenth microstrip line, 27. Twentieth microstrip line, 28. Inductor, 29. Transistor, 30. Twenty-first microstrip line, 31. Second DC blocking capacitor, 32. Twenty-second microstrip line, 33. Fifth PIN diode, 34. Twenty-third microstrip line, 35. Twenty-fourth microstrip line, 36. Twenty-fifth microstrip line, 37. Capacitor-inductor filter, 38. Twenty-sixth microstrip line, 39. Twenty-seventh microstrip line, 40. Twenty-eighth microstrip line, 41. Twenty-ninth microstrip line, 42. Thirtieth microstrip line, 43. Single-pole three-throw switch, 44. Thirty-first microstrip line. Port 1 is connected to one end of the first microstrip line 1, Port 2 is connected to one end of the second microstrip line 2, and Port 3 is connected to one end of the thirty-first microstrip line 44. The other end of the first microstrip line 1 is connected to one end of the sixth microstrip line 8 and one end of the ninth microstrip line 11, respectively. The other end of the second microstrip line 2 is connected to the positive terminal of the first PIN diode 3 and the other end of the sixth microstrip line 8, respectively. The negative terminal of the first PIN diode 3 is connected to one end of the third microstrip line 4, and the other end of the third microstrip line 4 is connected to one end of the seventh microstrip line 9 and the positive terminal of the second PIN diode 5, respectively. The negative terminal of the second PIN diode 5 is connected to one end of the fourth microstrip line 6, and the other end of the seventh microstrip line 9 is connected to the other end of the ninth microstrip line 11 and one end of the tenth microstrip line 12, respectively. The other end of the fourth microstrip line 6 is connected to one end of the fifth microstrip line 7, respectively. One end of the eighth microstrip line 10 is connected to the fifth microstrip line 7, which is connected to a 50-ohm matching load. The other end of the eighth microstrip line 10 is connected to the other end of the tenth microstrip line 12 and one end of the eleventh microstrip line 13. The other end of the eleventh microstrip line 13 is connected to the positive terminal of the third PIN diode 14 and the positive terminal of the fourth PIN diode 15. The negative terminal of the fourth PIN diode 15 is connected to one end of the twelfth microstrip line 16. The other end of the twelfth microstrip line 16 is connected to one end of the twenty-ninth microstrip line 41 and one end of the thirtieth microstrip line 42. The other end of the thirtieth microstrip line 42 is connected to the single-pole three-throw switch 43. The negative terminal of the third PIN diode 14 is connected to one end of the first DC blocking capacitor 18 through the thirteenth microstrip line 17. The other end of the first DC blocking capacitor 18 is connected to one end of the fifteenth microstrip line 20 through the fourteenth microstrip line 19.The other end of the fifteenth microstrip line is connected to one end of the seventeenth microstrip line 22, one end of the first resistor 23, and one end of the first capacitor 24 via the sixteenth microstrip line 21. One end of the eighteenth microstrip line 25 is connected to the other end of the first resistor 23 and the other end of the first capacitor 24. The other end of the eighteenth microstrip line 25 is connected to one end of the twenty-first microstrip line 30 via transistor 29. The eighteenth microstrip line is also connected to the nineteenth microstrip line 26 via inductor 28. The other end of the twenty-first microstrip line 30 is connected to one end of the twenty-second microstrip line 32 via the second DC blocking capacitor 31. The twenty-first microstrip line 30 is also connected to the twentieth microstrip line 26 via inductor 28. The other end of the twenty-second microstrip line 32 is connected to the positive terminal of the fifth PIN diode 33 and one end of the twenty-fifth microstrip line 36. The negative terminal of the fifth PIN diode 33 is connected to the single-pole triple-throw switch 43 via the twenty-third microstrip line 34 and the twenty-fourth microstrip line 35. The other end of the twenty-fifth microstrip line 36 is connected to one end of the twenty-sixth microstrip line 38 via the capacitor-inductor filter 37. The other end of the twenty-sixth microstrip line 38 is connected to the single-pole triple-throw switch 43 via the twenty-seventh microstrip line 39 and the twenty-eighth microstrip line 40. The other end of the thirty-first microstrip line 44 is connected to the single-pole triple-throw switch 43.

