Passive double-balanced mixer

Abstract

The invention relates to a passive double-balanced mixer. The passive double-balanced mixer comprises a local oscillator balun, a local oscillator coupling line, a diode ring, a radio frequency balun and an intermediate frequency lead-out circuit. The local oscillator balun and the radio frequency balun are each of a balun structure with three metal layers, and efficient coupling of differential signals is achieved through the mode that single-end signals flow in from the center feed-in point of the third metal structure in the balun structures and the vertically-overlapped microstrip lines. And the amplitude-phase consistency of differential signals is further improved through the local oscillator coupling line with the three-layer metal structure. According to the invention, the isolation performance of the passive double-balanced mixer is enhanced, low frequency conversion loss and high isolation are realized in an ultra-wideband range, and the mixing efficiency and signal integrity of the passive double-balanced mixer are improved.

Description

Technical Field

[0001] This application relates to the field of radio frequency microwave integrated circuit technology, and in particular to a passive double-balanced mixer. Background Technology

[0002] In military fields such as radar and electronic warfare, with the continuous proliferation of high-power transmission and jamming equipment, broadband transceiver systems have become crucial military equipment. The mixer is one of the core components of the transceiver system. Its working principle involves generating combined frequency components through the "multiplier" effect of nonlinear devices, filtering out useful frequency components and suppressing parasitic frequency components, thus achieving spectrum shifting of the input signal. Passive double-balanced mixers, due to their elimination of DC bias and ease of use, have become the preferred solution in current mixer design.

[0003] Currently, in the basic architecture of a passive double-balanced mixer, the local oscillator signal and the radio frequency (RF) signal are converted into two differential signals by a local oscillator balun and an RF balun, respectively, and then fed into a diode loop for mixing. The intermediate frequency (IF) signal after mixing is then extracted through the center of either the local oscillator balun or the RF balun.

[0004] Regarding the aforementioned technologies, both the local oscillator balun and the radio frequency balun adopt the method of feeding the local oscillator signal or radio frequency signal from the end of the metal layer. Both the local oscillator balun and the radio frequency balun are double-layer metal side-by-side structures. This design limits the effective coupling of the local oscillator signal or radio frequency signal inside the balun. Moreover, since it is difficult to achieve good symmetry in the layout of the double-layer metal balun structure, when the local oscillator signal and the radio frequency signal are converted into differential signals, the amplitude and phase consistency of the differential signal is difficult to maintain effectively, resulting in low isolation performance of the passive double balanced mixer. Summary of the Invention

[0005] The passive double-balanced mixer provided in this application adopts the following technical solution: A passive double-balanced mixer includes: a local oscillator balun, a local oscillator coupling line, a diode ring, an RF balun, and an intermediate frequency output circuit; The local oscillator balun includes a local oscillator balun integrated port, a local oscillator balun center ground port, a first local oscillator balun output port, a second local oscillator balun output port, and a first local oscillator balun metal layer, a second local oscillator balun metal layer, and a third local oscillator balun metal layer stacked sequentially. The third local oscillator balun metal layer contains a local oscillator balun center feed point and a first local oscillator balun microstrip line and a second local oscillator balun microstrip line symmetrically arranged relative to the local oscillator balun center feed point, which is connected to the local oscillator balun integrated port. The second local oscillator balun metal layer contains a local oscillator balun center intersection point and a third local oscillator balun microstrip line and a fourth local oscillator balun microstrip line symmetrically arranged relative to the local oscillator balun center intersection point, which is connected to the local oscillator balun center ground port. The second local oscillator balun microstrip line and the third local oscillator balun microstrip line overlap perpendicularly. The first local oscillator balun microstrip line is perpendicularly overlapped with the fourth local oscillator balun microstrip line; the first local oscillator balun metal layer is connected to the first local oscillator balun microstrip line, the second local oscillator balun microstrip line, the third local oscillator balun microstrip line, and the fourth local oscillator balun microstrip line, and the first local oscillator balun metal layer is also connected to the first local oscillator balun output port, the second local oscillator balun output port, and ground; wherein, the local oscillator signal flows into the local oscillator balun from the center feed point of the local oscillator balun, and is coupled through the first local oscillator balun microstrip line, the second local oscillator balun microstrip line, the third local oscillator balun microstrip line, and the fourth local oscillator balun microstrip line to form a first differential local oscillator signal component and a second differential local oscillator signal component, the first differential local oscillator signal component flows out from the first local oscillator balun output port, and the second differential local oscillator signal component flows out from the second local oscillator balun output port.

[0006] By adopting the above scheme, the amplitude and phase consistency of the differential signal is significantly improved in the ultra-wideband range, ensuring that the local oscillator signal is effectively converted into a high-quality differential signal, thereby improving the isolation and spurious suppression performance of the passive double-balanced mixer. In addition, the above scheme also provides the passive double-balanced mixer with stable and efficient mixing performance and has low frequency conversion loss characteristics.

[0007] Optionally, the first local oscillator balun metal layer is connected to the first local oscillator balun microstrip line, the second local oscillator balun microstrip line, the third local oscillator balun microstrip line, and the fourth local oscillator balun microstrip line; wherein, the first end of the first local oscillator balun microstrip line is connected to the center feed point of the local oscillator balun, the second end of the first local oscillator balun microstrip line is connected to the first local oscillator balun metal layer, and connected to the output port of the second local oscillator balun through the first local oscillator balun metal layer; the first end of the second local oscillator balun microstrip line is connected to the center feed point of the local oscillator balun, and the second local oscillator balun microstrip line... The second end of the third local oscillator balun microstrip line is connected to the first local oscillator balun metal layer and grounded through the first local oscillator balun metal layer; the first end of the third local oscillator balun microstrip line is connected to the center intersection of the local oscillator balun and the second end of the third local oscillator balun microstrip line is connected to the first local oscillator balun metal layer and grounded through the first local oscillator balun metal layer.

[0008] By adopting the above scheme, the local oscillator balun metal layers are effectively connected and properly grounded, reducing the parasitic effects during the interconnection and grounding process of the local oscillator balun metal layers, ensuring the amplitude and phase consistency of the local oscillator balun, and thus further improving the isolation and spurious suppression performance of the passive double-balanced mixer.

[0009] Optionally, the second ends of the first local oscillator balun microstrip line, the second ends of the second local oscillator balun microstrip line, the second ends of the third local oscillator balun microstrip line, and the second ends of the fourth local oscillator balun microstrip line are all connected to the first local oscillator balun metal layer through vias.

[0010] By adopting the above scheme, the parasitic effects in the interconnection process of the local oscillator balun metal layers are reduced.

[0011] Optionally, the RF balun includes an integrated RF balun port, an RF balun center ground port, a first RF balun output port, a second RF balun output port, and a first RF balun metal layer, a second RF balun metal layer, and a third RF balun metal layer stacked sequentially. The third RF balun metal layer contains an RF balun center feed point and a first RF balun microstrip line and a second RF balun microstrip line symmetrically arranged relative to the RF balun center feed point. The RF balun center feed point is connected to the integrated RF balun port. The second RF balun metal layer contains an RF balun center intersection point and a third RF balun microstrip line and a fourth RF balun microstrip line symmetrically arranged relative to the RF balun center intersection point. The RF balun center intersection point is connected to the RF balun center ground port. The second RF balun microstrip line and the third RF balun microstrip line overlap vertically. Furthermore, the first RF balun microstrip line and the fourth RF balun microstrip line are perpendicularly overlapped; the first RF balun metal layer is connected to the first RF balun microstrip line, the second RF balun microstrip line, the third RF balun microstrip line, and the fourth RF balun microstrip line, and the first RF balun metal layer is also connected to the first RF balun output port, the second RF balun output port, and ground; wherein, the RF signal flows into the RF balun from the center feed point of the RF balun, and is coupled through the first RF balun microstrip line, the second RF balun microstrip line, the third RF balun microstrip line, and the fourth RF balun microstrip line to form a first differential RF signal component and a second differential RF signal component, the first differential RF signal component flows out from the first RF balun output port, and the second differential RF signal component flows out from the second RF balun output port.

