Self-vibration mixer with adjustable broadband

Abstract

The invention discloses a broadband-adjustable natural vibration mixer, and relates to the technical field of radio frequency microwave mixing. Comprising a double-gate FET (Field Effect Transistor) which provides a local oscillation signal under the action of direct current bias and a YIG (Yttrium Indium Gallium) thin-film resonator and mixes the local oscillation signal with a radio-frequency signal, a direct current bias network which provides a direct current power supply for the double-gate FET, a source feedback network which is connected with a source of the double-gate FET, and a source feedback network which is connected with a source of the YIG thin-film resonator. And the YIG thin film resonator, the radio frequency input, filtering and matching network and the intermediate frequency output, filtering and matching network are connected with a grid electrode of the direct current bias network connected with the double-grid FET transistor. The YIG thin-film resonators are adopted to achieve the broadband adjustment range of multiple octaves and the excellent phase noise characteristic, the double-gate field effect transistors are adopted to achieve higher linear frequency conversion gain and better noise performance, meanwhile, the inherent isolation between the two gates reaches 20 dB or above, and the noise performance is improved. Good isolation between a local oscillator signal and a radio frequency signal can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency microwave mixing, and in particular to a broadband adjustable self-oscillating mixer. Background Art

[0002] In the receiving system link, the oscillator and the mixer are the key combination circuit units to realize signal frequency conversion. The main function of the mixer is to convert the high-frequency electromagnetic wave signal received by the antenna with the local oscillation signal as the reference signal to obtain a useful signal with a lower frequency. As an energy conversion component, the main function of the oscillator is to convert the energy provided by the DC power supply into a high-frequency AC signal with a certain frequency characteristic. In the receiving system, it is often used to generate the local oscillation reference signal source required by the mixing circuit. The two are often used as a combination circuit to realize frequency conversion and applied to the receiving link. In high-performance wireless communication equipment, in order to ensure the stability of the receiving system, the active circuit is usually required to have the characteristics of high quality and high reliability. Therefore, high requirements are placed on the performance of circuits such as oscillators and mixers. In the receiver link, the circuit structure of active circuits such as oscillators and mixers is usually more complex, and the circuit area is relatively large. At the same time, if an active mixing circuit is required to reduce the circuit gain lost during frequency changes, the power consumption of the mixing circuit will also increase, which does not meet the low power design requirements of the receiving system.

[0003] Self-oscillating mixing technology is a technology that integrates mixing function and local oscillation function, and can realize two functions on one active device. The self-oscillating mixer is a two-port device. Under the premise of making full use of the nonlinear effect of the tube itself, it selects the appropriate working point at the same time, so that the received RF signal is mixed with the free oscillation signal of the self-oscillating mixer to generate the corresponding intermediate frequency signal, thereby achieving the best mixing performance. This can not only reduce the use of active devices such as transistors and improve the utilization rate of active devices, but also reduce circuit power consumption and cost. It is of great significance to realize the miniaturization and integrated design of the receiving system link, and has great development prospects. Traditional self-oscillating mixing circuits based on FET transistors such as Figure 1 As shown, it requires a single-ended mixer and a common source oscillator. The oscillator outputs the local oscillator signal and the RF signal which are input by the mixer gate. After being mixed by the nonlinear effect of the transistor, the intermediate frequency signal of the required order is output through the intermediate frequency filter. In this mixer circuit, since the original oscillator resonant network is replaced, the frequency can only be adjusted by adding a varactor diode at the feedback end. The adjustable bandwidth is narrow and the phase noise performance is average. Summary of the invention

[0004] The present invention provides a broadband adjustable self-oscillator mixer, which not only overcomes the problem that the traditional mixer circuit requires at least two transistors, has high power consumption and large size, but also solves the problem that the current self-oscillator mixer is difficult to achieve broadband adjustment of the local oscillator signal.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A broadband adjustable self-oscillating mixer, comprising:

[0007] A dual-gate FET transistor provides a local oscillator signal under the action of a DC bias and a YIG thin film resonator, and mixes the local oscillator signal with a radio frequency signal;

[0008] A DC bias network, one end of the DC bias network is connected to the gate of the dual-gate FET transistor, and the other end of the DC bias network is connected to the drain of the dual-gate FET transistor, so as to provide a DC power supply for the dual-gate FET transistor;

[0009] A source feedback network is connected to the source of the dual-gate FET transistor and is used to increase circuit instability to ensure that the dual-gate FET transistor can generate a stable local oscillator signal;

[0010] A YIG thin film resonator is connected to the gate of a dual-gate FET transistor connected to a DC bias network, and the resonant frequency is adjusted by changing an external magnetic field to thereby change the oscillation frequency of the dual-gate FET transistor;

