Novel double-balance terahertz frequency multiplier

Abstract

The invention provides a novel double-balance terahertz frequency multiplier, and belongs to the technical field of terahertz communication. The frequency multiplier comprises an input Y-type waveguide power divider which comprises an input port and two output ports and is used for decomposing a path of subwave input signals into two paths of input signals with the same power and opposite phases; the output Y-shaped waveguide power divider comprises two input ports and an output port and is used for synthesizing the two paths of frequency multiplication signals into one path of output signal; the frequency multiplier circuit comprises four diodes, the diodes are connected in series end to end to form an annular symmetrical structure, and the joint of every two adjacent diodes is used as an external connection port; a group of symmetrical external connection ports are used as input ports to be connected with two output ports of the input Y-shaped waveguide power divider; and the other group of symmetrical external connection ports are used as output ports to be connected with two input ports of the output Y-shaped waveguide power divider. According to the invention, double balance can be realized, bandwidth is improved, and harmonic components are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of terahertz communication, and in particular to a novel double-balanced terahertz frequency multiplier. Background Art

[0002] The frequency range of terahertz waves is 0.1THz to 10THz. It has the characteristics of wide spectrum and high resolution, and has very broad application prospects in the fields of remote sensing, anti-terrorism security inspection, military radar and next-generation high-speed communications. The terahertz frequency multiplier based on planar Schottky diode has the advantages of good reliability and easy integration, and is an important technical approach to realize terahertz signal source.

[0003] Due to the high working frequency band and large relative transmission loss, terahertz frequency doublers mostly adopt a relatively simple single-balanced frequency doubler structure, using the cathode and anode pads of the planar diode to connect to the input signal and output signal ends of the peripheral circuit respectively. The input signal and the output signal enter the frequency doubler through the waveguide microstrip transition coupler port, and the microstrip low-pass filter circuit is used to select the harmonic components of the frequency doubler separation.

[0004] Although the single-balanced frequency doubler has the advantage of a simple structure, it has limited ability to recover harmonic signals, a narrow bandwidth and many harmonic components, making it difficult to meet the performance requirements for ultra-wideband and high frequency doubling efficiency of terahertz frequency doublers. Summary of the invention

[0005] The present invention provides a novel double-balanced terahertz frequency multiplier to solve the problem of narrow bandwidth and many harmonic components of a single-balanced frequency multiplier. The novel double-balanced terahertz frequency multiplier comprises: an input Y-type waveguide power divider, a frequency doubling circuit, and an output Y-type waveguide power divider;

[0006] The input Y-type waveguide power splitter comprises an input port and two output ports, and is used to decompose a fundamental wave input signal into two input signals with the same power and opposite phases;

[0007] The output Y-type waveguide power divider includes two input ports and one output port, and is used to combine two frequency-doubled signals with the same power and opposite phases into one output signal;

[0008] The frequency doubling circuit comprises four diodes, each diode being connected in series from beginning to end to form a ring-shaped symmetrical structure as a whole, and the connection point of two adjacent diodes serving as an external connection port; one group of symmetrical external connection ports serving as input ports connected to the two output ports of the input Y-type waveguide power divider to perform frequency doubling processing on the two input signals; and another group of symmetrical external connection ports serving as output ports connected to the two input ports of the output Y-type waveguide power divider.

[0009] In a possible implementation, the two output ports of the input Y-type waveguide power divider and the two input ports of the output Y-type waveguide power divider are arranged perpendicular to each other to form a waveguide cavity.

[0010] In a possible implementation, the frequency doubling circuit is arranged in the waveguide cavity in the form of an H-plane waveguide-microstrip probe transition;

[0011] A signal coupling structure is provided between two adjacent diodes for coupling between input signal, frequency doubling circuit and output signal; wherein the signal coupling structure includes a microstrip circuit and a waveguide-microstrip transition probe.

[0012] In a possible implementation manner, the waveguide-microstrip transition probe is connected to the two output ports of the input Y-type waveguide power divider and the two input ports of the output Y-type waveguide power divider by conductive adhesive or thermocompression welding.

[0013] In a possible implementation, each diode includes one or more terahertz planar Schottky diodes.