[0012] By adopting the above scheme, the amplitude and phase inconsistency of the radio frequency signal during transmission is effectively reduced, ensuring that the radio frequency signal can be effectively converted into a high-quality differential signal over a wide bandwidth. Furthermore, the overlapping radio frequency balun structure reduces the chip area, which is beneficial for circuit miniaturization and cost reduction.

[0013] Optionally, the first RF balun metal layer is connected to the first RF balun microstrip line, the second RF balun microstrip line, the third RF balun microstrip line, and the fourth RF balun microstrip line; wherein, the first end of the first RF balun microstrip line is connected to the center feed point of the RF balun, and the second end of the first RF balun microstrip line is connected to the first RF balun metal layer and connected to the second RF balun output port through the first RF balun metal layer; the first end of the second RF balun microstrip line is connected to the center feed point of the RF balun, and the second end of the second RF balun microstrip line is connected to the first RF balun metal layer and grounded through the first RF balun metal layer; the first end of the third RF balun microstrip line is connected to the center intersection of the RF balun, and the second end of the third RF balun microstrip line is connected to the first RF balun metal layer and connected to the first RF balun output port through the first RF balun metal layer; the first end of the fourth RF balun microstrip line is connected to the center intersection of the RF balun, and the second end of the fourth RF balun microstrip line is connected to the first RF balun metal layer and grounded through the first RF balun metal layer.

[0014] By adopting the above scheme, the RF balun metal layers are effectively connected and properly grounded, reducing the parasitic effects during the interconnection and grounding of the RF balun metal layers, ensuring the amplitude and phase consistency of the RF balun, and thus further improving the isolation and spurious suppression performance of the passive double-balanced mixer.

[0015] Optionally, the second end of the first RF balun microstrip line, the second end of the second RF balun microstrip line, the second end of the third RF balun microstrip line, and the second end of the fourth RF balun microstrip line are all connected to the first RF balun metal layer through vias.

[0016] By adopting the above scheme, the parasitic effects during the interconnection process of the radio frequency balun metal layers are reduced.

[0017] Optionally, the local oscillator coupling line includes a first local oscillator coupling line input port, a second local oscillator coupling line input port, a local oscillator coupling line center ground port, a first local oscillator coupling line output port, a second local oscillator coupling line output port, and a first local oscillator coupling metal layer, a second local oscillator coupling metal layer, and a third local oscillator coupling metal layer stacked sequentially. The second local oscillator coupling metal layer contains a center intersection point of the first local oscillator coupling line and symmetrically arranged first and second local oscillator coupling microstrip lines relative to this center intersection point. The center intersection point of the first local oscillator coupling line is connected to the local oscillator coupling line center ground port. The third local oscillator coupling metal layer contains a center intersection point of the second local oscillator coupling line and symmetrically arranged third and fourth local oscillator coupling microstrip lines relative to this center intersection point. The center intersection point of the second local oscillator coupling line is connected to the intermediate frequency output circuit. The first and third local oscillator coupling microstrip lines overlap perpendicularly, and the first local oscillator coupling microstrip lines overlap vertically. The second local oscillator coupled microstrip line is perpendicularly overlapped with the fourth local oscillator coupled microstrip line; the first local oscillator coupled metal layer is connected to the first local oscillator coupled microstrip line, the second local oscillator coupled microstrip line, the third local oscillator coupled microstrip line, and the fourth local oscillator coupled microstrip line, and the first local oscillator coupled metal layer is also connected to the output port of the first local oscillator coupled line, the output port of the second local oscillator coupled line, and the center ground port of the local oscillator coupled line; wherein, the first differential local oscillator signal component flows into the local oscillator coupled line from the input port of the first local oscillator coupled line, the second differential local oscillator signal component flows into the local oscillator coupled line from the input port of the second local oscillator coupled line, and is coupled through the first local oscillator coupled microstrip line, the second local oscillator coupled microstrip line, the third local oscillator coupled microstrip line, and the fourth local oscillator coupled microstrip line, and the first differential local oscillator signal component flows out from the output port of the first local oscillator coupled line, and the second differential local oscillator signal component flows out from the output port of the second local oscillator coupled line.

[0018] By adopting the above technical solution, the amplitude and phase consistency of the local oscillator differential signal is further optimized, ensuring the transmission quality of the local oscillator differential signal. In addition, the overlapping local oscillator coupling line structure reduces the chip area, which is beneficial to the miniaturization and low cost of the circuit.

[0019] Optionally, the first local oscillator coupling metal layer is connected to the first local oscillator coupling microstrip line, the second local oscillator coupling microstrip line, the third local oscillator coupling microstrip line, and the fourth local oscillator coupling microstrip line; wherein, the first end of the first local oscillator coupling microstrip line is connected to the input port of the first local oscillator coupling line, and the second end of the first local oscillator coupling microstrip line is connected to the first local oscillator coupling metal layer, and connected to the center intersection of the first local oscillator coupling line through the first local oscillator coupling metal layer; the first end of the second local oscillator coupling microstrip line is connected to the input port of the second local oscillator coupling line, and the second end of the second local oscillator coupling microstrip line is connected to the first local oscillator coupling microstrip line. A metal layer is provided, and the first end of the third local oscillator coupling microstrip line is connected to the center intersection of the second local oscillator coupling line through the first local oscillator coupling metal layer; the second end of the third local oscillator coupling microstrip line is connected to the first local oscillator coupling metal layer, and is connected to the output port of the first local oscillator coupling line through the first local oscillator coupling metal layer; the first end of the fourth local oscillator coupling microstrip line is connected to the center intersection of the second local oscillator coupling line, the second end of the fourth local oscillator coupling microstrip line is connected to the first local oscillator coupling metal layer, and is connected to the output port of the second local oscillator coupling line through the first local oscillator coupling metal layer.

[0020] By adopting the above technical solution, effective connection and reasonable grounding between the local oscillator coupling metal layers are achieved, reducing the parasitic effects during the interconnection process of the local oscillator coupling metal layers and the grounding process of the local oscillator coupling metal layers, further improving the amplitude and phase consistency of the local oscillator differential signal, thereby improving the isolation and spurious suppression performance of the passive double-balanced mixer.

[0021] Optionally, the diode ring includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The cathode of the first diode D1 is connected to the cathode of the second diode D2 to form a first diode ring port. The anode of the second diode D2 is connected to the cathode of the third diode D3 to form a second diode ring port. The anode of the third diode D3 is connected to the anode of the fourth diode D4 to form a third diode ring port. The cathode of the fourth diode D4 is connected to the anode of the first diode D1 to form a fourth diode ring port. The first diode ring port is connected to the first local oscillator coupling line output port. The second diode ring port is connected to the second RF balun output port. The third diode ring port is connected to the second local oscillator coupling line output port. The fourth diode ring port is connected to the first RF balun output port.

[0022] By adopting the above technical solution, effective mixing of local oscillator signal and radio frequency signal is achieved, improving the mixing efficiency and isolation of passive double balanced mixer, while reducing interference from spurious signals and improving the overall performance and stability of radio frequency system.

[0023] Optionally, the intermediate frequency (IF) output circuit includes an IF metal layer and an IF port. The IF signal flows in or out from the IF port. An IF microstrip line is constructed in the IF metal layer. The first end of the IF microstrip line is connected to the center intersection of the second local oscillator coupling line, and the second end of the IF microstrip line is connected to the IF port.

