Broadband double-balanced mixer

Abstract

The utility model discloses a broadband double-balanced mixer, which comprises an annular diode stack formed by sequentially connecting a diode D1, a diode D2, a diode D3 and a diode D4 end to end, and a radio frequency circuit, a local oscillator circuit and an intermediate frequency circuit which are connected with the annular diode stack. A ring bridge circuit formed by Schottky diodes and a coupling line Marchand balun structure are used, and the topological structure of a mixer circuit is improved, so that the working bandwidth is improved, and meanwhile, the chip size is reduced.

Description

Technical Field

[0001] The utility model relates to the field of monolithic microwave integrated circuits, and in particular to a broadband double-balanced mixer. Background Art

[0002] Theoretically, mixers are key components in nearly every RF microwave receiver. The performance and reliability of a mixer are crucial to the overall performance of the system. Therefore, developing high-performance mixers has been a key research focus for many years.

[0003] Mixers are indispensable components in today's RF, microwave, and millimeter-wave systems, playing a vital role and enjoying widespread application in a variety of fields, including radar, communications, satellites, remote sensing, measurement, and electronic countermeasures. Mixers are developing towards high performance, low cost, high integration, and wide bandwidth, thus providing a foundation for further system integration and miniaturization.

[0004] Due to the limitations of semiconductor technology, research on mixers is mostly in the stage of theoretical analysis and experimental verification, without many breakthroughs. Existing mixers usually have poor performance, high cost, low integration, and narrow bandwidth. The emergence of surface barrier diodes and tunnel diodes has brought the research on mixers to a whole new level. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a broadband double-balanced mixer that solves the problems of the prior art mixers, such as poor performance, high cost, low integration and narrow frequency band.

[0006] In order to achieve the above-mentioned purpose of the utility model, the technical solution adopted by the utility model is: a broadband double-balanced mixer, including: a ring diode stack composed of a diode D1, a diode D2, a diode D3 and a diode D4 connected end to end, and a radio frequency circuit, a local oscillator circuit and an intermediate frequency circuit connected to the ring diode stack.

[0007] Furthermore, the diode D1 , the diode D2 , the diode D3 and the diode D4 are all Schottky diodes with the same electrical characteristic parameters.

[0008] Furthermore: the radio frequency circuit includes a microstrip line TF2, one end of the microstrip line TF2 serves as a radio frequency input and output terminal LO, the other end of the microstrip line TF2 is connected to one end of a microstrip line TF5, and the other end of the microstrip line TF5 is connected to a ground capacitor C3;

[0009] The RF circuit further includes a ground microstrip line TF1 and a ground microstrip line TF4; the ground microstrip line TF1 is connected to the ground microstrip line TF3 and the cathode of the diode D1 respectively; the ground microstrip line TF4 is connected to the ground microstrip line TF6 and the cathode of the diode D3 respectively.

[0010] Furthermore, the local oscillator circuit includes a capacitor C1 and a capacitor C2, one end of the capacitor C1 is connected to the cathode of the diode D4, and the other end of the capacitor C1 is connected to the ground microstrip line TF7 and the ground microstrip line TF9 respectively; one end of the capacitor C2 is connected to the cathode of the diode D2, and the other end of the capacitor C2 is connected to the ground microstrip line TF10 and the ground microstrip line TF12 respectively;

[0011] The local oscillator circuit further includes a microstrip line TF8 , one end of which serves as a local oscillator input terminal RF, the other end of which is connected to one end of a microstrip line TF11 , and the other end of which is connected to a grounding capacitor C4 .

[0012] Furthermore: the intermediate frequency circuit includes an inductor L1 and an inductor L2; one end of the inductor L1 is connected to the cathode of the diode D2, the other end of the inductor L1 is connected to one end of the capacitor C5, and the other end of the capacitor C5 is also connected to the grounding resistor R; one end of the inductor L2 is connected to the cathode of the diode D4, and the other end of the inductor L2 serves as the intermediate frequency input and output terminal IF; the other end of the inductor L1 is also connected to the other end of the inductor L2.

[0013] Furthermore, the balun structure of the broadband double-balanced mixer adopts a Marchand balun structure.

[0014] The beneficial effects of the utility model are:

[0015] 1. Use parallel coupled lines and Schottky diodes in series to form a loop circuit, effectively increasing the mixer bandwidth;

[0016] 2. Inductor L1, inductor L2, capacitor C5 and resistor R form a filter to filter out the noise generated during the mixing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the topology diagram of the broadband double-balanced mixer.

[0018] Figure 2 This is the simulation result of frequency conversion loss.

[0019] Figure 3 This is the RF-IF isolation simulation result diagram.

[0020] Figure 4This is the RF-LO isolation simulation result diagram.

[0021] Figure 5 LO-IF isolation simulation results diagram DETAILED DESCRIPTION

[0022] The specific implementation methods of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific implementation methods. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations conceived using the present invention are protected.

[0023] like Figure 1 As shown, in one embodiment of the present invention, a broadband double-balanced mixer is provided, comprising: a ring diode stack formed by connecting diode D1, diode D2, diode D3 and diode D4 end to end in sequence, and a radio frequency circuit, a local oscillator circuit and an intermediate frequency circuit connected to the ring diode stack.

[0024] The diode D1 , the diode D2 , the diode D3 and the diode D4 are all Schottky diodes with the same electrical characteristic parameters.

