A terahertz voltage-controlled oscillator, a communication device, and a communication system
By introducing a fundamental frequency oscillation circuit and a nonlinear buffer circuit into silicon-based processes, the problem of silicon-based integrated circuits having difficulty in generating terahertz signals has been solved, realizing the generation of terahertz frequency band signals, which has the advantages of low cost and ease of implementation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHAN UNIV
- Filing Date
- 2022-11-24
- Publication Date
- 2026-04-10
AI Technical Summary
The fundamental frequency oscillators of existing silicon-based integrated circuits are difficult to directly generate terahertz signals, making it impossible to achieve terahertz frequencies.
By employing a fundamental frequency oscillator circuit and a nonlinear buffer circuit, the third harmonic signal in the terahertz band is generated through nonlinear enhancement processing of the differential fundamental frequency signal.
It realizes the generation of terahertz frequency signals under silicon-based technology. The structure is simple, easy to implement, and low in cost, and it is suitable for on-chip terahertz signal source circuits.
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Figure CN115940814B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of voltage-controlled oscillators, and in particular to a terahertz voltage-controlled oscillator, a communication device, and a communication system. BACKGROUND
[0002] Sub-millimeter wave terahertz (300 GHz-3 THz) can effectively provide greater transmission capacity and higher transmission rate, and can support the next generation of wireless communication. The terahertz signal source is the basis and premise of the terahertz wireless communication technology, and the performance index directly affects the stability of the entire communication transceiver system.
[0003] As a commonly used terahertz signal source, the integrated circuit of the terahertz voltage-controlled oscillator is mainly implemented by using compound III-V process under normal circumstances. However, the III-V process has high cost and large volume for mass production of integrated circuits. With the rapid development of silicon-based process, the size of the transistor continues to be proportionally reduced. Therefore, compared with the III-V process, it is increasingly feasible and more attractive to implement the terahertz voltage-controlled oscillator by using silicon-based process (such as BiCMOS) integrated circuit.
[0004] However, since the terahertz frequency is close to or greater than the maximum oscillation frequency f max , it is difficult to directly generate a terahertz signal by using a silicon-based process integrated circuit. SUMMARY
[0005] Embodiments of the present application provide a terahertz voltage-controlled oscillator, a communication device, and a communication system to solve the technical problem that the existing base frequency oscillator using silicon-based process integrated circuit cannot directly generate a terahertz signal in the related art.
[0006] In a first aspect, a terahertz voltage-controlled oscillator is provided, comprising:
[0007] a base frequency oscillation circuit configured to generate a pair of differential base frequency signals: a first base frequency signal and a second base frequency signal;
[0008] a nonlinear buffer circuit connected to the base frequency oscillation circuit, the nonlinear buffer circuit configured to perform nonlinear enhancement processing on the first base frequency signal and the second base frequency signal to generate a third harmonic signal in the terahertz frequency band.
[0009] In some embodiments, the nonlinear buffer circuit includes a first capacitor, a second capacitor, a first transistor, a second transistor, a frequency selective transformer, and a first bias voltage.
[0010] The first end of the first capacitor is connected with the fundamental frequency oscillation circuit to obtain the first fundamental frequency signal, and the second end of the first capacitor is connected with the first end of the first transistor and the first bias voltage;
[0011] The first end of the second capacitor is connected with the fundamental frequency oscillation circuit to obtain the second fundamental frequency signal, and the second end of the second capacitor is connected with the first end of the second transistor and the first bias voltage;
[0012] The second end of the first transistor and the second end of the second transistor are connected with both ends of the primary coil of the frequency selective transformer, the center tap of the primary coil of the frequency selective transformer is connected with the power supply voltage, and the third end of the first transistor and the third end of the second transistor are connected and grounded;
[0013] The first end of the secondary coil of the frequency selective transformer is the output end of the third harmonic signal, and the second end of the secondary coil of the frequency selective transformer is grounded.
[0014] In some embodiments, a first transmission line is arranged between the first end of the first transistor and the first bias voltage;
[0015] A second transmission line is arranged between the first end of the second transistor and the first bias voltage.