[0024] By adopting the above technical solution, a clear path is provided for the intermediate frequency (IF) signal, enabling effective extraction of the IF signal and improving the isolation between the IF signal and the local oscillator signal. In summary, this application includes at least one of the following beneficial technical effects: It significantly improves the amplitude and phase consistency of differential signals in the ultra-wideband range, ensuring that local oscillator signals and radio frequency signals are effectively converted into high-quality differential signals, thereby improving the isolation and spurious suppression performance of passive double-balanced mixers. In addition, it provides stable and efficient mixing performance for passive double-balanced mixers and has low frequency conversion loss characteristics. By effectively connecting and properly grounding the metal layers of the local oscillator / radio frequency balun, parasitic effects during the interconnection and grounding processes of the local oscillator / radio frequency balun are reduced, ensuring the amplitude and phase consistency of the local oscillator / radio frequency balun, thereby further improving the isolation and spurious suppression performance of the passive double-balanced mixer. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a passive double-balanced mixer based on related technologies; Figure 2 This is a schematic diagram of the planar structure of a passive double-balanced mixer according to an embodiment of this application; Figure 3 yes Figure 2 A schematic diagram of the planar structure of the oscillating balun in the image; Figure 4 yes Figure 2 A schematic diagram of the three-dimensional structure of the oscillating balun in the image; Figure 5 yes Figure 2 A schematic diagram of the planar structure of the radio frequency balun; Figure 6 yes Figure 2 A schematic diagram of the planar structure of the local oscillator coupling line and the intermediate frequency lead-out circuit; Figure 7 yes Figure 2 A schematic diagram of the planar structure of the diode ring in the image; Figure 8 This is a diagram showing the measured results of the downconversion loss of the passive double-balanced mixer in the embodiments of this application; Figure 9 This is a diagram showing the measured results of the isolation between the local oscillator signal and the radio frequency signal of the passive double-balanced mixer in the embodiments of this application; Figure 10 This is a diagram showing the measured results of the isolation between the local oscillator signal and the intermediate frequency signal of the passive double-balanced mixer in the embodiments of this application; Figure 11 This is a diagram showing the measured results of the isolation between the radio frequency signal and the intermediate frequency signal of the passive double-balanced mixer in this embodiment of the application.

[0026] Explanation of reference numerals in the attached figures: 110, Traditional local oscillator balun; 111, First traditional local oscillator balun microstrip line; 112, Second traditional local oscillator balun microstrip line; 113, Third traditional local oscillator balun microstrip line; 120, Traditional radio frequency balun; 121, First traditional radio frequency balun microstrip line; 122, Second traditional radio frequency balun microstrip line; 123, Third traditional radio frequency balun microstrip line; 130, Traditional diode ring; 140, Traditional intermediate frequency output circuit; 210, Local oscillator balun; 211, Local oscillator balun integrated port; 212, Local oscillator balun center feed. Input point; 213a, First local oscillator balun microstrip line; 213b, Second local oscillator balun microstrip line; 213c, Third local oscillator balun microstrip line; 213d, Fourth local oscillator balun microstrip line; 214, Local oscillator balun center intersection point; 215, Local oscillator balun center ground port; 216, First local oscillator balun output port; 217, Second local oscillator balun output port; 220, RF balun; 221, RF balun integrated port; 222, RF balun center feed-in point; 223a, First RF balun microstrip line; 223b, Second RF balun Microstrip line; 223c, Third RF balun microstrip line; 223d, Fourth RF balun microstrip line; 224, RF balun center intersection; 225, RF balun center ground port; 226, First RF balun output port; 227, Second RF balun output port; 230, Local oscillator coupling line; 231, First local oscillator coupling line input port; 232, Second local oscillator coupling line input port; 233, First local oscillator coupling line center intersection; 234a, First local oscillator coupling microstrip line; 234b, Second local oscillator coupling microstrip line; 23 4c. Third local oscillator coupled microstrip line; 234d. Fourth local oscillator coupled microstrip line; 235. Center ground port of local oscillator coupled line; 236. Output port of first local oscillator coupled line; 237. Output port of second local oscillator coupled line; 238. Center intersection of second local oscillator coupled line; 240. Diode ring; 241. Port of first diode ring; 242. Port of second diode ring; 243. Port of third diode ring; 244. Port of fourth diode ring; 250. Intermediate frequency lead-out circuit; 251. Intermediate frequency microstrip line; 252. Intermediate frequency port. Detailed Implementation

[0027] The following is in conjunction with the appendix Figures 1-11 This application will be described in further detail.

[0028] To achieve efficient conversion from single-ended to differential signals and to generate high-quality intermediate frequency signals during the mixing process, Figure 1 A passive double-balanced mixer of the relevant technology is shown.

[0029] like Figure 1 As shown, the passive double-balanced mixer includes a conventional local oscillator balun 110, a conventional radio frequency balun 120, a conventional diode ring 130, and a conventional intermediate frequency output circuit 140 connected in sequence to the conventional local oscillator balun. The conventional local oscillator balun 110 has a first conventional local oscillator balun metal layer and a second conventional local oscillator balun metal layer, and the first conventional local oscillator balun metal layer is constructed with a first conventional local oscillator balun microstrip line 111, the second conventional local oscillator balun metal layer is constructed with a second conventional local oscillator balun microstrip line 112 and a third conventional local oscillator balun microstrip line 113; the conventional radio frequency balun 120 has a first conventional radio frequency balun metal layer and a second conventional radio frequency balun metal layer, and the first conventional radio frequency balun metal layer is constructed with a first conventional radio frequency balun microstrip line 121, the second conventional radio frequency balun metal layer is constructed with a second conventional radio frequency balun microstrip line 122 and a third conventional radio frequency balun microstrip line 123; the conventional diode ring 130 is formed by four diodes forming a closed ring structure; the conventional intermediate frequency lead-out circuit 140 has a conventional intermediate frequency metal layer and a conventional intermediate frequency port.

[0030] The working principle of the passive double-balanced mixer is as follows: The local oscillator (LO) signal flows into the first traditional local oscillator balun microstrip line 111 from one end of the first traditional local oscillator balun metal layer, and is coupled to the second traditional local oscillator balun microstrip line 112 and the third traditional local oscillator balun microstrip line 113 in the second traditional local oscillator balun metal layer to be converted into a differential local oscillator signal. The differential local oscillator signal is then transmitted to the conventional diode ring 130 via the second conventional local oscillator balun microstrip line 112 and the third conventional local oscillator balun microstrip line 113. The conventional radio frequency (RF) signal flows into the first conventional RF balun microstrip line 121 from one end of the first conventional RF balun metal layer and is coupled to the second conventional RF balun microstrip line 122 and the third conventional RF balun microstrip line 123 in the second conventional RF balun metal layer to be converted into a differential RF signal. The differential RF signal is then transmitted to the conventional diode ring 130 via the second conventional RF balun microstrip line 122 and the third conventional RF balun microstrip line 123. The conventional diode ring 130 mixes the received differential local oscillator signal and the differential RF signal to generate an intermediate frequency (IF) signal. The mixed IF signal is then led out through the center of the conventional local oscillator balun 110.

[0031] However, passive double-balanced mixers in related technologies still have the following drawbacks: both the traditional local oscillator balun 110 and the traditional RF balun 120 feed the local oscillator signal or RF signal from the end of the metal layer, and both the traditional local oscillator balun 110 and the traditional RF balun 120 are double-layer metal side-by-side structures. This design limits the effective coupling and transmission distance of the local oscillator signal or RF signal inside the balun. Moreover, because it is difficult to achieve good symmetry in the layout of the double-layer metal balun structure, it is difficult to maintain amplitude and phase consistency during signal transmission, resulting in low isolation performance of the passive double-balanced mixer.

[0032] In view of the above-mentioned related technologies, this application discloses a passive double-balanced mixer.