[0014] In a possible implementation, the Schottky diode includes a semi-insulating substrate material, a heavily doped GaAs layer, a low-doped GaAs layer, silicon dioxide and an ohmic contact metal, and a passivation layer in sequence.

[0015] In a possible implementation, the Schottky diode further includes beams of different sizes suspended outside the Pad.

[0016] In a possible implementation, an epitaxial layer of a Schottky diode is grown on a GaAs substrate using Metal-organic Chemical Vapor Deposition (MOCVD), wherein the epitaxial layer includes a heavily doped N+ type buffer layer and a low doped N- epitaxial layer.

[0017] In one possible implementation, an anode Schottky gold semi-contact and a cathode ohmic gold semi-contact are fabricated, and after the front structure of the device is prepared, a thinning and slicing process is used to separate a single Schottky diode.

[0018] In a possible implementation manner, the size of the input port of the input Y-type waveguide power divider is determined according to the frequency of the fundamental wave signal.

[0019] In a possible implementation manner, the input Y-type waveguide power divider and the output Y-type waveguide power divider are made of brass.

[0020] In a possible implementation manner, the frequency multiplication circuit is disposed on a substrate; and a material of the substrate is gallium arsenide.

[0021] The present invention provides a novel double-balanced terahertz frequency multiplier, which is composed of an input Y-type waveguide power divider, a frequency multiplication circuit, and an output Y-type waveguide power divider. The frequency multiplication circuit is constructed as a ring-shaped double-balanced frequency multiplication structure, which realizes the coupling of two fundamental wave signals in circuit design, enters two symmetrical diode chip input ports respectively, and completes the frequency multiplication process in a double-balanced loop. Due to its topological structure principle, in the harmonic signal generated when the fundamental wave signal is frequency multiplied in the double-balanced loop, the combined components of all even harmonics are offset by each other, while the odd harmonic signal is coupled to the other two symmetrical ports of the Y-type waveguide power divider through a waveguide-microstrip transition structure. Finally, the Y-type waveguide power divider synthesizes two signals with equal power and a phase difference of 180 degrees into one signal output. Therefore, the embodiment of the present application provides an improvement in bandwidth and a reduction in harmonic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 is a schematic structural diagram of a novel double-balanced terahertz frequency multiplier provided by an embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the circuit principle of a novel double-balanced terahertz frequency multiplier provided by an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of the structure of a frequency multiplication circuit provided by an embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of the structure of each diode provided by an embodiment of the present invention;

[0027] Figure 5 It is a side view of the input Y-type waveguide power divider provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to enable people in the technical field to better understand the present solution, the technical solution in the embodiment of the present solution will be clearly described below in conjunction with the drawings in the embodiment of the present solution. Obviously, the described embodiment is an embodiment of a part of the present solution, not all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0029] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0030] The following is a detailed description of the implementation of the present invention in conjunction with the specific drawings:

[0031] Figure 1 A schematic diagram of the structure of a novel double-balanced terahertz frequency multiplier provided by an embodiment of the present invention. Figure 1 The novel double-balanced terahertz frequency multiplier includes: an input Y-type waveguide power divider 100, a frequency multiplication circuit 200, and an output Y-type waveguide power divider 300.

[0032] The input Y-type waveguide power splitter 100 includes an input port 101 and two output ports 102 and 103, and is used to decompose a fundamental wave input signal into two input signals with the same power and opposite phases.

[0033] The output Y-type waveguide power divider 300 includes two input ports 301 and 302 and one output port 303, and is used to combine two frequency-doubled signals with the same power and opposite phases into one output signal.

[0034] The frequency doubling circuit 200 includes four diodes, each of which is connected in series from beginning to end to form a ring-shaped symmetrical structure as a whole, and the connection point between two adjacent diodes serves as an external connection port. Figure 2 This is a schematic diagram of the circuit principle of the new double-balanced terahertz frequency multiplier. The connection relationship of the four diodes D1, D2, D3 and D4 is as follows: Figure 2 shown.

[0035] A set of symmetrical external connection ports (such as Figure 2 a1 and a2) as input ports are connected to the two output ports 102 and 103 of the input Y-type waveguide power divider 100 to perform frequency doubling processing on the two input signals; another set of symmetrical external connection ports (such as Figure 2 b1 and b2) are shown as output ports connected to the two input ports 301 and 302 of the output Y-type waveguide power divider 300.