[0031] Example 1: A hybrid-function reconfigurable circuit implements antenna functionality. When the first PIN diode 3, the second PIN diode 5, the third PIN diode 14, the fourth PIN diode 15, and the fifth PIN diode 33 are all off, the twelfth microstrip line 16, the twenty-ninth microstrip line 41, the thirtieth microstrip line 42, and the thirty-first microstrip line 44 operate to form an inverted-F monopole antenna. Port 3 is the antenna receiving port, and the device is in antenna function mode, such as... Figure 2 As shown.

[0032] The design of an inverted-F antenna is mainly determined by three parameters: the radiating microstrip line (i.e., the 29th microstrip line), and the length L. 41 The matching line, i.e., the twelfth microstrip line, is 16mm long. 16 And the position of the twelfth microstrip line 16 at the antenna receiving port line, i.e., the thirtieth microstrip line 42.

[0033] Length L of the radiating microstrip line 41 Roughly equal to λ e / 2, primarily determines the antenna's resonant frequency.

[0034]

[0035] λ e Where λ is the operating wavelength, c is the speed of light, f is the operating frequency, and ε is the operating frequency. eff It is the effective dielectric constant.

[0036] In practical design, the microstrip open-circuit edge shortening effect needs to be taken into account.

[0037]

[0038] Where ΔL is the equivalent microstrip line length of the open-circuit capacitance.

[0039] Since the inverted-F antenna radiating microstrip introduces capacitive reactance, we need to introduce inductive matching for the purpose of matching. Here, we use a value greater than λ. e The open-circuit microstrip line 16 (i.e., the twelfth microstrip line) introduces inductive reactance to counteract the reactance of the radiating microstrip. The reactance component introduced by the matching line can be derived from the following formula.

[0040] Z in =jZ0tanθ

[0041] Among them, Z in Z0 is the input impedance, Z0 is the characteristic impedance of the microstrip line, and θ is the electrical length of the microstrip line.

[0042] The position of the matching line, i.e., the twelfth microstrip line 16, also affects the antenna's resonant frequency. Increasing L... 16 This will increase the capacitance, and a suitable location can be obtained through software simulation. The simulation results are as follows: Figure 6 As shown.

[0043] Example 2: A hybrid-function reconfigurable circuit implements a filter function. When the fourth PIN diode 15 is turned on, and the first PIN diode 3, the second PIN diode 5, the third PIN diode 14, and the fifth PIN diode 33 are turned off, the first microstrip line 1, the second microstrip line 2, the third microstrip line 4, the fourth microstrip line 6, the sixth microstrip line 8, the seventh microstrip line 9, the eighth microstrip line 10, the ninth microstrip line 11, the tenth microstrip line 12, the eleventh microstrip line 13, the twelfth microstrip line 16, the thirtieth microstrip line 42, and the thirty-first microstrip line 44 are operational. Port 1 is the input port, and Port 3 is the output port. The device is in filter function mode, as shown below. Figure 3 As shown.

[0044] The functionally reconfigurable filter of this invention is a branch-line bandwidth filter. It utilizes PIN diodes to achieve functional reconfigurability. The function switching between the filter and a broadband 3-branch coupler is achieved by controlling the on / off states of the first PIN diode 3 and the second PIN diode 5. When the first PIN diode 3 and the second PIN diode 5 are on, it functions as a broadband 3-branch coupler with an operating bandwidth of 1.2GHz-1.8GHz and a coupler isolation of 25dB. When the first PIN diode 3 and the second PIN diode 5 are off, it functions as a filter with an operating bandwidth of 1.2GHz-1.8GHz, an insertion loss of 0.9dB, and an in-band reflection of 15dB. Simulation results are as follows: Figure 7As shown.

[0045] The design process is as follows: the functional reconstructed filter in this design mainly consists of λ g The filter consists of a 4-terminal short-circuit resonator and a JK converter, forming a third-order filter with a parallel-series-parallel resonant topology. To achieve functional reconfiguration, considering the reuse of the filter with a 3-branch coupler structure, the main idea is to change the current flow path of one main circuit in the coupler. The bandwidth of a 2-branch coupler structure is generally no more than 20%, so a 3-branch coupler structure is adopted to extend the bandwidth. Coupler size design is relatively easy; the lengths of the three branches—the sixth microstrip line 8, the seventh microstrip line 9, and the eighth microstrip line 10—are all λ. g / 4 line segment, the third microstrip line 4, the fourth microstrip line 6, the ninth microstrip line 11, and the tenth microstrip line 12 of each segment of the two main roads are also λ. g / 4 segment length. To achieve matching and isolation between port1 and port2, the width of each branch line and the width of the main path are controlled.