[0016] In some embodiments, a third transmission line is arranged between the second end of the first transistor and the primary coil of the frequency selective transformer;
[0017] A fourth transmission line is arranged between the second end of the second transistor and the primary coil of the frequency selective transformer.
[0018] In some embodiments, the fundamental frequency oscillation circuit comprises a first inductor, a second inductor, a third capacitor, a fourth capacitor, a third transistor, a fourth transistor and a second bias power supply;
[0019] The first end of the first inductor and the first end of the second inductor are both connected with a control voltage;
[0020] The second end of the first inductor is connected with the first end of the first capacitor and the first end of the third capacitor;
[0021] The second end of the second inductor is connected with the first end of the second capacitor and the first end of the fourth capacitor;
[0022] The second end of the third capacitor is connected with the first end of the fourth transistor and the second bias voltage;
[0023] The second end of the fourth capacitor is connected with the first end of the third transistor and the second bias voltage;
[0024] The third end of the third transistor and the third end of the fourth transistor are connected and grounded.
[0025] In some embodiments, a fifth transmission line is arranged between the first end of the third transistor and the second bias voltage.
[0026] A sixth transmission line is arranged between the first end of the fourth transistor and the second bias voltage.
[0027] In some embodiments, the first transistor, the second transistor, the third transistor and the fourth transistor are crystal triodes.
[0028] In some embodiments, the first transistor, the second transistor, the third transistor and the fourth transistor are MOS tubes.
[0029] In some embodiments, the first transistor, the second transistor, the third transistor and the fourth transistor are MOS tubes.
[0030] In some embodiments, the first transistor, the second transistor, the third transistor and the fourth transistor are MOS tubes.
[0031] The technical scheme provided by the present application has the following beneficial effects:
[0032] The present application provides a terahertz voltage-controlled oscillator, a communication device and a communication system, the terahertz voltage-controlled oscillator is provided with a fundamental frequency oscillation circuit and a nonlinear buffer circuit, the nonlinear buffer circuit can perform nonlinear enhancement processing on a pair of differential fundamental frequency signals generated by the fundamental frequency oscillation circuit, and then generate a third harmonic signal in the terahertz frequency band. BRIEF DESCRIPTION OF DRAWINGS
[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0034] Figure 1 A circuit diagram of a terahertz voltage-controlled oscillator provided by the present application;
[0035] Figure 2 A tuning curve diagram of the output frequency of a terahertz voltage-controlled oscillator provided by the present application;
[0036] Figure 3 A phase noise performance diagram of the output frequency of a terahertz voltage-controlled oscillator provided by the present application;
[0037] Figure 4The application provides a selection transformer of a terahertz voltage-controlled oscillator 21 Parameter characteristic diagram. DETAILED DESCRIPTION
[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.
[0039] The application provides a terahertz voltage-controlled oscillator, which can solve the technical problem that a base frequency oscillator adopting a silicon-based process integrated circuit is difficult to directly generate a terahertz signal.
[0040] Referring to Figure 1 The application provides a terahertz voltage-controlled oscillator, which comprises a base frequency oscillation circuit and a nonlinear buffer circuit.
[0041] The base frequency oscillation circuit generates a pair of differential base frequency signals, i.e. a first base frequency signal V(f0+) and a second base frequency signal V(f0-). The nonlinear buffer circuit is connected with the base frequency oscillation circuit, and the nonlinear buffer circuit performs nonlinear enhancement processing on the first base frequency signal V(f0+) and the second base frequency signal V(f0-) to generate a third harmonic signal V(3f0) in a terahertz frequency band.
[0042] The terahertz voltage-controlled oscillator in the embodiments of the present application is provided with a base frequency oscillation circuit and a nonlinear buffer circuit, the nonlinear buffer circuit can perform nonlinear enhancement processing on a pair of differential base frequency signals generated by the base frequency oscillation circuit, and then generate a third harmonic signal in a terahertz frequency band. Alternatively, it can be understood that the embodiments of the present application extract a third harmonic signal higher than f max from a base frequency signal lower than the maximum oscillation frequency f max of a silicon-based process integrated circuit to generate a signal in a terahertz frequency band. In addition, the terahertz voltage-controlled oscillator in the embodiments of the present application has the advantages of simple structure, easy implementation, small size and low cost, and has a wide application prospect in a terahertz signal source circuit on a chip.
