A ring-type combined full-band terahertz even-order harmonic frequency multiplier

Abstract

This invention belongs to the field of terahertz communication technology and provides a ring-combined full-band terahertz even-harmonic frequency multiplier to solve the problem of low efficiency in broadband frequency multipliers. The invention includes an input waveguide, an on-chip integrated circuit, and an output waveguide. The on-chip integrated circuit includes an input probe, an input matching microstrip line, a ring-combined structure, an output matching circuit, and an output probe. The ring-combined structure consists of two parallel signal branches. Each signal branch is composed of a bandpass filter and a diode array connected in series, with the diode arrays in the two signal branches forming an anti-parallel structure. This invention proposes a ring-combined structure that separately sets a high-frequency narrow-passband filter and a low-frequency narrow-passband filter on the two signal branches of the ring-combined structure, improving the signal from full-band filtering to two narrow-band filtering, and finally merging the two narrow-band signals into a broadband signal, thereby improving the full-band frequency multiplication efficiency of the device.

Description

Technical Field

[0001] This invention belongs to the field of terahertz communication technology and relates to frequency multiplier structure, specifically providing a ring-type combined full-band terahertz even-order harmonic frequency multiplier. Background Technology

[0002] Currently, most research on terahertz frequency multipliers focuses on two main directions: full-bandwidth and high efficiency. However, full-bandwidth frequency multipliers have low efficiency, and high-efficiency frequency multipliers have narrow bandwidth. Terahertz frequency multipliers mainly utilize the nonlinear characteristics of Schottky diodes to generate harmonic components, resulting in the desired multiplied frequency signal. The target multiplied frequency signal is then filtered using subsequent methods before being output. The design challenges of frequency multipliers lie primarily in the filter and the Schottky diode. The performance of the filter directly affects the bandwidth of the frequency multiplier and the degree of interference from other signals to the fundamental signal. High-performance filters require low insertion loss in the passband and high suppression capability in the stopband. Generally, wide-passband filters are more difficult to design and have higher insertion loss than narrow-passband filters. Therefore, the efficiency of wideband frequency multipliers is generally lower than that of narrowband frequency multipliers. Summary of the Invention

[0003] The purpose of this invention is to address the problem of low efficiency in broadband frequency multipliers by providing a ring-type combined full-band terahertz even-order harmonic multiplier that effectively combines the advantages of a full-band mixer and a high-efficiency mixer to achieve high conversion efficiency over a wide bandwidth.

[0004] To achieve the above objectives, the beneficial effects of the present invention are as follows:

[0005] A ring-type full-band terahertz even-order harmonic multiplier includes: an input waveguide 1, an on-chip integrated circuit 2, and an output waveguide 3. The on-chip integrated circuit comprises: an input probe 21, an input matching microstrip line 22, a ring-type combined structure 23, an output matching circuit 24, and an output probe 25 connected in sequence. The ring-type combined structure 23 is composed of two parallel signal branches, each consisting of a bandpass filter 231 connected in series with a diode array 232, and the diode arrays in the two signal branches are connected in anti-parallel.

[0006] Furthermore, in the ring-shaped combined structure, the passband of the bandpass filter on one signal branch is f. min ~f a The passband of the bandpass filter on the other signal branch is f. b ~f max 0.9f a ≤f b ≤f a f min f is the minimum operating frequency of the frequency multiplier. maxf is the maximum operating frequency of the frequency multiplier. a For 180GHz, f b It is 180GHz.

[0007] Furthermore, in the ring-shaped composite structure, f a =f b =(f max -f min ) / 2.

[0008] Furthermore, the input waveguide is composed of a standard input waveguide and an input height reduction waveguide connected together. The standard input waveguide adopts a standard rectangular waveguide WR-5. The input fundamental signal is input from the standard input waveguide, passes through the input height reduction waveguide, and is coupled to the input matching microstrip line 22 by the input probe 21, thereby entering the ring combination structure 23 for frequency doubling.

[0009] Furthermore, the output waveguide includes a standard output waveguide and an output height reduction waveguide. The standard output waveguide adopts a standard rectangular waveguide WR-10. The even harmonic signal output by the ring combination structure 23 is coupled to the output height reduction waveguide by the output probe 25 through the output matching circuit 24, and then the even harmonic frequency multiplication signal is output by the standard output waveguide.

