A broadband tunable self-oscillating mixer

Abstract

The application relates to a broadband adjustable self-oscillation mixer, relating to the field of radio frequency microwave mixing technology. The application comprises a double-gate FET transistor which provides a local oscillation signal under the action of a DC bias and a YIG film resonator, a DC bias network which provides a DC power supply for the double-gate FET transistor, a source feedback network connected with the source of the double-gate FET transistor, a YIG film resonator connected with the gate of the double-gate FET transistor and connected with the DC bias network, a radio frequency input, filtering and matching network, and an intermediate frequency output, filtering and matching network. The application adopts the YIG film resonator to realize a wideband adjustment range of multiple frequency ranges and excellent phase noise characteristics, adopts the double-gate field effect transistor to realize higher linear frequency conversion gain and better noise performance, meanwhile, the inherent isolation between the two gates reaches more than 20 dB, and good isolation between the local oscillation signal and the radio frequency signal can be realized.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microwave mixing technology, and more specifically to a broadband adjustable self-oscillating mixer. Background Technology

[0002] In the receiver link, oscillators and mixers are key combined circuit units for signal frequency conversion. The main function of a mixer is to convert the high-frequency electromagnetic wave signal received by the antenna into a lower-frequency useful signal by using a local oscillator signal as a reference signal. The oscillator, as an energy conversion component, primarily converts the energy provided by the DC power supply into a high-frequency AC signal with specific frequency characteristics. In the receiver system, it is often used to generate the local oscillator reference signal source required by the mixing circuit. Both are frequently used as a combined circuit in the receiver link to achieve frequency conversion. In high-performance wireless communication equipment, to ensure the stability of the receiver system, active circuits are typically required to possess high quality and high reliability. Therefore, high performance requirements are placed on circuits such as oscillators and mixers. In the receiver link, the circuit structure of active circuits such as oscillators and mixers is usually complex, with a relatively large circuit area. Furthermore, if an active mixing circuit is used to reduce the circuit gain loss during frequency changes, the power consumption of the mixing circuit will also increase, which does not meet the low-power design requirements of the receiver system.

[0003] Self-oscillating mixer technology is a technique that integrates mixing and local oscillation functions, enabling both functions to be implemented on a single active device. The self-oscillating mixer is a two-port device that, while fully utilizing the nonlinear effect of the transistor itself and selecting an appropriate operating point, mixes the received RF signal with the free-oscillating signal of the self-oscillating mixer to generate a corresponding intermediate frequency signal, achieving optimal mixing performance. This not only reduces the use of active devices such as transistors, improving their utilization rate, but also reduces circuit power consumption and cost. It is of great significance for realizing the miniaturization and integration of receiving system links and has great development potential. Traditional self-oscillating mixer circuits based on FET transistors, such as... Figure 1 As shown, it requires a single-ended mixer and a common-source oscillator. The local oscillator signal and the radio frequency signal output by the oscillator are input through the gate of the mixer. 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 terminal. The adjustable bandwidth is narrow and the phase noise performance is generally poor. Summary of the Invention

[0004] This invention provides a broadband adjustable self-oscillating mixer, which not only overcomes the problems of traditional mixer circuits requiring at least two transistors, high power consumption, and large size, but also solves the problem that current self-oscillating mixers are difficult to achieve broadband adjustment of the local oscillator signal.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A broadband adjustable self-oscillation mixer comprises:

[0007] A double-gate FET transistor, which provides a local oscillation signal under the action of a YIG film resonator and mixes the local oscillation signal with a radio frequency signal;

[0008] A direct current biasing network, one end of which is connected with the gate of the double-gate FET transistor and the other end of which is connected with the drain of the double-gate FET transistor, for providing a direct current power supply for the double-gate FET transistor;

[0009] A source feedback network, which is connected with the source of the double-gate FET transistor, for increasing the instability of the circuit and ensuring that the double-gate FET transistor can generate a stable local oscillation signal;

[0010] A YIG film resonator, which is connected with the gate of the double-gate FET transistor connected with the direct current biasing network, for adjusting the resonant frequency by changing an applied magnetic field and then changing the oscillation frequency of the double-gate FET transistor;