[0043] As an optional implementation, in one embodiment of the application, the nonlinear buffer circuit comprises a first capacitor C1, a second capacitor C2, a first transistor Q1, a second transistor Q2, a selection transformer T and a first bias voltage V b1The transistor Q1 and the second transistor Q2 can be a crystal triode or a MOS tube. Hereinafter, the crystal triode is taken as an example.
[0044] The first end of the first capacitor C1 is connected with the base frequency oscillation circuit to obtain the first base frequency signal V(f0+), and the second end of the first capacitor C1 is connected with the first end (base) of the first transistor Q1 and the first bias voltage V b1 .
[0045] The first end of the second capacitor C2 is connected with the base frequency oscillation circuit to obtain the second base frequency signal V(f0-), and the second end of the second capacitor C2 is connected with the first end (base) of the second transistor Q2 and the first bias voltage V b1 .
[0046] The second end (collector) of the first transistor Q1 and the second end (collector) of the second transistor Q2 are connected with the two ends of the primary coil of the frequency selective transformer T, and the center tap of the primary coil of the frequency selective transformer T is connected with the power supply voltage V DD , and the third end (emitter) of the first transistor Q1 and the third end (emitter) of the second transistor Q2 are connected and grounded.
[0047] The first end of the secondary coil of the frequency selective transformer T is the output end of the third harmonic signal V(3f0), and the second end of the secondary coil of the frequency selective transformer T is grounded.
[0048] Specifically, referring to Figure 1 , the first capacitor C1 and the second capacitor C2 couple a pair of differential base frequency signals V(f0+) and V(f0-) with large output swing to the bases of the first transistor Q1 and the second transistor Q2 differential pair tube respectively. The first bias voltage V b1 , under the action of the first capacitor C1 and the second capacitor C2 isolating direct current, provides bias voltage for the bases of the first transistor Q1 and the second transistor Q2 differential pair tube, and the power supply voltage V DD , so that the first transistor Q1 and the second transistor Q2 reach a suitable bias condition, and the first base frequency signal V(f0+) and the second base frequency signal V(f0-) are subjected to nonlinear enhancement processing to obtain a third harmonic component with maximum power. The frequency selective transformer T extracts the third harmonic component and couples it to the first end of the secondary coil of the frequency selective transformer T to output the third harmonic signal V(3f0). Optionally, considering the requirements of the test, the first end of the secondary coil of the frequency selective transformer T is matched with the test probe at the target frequency with a 50Ω impedance.
[0049] As an optional implementation, in one embodiment of the application, a first transmission line TL1 is arranged between the first end of the first transistor Q1 and the first bias voltage V b1 .
[0050] A second transmission line TL2 is arranged between the first end of the second transistor Q2 and the first bias voltage V b1 .
[0051] Specifically, as shown in Figure 1 , the first bias voltage V b1 is provided to the base of the differential pair of the first transistor Q1 and the second transistor Q2 through the symmetrically arranged first transmission line TL1 and the second transmission line TL2.
[0052] As an optional implementation, in one embodiment of the application, a third transmission line TL3 is arranged between the second end of the first transistor Q1 and the primary coil of the frequency selective transformer T.
[0053] A fourth transmission line TL4 is arranged between the second end of the second transistor Q2 and the primary coil of the frequency selective transformer T.
[0054] Specifically, as shown in Figure 1 , the third transmission line TL3 and the fourth transmission line TL4 are used to complete the conjugate matching of the first transistor Q1, the second transistor Q2 and the frequency selective transformer T, to ensure that the loss of the third harmonic component reaching the primary coil of the frequency selective transformer T is as small as possible, and the output power of the terahertz signal is high.