[0011] The RF input, filtering and matching network is connected to the other gate of the dual-gate FET transistor as the input end of the RF signal, and filters out the spurious signals of the input RF signal, and at the same time filters out the local oscillator signal and its higher harmonics, intermediate frequency signal and other intermodulation signal products, and achieves good matching with the subsequent circuit;

[0012] The intermediate frequency output, filtering and matching network are connected to the drain of the dual-gate FET transistor to filter out the RF signal, the local oscillator signal and its higher harmonics, and other intermodulation products other than the required intermediate frequency signal, and suppress the leakage of the oscillation signal and RF signal generated by the self-oscillating mixer itself, so as to achieve good output impedance matching.

[0013] Furthermore, the YIG thin film resonator and the RF input, filtering and matching networks are respectively connected to the two gates of the dual-gate field effect transistor, and the intermediate frequency signal after the input RF signal is mixed with the local oscillator signal generated by the dual-gate field effect transistor is output from the drain of the dual-gate field effect transistor to obtain better frequency conversion gain.

[0014] Furthermore, the DC bias network provides a negative voltage at the gate end of the dual-gate field effect transistor connected to the YIG thin film resonator, and provides a positive voltage at the drain end of the intermediate frequency signal output, so that the dynamic operating point of the FET at one end connected to the YIG thin film resonator passes through its partial linear region and saturation region, and the dynamic operating point of the FET at one end connected to the RF input, filtering and matching network is completely in the saturation region, thereby making the dual-gate field effect transistor operate in a strong nonlinear region to obtain higher receiving sensitivity and frequency conversion gain.

[0015] Furthermore, the dual-gate field effect transistor (dual-gate FET transistor) adopts a common source structure to ensure a larger output power.

[0016] Furthermore, the other gate of the dual-gate FET transistor is connected to the RF input, filtering and matching network as the input end of the RF signal, and the spurious signals of the input RF signal are filtered out, while the local oscillator signal and its higher harmonics, intermediate frequency signal and other intermodulation signal products are filtered out, and good matching with the subsequent circuit is achieved.

[0017] Furthermore, the YIG thin film resonator is selected to have a loaded Q value of 600 or more.

[0018] Furthermore, the drain of the dual-gate field effect transistor is connected to an intermediate frequency output, a filtering and matching network to filter out radio frequency signals, local oscillator signals and their higher harmonics, and other intermodulation products other than the required intermediate frequency signal.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention provides a broadband adjustable self-oscillating mixer, which occupies fewer transistors, reduces power consumption and cost, and has higher reliability, compared with traditional single-ended mixers and common-source oscillators requiring FET tubes. Compared with conventional FET tube self-oscillating mixers, the use of YIG thin film resonators can achieve a broadband adjustment range of multiple octaves and excellent phase noise characteristics. The use of dual-gate field-effect transistors can achieve higher linear frequency conversion gain and better noise performance. At the same time, the inherent isolation between the two gates reaches more than 20 dB, which can achieve good isolation between the local oscillator signal and the radio frequency signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a traditional self-oscillating mixer circuit based on FET transistors;

[0022] Figure 2 A schematic diagram of a broadband adjustable self-oscillating mixer provided by the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] A broadband tunable self-oscillating mixer, such as Figure 2 As shown, including:

[0025] A dual-gate FET transistor provides a local oscillator signal under the action of a DC bias and a YIG thin film resonator, and mixes the local oscillator signal with a radio frequency signal;

[0026] A DC bias network, one end of which is connected to the gate of the dual-gate FET transistor and the other end is connected to the drain of the dual-gate FET transistor, providing a DC power supply for the dual-gate FET transistor to ensure that it has stronger nonlinearity at a suitable operating point, thereby improving receiving sensitivity and frequency conversion gain;

[0027] A source feedback network is connected to the source of the dual-gate FET transistor and is used to increase circuit instability to ensure that the dual-gate FET transistor can generate a stable local oscillator signal;

[0028] A YIG thin film resonator is connected to the gate of a dual-gate FET transistor connected to a DC bias network, and the resonant frequency is adjusted by changing an external magnetic field to thereby change the oscillation frequency of the dual-gate FET transistor;

[0029] The RF input, filtering and matching network is connected to the other gate of the dual-gate FET transistor as the input end of the RF signal, and filters out the spurious signals of the input RF signal, and at the same time filters out the local oscillator signal and its higher harmonics, intermediate frequency signal and other intermodulation signal products, and achieves good matching with the subsequent circuit;

[0030] The intermediate frequency output, filtering and matching network are connected to the drain of the dual-gate FET transistor to filter out the RF signal, the local oscillator signal and its higher harmonics, and other intermodulation products other than the required intermediate frequency signal, and suppress the leakage of the oscillation signal and RF signal generated by the self-oscillating mixer itself, so as to achieve good output impedance matching.