[0036] The four-way diode forms a ring-shaped symmetrical structure, which is symmetrically divided into two diode pairs. The two diode pairs form two current paths, and the diodes in the paths are connected in reverse parallel. Therefore, the four-way diode forms a ring-shaped double-balanced frequency multiplication structure in the circuit topology. The two fundamental wave signals are coupled to the two symmetrical diode chip input ports respectively, and the frequency is multiplied in the double-balanced loop. Based on the principle of its topological structure, the fundamental wave signal is multiplied in the double-balanced loop to generate harmonic signals, and the combination components of all even harmonics are eliminated, while the odd harmonic signals are coupled to the other two symmetrical ports of the Y-type waveguide power divider through the waveguide-microstrip transition structure. Finally, the Y-type waveguide power divider combines two signals with equal power and a phase difference of 180 degrees into one signal output.

[0037] The embodiment of the present application abandons the method of processing diodes and microstrip circuits using only a monolithic integrated circuit chip, which will cause a large crosstalk effect between the input and output signals. Instead, a spatially omnidirectional double-balanced technology is adopted, thereby significantly reducing the interference between the input and output signals of the frequency multiplication circuit. On the premise of maintaining the high integration of the monolithic circuit and the simple spatial design, a wider operating bandwidth and stable in-band output performance are achieved. Compared with the single-balanced structure, the output clutter signal of the double-balanced frequency multiplier is greatly reduced. The double-balanced frequency multiplier is composed of four diodes, each of which only provides one-quarter of the output power. Compared with the single-balanced structure, its power capacity has inherent advantages. Therefore, the double-balanced frequency multiplier structure proposed in the present invention has the significant characteristics of wide bandwidth, high efficiency and large power capacity.

[0038] In this embodiment, the novel double-balanced terahertz frequency multiplier is composed of an input Y-type waveguide power divider, a frequency multiplication circuit, and an output Y-type waveguide power divider 300. The frequency multiplication circuit is constructed as a ring-shaped double-balanced frequency multiplication structure, which realizes the coupling of two fundamental wave signals in circuit design, enters two symmetrical diode chip input ports respectively, and completes the frequency multiplication process in the double-balanced loop. Due to its topological structure principle, in the harmonic signal generated when the fundamental wave signal is frequency multiplied in the double-balanced loop, the combined components of all even harmonics are offset by each other, while the odd harmonic signal is coupled to the other two symmetrical ports of the Y-type waveguide power divider through the waveguide-microstrip transition structure. Finally, the Y-type waveguide power divider synthesizes two signals with equal power and a phase difference of 180 degrees into one signal output. Therefore, the embodiment of the present application provides an improved bandwidth and reduced harmonic components.

[0039] In a possible implementation, the two output ports 102 and 103 of the input Y-type waveguide power splitter 100 and the two input ports 301 and 302 of the output Y-type waveguide power splitter 300 are arranged perpendicular to each other to form a waveguide cavity.

[0040] In this embodiment, the Y-type waveguide power divider 100 and the output Y-type waveguide power divider 300 form full balance in all directions in space, and the interference between the input and output signals of the frequency multiplication circuit 200 is small.

[0041] In a possible implementation, the frequency doubling circuit 200 is disposed in a waveguide cavity in the form of an H-plane waveguide-microstrip probe transition;

[0042] A signal coupling structure is provided between two adjacent diodes for coupling between input signal-frequency multiplication circuit 200-output signal; wherein the signal coupling structure includes a microstrip circuit and a waveguide-microstrip transition probe.

[0043] In a possible implementation, the waveguide-microstrip transition probe is connected to the two output ports 102 and 103 of the input Y-type waveguide power divider 100 and the two input ports 301 and 302 of the output Y-type waveguide power divider 300 by conductive adhesive or thermocompression welding.