[0046] The design width of the main paths of the third microstrip line 4, the fourth microstrip line 6, the ninth microstrip line 11, and the tenth microstrip line 12 is:

[0047]

[0048] W4, W6, W11, and W12 are the widths of the third microstrip line 4, the fourth microstrip line 6, the ninth microstrip line 11, and the tenth microstrip line 12, respectively.

[0049] The design widths of branches 8 (sixth microstrip line), 9 (seventh microstrip line), and 10 (eighth microstrip line) are:

[0050]

[0051]

[0052] W8, W9, W 10 These are the widths of the sixth microstrip line 8, the seventh microstrip line 9, and the eighth microstrip line 10, respectively.

[0053] The structure of the 3-branch broadband coupler has been given, and it can be seen that the length of each main branch segment is λ. g / 4, for a filter, this constitutes the resonant unit of the filter. In order to realize a bandpass filter, all three branches are designed to be short-circuited at the termination λ. gA 4-segment microstrip line is used to form three parallel resonant units. The main path's third microstrip line 4, fourth microstrip line 6, ninth microstrip line 11, and tenth microstrip line 12 constitute a JK converter, transforming the parallel resonance formed by the seventh microstrip line 9 into a series resonance, thus forming a bandpass topology. By disconnecting the first PIN diode 3 and the second PIN diode 5, three independent branches—the sixth microstrip line 8, the seventh microstrip line 9, and the eighth microstrip line 10—are formed, along with two independent main path segments: the third microstrip line 4 and the fourth microstrip line 6. The λ-strip line is terminated with an open circuit. g The input impedance of the / 4 segment is 0, which precisely forms a short-circuit ground for three resonant units; however, simply disconnecting the first PIN diode 3 and the second PIN diode 5 only forms two parallel resonant units. Therefore, without changing the function of the coupler, we modified the length of the coupler transmission segment, i.e., the second microstrip line 2, and designed it to be λ. g / 4, For phase balance, the coupler transmission line segment, i.e., the first microstrip line 1, is also designed as λ. g / 4. By turning off the PIN diode, we change the current path of the coupler, thus achieving a filtering path.

[0054] Example 3: A hybrid reconfigurable circuit implements a power amplifier function. When the third PIN diode 14 and the fifth PIN diode 33 are turned on, and the first PIN diode 3, the second PIN diode 5, and the fourth PIN diode 15 are turned off, the following microstrip lines are connected: first microstrip line 1, second microstrip line 2, third microstrip line 4, fourth microstrip line 6, sixth microstrip line 8, seventh microstrip line 9, eighth microstrip line 10, ninth microstrip line 11, tenth microstrip line 12, eleventh microstrip line 13, thirteenth microstrip line 17, first DC blocking capacitor 18, fourteenth microstrip line 19, fifteenth microstrip line 20, sixteenth microstrip line 21, and seventeenth microstrip line. 22. First resistor; 23. First capacitor; 24. Eighteenth microstrip line; 25. Nineteenth microstrip line; 26. Twentieth microstrip line; 27. Inductor; 28. Transistor; 29. ​​Twenty-first microstrip line; 30. Second DC blocking capacitor; 31. Twenty-second microstrip line; 32. Twenty-third microstrip line; 34. Twenty-fourth microstrip line; 35. Twenty-fifth microstrip line; 36. Capacitor-inductor filter; 37. and thirty-first microstrip line 44 are operating. Port 1 is the RF signal input port, and Port 3 is the power amplifier output port. The device is in power amplifier mode. Figure 4 As shown.

[0055] The power amplifier designed in this invention operates in the frequency band of 0.8GHz-1.8GHz, maintains an in-band 1dB gain compression point above 38dBm, achieves a 1dB gain of above 14.5dB, and maintains an efficiency of above 50%.

[0056] The main function of a power amplifier is to amplify power. Commonly used power amplifiers include Class A, Class B, and Class AB. Class A has the best linearity, but its efficiency is only up to 50%. Class B can theoretically reach 100% efficiency, but its linearity is poor. Considering all factors, Class AB power amplifiers are the best choice.