[0011] A radio frequency input, filtering and matching network, which is connected with the other gate of the double-gate FET transistor, as an input end of the radio frequency signal, filters out the spurious signals of the input radio frequency signal, filters out the local oscillation signal and its high-order harmonics, intermediate frequency signals and other intermodulation signal products, and realizes good matching with the subsequent circuit;

[0012] An intermediate frequency output, filtering and matching network, which is connected with the drain of the double-gate FET transistor, filters out other intermodulation products except the radio frequency signal, the local oscillation signal and its high-order harmonics, and the required intermediate frequency signal, and suppresses the leakage of the oscillation signal and the radio frequency signal generated by the self-oscillation mixer, so as to realize good output impedance matching.

[0013] Further, the YIG film resonator and the radio frequency input, filtering and matching network are respectively connected with the two gates of the double-gate field effect transistor, the intermediate frequency signal after the mixing of the input radio frequency signal and the local oscillation signal generated by the double-gate field effect transistor is output from the drain of the double-gate field effect transistor, so as to obtain better frequency conversion gain.

[0014] Further, the direct current biasing network provides a negative voltage at the gate end connected with the YIG film resonator and a positive voltage at the drain end outputting the intermediate frequency signal, so that the dynamic operating point of the FET connected with the YIG film resonator passes through the partial linear region and the saturation region, the dynamic operating point of the FET connected with the radio frequency input, filtering and matching network is completely in the saturation region, and thus the double-gate field effect transistor works in the strong nonlinear region, so as to obtain higher receiving sensitivity and frequency conversion gain.

[0015] Further, the double-gate field effect transistor (double-gate FET transistor) adopts a common source structure to ensure a large output power.

[0016] Further, the other gate of the double-gate FET transistor is connected with a radio frequency input, filtering and matching network as an input terminal of the radio frequency signal, and the stray signal of the input radio frequency signal is filtered out, and the local oscillator signal and its high-order harmonic, intermediate frequency signal and other intermodulation signal products are filtered out, and good matching with the subsequent circuit is realized.

[0017] Further, the YIG thin film resonator selects a YIG thin film resonator with a loaded Q value of 600 or more.

[0018] Further, the intermediate frequency output, filtering and matching network is connected to the drain of the double-gate field effect transistor, and the radio frequency signal, the local oscillator signal and its high-order harmonic, and other intermodulation products other than the required intermediate frequency signal are filtered out.

[0019] Compared with the prior art, the beneficial effects of the present application are:

[0020] The wideband adjustable self-oscillation mixer provided by the present application occupies fewer transistors than the conventional FET single-ended mixer and common-source oscillator, reduces power consumption and cost, and has higher reliability; compared with the conventional FET self-oscillation mixer, the YIG thin film resonator can realize a wideband adjustment range of multiple frequency multiplication and excellent phase noise characteristics, and the double-gate field effect transistor can realize higher linear frequency conversion gain and better noise performance, and the inherent isolation between the two gates is more than 20 dB, which can realize good isolation between the local oscillator signal and the radio frequency signal. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The traditional self-oscillation mixer circuit based on FET transistor;

[0022] Figure 2 The wideband adjustable self-oscillation mixer provided by the present application is shown in the schematic diagram. DETAILED DESCRIPTION

[0023] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the claimed present application, but only represents some embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0024] A self-oscillation mixer with wideband tunability, as shown in Figure 2 comprises:

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

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

[0027] A source feedback network, which is connected to the source of the double-gate FET transistor, is used to increase the circuit instability, and ensures that the double-gate FET transistor can generate a stable local oscillation signal;

[0028] A YIG film resonator, which is connected to the gate of the double-gate FET transistor connected to the DC bias network, adjusts the resonant frequency by changing the applied magnetic field, and thus changes the oscillation frequency of the double-gate FET transistor;

[0029] A radio frequency input, filtering and matching network, which is connected to the other gate of the double-gate FET transistor, serves as an input end of the radio frequency signal, filters out the spurious signals of the input radio frequency signal, filters out the local oscillation signal and its higher harmonics, the intermediate frequency signal and other intermodulation signal products, and realizes good matching with the subsequent circuit;

[0030] An intermediate frequency output, filtering and matching network, which is connected to the drain of the double-gate FET transistor, filters out other intermodulation products other than the radio frequency signal, the local oscillation signal and its higher harmonics, and the required intermediate frequency signal, and suppresses the leakage of the oscillation signal and the radio frequency signal generated by the self-oscillation mixer itself, to realize good output impedance matching.