[0033] Reference Figure 2The passive double-balanced mixer includes a local oscillator balun 210, a local oscillator coupling line 230, a diode ring 240, an RF balun 220, and an intermediate frequency (IF) output circuit 250. The local oscillator balun 210, local oscillator coupling line 230, and RF balun 220 achieve efficient signal coupling through their unique stacked metal layer structures and microstrip line layouts. The diode ring 240 utilizes nonlinear characteristics to mix the signal, and the IF output circuit 250 is responsible for extracting the mixed IF signal, achieving the effect of reducing conversion loss and improving isolation over an ultra-wideband range. The local oscillator balun 210 and RF balun 220 convert single-ended signals into high-quality differential signals, the local oscillator coupling line 230 enhances signal transmission, the diode ring 240 performs mixing, and the IF output circuit 250 ensures stable IF signal output.

[0034] Reference Figure 3 and Figure 4 The local oscillator balun 210 includes a local oscillator balun integrated port 211, a local oscillator balun center ground port 215, a first local oscillator balun output port 216, a second local oscillator balun output port 217, and a first local oscillator balun metal layer, a second local oscillator balun metal layer, and a third local oscillator balun metal layer stacked sequentially. The local oscillator balun integrated port 211 is used to input the local oscillator signal, and the local oscillator balun center ground port 215 serves as a grounding function to ensure the stability of signal transmission. The first local oscillator balun output port 216 and the second local oscillator balun output port 217 are used to output differential local oscillator signals. The second and third local oscillator balun metal layers are stacked sequentially on top of the first local oscillator balun metal layer.

[0035] The third local oscillator balun metal layer contains a local oscillator balun center feed point 212 and two symmetrically arranged local oscillator balun microstrip lines 213a and 213b. The local oscillator balun center feed point 212 is connected to the local oscillator balun synthesis port 211. The local oscillator balun center feed point 212 is the input node for the local oscillator signal, ensuring efficient signal transmission. The second local oscillator balun metal layer contains a local oscillator balun center intersection point 214 and a third local oscillator balun microstrip line 213c and a fourth local oscillator balun microstrip line 213d symmetrically arranged relative to the local oscillator balun center intersection point 214. The local oscillator balun center intersection point 214 is connected to the local oscillator balun center grounding port 215. The second local oscillator balun microstrip line 213b and the third local oscillator balun microstrip line 213c overlap perpendicularly, and the first local oscillator balun microstrip line 213a and the fourth local oscillator balun microstrip line 213d overlap perpendicularly. The local oscillator balun center intersection point 214 is the signal crossing point, serving the functions of signal distribution and grounding.

[0036] The first local oscillator balun metal layer is connected to the first local oscillator balun microstrip line 213a, the second local oscillator balun microstrip line 213b, the third local oscillator balun microstrip line 213c, and the fourth local oscillator balun microstrip line 213d. The first end of the first local oscillator balun microstrip line 213a is connected to the center feed point 212 of the local oscillator balun, and the second end of the first local oscillator balun microstrip line 213a is connected to the first local oscillator balun metal layer via a via, and then connected to the output port 217 of the second local oscillator balun through the first local oscillator balun metal layer. The first end of the second local oscillator balun microstrip line 213b is connected to the center feed point 212 of the local oscillator balun. The second end of the third MOSFET microstrip line 213c is connected to the first MOSFET balun metal layer via a via, and is grounded through the first MOSFET balun metal layer. The first end of the third MOSFET microstrip line 213c is connected to the center intersection point 214 of the MOSFET balun, and the second end of the third MOSFET microstrip line 213c is connected to the first MOSFET balun metal layer via a via, and is grounded through the first MOSFET balun metal layer. The first end of the fourth MOSFET microstrip line 213d is connected to the center intersection point 214 of the MOSFET balun, and the second end of the fourth MOSFET microstrip line 213d is connected to the first MOSFET balun metal layer via a via, and is grounded through the first MOSFET balun metal layer. A via is a vertical conductive channel used to connect microstrip lines between different metal layers.

[0037] The local oscillator signal flows into the local oscillator balun 210 from the center feed point 212, and is coupled and transmitted through the first local oscillator balun microstrip line 213a, the second local oscillator balun microstrip line 213b, the third local oscillator balun microstrip line 213c, and the fourth local oscillator balun microstrip line 213d. The second local oscillator balun microstrip line 213b and the third local oscillator balun microstrip line 213c are coupled to form the first differential local oscillator signal component; the first local oscillator balun microstrip line 213a and the fourth local oscillator balun microstrip line 213d are coupled to form the second differential local oscillator signal component; the first differential local oscillator signal component and the second differential local oscillator signal component form a local oscillator signal differential pair with equal amplitude and opposite phase, thereby forming a differential local oscillator signal. The first differential local oscillator signal component flows out from the first local oscillator balun output port 216, and the second differential local oscillator signal component flows out from the second local oscillator balun output port 217. This structural design enables the local oscillator signal to be efficiently coupled in vertically overlapping microstrip lines, improving the amplitude and phase consistency of the differential signal.

[0038] Reference Figure 5The RF balun 220 includes an RF balun integrated port 221, an RF balun center ground port 225, a first RF balun output port 226, a second RF balun output port 227, and a first RF balun metal layer, a second RF balun metal layer, and a third RF balun metal layer stacked sequentially. The RF balun 220 has a structure basically the same as the local oscillator balun 210. The RF balun integrated port 221 is used to input RF signals and can also use standard RF interfaces such as the SMA interface. The RF balun center ground port 225 serves as a grounding function to ensure the stability of RF signal transmission. The first RF balun output port 226 and the second RF balun output port 227 are used to output differential RF signals, and their connection to subsequent circuits must ensure accurate signal transmission. The first RF balun metal layer is the base layer of the RF balun 220 and is manufactured using similar metal materials and processes as the local oscillator balun 210 metal layer. The second and third radio frequency balun metal layers are stacked sequentially on top of the first radio frequency balun metal layer and separated from the first radio frequency balun metal layer by an insulating medium.

[0039] The third RF balun metal layer contains an RF balun center feed point 222 and a first RF balun microstrip line 223a and a second RF balun microstrip line 223b symmetrically arranged relative to the RF balun center feed point 222. The RF balun center feed point 222 is connected to the RF balun integrated port 221. The design of the RF balun center feed point 222 is similar to that of the local oscillator balun center feed point 212 to ensure efficient RF signal input. The second RF balun metal layer contains an RF balun center intersection point 224 and a third RF balun microstrip line 223c and a fourth RF balun microstrip line 223d symmetrically arranged relative to the RF balun center intersection point 224. The RF balun center intersection point 224 is connected to the RF balun center ground port 225. The second RF balun microstrip line 223b and the third RF balun microstrip line 223c overlap vertically, and the first RF balun microstrip line 223a and the fourth RF balun microstrip line 223d overlap vertically. The function of the RF balun center intersection 224 is similar to that of the local oscillator balun center intersection 214, ensuring signal symmetry and grounding effect.

[0040] The first RF balun metal layer is connected to the first RF balun microstrip line 223a, the second RF balun microstrip line 223b, the third RF balun microstrip line 223c, and the fourth RF balun microstrip line 223d. The first end of the first RF balun microstrip line 223a is connected to the RF balun center feed point 222, and the second end of the first RF balun microstrip line 223a is connected to the first RF balun metal layer via a via, and also connected to the second RF balun output port 227 through the first RF balun metal layer. The first end of the second RF balun microstrip line 223b is connected to the RF balun center feed point 222, and the second RF balun microstrip line 223b... The second end of the third RF balun microstrip line 223c is connected to the first RF balun metal layer through a via, and is grounded through the first RF balun metal layer; the first end of the third RF balun microstrip line 223c is connected to the center intersection 224 of the RF balun, and the second end of the third RF balun microstrip line 223c is connected to the first RF balun metal layer through a via, and is grounded through the first RF balun metal layer.