[0057] As an active circuit, the power amplifier requires transistor 29. Here we need to use GaAs-based METFET as the amplification device. The main work of the power amplifier focuses on stability analysis, gate and drain bias circuit design, and input and output matching circuit.

[0058] The standard procedure for designing a power amplifier is to first perform a DC scan based on the amplifier's operating type to determine the quiescent operating point. Here, we choose a Class AB power amplifier. After performing a DC scan on transistor 29 using ADS software, the quiescent operating points are determined to be Ugs = -2.2V, Uds = 28V, and ids = 200mA. Ugs is the gate bias voltage, Uds is the drain bias voltage, and ids is the drain current.

[0059] Next, the bias circuits for the gate and drain need to be determined. For the bias circuit design, it's generally desirable to prevent RF signals from entering the bias circuit as much as possible, while DC signals should be prevented from entering the input / output ports of the power amplifier, i.e., Port1 and Port2. Because capacitors pass AC while blocking DC, and inductors pass DC while blocking AC, capacitors of several tens of picofarads are typically placed at Port1 and Port2 to suppress DC signals, while inductors of type 28 are generally used in the bias circuit to suppress RF signals. Besides using a lumped inductor of type 28, the bias circuit can also be configured as a 1 / 4 wavelength microstrip line, grounded through a microstrip sector capacitor. However, the bandwidth achieved by this method is often less than 50% due to the 1 / 4 wavelength microstrip line. Therefore, to achieve a broadband power amplifier, a lumped inductor of type 28 is used to build the bias circuit. Furthermore, since the bias circuit ultimately requires an external bias voltage, three capacitors of different magnitudes need to be added near the power supply to filter low-frequency spurious signals from the power supply, ultimately increasing the stability of the bias voltage.

[0060] After the bias circuit design is completed, stability analysis of transistor 29 is required. The bias circuit and transistor 29 are analyzed together for stability. According to the transistor 29 manufacturer's datasheet, transistor 29 is unstable in the operating frequency range of 0.8-1.8 ohms. However, in practice, by simulating the S-parameters using software and calculating K using formulas, a stable result is achieved. Both the calculation and software simulation show that transistor 29 is unstable at the operating frequency. Therefore, a parallel network of resistors and capacitors is needed to achieve stability. Here, we choose an 18-ohm resistor and a 3pF capacitor.

[0061] After the stability analysis is completed, the input and output matching circuits need to be designed. Since transistor 29 has good reverse isolation, a unidirectional design can be adopted. First, consider the output matching circuit design. The purpose of a power amplifier is to transfer more power to the load. To achieve maximum power transfer, conjugate matching is generally used, that is, matching the 50-ohm load to the conjugate of the output impedance of transistor 29 through a matching circuit. Following this principle, the output impedance of transistor 29 needs to be known first. Here, the load impedance is obtained using the load pulling tool in ADS software, and the matching circuit is designed based on this impedance. To create a broadband power amplifier, stepped impedance is used for matching, and a short-circuit stub is added to adjust the matching. The input matching circuit design is similar and will not be elaborated further.

[0062] In order not to affect the power amplifier gain, the first PIN diode 3 and the second PIN diode 5 need to be turned off to suppress the 3dB coupler function at the input end and convert it into an input with low insertion loss filtering characteristics.

[0063] After the circuit modules are designed, the power amplifier needs to be simulated in ADS software. First, S-parameter small-signal simulation is performed, followed by harmonic simulation to observe the 1dB gain compression point, third-order intermodulation, efficiency, and other large-signal simulation results. The results are as follows: Figures 8-9 As shown. Figure 8 The harmonic simulation results of the power amplifier are presented. From the figure, we can see that the saturated output power of the power amplifier reaches 41dBm in the operating frequency range of 1.2GHz-1.8GHz, the 1dB gain compression point is greater than 38dBm, and the third-order intermodulation rejection ratio is greater than 13dB. Figure 9 The small-signal simulation results of the power amplifier are presented. Figure 9 (a) and Figure 9 (d) represents the reflection coefficients of the input and output ports of the power amplifier, respectively. It can be seen that the input port operates in the range of 1.2-1.8 GHz, and the output port operates in the range of 0.8-2.2 GHz. Figure 9 (b) indicates the small-signal gain of the power amplifier, with an average gain of 13dB in the 1.2-1.8GHz bandwidth range. Figure 9 (c) indicates the reverse isolation characteristic of the power amplifier, showing an isolation level of over 30dB.