[0044] In this embodiment, the conductive adhesive, as an adhesive, not only has good electrical conductivity, but also can absorb the stress caused by thermal expansion to a certain extent, thereby improving the stability of the overall structure. Hot pressing welding is a technology that achieves connection between metals through heating and pressure, which can provide stronger mechanical strength and better electrical connection performance. By using conductive adhesive or hot pressing welding technology, the waveguide-microstrip transition probe can be tightly connected to the port of the Y-type waveguide power divider, ensuring that the signal loss during transmission is minimized, ensuring stable and reliable signal transmission, and facilitating precise alignment and fixation during the manufacturing process, thereby improving the performance of the entire microwave system.

[0045] In a possible implementation, each diode includes one or more terahertz planar Schottky diodes.

[0046] like Figure 3 As shown, the frequency doubling circuit 200 includes H-plane input waveguide-microstrip probe transitions 201 and 202 , H-plane output waveguide-microstrip probe transitions 203 and 204 , and a terahertz planar Schottky diode 205 .

[0047] Among them, the H-plane input waveguide-microstrip probe transitions 201 and 202 are respectively connected to the two output ports 102 and 103 of the input Y-type waveguide power divider 100; the H-plane output waveguide-microstrip probe transitions 203 and 204 are respectively connected to the two input ports 301 and 302 of the output Y-type waveguide power divider 300.

[0048] In the actual implementation process, Figure 4 As shown, the number of single-channel diodes can be one or more, and the specific number is determined according to the technical index requirements of the new double-balanced terahertz frequency multiplier.

[0049] In a possible implementation, the frequency multiplication circuit 200 is disposed on a substrate; the material of the substrate is gallium arsenide.

[0050] Among them, gallium arsenide has the advantages of high electron mobility, direct bandgap structure, good thermal stability and radiation resistance. Gallium arsenide, as the substrate material of the frequency doubling circuit 200, can ensure the stability and reliability of the circuit when working at high frequencies.

[0051] In a possible implementation, the Schottky diode includes a semi-insulating substrate material, a heavily doped GaAs layer, a low-doped GaAs layer, silicon dioxide and an ohmic contact metal, and a passivation layer in sequence.

[0052] In this embodiment, the multi-layer structure design ensures that the Schottky diode has excellent performance and good stability during operation.

[0053] In a possible implementation, the Schottky diode further includes beams of different sizes suspended outside the Pad.

[0054] In this embodiment, beams of different sizes optimize the electrical and thermal performance of the device, thereby improving the performance of the entire circuit.

[0055] In a possible implementation, an epitaxial layer of a Schottky diode is prepared on a GaAs substrate by MOCVD growth; wherein the epitaxial layer includes a heavily doped N+ type buffer layer and a low doped N- epitaxial layer.

[0056] In this embodiment, the epitaxial layer of the Schottky diode is prepared on the GaAs substrate by MOCVD growth, and the thickness and doping concentration of the epitaxial layer can be precisely controlled, thereby ensuring that the device has excellent electrical properties.

[0057] In one possible implementation, an anode Schottky gold semi-contact and a cathode ohmic gold semi-contact are fabricated, and after the front structure of the device is prepared, a thinning and slicing process is used to separate a single Schottky diode.

[0058] In one possible implementation, the front structure of the device is first prepared by making a Schottky semi-contact for the anode and an Ohm gold semi-contact for the cathode. Then, the prepared device is processed by a thinning and slicing process to effectively separate the individual Schottky diodes.

[0059] like Figure 5 , which is a side view of the input Y-type waveguide power divider 100, as shown in Figure 5As shown, the two output ports 102 and 103 of the input Y-type waveguide power splitter 100 are structurally different from the input port 101. The side view of the output Y-type waveguide power splitter 300 is similar to the side view of the input Y-type waveguide power splitter 100, but the size is adjusted according to specific communication requirements.

[0060] In a possible implementation, the size of the input port 101 of the input Y-type waveguide power divider 100 is determined according to the frequency of the fundamental wave signal.

[0061] In this embodiment, the size of the input port 101 of the Y-type waveguide power divider 100 is set according to the frequency of the fundamental signal to ensure that the power divider operates efficiently within a specific frequency range, realizes accurate transmission and distribution of signals, and thus achieves the best power division effect.

[0062] In a possible implementation, the input Y-type waveguide power splitter 100 and the output Y-type waveguide power splitter 300 are made of brass.

