An improved multi-tube parallel structure double-balanced mixer

Abstract

The present invention discloses an improved multi-tube parallel structure double-balanced mixer, comprising a first balun, a diode mixing network, a second balun and an output matching network; the first balun and the second balun respectively convert a radio frequency signal and a local oscillator signal into a balanced signal and input them into the diode mixing network; after the diode mixing network performs branching and combining processing on the balanced signal, the mixing signal is output through an output matching network connected to the first balun tap. The present invention adopts a power-splitting-combining structure to improve the output power of the double-balanced mixer, so that the double-balanced mixer can achieve higher linearity, and at the same time, other indicators will not be deteriorated due to the increase in the size of the diode. In addition, the advantages of the double-balanced mixer, such as good intermodulation suppression, are retained, and good power output capacity and good input-output matching characteristics are achieved, avoiding the mismatch and performance deterioration caused by the increase in the diode size.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated circuit design, and in particular relates to an improved multi-tube parallel structure double-balanced mixer. Background Art

[0002] With the rapid development of the satellite communication market with demands for broadband digital transmission and high-speed satellite communication, video transceiver systems are also required to develop in the direction of high integration, compact structure and low price.

[0003] As an important component of the transceiver system, the RF and microwave mixers have a great impact on the overall performance of the link in terms of frequency conversion loss, input 1dB compression point, input and output standing waves, isolation, etc. When the RF and microwave mixer chip circuit is designed and implemented using integrated circuit technology, its performance is subject to certain restrictions, which are mainly reflected in the following aspects:

[0004] (1) Limited high power and low loss capabilities: With the development of semiconductor technology and the trend of proportional reduction in the size of Schottky tubes, the breakdown voltage has decreased and the knee voltage has increased, thereby limiting the power output capacity of a single Schottky tube. It is difficult to achieve low frequency conversion loss and high power output at the same time.

[0005] (2) Poor input and output standing waves: Generally, the bandwidth of a mixer is wide and impedance matching is difficult. While ensuring indicators such as frequency conversion loss, isolation, and input 1dB compression point, the standing wave is usually poor.

[0006] At present, there are many common low-loss, high-power mixer circuit structures. It is very difficult to meet the requirements of various parameters at the same time. Usually, its high power index will inevitably lead to the deterioration of the loss index, and is obtained at the cost of the deterioration of the standing wave.

[0007] It can be seen from this that the design difficulties of RF and microwave low-loss, high-power mixers based on integrated circuit technology are: (1) It is difficult for RF and microwave mixers to output high power; (2) It is difficult for RF and microwave mixers to obtain good standing waves. Summary of the invention

[0008] In view of the above-mentioned deficiencies in the prior art, the improved multi-tube parallel structure double-balanced mixer provided by the present invention solves the problems in the existing mixer design that the RF and microwave mixers are difficult to output high power and the RF and microwave mixers are difficult to obtain good standing waves.

[0009] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: an improved multi-tube parallel structure double-balanced mixer, including a first balun, a diode mixing network, a second balun and an output matching network;

[0010] The first balun and the second balun convert the radio frequency signal and the local oscillator signal into balanced signals respectively and input them into the diode mixing network;

[0011] The diode mixer network performs branching and combining processing on the balanced signal and then outputs the mixed signal through an output matching network connected to the first balun tap.

[0012] Further, one end of the first balun is connected to the first power splitter-combiner structure, the second power splitter-combiner structure and one end of the second balun in sequence;

[0013] The other end of the first balun is connected to the third power splitting-combining structure, the fourth power splitting-combining structure and the other end of the second balun in sequence;

[0014] The first power division-combining structure is also connected to the third power division-combining structure, and the second power division-combining structure is also connected to the fourth power division-combining structure;

[0015] The output ends of the first to fourth power splitting-combining structures are all connected to an output matching network.

[0016] Furthermore, the structures of the first to fourth power dividing-combining structures are completely the same.

[0017] Furthermore, the phase difference between the output ports of the first to fourth power division-combination structures is 0°.

[0018] Furthermore, the first to fourth power dividing-combining structures all include an input power dividing network, n identical diodes and an output power dividing network which are connected in sequence.

[0019] Furthermore, the number of the diodes is determined according to output power requirements and area limitations of the double-balanced mixer.

[0020] Furthermore, the number of the diodes is proportional to the output power and area of ​​the double-balanced mixer.