[0041] The radio frequency (RF) signal flows into the RF balun from the center feed point 222 and is coupled and transmitted through the first RF balun microstrip line 223a, the second RF balun microstrip line 223b, the third RF balun microstrip line 223c, and the fourth RF balun microstrip line 223d. The second RF balun microstrip line 223b and the third RF balun microstrip line 223c are coupled to form a first differential RF signal component; the first RF balun microstrip line 223a and the fourth RF balun microstrip line 223d are coupled to form a second differential RF signal component. The first and second differential RF signal components form a differential pair with equal amplitude and opposite phase, thereby generating a differential RF signal. The first differential RF signal component flows out from the first RF balun output port 226, and the second differential RF signal component flows out from the second RF balun output port 227.

[0042] Reference Figure 6 The local oscillator coupling line 230 includes a first local oscillator coupling line input port 231, a second local oscillator coupling line input port 232, a local oscillator coupling line center ground port 235, a first local oscillator coupling line output port 236, a second local oscillator coupling line output port 237, and a first local oscillator coupling metal layer, a second local oscillator coupling metal layer, and a third local oscillator coupling metal layer stacked sequentially. The first local oscillator coupling metal layer is the base layer of the local oscillator coupling line and is made of a metal material with good conductivity. The second local oscillator coupling metal layer and the third local oscillator coupling metal layer are stacked sequentially on top of the first local oscillator coupling metal layer and separated from the first local oscillator coupling metal layer by an insulating medium.

[0043] The second local oscillator coupling metal layer contains the center intersection point 233 of the first local oscillator coupling line and symmetrically arranged first local oscillator coupling microstrip lines 234a and 234b relative to the center intersection point 233. The center intersection point 233 of the first local oscillator coupling line is connected to the center grounding port 235 of the local oscillator coupling line. The third local oscillator coupling metal layer contains the center intersection point 238 of the second local oscillator coupling line and symmetrically arranged third local oscillator coupling microstrip lines 234c and 234d relative to the center intersection point 238. The center intersection point 238 of the second local oscillator coupling line is connected to the intermediate frequency lead-out circuit 250. The first local oscillator coupling microstrip lines 234a and 234c overlap perpendicularly, and the second local oscillator coupling microstrip lines 234b and 234d overlap perpendicularly. The center intersection point 233 of the first local oscillator coupling line and the center intersection point 238 of the second local oscillator coupling line serve the functions of signal distribution and connection, respectively.

[0044] The first local oscillator coupling metal layer is connected to the first local oscillator coupling microstrip line 234a, the second local oscillator coupling microstrip line 234b, the third local oscillator coupling microstrip line 234c, and the fourth local oscillator coupling microstrip line 234d, realizing efficient coupling and transmission of differential local oscillator signals. Specifically, the first end of the first local oscillator coupling microstrip line 234a is connected to the first local oscillator coupling line input port 231, and the second end of the first local oscillator coupling microstrip line 234a is connected to the first local oscillator coupling metal layer through a via, and then connected to the center intersection point 233 of the first local oscillator coupling line through the first local oscillator coupling metal layer. The first end of the second local oscillator coupling microstrip line 234b is connected to the second local oscillator coupling line input port 232, and the second end of the second local oscillator coupling microstrip line 234b is connected to the first local oscillator coupling metal layer through a via, and then connected to the center intersection point 233 of the first local oscillator coupling line through the first local oscillator coupling metal layer. The first end of the third local oscillator coupling microstrip line 234c is connected to the center intersection point 238 of the second local oscillator coupling line. The second end of the third local oscillator coupling microstrip line 234c is connected to the first local oscillator coupling metal layer through a via, and then connected to the output port 236 of the first local oscillator coupling line through the first local oscillator coupling metal layer. The first end of the fourth local oscillator coupling microstrip line 234d is connected to the center intersection point 238 of the second local oscillator coupling line. The second end of the fourth local oscillator coupling microstrip line 234d is connected to the first local oscillator coupling metal layer through a via, and then connected to the output port 237 of the second local oscillator coupling line through the first local oscillator coupling metal layer. The input port 231 and the input port 232 of the first local oscillator coupling line are used to input the two components of the differential local oscillator signal, respectively. The center ground port 235 of the local oscillator coupling line serves as a ground to ensure the stability of signal transmission. The output port 236 and the output port 237 of the first local oscillator coupling line are used to output the coupled differential local oscillator signal.

[0045] The first differential local oscillator signal component flows into the local oscillator coupling line 230 from the input port 231 of the first local oscillator coupling line, and the second differential local oscillator signal component flows into the local oscillator coupling line 230 from the input port 232 of the second local oscillator coupling line. The first local oscillator coupling microstrip line 234a and the third local oscillator coupling microstrip line 234c are coupled together for transmission, and the first differential local oscillator signal component flows out from the output port 236 of the first local oscillator coupling line; the second local oscillator coupling microstrip line 234b and the fourth local oscillator coupling microstrip line 234d are coupled together for transmission, and the second differential local oscillator signal component flows out from the output port 237 of the second local oscillator coupling line. This structural design enhances the transmission efficiency and coupling of the differential local oscillator signal, further improving the signal quality.

[0046] Reference Figure 7 The diode ring 240 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4, all of which are high-performance Schottky diodes, offering advantages such as fast switching speed and good nonlinear characteristics. The cathode of the first diode D1 is connected to the cathode of the second diode D2, forming the first diode ring port 241. The anode of the second diode D2 is connected to the cathode of the third diode D3, forming the second diode ring port 242. The anode of the third diode D3 is connected to the anode of the fourth diode D4, forming the third diode ring port 243. The cathode of the fourth diode D4 is connected to the anode of the first diode D1, forming the fourth diode ring port 244. The first diode ring port 241 is connected to the first local oscillator coupling line output port 236, the second diode ring port 242 is connected to the second RF balun output port 227, the third diode ring port 243 is connected to the second local oscillator coupling line output port 237, and the fourth diode ring port 244 is connected to the first RF balun output port 226. This connection method allows the diode ring 240 to receive differential local oscillator signals and differential radio frequency signals from the local oscillator coupling line 230 and the radio frequency balun 220, and to mix these two signals using the nonlinear characteristics of the diode to generate an intermediate frequency signal. Furthermore, in up-conversion mode, it can also operate in reverse, mixing the input differential local oscillator signal with the intermediate frequency signal and feeding the up-converted differential radio frequency signal into the radio frequency balun 220.

[0047] When the intermediate frequency output circuit 250 is in the down-conversion working state, it receives the mixed intermediate frequency signal and outputs it to the intermediate frequency port 252; when the intermediate frequency output circuit 250 is in the up-conversion working state, it serves as the input channel for the unmixed intermediate frequency signal, introducing the unmixed intermediate frequency signal from the intermediate frequency port 252 into the local oscillator coupling line 230.

[0048] The intermediate frequency (IF) output circuit 250 includes an IF metal layer and an IF port 252. The IF metal layer is made of a highly conductive metal material, such as copper, and contains an IF microstrip line 251. The first end of the IF microstrip line 251 is connected to the center intersection point 238 of the second local oscillator coupling line, and the second end is connected to the IF port 252. The IF signal flows in or out of the IF port 252. In down-conversion operation, the IF output circuit 250 receives the mixed IF signal and outputs it to the IF port 252; in up-conversion operation, the IF output circuit 250 serves as the input channel for the unmixed IF signal, introducing the unmixed IF signal from the IF port 252 into the local oscillator coupling line 230.