[0031] Further, the YIG thin film resonator and the radio frequency input, filtering and matching network are connected with two gates of the double-gate field effect transistor respectively, the intermediate frequency signal after mixing of the input radio frequency signal and the local oscillation signal generated by the double-gate field effect transistor is output from the drain of the double-gate field effect transistor, so that better frequency conversion gain is obtained.

[0032] Further, the direct current bias network provides negative voltage at one end of the gate of the double-gate field effect transistor connected with the YIG thin film resonator and positive voltage at one end of the drain of the double-gate field effect transistor outputting the intermediate frequency signal, so that the dynamic working point of the one end of the FET connected with the YIG thin film resonator passes through the partial linear region and the saturation region, the dynamic working point of the one end of the FET connected with the radio frequency input, filtering and matching network is completely in the saturation region, and the double-gate field effect transistor works in the strong nonlinear region, so that higher receiving sensitivity and frequency conversion gain are obtained.

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

[0034] Further, the radio frequency input, filtering and matching network is connected with the other gate of the double-gate FET transistor as the input end of the radio frequency signal, and filters out the spurious signal of the input radio frequency signal, the local oscillation signal and its higher harmonics, the intermediate frequency signal and other intermodulation signal products, and realizes good matching with the subsequent circuit.

[0035] Further, the YIG thin film resonator selects the YIG thin film resonator with load Q value of 600 or above, which helps to realize wideband adjustment of the self-oscillation mixer, reduce phase noise, and is easier to integrate compared with the YIG small ball resonator occupying a certain space volume, so as to facilitate circuit miniaturization design.

[0036] Further, the intermediate frequency output, filtering and matching network is connected with the drain of the double-gate field effect transistor, filters out other intermodulation products except the radio frequency signal, the local oscillation signal and its higher harmonics, and the required intermediate frequency signal, and suppresses the oscillation signal generated by the self-oscillation mixer itself and the leakage of the radio frequency signal, so as to realize good output end impedance matching.

[0037] In summary, the self-oscillation mixer with wideband adjustment provided by the application not only overcomes the problems of the conventional mixer, such as needing at least two transistors, large power consumption and large volume, but also solves the problem that the current self-oscillation mixer is difficult to realize wideband adjustment of the local oscillation signal.

Claims

1. A wideband tunable self-oscillating mixer characterized by, The application relates to a double-gate FET transistor, a DC bias network, a source feedback network, a YIG thin film resonator and a RF input, filter and matching network. The DC bias network is connected with the gate of the double-gate FET transistor at one end and with the drain of the double-gate FET transistor at the other end, and provides DC power for the double-gate FET transistor. The source feedback network is connected with the source of the double-gate FET transistor. The YIG thin film resonator is connected with the gate of the double-gate FET transistor, and the resonant frequency is adjusted by changing the external magnetic field to change the oscillation frequency of the double-gate FET transistor. The RF input, filter and matching network is connected with the other gate of the double-gate FET transistor, and serves as the input end of the RF signal and performs filtering and matching. The IF output, filter and matching network is connected with the drain of the double-gate FET transistor, and serves as the output end of the IF signal and performs filtering and matching. The DC bias network provides negative voltage at the end of the gate connected with the YIG thin film resonator and positive voltage at the end of the drain connected with the IF signal output.

2. The wideband tunable self-oscillating mixer of claim 1, wherein, The double-gate FET transistor adopts a common source structure.

3. The wideband tunable self-oscillating mixer of claim 1, wherein, The YIG thin film resonator is a YIG thin film resonator with a loaded Q value of 600 or above.

4. The wideband tunable self-oscillating mixer of claim 1, wherein, ​

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