[0064] Example 4: A hybrid reconfigurable circuit implements a mixer function. When the first PIN diode 3, the second PIN diode 5, and the third PIN diode 14 are turned on, and the fourth PIN diode 15 and the fifth PIN diode 33 are turned off, the following microstrip lines are connected: first microstrip line 1, second microstrip line 2, third microstrip line 4, fourth microstrip line 6, sixth microstrip line 8, seventh microstrip line 9, eighth microstrip line 10, ninth microstrip line 11, tenth microstrip line 12, eleventh microstrip line 13, thirteenth microstrip line 17, first DC blocking capacitor 18, fourteenth microstrip line 19, fifteenth microstrip line 20, sixteenth microstrip line 21, seventeenth microstrip line 22, and first resistor 23. The following components are in operation: 1. First capacitor 24; 2. Eighteenth microstrip line 25; 2. Nineteenth microstrip line 26; 2. Twentieth microstrip line 27; 2. Inductor 28; 29. ​​Transistor 29; 30. Twenty-first microstrip line 31; 31. Second DC blocking capacitor 32; 32. Twenty-fifth microstrip line 36; 37. Capacitor-inductor filter 37; 38. Twenty-sixth microstrip line 38; 39. Twenty-seventh microstrip line 39; 40. Twenty-eighth microstrip line 40; and 44. Port 1 is the RF input port, Port 2 is the local oscillator input port, and Port 3 is the intermediate frequency output port. The device is in mixer mode. Figure 5 As shown.

[0065] The mixer designed in this invention has an intermediate frequency output of 200MHz-600MHz, a local oscillator input of 1.2GHz-1.8GHz, and an RF input of 1.2GHz-1.8GHz. Combined with... Figure 5 As can be seen, this invention designs an active down-conversion mixer. Port 1 is the RF input port, Port 2 is the local oscillator input port, and Port 3 is the intermediate frequency output port. Single-ended mixers are characterized by their simple structure and earliest application. Based on the location of the local oscillator signal, they can be classified into gate mixers, drain mixers, and source mixers. Since gate mixers are simple to design, this mixer design adopts a single-ended gate mixer topology for the purpose of verifying the idea.

[0066] This invention is a functionally reconfigurable design. To realize the idea of ​​an active functionally reconfigurable circuit, a transistor 29 multiplexing strategy is adopted. By controlling the bias voltage of transistor 29, transistor 29 can operate in different operating regions. That is, when a transistor 29 is in a power amplifier circuit, it controls the bias voltage and is used as a power amplifier tube; when it is in a mixer circuit, it acts as a nonlinear device to achieve mixing.

[0067] The standard procedure for mixer design is to first determine the quiescent operating point. Since gate mixing typically relies on strong transconductance switching characteristics, the quiescent operating point is usually chosen near the cutoff region. Based on the output characteristic curve of transistor 29, the quiescent operating bias voltage and current parameters can be determined, with Vgs controlled at -3V and Vds controlled at 28V.