[0055] As an optional implementation, in one embodiment of the application, the fundamental frequency oscillation circuit comprises a first inductor L1, a second inductor L2, a third capacitor C3, a fourth capacitor C4, a third transistor Q3, a fourth transistor Q4 and a second bias voltage V b2 .
[0056] The first end of the first inductor L1 and the first end of the second inductor L2 are connected to a control voltage V ctrl .
[0057] The second end of the first inductor L1 is connected to the first end of the first capacitor C1 and the first end of the third capacitor C3.
[0058] The second end of the second inductor L2 is connected to the first end of the second capacitor C2 and the first end of the fourth capacitor C4.
[0059] The second end of the third capacitor C3 is connected to the first end of the fourth transistor Q4 and the second bias voltage V b2 .
[0060] The second end of the fourth capacitor C4 is connected with the first end of the third transistor Q3 and the second bias voltage V b2 Connection.
[0061] The third end of the third transistor Q3 and the third end of the fourth transistor Q4 are connected and grounded.
[0062] Specifically, referring to Figure 1 As shown, the third transistor Q3 and the fourth transistor Q4 constitute a cross-coupled structure, and the parasitic capacitance of the cross-coupled pair of the third transistor Q3 and the fourth transistor Q4 serves as a variable capacitor of the base frequency oscillation circuit. The first inductor L1, the second inductor L2, and the parasitic capacitance of the cross-coupled pair of the third transistor Q3 and the fourth transistor Q4 together constitute a resonance loop, which determines the oscillation frequency of the base frequency oscillation circuit. The control voltage V ctrl On the one hand, it serves as a power voltage of the base frequency oscillation circuit to drive the third transistor Q3 and the fourth transistor Q4, and on the other hand, it serves as a control voltage to adjust the parasitic capacitance of the cross-coupled pair of the third transistor Q3 and the fourth transistor Q4 in the resonance loop to achieve parasitic tuning, so as to control the oscillation frequency of the base frequency oscillation circuit. ctrl The control of the oscillation frequency can realize frequency tuning within a certain bandwidth. The third capacitor C3 and the fourth capacitor C4 as feedback factors have the effect of isolating direct current. The quality factor of the conventional varactor decreases with the increase of the frequency, thereby reducing the overall quality factor of the resonance loop. The embodiment of the present application removes the conventional varactor in the base frequency oscillation circuit, so that the output signal phase noise is low, and the overall quality factor of the resonance loop is guaranteed.
[0063] As an optional embodiment, in one embodiment of the present application, the first end of the third transistor Q3 and the second bias voltage V b2 are connected through a fifth transmission line TL5.
[0064] The first end of the fourth transistor Q4 and the second bias voltage V b2 are connected through a sixth transmission line TL6.
[0065] Specifically, referring to Figure 1 As shown, the fifth transmission line TL5 and the sixth transmission line TL6 are symmetrically arranged in the embodiment of the present application to constitute a direct current voltage bias structure, and the second bias voltage V b2 is loaded to the base of the cross-coupled pair of the third transistor Q3 and the fourth transistor Q4 through the fifth transmission line TL5 and the sixth transmission line TL6, so that the third transistor Q3 and the fourth transistor Q4 exhibit linear characteristics. At this time, the base frequency oscillation circuit works in a class C state, which can improve the output swing of the differential base frequency signal and further improve the phase noise.
[0066] The control voltage V ctrl The embodiment of the present application is further illustrated when the control voltage V
[0067] Referring to Figure 2 The control voltage V ctrl The frequency of the output third harmonic signal V(3f0) is 304.3-320GHz when the control voltage V
[0068] Figure 3 The control voltage V ctrl The output phase noise performance diagram of the embodiment of the present application when the control voltage V
[0069] Figure 4 The S 21 The insertion loss |S 21 | is 34dB at the fundamental frequency f0=106GHz, while the insertion loss |S 21 | is about 7.49dB at the target frequency third harmonic 3f0=318GHz. The insertion loss at the fundamental frequency is much larger than that at the third harmonic, and the frequency-selective transformer T in the embodiment of the present application can attenuate the fundamental frequency signal while extracting the third harmonic signal with maximum power at a lower loss.