[0010] Furthermore, in the ring-type combined structure, the bandpass filter adopts a CMRC filter and a high- and low-impedance filter.

[0011] Furthermore, the diode array includes: N Schottky diodes connected in series, where N≥6; the Schottky diode loop is combined with the filter loop to realize a nonlinear frequency conversion network. The more diodes there are, the higher the frequency multiplication power that can be handled, and the adjustments can be made according to actual needs.

[0012] Furthermore, both the input and output probes are E-plane probes.

[0013] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0014] This invention provides a ring-type combined full-band terahertz even-harmonic frequency multiplier. It employs a nonlinear Schottky diode as the core component and improves upon the traditional structure of a fundamental frequency filter circuit and a reverse-parallel diode by proposing a ring-type combined structure. A high-frequency narrow-passband filter and a low-frequency narrow-passband filter are respectively placed on the two signal branches of the ring-type combined structure, improving the signal filtering from full-bandwidth filtering to two narrow-passband filters. Finally, the two narrow-passband signals are combined into a broadband signal, thereby improving the device's full-band frequency multiplication efficiency. The signal is input from the input waveguide and coupled to the cavity microstrip line. After matching to retain the desired signal frequency band, the nonlinearity of the diodes yields a signal containing all harmonic signals, while the filter simultaneously yields the second harmonic signal, which is finally output through the output waveguide. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the ring-type combined full-band terahertz even-order harmonic frequency multiplier in this invention;

[0016] Figure 2 This is a schematic diagram of the on-chip integrated circuit of the ring-type combined full-band terahertz even-order harmonic frequency multiplier in this invention;

[0017] Figure 3 This is a schematic diagram of the principle of the ring-type combined full-band terahertz even-order harmonic multiplier in this invention;

[0018] Figure 4 This is a schematic diagram of the first ring-combined structure of the ring-combined full-band terahertz even-order harmonic frequency multiplier in this invention.

[0019] Figure 5 This is a schematic diagram of the second ring-combined structure of the ring-combined full-band terahertz even-order harmonic frequency multiplier in this invention.

[0020] Figure 6 This is a schematic diagram of the third type of ring-combined structure of the ring-combined full-band terahertz even-order harmonic frequency multiplier in this invention;

[0021] Figure 7 The filtering performance of the two narrowband filters when separated;

[0022] Figure 8 The performance of a broadband filter formed by parallel connection of filters in a ring structure;

[0023] In this array, 1 is the input waveguide, 2 is the on-chip integrated circuit, 3 is the output waveguide, 21 is the input probe, 22 is the input matching microstrip line, 23 is the ring combination structure, 24 is the output matching circuit, 25 is the output probe, 231 is the bandpass filter, and 232 is the diode array in series. Detailed Implementation

[0024] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] This embodiment provides a frequency doubler based on a ring-type combined full-band terahertz even-order harmonic frequency doubler, with a frequency band of 145–220 GHz. The specific structure is as follows: Figure 1As shown, the system includes: an input waveguide 1, an on-chip integrated circuit 2, and an output waveguide 3. The input waveguide includes a standard input waveguide and an input height reduction waveguide, and the output waveguide includes a standard output waveguide and an output height reduction waveguide. The on-chip integrated circuit includes: an input probe 21, an input matching microstrip line 22, a ring-shaped combination structure 23, an output matching circuit 24, and an output probe 25. The input fundamental signal is input from the standard input waveguide, passes through the input height reduction waveguide, and is coupled to the input matching microstrip line 22 by the input probe 21, thereby entering the ring-shaped combination structure 23 for frequency multiplication. The second harmonic signal output from the ring-shaped combination structure 23 passes through the output matching circuit 24 and is coupled to the output height reduction waveguide by the output probe 25. Finally, the second harmonic signal is output from the standard output waveguide.