[0063] Brass has good electrical conductivity and mechanical strength, which can effectively transmit and distribute microwave signals while ensuring structural stability and durability. In addition, brass has good processing performance, which facilitates the manufacture of precise waveguide structures, thus ensuring high performance and reliability of the power divider.

[0064] In the specific implementation process, under ideal conditions, the insertion loss of the two output ports 102 and 103 of the input Y-type waveguide power divider 100 should be 3dB, and the phase difference should be 180 degrees. The two output ports 102 and 103 of the input Y-type waveguide power divider 100 are respectively combined with the H-plane input waveguide-microstrip probe transitions 201 and 202 in the form of H-plane waveguide-microstrip probe transitions. The length and cross-sectional dimensions of the two output ports 102 and 103 of the input Y-type waveguide power divider 100 are determined by circuit impedance matching, transition structure coupling performance and index requirements.

[0065] In addition, the design principle of the two input ports 301 and 302 of the output Y-type waveguide power splitter 300 is the same as that of the two output ports 102 and 103 of the input Y-type waveguide power splitter 100 .

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel double-balanced terahertz frequency multiplier, characterized in that: include: Input Y-type waveguide power divider, frequency doubling circuit, output Y-type waveguide power divider; The input Y-type waveguide power splitter comprises an input port and two output ports, and is used to decompose a fundamental wave input signal into two input signals with the same power and opposite phases; The output Y-type waveguide power divider includes two input ports and one output port, and is used to combine two frequency-doubled signals with the same power and opposite phases into one output signal; The frequency doubling circuit comprises four diodes, each diode being connected in series from beginning to end to form a ring-shaped symmetrical structure as a whole, and the connection point of two adjacent diodes serving as an external connection port; one group of symmetrical external connection ports serving as input ports connected to the two output ports of the input Y-type waveguide power divider to perform frequency doubling processing on the two input signals; and another group of symmetrical external connection ports serving as output ports connected to the two input ports of the output Y-type waveguide power divider.

2. The novel double-balanced terahertz frequency multiplier according to claim 1, characterized in that: The two output ports of the input Y-type waveguide power divider and the two input ports of the output Y-type waveguide power divider are arranged perpendicular to each other to form a waveguide cavity.

3. The novel double-balanced terahertz frequency multiplier as claimed in claim 2, characterized in that: The frequency doubling circuit is arranged in the waveguide cavity in the form of an H-plane waveguide-microstrip probe transition; A signal coupling structure is provided between two adjacent diodes for coupling between input signal, frequency doubling circuit and output signal; wherein the signal coupling structure includes a microstrip circuit and a waveguide-microstrip transition probe.

4. The novel double-balanced terahertz frequency multiplier as claimed in claim 3, characterized in that: The waveguide-microstrip transition probe is connected to the two output ports of the input Y-type waveguide power divider and the two input ports of the output Y-type waveguide power divider by conductive glue or thermal compression welding.

5. The novel double-balanced terahertz frequency multiplier according to claim 1, characterized in that: Each diode path includes one or more terahertz planar Schottky diodes.

6. The novel double-balanced terahertz frequency multiplier as claimed in claim 5, characterized in that: The Schottky diode comprises a semi-insulating substrate material, a heavily doped GaAs layer, a low-doped GaAs layer, silicon dioxide and an ohmic contact metal, and a passivation layer in sequence.

7. The novel double-balanced terahertz frequency multiplier as claimed in claim 6, characterized in that: The epitaxial layer of the Schottky diode is prepared on a GaAs substrate by metal organic chemical vapor deposition (MOCVD) growth; wherein the epitaxial layer includes a heavily doped N+ type buffer layer and a low doped N- epitaxial layer.

8. The novel double-balanced terahertz frequency multiplier according to claim 1, characterized in that: The input port size of the input Y-type waveguide power divider is determined according to the frequency of the fundamental wave signal.

9. The novel double-balanced terahertz frequency multiplier according to claim 1, characterized in that: The input Y-type waveguide power divider and the output Y-type waveguide power divider are made of brass.

10. The novel double-balanced terahertz frequency multiplier according to claim 1, characterized in that: The frequency multiplication circuit is arranged on a substrate; the material of the substrate is gallium arsenide.

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