[0025] The radio frequency circuit includes a microstrip line TF2, one end of the microstrip line TF2 serves as a radio frequency input and output terminal LO, the other end of the microstrip line TF2 is connected to one end of a microstrip line TF5, and the other end of the microstrip line TF5 is connected to a ground capacitor C3;

[0026] The RF circuit further includes a ground microstrip line TF1 and a ground microstrip line TF4; the ground microstrip line TF1 is connected to the ground microstrip line TF3 and the cathode of the diode D1 respectively; the ground microstrip line TF4 is connected to the ground microstrip line TF6 and the cathode of the diode D3 respectively.

[0027] The local oscillator circuit includes a capacitor C1 and a capacitor C2, one end of the capacitor C1 is connected to the cathode of the diode D4, and the other end of the capacitor C1 is connected to the ground microstrip line TF7 and the ground microstrip line TF9 respectively; one end of the capacitor C2 is connected to the cathode of the diode D2, and the other end of the capacitor C2 is connected to the ground microstrip line TF10 and the ground microstrip line TF12 respectively;

[0028] The local oscillator circuit further includes a microstrip line TF8 , one end of which serves as a local oscillator input terminal RF, the other end of which is connected to one end of a microstrip line TF11 , and the other end of which is connected to a grounding capacitor C4 .

[0029] The intermediate frequency circuit includes an inductor L1 and an inductor L2; one end of the inductor L1 is connected to the cathode of the diode D2, the other end of the inductor L1 is connected to one end of the capacitor C5, and the other end of the capacitor C5 is also connected to the ground resistor R; one end of the inductor L2 is connected to the cathode of the diode D4, and the other end of the inductor L2 serves as the intermediate frequency input and output terminal IF; the other end of the inductor L1 is also connected to the other end of the inductor L2.

[0030] The balun structure of the broadband double-balanced mixer adopts the Marchand balun structure. Since the spiral inductor balun is often used in the low frequency band, compared with the coupled line balun, it can effectively reduce the chip area due to the winding coil, but the spiral line will increase high-frequency parasitic noise. Capacitor C3 and capacitor C4 are connected in series at the ends of the local oscillator end LO and the radio frequency end RF balun. Capacitors C3 and C4 can play a role in widening the working bandwidth and improving the balance of the circuit. Their values ​​are often very small. In chip design, we often use open microstrip lines to replace small MIM capacitors. Capacitors C1 and C2 play the role of isolating the intermediate frequency signal and the radio frequency signal, so that the signal is output to the IF port after filtering out the noise through the filter composed of inductor L1, inductor L2, capacitor C5 and resistor R.

[0031] In one embodiment of the present invention, the broadband double-balanced mixer chip is optimized using ADS software, and the simulation results are as follows: Figure 2 、 Figure 3 、 Figure 4 and Figure 5 As shown;

[0032] according to Figure 2-Figure 5 From the simulation results, we can see that the mixer has the characteristics of small frequency conversion loss, large isolation and wide bandwidth.

[0033] In the description of the present invention, it should be understood that the terms "center," "thickness," "upper," "lower," "horizontal," "top," "bottom," "inner," "outer," "radial," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Therefore, features defined by "first," "second," and "third" may explicitly or implicitly include one or more of such features.

Claims

1. A broadband double-balanced mixer, characterized in that: include: A ring diode stack formed by connecting diode D1, diode D2, diode D3 and diode D4 end to end in sequence, and a radio frequency circuit, a local oscillator circuit and an intermediate frequency circuit connected to the ring diode stack; The radio frequency circuit includes a microstrip line TF2, one end of the microstrip line TF2 serves as a radio frequency input and output terminal LO, the other end of the microstrip line TF2 is connected to one end of a microstrip line TF5, and the other end of the microstrip line TF5 is connected to a ground capacitor C3; The radio frequency circuit further includes a ground microstrip line TF1 and a ground microstrip line TF4; The ground microstrip line TF1 is connected to the ground microstrip line TF3 and the cathode of the diode D1 respectively; the ground microstrip line TF4 is connected to the ground microstrip line TF6 and the cathode of the diode D3 respectively; The local oscillator circuit includes a capacitor C1 and a capacitor C2, one end of the capacitor C1 is connected to the cathode of the diode D4, and the other end of the capacitor C1 is connected to the ground microstrip line TF7 and the ground microstrip line TF9 respectively; one end of the capacitor C2 is connected to the cathode of the diode D2, and the other end of the capacitor C2 is connected to the ground microstrip line TF10 and the ground microstrip line TF12 respectively; The local oscillator circuit further includes a microstrip line TF8, one end of the microstrip line TF8 serves as a local oscillator input terminal RF, the other end of the microstrip line TF8 is connected to one end of a microstrip line TF11, and the other end of the microstrip line TF11 is connected to a ground capacitor C4; The intermediate frequency circuit includes an inductor L1 and an inductor L2; one end of the inductor L1 is connected to the cathode of the diode D2, the other end of the inductor L1 is connected to one end of the capacitor C5, and the other end of the capacitor C5 is also connected to the ground resistor R; one end of the inductor L2 is connected to the cathode of the diode D4, and the other end of the inductor L2 serves as the intermediate frequency input and output terminal IF; the other end of the inductor L1 is also connected to the other end of the inductor L2.

2. The broadband double-balanced mixer according to claim 1, wherein The diode D1 , the diode D2 , the diode D3 and the diode D4 are all Schottky diodes with the same electrical characteristic parameters.

3. The broadband double-balanced mixer according to any one of claims 1 to 2, characterized in that: The balun structure of the broadband double-balanced mixer adopts a Marchand balun structure.

Images