[0070] The embodiment of the present application also provides a communication device, comprising the aforementioned terahertz voltage-controlled oscillator.
[0071] The embodiment of the present application also provides a communication system, comprising at least one of the aforementioned communication devices.
[0072] In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0073] It should be noted that in the present application, relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or apparatus including the element.
[0074] The above is only a specific embodiment of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features of the present application.
Claims
1. A terahertz voltage-controlled oscillator, characterized in that, include: A fundamental frequency oscillator circuit is used to generate a pair of differential fundamental frequency signals: a first fundamental frequency signal and a second fundamental frequency signal; A nonlinear buffer circuit is connected to the fundamental frequency oscillation circuit. The nonlinear buffer circuit is used to perform nonlinear enhancement processing on the first fundamental frequency signal and the second fundamental frequency signal to generate the third harmonic signal in the terahertz band. The nonlinear buffer circuit includes a first capacitor, a second capacitor, a first transistor, a second transistor, a frequency selective transformer, and a first bias voltage. The first terminal of the first capacitor is connected to the base frequency oscillation circuit to obtain the first base frequency signal, and the second terminal of the first capacitor is connected to the first terminal of the first transistor and the first bias voltage. The first terminal of the second capacitor is connected to the base frequency oscillation circuit to obtain the second base frequency signal, and the second terminal of the second capacitor is connected to the first terminal of the second transistor and the first bias voltage. The second terminals of the first transistor and the second transistor are connected to the two ends of the primary coil of the frequency selective transformer, the center tap of the primary coil of the frequency selective transformer is connected to the power supply voltage, and the third terminals of the first transistor and the second transistor are connected and grounded. The first terminal of the secondary coil of the frequency selective transformer is the output terminal of the third harmonic signal, and the second terminal of the secondary coil of the frequency selective transformer is grounded. The fundamental frequency oscillation circuit includes a first inductor, a second inductor, a third capacitor, a fourth capacitor, a third transistor, a fourth transistor, and a second bias power supply. Both the first terminal of the first inductor and the first terminal of the second inductor are connected to a control voltage; The second terminal of the first inductor is connected to the first terminal of the first capacitor and the first terminal of the third capacitor; The second terminal of the second inductor is connected to the first terminal of the second capacitor and the first terminal of the fourth capacitor; The second terminal of the third capacitor is connected to the first terminal of the fourth transistor and the second bias voltage. The second terminal of the fourth capacitor is connected to the first terminal of the third transistor and the second bias voltage. The third terminal of the third transistor and the third terminal of the fourth transistor are connected and grounded.
2. The terahertz voltage-controlled oscillator according to claim 1, characterized in that: A first transmission line is provided between the first terminal of the first transistor and the first bias voltage; A second transmission line is provided between the first terminal of the second transistor and the first bias voltage.
3. The terahertz voltage-controlled oscillator according to claim 1, characterized in that: A third transmission line is provided between the second terminal of the first transistor and the primary coil of the frequency selective transformer; A fourth transmission line is provided between the second terminal of the second transistor and the primary coil of the frequency selective transformer.
4. The terahertz voltage-controlled oscillator according to claim 1, characterized in that: A fifth transmission line is provided between the first terminal of the third transistor and the second bias voltage; A sixth transmission line is provided between the first terminal of the fourth transistor and the second bias voltage.
5. The terahertz voltage-controlled oscillator according to claim 1, characterized in that: The first transistor, the second transistor, the third transistor, and the fourth transistor are bipolar junction transistors (BJTs).
6. The terahertz voltage-controlled oscillator according to claim 1, characterized in that: The first transistor, the second transistor, the third transistor, and the fourth transistor are MOS transistors.
7. A communication device, characterized in that, Includes the terahertz voltage-controlled oscillator as described in any one of claims 1 to 6.
8. A communication system, characterized in that, It includes at least one of the communication devices described in claim 7.
Citation Information
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