[0049] In down-conversion operation, the local oscillator signal flows from the local oscillator balun integrated port 211 into the local oscillator balun 210 via the local oscillator balun center feed point 212, and is coupled and transmitted through the first local oscillator coupling microstrip line 234a, the second local oscillator coupling microstrip line 234b, the third local oscillator coupling microstrip line 234c, and the fourth local oscillator coupling microstrip line 234d. The second local oscillator balun microstrip line 213b and the third local oscillator balun microstrip line 213c are coupled to form the first differential local oscillator signal component; the first local oscillator balun microstrip line 213a and the fourth local oscillator balun microstrip line 213d are coupled to form the second differential local oscillator signal component; the first differential local oscillator signal component and the second differential local oscillator signal component form a local oscillator signal differential pair with equal amplitude and opposite phase, thereby forming a differential local oscillator signal. The first differential local oscillator signal component flows out from the first local oscillator balun output port 216, and the second differential local oscillator signal component flows out from the second local oscillator balun output port 217; the first differential local oscillator signal component flows into the local oscillator coupling line 230 from the first local oscillator coupling line input port 231, and the second differential local oscillator signal component flows into the local oscillator coupling line 230 from the second local oscillator coupling line input port 232. The first local oscillator coupling microstrip line 234a and the third local oscillator coupling microstrip line 234c are coupled to each other for transmission, and the first differential local oscillator signal component flows out from the output port 236 of the first local oscillator coupling line; the second local oscillator coupling microstrip line 234b and the fourth local oscillator coupling microstrip line 234d are coupled to each other for transmission, and the second differential local oscillator signal component flows out from the output port 237 of the second local oscillator coupling line; the radio frequency signal flows into the radio frequency balun 220 from the center feed point 222 of the radio frequency balun, and is coupled and transmitted through the first radio frequency balun microstrip line 223a, the second radio frequency balun microstrip line 223b, the third radio frequency balun microstrip line 223c and the fourth radio frequency balun microstrip line 223d. The second RF balun microstrip line 223b and the third RF balun microstrip line 223c are coupled to form a first differential RF signal component; the first RF balun microstrip line 223a and the fourth RF balun microstrip line 223d are coupled to form a second differential RF signal component; the first differential RF signal component and the second differential RF signal component form a differential pair with equal amplitude and opposite phase, thereby generating a differential RF signal. The first differential RF signal component flows out from the first RF balun output port 226, and the second differential RF signal component flows out from the second RF balun output port 227. Simultaneously, in diode ring 240, the first local oscillator differential signal component flowing out from the first local oscillator coupling line output port 236 flows into the first diode ring port 241, the second radio frequency differential signal component flowing out from the second radio frequency balun output port 227 flows into the second diode ring port 242, the third diode ring port 243 flows into the second local oscillator differential signal component flowing out from the second local oscillator coupling line output port 237, and the fourth diode ring port 244 flows into the first radio frequency differential signal component flowing out from the first radio frequency balun output port 226. Finally, the first local oscillator differential signal component, the second local oscillator differential signal component, the first radio frequency differential signal component, and the second radio frequency differential signal component are nonlinearly mixed in the diode ring 240 to form a mixed intermediate frequency signal. The mixed intermediate frequency signal flows into the local oscillator coupling line 230 through the first diode ring port 241 and the third diode ring port 243, and converges at the center intersection point 238 of the second local oscillator coupling line to flow into the first end of the intermediate frequency microstrip line 251, and is transmitted to the second end of the intermediate frequency microstrip line 251, and finally output through the intermediate frequency port 252.

[0050] In the up-conversion operation, the local oscillator signal flows from the local oscillator balun integrated port 211 through the local oscillator balun center feed point 212 into the local oscillator balun 210, where it is converted into a first local oscillator differential signal component and a second local oscillator differential signal component. This process, transmitted via the local oscillator coupling line 230 to the diode ring 240, is essentially the same as in the down-conversion operation described above. In the diode ring 240, the first local oscillator differential signal component flowing out from the first local oscillator coupling line output port 236 flows into the first diode ring port 241, and the second local oscillator differential signal component flowing out from the second local oscillator coupling line output port 237 flows into the third diode ring port 243. Simultaneously, the unmixed intermediate frequency (IF) signal flows in from the IF port 252, passes through the IF lead-out circuit 250, enters the local oscillator coupling line 230 via the center intersection point 238 of the second local oscillator coupling line, and then enters the diode ring 240 via the first diode ring port 241 and the third diode ring port 243. Finally, the intermediate frequency signal is mixed with the first local oscillator differential signal component and the second local oscillator differential signal component in diode ring 240 to generate a first differential RF signal component and a second differential RF signal component. The first differential RF signal component flows into the RF balun 220 from the fourth diode ring port 244 of the diode ring, and the second differential RF signal component flows into the RF balun 220 from the second diode ring port 242 of the diode ring. The first differential RF signal is coupled to the second RF balun microstrip line 223b through the third RF balun microstrip line 223c, and the second differential RF signal is coupled to the fourth RF balun microstrip line 223d through the first RF balun microstrip line 223a. The coupled first and second differential RF signal components form a differential RF signal pair with equal amplitude and opposite phase, thus forming a differential RF signal. The differential RF signal flows out from the center feed point 222 of the RF balun through the RF balun synthesis port 221.

[0051] The passive double-balanced mixer can enhance the amplitude and phase consistency of the signal by fine-tuning the balun structure of the local oscillator balun 210 and the radio frequency balun 220, thereby improving the isolation of the passive double-balanced mixer. The following is an explanation with a specific example.

[0052] Taking the Local Oscillator Balun 210 as an example, the balun structure of the 210 is initially a completely symmetrical design, in which the third local oscillator balun microstrip line 213c and the fourth local oscillator balun microstrip line 213d have the same odd-mode impedance and even-mode impedance. If the 210 local oscillator balun is equivalent to a three-port network, then the amplitude imbalance of the 210 local oscillator balun can be expressed as follows:

[0053] Where S represents the scattering parameters of the network; S 21This represents the transmission coefficient from the integrated local oscillator balun port 211 to the output port 216 of the first local oscillator balun when the integrated local oscillator balun port 211 is matched with the output port 217 of the second local oscillator balun; S 31 Z1 represents the transmission coefficient from the local oscillator balun integrated port 211 to the second local oscillator balun output port 217 when the local oscillator balun integrated port 211 is matched with the first local oscillator balun output port 216; Z2 represents the input impedance of the first local oscillator balun output port 216, and Z3 represents the input impedance of the second local oscillator balun output port 217. 0e Z 0o This indicates that the third local oscillator balun microstrip line 213c and the fourth local oscillator balun microstrip line 213d have the same odd-mode impedance and even-mode impedance, and C represents the coupling degree.

[0054] This expression shows that when the coupling degree approaches the ideal value of 1 (i.e., 0dB), the amplitude imbalance of the local oscillator balun 210 will approach 0 (infinitesimal). Therefore, it can be concluded that the upper limit of the maximum coupling potential achievable by the balun structure of the local oscillator balun 210 directly affects the amplitude consistency of the local oscillator balun 210.

[0055] To further illustrate the quantitative relationship between the input impedance of the first oscillator balun output port 216 and the odd-mode and even-mode of the third oscillator balun microstrip line 213c, and between the input impedance of the second oscillator balun output port 217 and the odd-mode and even-mode of the fourth oscillator balun microstrip line 213d, a more detailed analysis of the third oscillator balun microstrip line 213c and the fourth oscillator balun microstrip line 213d is conducted, expressed as follows:

[0056] in, This represents the equivalent reflection coefficient at the output port 216 of the first vibratory balun. Z represents the equivalent reflection coefficient at the output port 217 of the second oscillating balun. L1 Z represents the load impedance at the output port 216 of the first oscillator balun. L2 This indicates the load impedance of the output port 217 of the second local oscillator balun.

[0057] From the above equation, the input impedance Z1 of the first local oscillator balun output port 216 and the input impedance Z2 of the second local oscillator balun output port 217 can be further derived, expressed as follows:

[0058] Among them, Z 0e1 Z represents the odd-mode impedance of the third oscillator balun microstrip line 213c. 0o1 Z represents the even-mode impedance of the third local oscillator balun microstrip line 213c. 0e2 Z represents the odd-mode impedance of the fourth oscillator balun microstrip line 213d.0o2 This represents the even-mode impedance of the fourth local oscillator balun microstrip line 213d.