[0031] Furthermore, the YIG thin film resonator and the RF input, filtering and matching networks are respectively connected to the two gates of the dual-gate field effect transistor, and the intermediate frequency signal after the input RF signal is mixed with the local oscillator signal generated by the dual-gate field effect transistor is output from the drain of the dual-gate field effect transistor to obtain better frequency conversion gain.

[0032] Furthermore, the DC bias network provides a negative voltage at the gate end of the dual-gate field effect transistor connected to the YIG thin film resonator, and provides a positive voltage at the drain end of the intermediate frequency signal output, so that the dynamic operating point of the FET at one end connected to the YIG thin film resonator passes through its partial linear region and saturation region, and the dynamic operating point of the FET at one end connected to the RF input, filtering and matching network is completely in the saturation region, thereby making the dual-gate field effect transistor operate in a strong nonlinear region to obtain higher receiving sensitivity and frequency conversion gain.

[0033] Furthermore, the dual-gate field effect transistor (dual-gate FET transistor) adopts a common source structure to ensure a larger output power. The common source structure only needs to design an equivalent inductor or capacitor at the source, and then convert it into an equivalent microstrip structure to generate instability in a wider frequency band, that is, to generate negative resistance; at the same time, a series feedback network is selected at the source end of the dual-gate field effect transistor to simplify the circuit structure and realize circuit miniaturization.

[0034] Furthermore, the other gate of the dual-gate FET transistor is connected to the RF input, filtering and matching network as the input end of the RF signal, and the spurious signals of the input RF signal are filtered out, while the local oscillator signal and its higher harmonics, intermediate frequency signal and other intermodulation signal products are filtered out, and good matching with the subsequent circuit is achieved.

[0035] Furthermore, the YIG thin film resonator selects a YIG thin film resonator with a loaded Q value of more than 600. On the one hand, it helps to achieve broadband adjustment of the self-oscillating mixer and reduce phase noise. On the other hand, compared with the YIG small ball resonator that occupies a certain space volume, the planar YIG thin film resonator is easier to integrate and facilitates the miniaturization design of the circuit.

[0036] Furthermore, the drain of the dual-gate field effect transistor is connected to an intermediate frequency output, a filtering and matching network to filter out the radio frequency signal, the local oscillator signal and its higher harmonics, and other intermodulation products other than the required intermediate frequency signal, and to suppress the leakage of the oscillation signal and the radio frequency signal generated by the self-oscillating mixer itself, so as to achieve good output impedance matching.

[0037] In summary, the present invention provides a broadband adjustable self-oscillator mixer, which not only overcomes the problem that the traditional mixer requires at least two transistors, has high power consumption and large size, but also solves the problem that the current self-oscillator mixer is difficult to achieve broadband adjustment of the local oscillator signal.

Claims

1. A broadband adjustable self-oscillating mixer, characterized in that: include: A dual-gate FET transistor provides a local oscillator signal under the action of a DC bias and a YIG thin film resonator, and mixes the local oscillator signal with an input RF signal; A DC bias network, one end of the DC bias network is connected to the gate of the dual-gate FET transistor, and the other end of the DC bias network is connected to the drain of the dual-gate FET transistor, so as to provide a DC power supply for the dual-gate FET transistor; a source feedback network connected to the source of the dual-gate FET transistor; A YIG thin film resonator is connected to the gate of a dual-gate FET transistor connected to a DC bias network, and the resonant frequency is adjusted by changing an external magnetic field to thereby change the oscillation frequency of the dual-gate FET transistor; The RF input, filtering and matching network is connected to the other gate of the dual-gate FET transistor, serving as the input end of the RF signal, and performs filtering and matching; The intermediate frequency output, filtering and matching network is connected to the drain of the dual-gate FET transistor as the output end of the intermediate frequency signal, and performs filtering and matching.

2. The broadband adjustable self-oscillating mixer according to claim 1, characterized in that: The DC bias network provides a negative voltage at a gate terminal of the dual-gate field effect transistor connected to the YIG thin film resonator, and provides a positive voltage at a drain terminal of the intermediate frequency signal output.

3. The broadband adjustable self-oscillating mixer according to claim 1, characterized in that: The dual-gate FET transistor adopts a common-source structure.

4. The broadband adjustable self-oscillating mixer according to claim 1, characterized in that: The YIG thin film resonator is a YIG thin film resonator with a loaded Q value of 600 or more.

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