[0068] Once the quiescent operating point is determined, the mixer's bias circuit can be designed. For functional reconfiguration, the nineteenth microstrip line 26, the twentieth microstrip line 27, and the inductor and capacitor 28 are multiplexed with the power amplifier circuit. Since the gate bias voltage change is not significant and the frequency bands are consistent during functional multiplexing, the input matching circuit of the power amplifier is used for the mixer input matching. Because the mixer's gate input requires two signals—an RF signal and a local oscillator signal—and these signals are in close frequency bands, a coupler is designed to increase the isolation between the two input ports and prevent interference with other devices. The coupler design has been described previously. After the mixer input section is processed, the intermediate frequency (IF) output matching section needs to be designed. Since the IF output frequency is generally low, a bandpass matching circuit for the power amplifier cannot be used for matching; instead, a low-pass matching circuit, i.e., a high-low impedance type input matching, is designed. Simultaneously, to increase port isolation, conversion gain, and linearity, the fifth microstrip line 7 (labeled 7 in the figure) and a low-pass filter circuit are designed. To improve the circuit reuse rate of the reconfigurable circuit, the intermediate frequency (IF) matching circuits are all placed on the short-circuit matching stub of the power amplifier. The advantages of this approach are: firstly, it improves circuit reuse and reduces circuit area; secondly, it reduces the impact of the power amplifier on the mixer; and thirdly, since the power amplifier frequency band and the mixer frequency band differ significantly, the low-pass filter of the IF circuit is equivalent to a short circuit for the high frequencies. Therefore, placing the IF circuit on the short-circuit stub of the power amplifier does not affect the matching characteristics of the power amplifier. The mixer simulation results are as follows... Figures 10-11 As shown. Figure 10 The figure shows the frequency spectrum simulation results of the mixer. As can be seen from the figure, the frequency conversion gain of the mixer reaches more than 10dB in the intermediate frequency output range of 200-600MHz, and the third-order intermodulation rejection ratio is more than 20dB. Figure 11 This represents the small-signal simulation results of the mixer. Figure 11 (a) Figure 11 (b) Figure 11 (c) represents the port matching degree of the mixer RF input port, local oscillator input port, and intermediate frequency output port, respectively. It can be seen that the operating bandwidth of the input port is 1.2GHz-1.8GHz, and the operating bandwidth of the output port is 0.2GHz-0.6GHz. Figure 11 (d) represents the isolation of the three ports. It can be seen that the port isolation is above 10dB, and generally above 30dB.

[0069] The power amplifier and mixer of this invention utilize a single transistor 29 for functional multiplexing. Through proper control of the bias voltage, transistor 29 can function as both a power amplifier transistor 29 and a mixer transistor 29. The input matching circuit of the power amplifier and mixer multiplexes the thirteenth microstrip line 17, the first DC blocking capacitor 18, the fourteenth microstrip line 19, the fifteenth microstrip line 20, the sixteenth microstrip line 21, the seventeenth microstrip line 22, the first resistor 23, the first capacitor 24, and the eighteenth microstrip line 25. The gate-drain bias circuit of the power amplifier and mixer multiplexes the nineteenth microstrip line 26, the twentieth microstrip line 27, and the inductor 28. Part of the output matching circuit of the power amplifier and the intermediate frequency output circuit of the mixer multiplexes the twenty-fifth microstrip line 36. The filter transmission line and the antenna matching circuit multiplex the twelfth microstrip line 16. The filter circuit and the mixer port isolation circuit realize the passive and active hybrid microstrip circuit to realize the multiplexing of the first microstrip line 1, the second microstrip line 2, the first PIN diode 3, the third microstrip line 4, the second PIN diode 5, the fourth microstrip line 6, the sixth microstrip line 8, the seventh microstrip line 9, the eighth microstrip line 10, the ninth microstrip line 11, the tenth microstrip line 12, and the eleventh microstrip line 13.

[0070] This invention discloses a novel functionally reconfigurable planar microwave passive-active hybrid circuit, comprising an upper microstrip structure, resistors, capacitors, transistors, and PIN diodes, an intermediate dielectric substrate, and a lower metal grounding portion. The upper resistors, capacitors, and transistors are strategically placed on the microstrip line and fabricated together with the PIN diodes on the upper surface of the intermediate dielectric layer. The lower surface of the dielectric layer is connected to a metal ground plane, the dimensions of which are identical to those of the lower surface of the dielectric layer. By controlling the forward and reverse voltages of the PIN diodes, the diodes can be switched on and off, thereby controlling the switching of the microstrip circuit and achieving functional reconfigurability of the device. This functionally reconfigurable device incorporates four functions: an antenna, a filter, a power amplifier, and a mixer. The filter is a third-order bandpass filter, the antenna is a microstrip monopole antenna, the power amplifier is a broadband power amplifier, and the mixer is an active downconverter. This functionally reconfigurable device features a compact structure, high port reuse rate, wide application range, high integration, rapid switching between the four functions, and time-division multiplexing operation without interference between functions.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without creative effort should be included within the scope of protection of the present invention.