[0059] To ensure the balun's output signal achieves ideal amplitude-phase consistency, the following conditions must be met simultaneously, expressed as the following formula: S 21 =-S 31 And S 11 =0

[0060] That is, the output amplitudes of the first local oscillator balun output port 216 and the second local oscillator balun output port 217 are equal, the output phases of the first local oscillator balun output port 216 and the second local oscillator balun output port 217 differ by 180°, and the combined local oscillator balun port 211 is perfectly matched with its characteristic impedance, with no energy reflection. The equivalent relationship is expressed as follows: S 11 =0 can be equivalent to Z1=Z2=2Z S

[0061] Among them, S 11 Z represents the reflection coefficient of the local oscillator balun integrated port 211 network when the first local oscillator balun output port 216 is matched with the second local oscillator balun output port 217. S This represents the characteristic impedance of the local oscillator balun composite port 211.

[0062] Substituting the specific expressions for the input impedance Z1 of the first local oscillator balun output port 216 and the input impedance Z2 of the second local oscillator balun output port 217 into the above ideal balun characteristic conditions, we can obtain the matching relationship between the odd-mode impedance and even-mode impedance of the third local oscillator balun microstrip line 213c and the characteristic impedance of the local oscillator balun combined port 211, expressed as follows:

[0063] The matching relationship between the odd-mode and even-mode impedances of the fourth local oscillator balun microstrip line 213d and the characteristic impedance of the local oscillator balun synthesis port 211 is expressed by the following formula:

[0064] As can be seen from the above formula, in order to achieve ideal amplitude and phase consistency in the output signal of the balun, the odd-mode impedance and even-mode impedance required for the third local oscillator balun microstrip line 213c and the fourth local oscillator balun microstrip line 213d are not exactly the same, that is... and Therefore, based on the completely symmetrical balun structure, in this embodiment of the invention, the local oscillator balun 210, the radio frequency balun 220, and the local oscillator coupling line 230 all adopt a three-layer vertical metal layer structure. The isolation of the passive double-balanced mixer is improved by the metal layer connection method of vias and the symmetrical microstrip line layout.

[0065] Reference Figure 8 and Figure 11 This mixer achieves low conversion loss and excellent isolation performance in the ultra-wideband range of 2–22 GHz. Typical down-conversion loss is approximately 10 dB; typical local oscillator-to-radio frequency (LO-RF) isolation is approximately 55 dB, typical local oscillator-to-intermediate frequency (LO-IF) isolation is approximately 40 dB, and typical radio frequency-to-intermediate frequency (RF-IF) isolation is approximately 42 dB.

[0066] The implementation principle of a passive double-balanced mixer according to an embodiment of this application is as follows: In the passive double-balanced mixer, both the local oscillator balun 210 and the radio frequency balun 220 adopt a three-layer metal balun structure. The differential signal is efficiently coupled to the vertically overlapping microstrip line by allowing the single-ended signal to flow in from the center feed point of the third metal layer in the balun structure. The amplitude and phase consistency of the differential signal is further improved through the local oscillator coupling line 230 of the three-layer metal structure. In the ultra-wideband range, this ensures that the local oscillator signal and the radio frequency signal are effectively converted into high-quality differential signals, thereby improving the isolation and spurious suppression performance of the passive double-balanced mixer. Furthermore, this structure provides stable and efficient mixing performance for the passive double-balanced mixer and has low conversion loss characteristics.

[0067] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A passive double-balanced mixer, characterized in that, include: Local oscillator balun (210), local oscillator coupling line (230), diode ring (240), RF balun (220) and intermediate frequency lead-out circuit (250); The local oscillator balun (210) has a local oscillator balun integrated port (211), a local oscillator balun center ground port (215), a first local oscillator balun output port (216), a second local oscillator balun output port (217), and a first local oscillator balun metal layer, a second local oscillator balun metal layer, and a third local oscillator balun metal layer stacked sequentially. The third local oscillator balun metal layer contains a local oscillator balun center feed point (212) and a first local oscillator balun microstrip line (213a) and a second local oscillator balun microstrip line (213a) symmetrically arranged relative to the local oscillator balun center feed point (212). 213b), the local oscillator balun center feed point (212) is connected to the local oscillator balun integrated port (211); the second local oscillator balun metal layer has a local oscillator balun center intersection point (214) and a third local oscillator balun microstrip line (213c) and a fourth local oscillator balun microstrip line (213d) symmetrically arranged relative to the local oscillator balun center intersection point (214), the local oscillator balun center intersection point (214) is connected to the local oscillator balun center ground port (215), the second local oscillator balun microstrip line (213b) and the third local oscillator balun microstrip line (213c) The first local oscillator balun microstrip line (213a) and the fourth local oscillator balun microstrip line (213d) are vertically overlapped; the first local oscillator balun metal layer is connected to the first local oscillator balun microstrip line (213a), the second local oscillator balun microstrip line (213b), the third local oscillator balun microstrip line (213c) and the fourth local oscillator balun microstrip line (213d), and the first local oscillator balun metal layer is also connected to the first local oscillator balun output port (216), the second local oscillator balun output port (217) and ground; wherein, the local oscillator signal... The signal flows into the local oscillator balun (210) from the center feed point (212), and is coupled through the first local oscillator balun microstrip line (213a), the second local oscillator balun microstrip line (213b), the third local oscillator balun microstrip line (213c) and the fourth local oscillator balun microstrip line (213d) to form a first differential local oscillator signal component and a second differential local oscillator signal component. The first differential local oscillator signal component flows out from the first local oscillator balun output port (216), and the second differential local oscillator signal component flows out from the second local oscillator balun output port (217).

2. The passive double-balanced mixer according to claim 1, characterized in that, The first local oscillator metal layer is connected to the first local oscillator microstrip line (213a), the second local oscillator microstrip line (213b), the third local oscillator microstrip line (213c), and the fourth local oscillator microstrip line (213d). The first end of the first local oscillator microstrip line (213a) is connected to the center feed point (212) of the local oscillator, and the second end of the first local oscillator microstrip line (213a) is connected to the first local oscillator metal layer and then connected to the output port (217) of the second local oscillator through the first local oscillator metal layer. The first end of the second local oscillator microstrip line (213b) is connected to the center feed point (212) of the local oscillator, and the second local oscillator... The second end of the microstrip line (213b) is connected to the first local oscillator balun metal layer and grounded through the first local oscillator balun metal layer; the first end of the third local oscillator balun microstrip line (213c) is connected to the center intersection point (214) of the local oscillator balun, and the second end of the third local oscillator balun microstrip line (213c) is connected to the first local oscillator balun metal layer and grounded through the first local oscillator balun metal layer.

3. The passive double-balanced mixer according to claim 2, characterized in that, The second end of the first oscillating balun microstrip line (213a), the second end of the second oscillating balun microstrip line (213b), the second end of the third oscillating balun microstrip line (213c), and the second end of the fourth oscillating balun microstrip line (213d) are all connected to the first oscillating balun metal layer through vias.