[0021] Furthermore, the output matching network is a matching circuit with an LC structure.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention adopts a power splitter-combiner structure to improve the output power of the double-balanced mixer, so that the double-balanced mixer can achieve higher linearity, while not causing other indicators to deteriorate due to increasing the size of the diode. In addition, the advantages of the double-balanced mixer, such as good intermodulation suppression, are retained, achieving good power output capability and good input-output matching characteristics, avoiding mismatch and performance degradation caused by increasing the size of the diode.

[0024] (2) The power splitter-combiner structure adopted in the present invention can not only improve the output power of the mixer, but also realize the impedance matching function to improve the standing wave of the circuit. By connecting n diodes in parallel to first split and then combine, the linearity and output power of the circuit are improved. At the same time, due to the existence of the power divider, the impedance is easier to match, thereby obtaining a better standing wave. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of an improved multi-tube parallel structure double-balanced mixer provided by the present invention.

[0026] Figure 2 This is a schematic diagram of the power splitter-combiner structure provided by the present invention. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0028] The embodiment of the present invention provides an improved multi-tube parallel structure double-balanced mixer, such as Figure 1 As shown, it includes a first balun, a diode mixing network, a second balun and an output matching network;

[0029] The first balun and the second balun convert the radio frequency signal and the local oscillator signal into balanced signals respectively and input them into the diode mixing network;

[0030] The diode mixer network performs branching and combining processing on the balanced signal and then outputs the mixed signal through an output matching network connected to the first balun tap.

[0031] In the embodiment of the present invention, Figure 1 As shown, one end of the first balun is connected to the first power division-combining structure, the second power division-combining structure and one end of the second balun in sequence; the other end of the first balun is connected to the third power division-combining structure, the fourth power division-combining structure and the other end of the second balun in sequence;

[0032] The first power division-combining structure is also connected to the third power division-combining structure, and the second power division-combining structure is also connected to the fourth power division-combining structure;

[0033] The output ends of the first to fourth power splitting-combining structures are all connected to an output matching network.

[0034] In the embodiment of the present invention, the structures of the first to fourth power splitting-combining structures are completely the same, and the phase difference between their output ports is 0°.

[0035] In the embodiment of the present invention, Figure 2 As shown, the first to fourth power dividing-combining structures all include an input power dividing network, n identical diodes and an output power dividing network which are connected in sequence.

[0036] In the embodiment of the present invention, the number of diodes in the power splitter-combiner structure is determined according to the output power requirement and area limitation of the double-balanced mixer; and the number of diodes is proportional to the output power and area of ​​the double-balanced mixer, that is, the more the number, the greater the final output power and the larger the area.

[0037] The output matching network in the embodiment of the present invention is a matching circuit with an LC structure.

[0038] Embodiment 2:

[0039] The embodiment of the present invention provides the working process of the double-balanced mixer in Embodiment 1:

[0040] The RF signal and the local oscillator signal are converted into balanced signals through the first balun and the second balun, and then enter the diode mixing network. After the signal enters each power splitter-combiner structure, the signal is first split through each diode and then combined. The combined signal is output through the balun tap; specifically, the signal passes through the diode and then through the same microstrip structure for combination, thereby effectively improving the 1dB compression point and output power of the mixer. At the same time, the port standing wave of the mixing circuit can be further optimized by reducing the size of the diode and adjusting the impedance matching.

[0041] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0042] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. An improved multi-tube parallel structure double-balanced mixer, characterized in that: It includes a first balun, a diode mixing network, a second balun and an output matching network; The first balun and the second balun convert the radio frequency signal and the local oscillator signal into balanced signals respectively and input them into the diode mixing network; The diode mixer network performs splitting and combining processing on the balanced signal and then outputs the mixed signal through an output matching network connected to the first balun tap; One end of the first balun is connected to the first power splitter-combiner structure, the second power splitter-combiner structure and one end of the second balun in sequence; The other end of the first balun is connected to the third power splitting-combining structure, the fourth power splitting-combining structure and the other end of the second balun in sequence; The first power division-combining structure is also connected to the third power division-combining structure, and the second power division-combining structure is also connected to the fourth power division-combining structure; The structures of the first to fourth power splitting-combining structures are completely the same; The first to fourth power splitter-combiner structures each include an input power splitter network connected in sequence, n identical diodes connected in parallel, and an output power splitter network; the number of the diodes is determined according to the output power requirement and area limitation of the double-balanced mixer; The number of the diodes is proportional to the output power and the area of ​​the double-balanced mixer.

2. The improved multi-tube parallel double-balanced mixer according to claim 1, characterized in that: The phase difference between the output ports of the first to fourth power splitting-combining structures is 0°.

3. The improved multi-tube parallel double-balanced mixer according to claim 1, characterized in that: The output matching network is a matching circuit with an LC structure.

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