Claims

1. A passive-active hybrid circuit capable of reconfiguring four microwave functions, the hybrid circuit being disposed on a circuit board, the circuit board comprising an upper, middle, and lower three-layer structure, characterized in that, The hybrid circuit is located on the upper layer of the circuit board, and the lower layer of the circuit board is a metal ground plane. The hybrid circuit adopts the design concept of transistor multiplexing, microstrip line multiplexing, and port multiplexing. By adjusting the microwave current flow through PIN diodes, four operating modes are reconstructed on a microwave device, namely antenna mode, filter mode, power amplifier mode, and mixer mode. The hybrid circuit has three ports, namely Port1, Port2, and Port3. The hybrid circuit also includes several PIN diodes, several microstrip lines, resistors, capacitors, transistors, and switches. The several PIN diodes include the first PIN diode to the fifth PIN diode. Different operating modes are switched by controlling the on and off of the first PIN diode to the fifth PIN diode. The hybrid circuit is specifically configured as follows: Port 1 is connected to one end of the sixth microstrip line and one end of the ninth microstrip line via the first microstrip line; Port 2 is connected to the positive terminal of the first PIN diode and the other end of the sixth microstrip line via the second microstrip line; Port 3 is connected to a single-pole triple-throw switch via the thirty-first microstrip line; the negative terminal of the first PIN diode is connected to one end of the seventh microstrip line and the positive terminal of the second PIN diode via the third microstrip line; and the negative terminal of the second PIN diode is connected to one end of the fifth microstrip line and the other end of the sixth microstrip line via the fourth microstrip line. One end of the eighth microstrip line is connected to the first microstrip line. The other end of the ninth microstrip line is connected to the other end of the seventh microstrip line and one end of the tenth microstrip line. The other end of the tenth microstrip line is connected to the other end of the eighth microstrip line and one end of the eleventh microstrip line. The other end of the eleventh microstrip line is connected to the positive terminal of the third PIN diode and the positive terminal of the fourth PIN diode. The negative terminal of the third PIN diode is connected to one end of the first DC blocking capacitor through the thirteenth microstrip line. The other end of the first DC blocking capacitor is connected to the seventeenth microstrip line, the fifteenth microstrip line, and the sixteenth microstrip line in sequence. One end of the microstrip line, one end of the first resistor, and one end of the first capacitor are connected. The negative terminal of the fourth PIN diode is connected to one end of the twenty-ninth microstrip line and one end of the thirtieth microstrip line via the twelfth microstrip line. The other end of the thirtieth microstrip line is connected to a single-pole three-throw switch. One end of the eighteenth microstrip line is connected to the other end of the first resistor and the other end of the first capacitor. The other end of the eighteenth microstrip line is connected to one end of the twenty-first microstrip line via a transistor. The eighteenth microstrip line is also connected to the nineteenth microstrip line via an inductor. The other end of the twenty-first microstrip line is connected to a second DC blocking circuit. The capacitor is connected to one end of the 22nd microstrip line. The 21st microstrip line is also connected to the 20th microstrip line through an inductor. The other end of the 22nd microstrip line is connected to the positive terminal of the 5th PIN diode and one end of the 25th microstrip line. The negative terminal of the 5th PIN diode is connected to the single-pole triple-throw switch through the 23rd and 24th microstrip lines in sequence. The other end of the 25th microstrip line is connected to one end of the 26th microstrip line through a capacitor-inductor filter. The other end of the 26th microstrip line is connected to the single-pole triple-throw switch through the 27th and 28th microstrip lines in sequence.

2. The passive-active hybrid circuit capable of reconfiguring four microwave functions according to claim 1, characterized in that, The hybrid circuit reuses transistors when operating in power amplifier mode and mixer mode. By controlling the bias voltage of the transistors, the transistors can function as both power amplifier transistors and mixer transistors.

3. The passive-active hybrid circuit capable of reconfiguring four microwave functions according to claim 1, characterized in that, By calling the 12th, 29th, 30th, and 31st microstrip lines and Port3 in the circuit, the antenna function is reconstructed. When the hybrid circuit operates in antenna mode, the first, second, third, fourth, and fifth PIN diodes are all disconnected, and the single-pole triple-throw switch turns on the 31st and 30th microstrip lines, thus enabling the 12th, 29th, 30th, and 31st microstrip lines to operate.