4. The passive double-balanced mixer according to claim 1, characterized in that, The radio frequency balun (220) includes a radio frequency balun integrated port (221), a radio frequency balun center ground port (225), a first radio frequency balun output port (226), a second radio frequency balun output port (227), and a first radio frequency balun metal layer, a second radio frequency balun metal layer, and a third radio frequency balun metal layer stacked sequentially; the third radio frequency balun metal layer has a radio frequency balun center feed point (222) and a first radio frequency balun microstrip line (223a) and a second radio frequency balun microstrip line (223a) symmetrically arranged relative to the radio frequency balun center feed point (222). 23b), the RF balun center feed point (222) is connected to the RF balun integrated port (221); the second RF balun metal layer is constructed with an RF balun center intersection (224) and a third RF balun microstrip line (223c) and a fourth RF balun microstrip line (223d) symmetrically arranged relative to the RF balun center intersection (224), the RF balun center intersection (224) is connected to the RF balun center ground port (225), and the second RF balun microstrip line (223b) and the third RF balun microstrip line (223c) are perpendicular to each other. The first RF balun microstrip line (223a) and the fourth RF balun microstrip line (223d) are perpendicularly overlapped; the first RF balun metal layer is connected to the first RF balun microstrip line (223a), the second RF balun microstrip line (223b), the third RF balun microstrip line (223c), and the fourth RF balun microstrip line (223d), and the first RF balun metal layer is also connected to the first RF balun output port (226), the second RF balun output port (227), and ground; wherein, the RF signal originates from... The RF balun's center feed point (222) flows into the RF balun (220), and is coupled through the first RF balun microstrip line (223a), the second RF balun microstrip line (223b), the third RF balun microstrip line (223c), and the fourth RF balun microstrip line (223d) to form a first differential RF signal component and a second differential RF signal component. The first differential RF signal component flows out from the first RF balun output port (226), and the second differential RF signal component flows out from the second RF balun output port (227).

5. The passive double-balanced mixer according to claim 4, characterized in that, The first RF balun metal layer is connected to the first RF balun microstrip line (223a), the second RF balun microstrip line (223b), the third RF balun microstrip line (223c), and the fourth RF balun microstrip line (223d); wherein, the first end of the first RF balun microstrip line (223a) is connected to the center feed point (222) of the RF balun, and the second end of the first RF balun microstrip line (223a) is connected to the first RF balun metal layer, and is connected to the second RF balun output port (227) through the first RF balun metal layer; the first end of the second RF balun microstrip line (223b) is connected to the center feed point (222) of the RF balun, and the second RF balun... The second end of the third RF balun microstrip line (223b) is connected to the first RF balun metal layer and grounded through the first RF balun metal layer; the first end of the third RF balun microstrip line (223c) is connected to the center intersection point (224) of the RF balun, and the second end of the third RF balun microstrip line (223c) is connected to the first RF balun metal layer and grounded through the first RF balun metal layer.

6. The passive double-balanced mixer according to claim 5, characterized in that, The second end of the first RF balun microstrip line (223a), the second end of the second RF balun microstrip line (223b), the second end of the third RF balun microstrip line (223c), and the second end of the fourth RF balun microstrip line (223d) are all connected to the first RF balun metal layer through vias.

7. The passive double-balanced mixer according to claim 4, characterized in that, The local oscillator coupling line (230) includes a first local oscillator coupling line input port (231), a second local oscillator coupling line input port (232), a local oscillator coupling line center ground port (235), a first local oscillator coupling line output port (236), a second local oscillator coupling line output port (237), and a first local oscillator coupling metal layer, a second local oscillator coupling metal layer, and a third local oscillator coupling metal layer stacked sequentially; wherein, the second local oscillator coupling metal layer has a first local oscillator coupling line center intersection point (233) and a first local oscillator coupling microstrip line (234a) symmetrically arranged relative to the first local oscillator coupling line center intersection point (233) and the second local oscillator coupling microstrip line (234a). The first local oscillator coupling line (234b) has its center intersection point (233) connected to the center grounding port (235) of the local oscillator coupling line. The third local oscillator coupling metal layer contains the center intersection point (238) of the second local oscillator coupling line and symmetrically arranged third local oscillator coupling microstrip lines (234c and 234d) relative to the center intersection point (238). The center intersection point (238) of the second local oscillator coupling line is connected to the intermediate frequency lead-out circuit (250). The first local oscillator coupling microstrip line (234a) and the third local oscillator coupling microstrip line (234c) overlap vertically, and the second local oscillator coupling microstrip line... The local oscillator coupling microstrip line (234b) is perpendicularly overlapped with the fourth local oscillator coupling microstrip line (234d); the first local oscillator coupling metal layer is connected to the first local oscillator coupling microstrip line (234a), the second local oscillator coupling microstrip line (234b), the third local oscillator coupling microstrip line (234c), and the fourth local oscillator coupling microstrip line (234d), and the first local oscillator coupling metal layer is also connected to the output port (236) of the first local oscillator coupling line, the output port (237) of the second local oscillator coupling line, and the center ground port (235) of the local oscillator coupling line; wherein, the first differential local oscillator signal component originates from the first local oscillator coupling microstrip line. The input port (231) of the line flows into the local oscillator coupling line (230), and the second differential local oscillator signal component flows into the local oscillator coupling line (230) from the input port (232) of the second local oscillator coupling line. It is coupled through the first local oscillator coupling microstrip line (234a), the second local oscillator coupling microstrip line (234b), the third local oscillator coupling microstrip line (234c) and the fourth local oscillator coupling microstrip line (234d). The first differential local oscillator signal component flows out from the output port (236) of the first local oscillator coupling line, and the second differential local oscillator signal component flows out from the output port (237) of the second local oscillator coupling line.

8. The passive double-balanced mixer according to claim 7, characterized in that, The first local oscillator coupling metal layer is connected to the first local oscillator coupling microstrip line (234a), the second local oscillator coupling microstrip line (234b), the third local oscillator coupling microstrip line (234c), and the fourth local oscillator coupling microstrip line (234d). The first end of the first local oscillator coupling microstrip line (234a) is connected to the first local oscillator coupling line input port (231), and the second end of the first local oscillator coupling microstrip line (234a) is connected to the first local oscillator coupling metal layer and connected to the center intersection point (233) of the first local oscillator coupling line through the first local oscillator coupling metal layer. The first end of the second local oscillator coupling microstrip line (234b) is connected to the second local oscillator coupling line input port (232), and the second end of the second local oscillator coupling microstrip line (234b) is connected to the first local oscillator coupling microstrip line (234d). The local oscillator coupling metal layer is connected to the center intersection (233) of the first local oscillator coupling line through the first local oscillator coupling metal layer; the first end of the third local oscillator coupling microstrip line (234c) is connected to the center intersection (238) of the second local oscillator coupling line, and the second end of the third local oscillator coupling microstrip line (234c) is connected to the first local oscillator coupling metal layer, and is connected to the output port (236) of the first local oscillator coupling line through the first local oscillator coupling metal layer; the first end of the fourth local oscillator coupling microstrip line (234d) is connected to the center intersection (238) of the second local oscillator coupling line, and the second end of the fourth local oscillator coupling microstrip line (234d) is connected to the first local oscillator coupling metal layer, and is connected to the output port (237) of the second local oscillator coupling line through the first local oscillator coupling metal layer.

9. The passive double-balanced mixer according to claim 7, characterized in that, The diode ring (240) includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The cathode of the first diode D1 is connected to the cathode of the second diode D2 to form a first diode ring port (241). The anode of the second diode D2 is connected to the cathode of the third diode D3 to form a second diode ring port (242). The anode of the third diode D3 is connected to the anode of the fourth diode D4 to form a third diode ring port (243). The cathode of the fourth diode D4 is connected to the anode of the first diode D1 to form a fourth diode ring port (244). The first diode ring port (241) is connected to the first local oscillator coupling line output port (236). The second diode ring port (242) is connected to the second radio frequency balun output port (227). The third diode ring port (243) is connected to the second local oscillator coupling line output port (237). The fourth diode ring port (244) is connected to the first radio frequency balun output port (226).

10. The passive double-balanced mixer according to claim 7, characterized in that, The intermediate frequency output circuit (250) includes an intermediate frequency metal layer and an intermediate frequency port (252), through which intermediate frequency signals flow in or out; wherein, an intermediate frequency microstrip line (251) is constructed in the intermediate frequency metal layer, the first end of the intermediate frequency microstrip line (251) is connected to the center intersection point (238) of the second local oscillator coupling line, and the second end of the intermediate frequency microstrip line (251) is connected to the intermediate frequency port (252).

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