4. The passive-active hybrid circuit capable of reconfiguring four microwave functions according to claim 1, characterized in that, By calling the first to fourth microstrip lines, the sixth to twelfth microstrip lines, the thirtieth microstrip line, the thirty-first microstrip line, and ports Port1 and Port3 in the circuit, the filter function is reconstructed. When the hybrid circuit operates in filter mode, the fourth PIN diode is turned on, and the first, second, third, and fifth PIN diodes are turned off. The single-pole triple-throw switch turns on the thirty-first and thirtieth microstrip lines, and the first, second, third, fourth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirtieth, and thirty-first microstrip lines are operational.

5. A reconfigurable passive-active hybrid circuit with four microwave functions according to claim 1, characterized in that, By calling the first to fourth microstrip lines, the sixth to eleventh microstrip lines, the thirteenth to twenty-fifth microstrip lines, the thirty-first microstrip line, and ports Port1 and Port3 in the circuit, the power amplifier function is reconstructed. When the hybrid circuit operates in power amplifier mode, the third and fifth PIN diodes are turned on, while the first, second, and fourth PIN diodes are turned off. A single-pole three-throw switch turns on the thirty-first and twenty-fourth microstrip lines, and the first, second, third, and fourth microstrip lines are turned on. Microstrip line, sixth microstrip line, seventh microstrip line, eighth microstrip line, ninth microstrip line, tenth microstrip line, eleventh microstrip line, thirteenth microstrip line, first DC blocking capacitor, fourteenth microstrip line, fifteenth microstrip line, sixteenth microstrip line, seventeenth microstrip line, first resistor, first capacitor, eighteenth microstrip line, nineteenth microstrip line, twentieth microstrip line, inductor, transistor, twenty-first microstrip line, second DC blocking capacitor, twenty-second microstrip line, twenty-third microstrip line, twenty-fourth microstrip line, twenty-fifth microstrip line, capacitor-inductor filter, and thirty-first microstrip line are in operation.

6. A reconfigurable passive-active hybrid circuit with four microwave functions according to claim 1, characterized in that, By invoking the first to fourth microstrip lines, the sixth to eleventh microstrip lines, the thirteenth microstrip line, the first DC blocking capacitor, the fourteenth to seventeenth microstrip lines, the first resistor, the first capacitor, the eighteenth to twentieth microstrip lines, the inductor, the transistor, the twenty-first microstrip line, the second DC blocking capacitor, the twenty-second and twenty-fifth microstrip lines, the capacitor-inductor filter, the twenty-sixth microstrip line, the twenty-seventh microstrip line, the twenty-eighth microstrip line, the thirty-first microstrip line, and ports Port1, Port2, and Port3 in the circuit, the mixer function is reconstructed. When the mixing circuit operates in mixer mode, the first PIN diode, the second PIN diode, and the third PIN diode are turned on, while the fourth PIN diode and the fifth PIN diode are turned off. When the single-pole triple-throw switch is turned on, the 31st and 28th microstrip lines are connected, and the 1st, 2nd, 3rd, 4th, 6th, 7th, 8th, 9th, 10th, 11th, 13th microstrip lines, the 1st DC blocking capacitor, the 14th, 15th, 16th, 17th microstrip lines, the 1st resistor, the 1st capacitor, the 18th, 19th, and 20th microstrip lines, the inductor, the transistor, the 21st microstrip line, the 2nd DC blocking capacitor, the 22nd and 25th microstrip lines, the capacitor-inductor filter, the 26th, 27th, 28th, and 31st microstrip lines are activated.

7. A reconfigurable passive-active hybrid circuit with four microwave functions according to claim 1, characterized in that, Port1, Port2, and Port3 can be multiplexed according to functional requirements. When the hybrid circuit operates in antenna mode, Port3 is the antenna receiving port; when the hybrid circuit operates in filter mode, Port1 is the input port and Port3 is the output port; when the hybrid circuit operates in power amplifier mode, Port1 is the RF signal input port and Port3 is the power amplifier output port; when the hybrid circuit operates in mixer mode, Port1 is the RF input port, Port2 is the local oscillator input port, and Port3 is the intermediate frequency output port.

8. A reconfigurable passive-active hybrid circuit with four microwave functions according to claim 1, characterized in that, The circuit board has a dielectric layer in the middle layer with a relative permittivity of 3.66, a dielectric substrate thickness of 0.762 mm, and the metal part is made of copper.

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