[0026] Specifically, the ring-shaped combined structure 23 consists of two parallel signal branches. Each signal branch is composed of a bandpass filter 231 connected in series with a diode array 232, and the diode arrays in the two signal branches are connected in reverse parallel. In one of the two signal branches, the passband of the bandpass filter in that branch is f. min ~f a The passband of the bandpass filter on the other signal branch is f. b ~f max 0.9f a ≤f b ≤f a f min f is the minimum operating frequency of the frequency multiplier. max The maximum operating frequency of the frequency multiplier, after actual performance testing and adjustments, is f. a =181GHz, f b =179GHz; In the two signal branches, the diode array generates harmonics through nonlinear characteristics. Since the two diode arrays are opposite in direction of signal transmission, the odd harmonics are canceled out in the ring-combined structure. The remaining even harmonics are combined from two narrowband signals into a broadband signal after passing through the ring-combined structure, achieving full-band terahertz even harmonic frequency doubling; such as Figure 7 The figure shows the performance of two separately designed simplex CMRC bandpass filters, such as... Figure 8 The image shows the overall filtering performance of the ring structure filter in this invention. As can be seen from the comparison, the filtering bandwidth of the ring combination structure can cover the entire frequency band from 145 to 220 GHz, and the filtering effect can also achieve the effect of a narrowband filter, basically achieving filtering below -20 dB.

[0027] It should also be noted that:

[0028] Firstly, the core innovation of this invention lies in merging two narrowband signals into a wideband signal through a ring-shaped combination structure to achieve full bandwidth. Therefore, in the optimized design of the frequency multiplier, the passband of the bandpass filter on the two signal branches should be as narrow as possible, then f a with f b Preferably located in (f) max -f min Around ) / 2, or even f a =f b =(f max -f min ) / 2; such as Figure 4 As shown, in this embodiment, the passband of the upper bandpass filter is 145-180GHz, and the passband of the lower bandpass filter is 180-220GHz. By merging the two narrowband signals into a wideband signal, a full-band frequency doubler of 145-220GHz is obtained.

[0029] Secondly, in each signal branch of the ring-shaped combined structure of this invention, the filter and diode array are not limited by order. That is, from the perspective of signal transmission direction, the filter and diode array can be connected in series, the diode array and filter can be connected in series, or the filter can be connected between multiple individual diodes in the diode array, such as... Figure 4 , Figure 5 , Figure 6 As shown, this embodiment provides three possible ring-shaped combination structures.

[0030] Specifically, the input probe and the output probe are both E-plane probes; the standard input waveguide is a standard rectangular waveguide WR-5, and the standard output waveguide is a standard rectangular waveguide WR-10; the filter in the ring combination structure is a CMRC filter; the diode is a Schottky diode, which utilizes the nonlinear characteristics of the Schottky diode to generate even-order harmonic signals.

[0031] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A ring-type combined full-band terahertz even-order harmonic multiplier, comprising: The input waveguide (1), on-chip integrated circuit (2), and output waveguide (3) are characterized in that the on-chip integrated circuit comprises: an input probe (21), an input matching microstrip line (22), a ring combination structure (23), an output matching circuit (24), and an output probe (25) connected in sequence; the ring combination structure (23) is composed of two signal branches connected in parallel, each signal branch is composed of a bandpass filter (231) and a diode array (232) connected in series, and the diode arrays in the two signal branches form an anti-parallel structure; In a ring-shaped composite structure, the passband of the bandpass filter on one signal branch is... f min ~ f a The passband of the bandpass filter on the other signal branch is f b ~ f max 0.9 f a ≤ f b ≤ f a , f min This is the minimum operating frequency of the frequency multiplier. f max This is the maximum operating frequency of the frequency multiplier. f a This is the upper cutoff frequency of the low-frequency bandpass filter. f b This is the lower cutoff frequency of the high-frequency bandpass filter.

2. The ring-type combined full-band terahertz even-order harmonic frequency multiplier according to claim 1, characterized in that, In a ring-shaped composite structure, f a = f b =( f max - f min ) / 2.

3. The ring-type combined full-band terahertz even-order harmonic frequency multiplier according to claim 1, characterized in that, The input waveguide is composed of a standard input waveguide and an input height reduction waveguide. The standard input waveguide adopts the standard rectangular waveguide WR-5. The input fundamental signal is input from the standard input waveguide, passes through the input height reduction waveguide, and is coupled to the input matching microstrip line (22) by the input probe (21), thereby entering the ring combination structure (23) for frequency doubling.

4. The ring-type combined full-band terahertz even-order harmonic frequency multiplier according to claim 1, characterized in that, The output waveguide includes a standard output waveguide and an output height reduction waveguide. The standard output waveguide adopts a standard rectangular waveguide WR-10. The even harmonic signal output by the ring combination structure (23) is coupled to the output height reduction waveguide by the output probe (25) through the output matching circuit (24), and then the even harmonic frequency multiplication signal is output by the standard output waveguide.

5. The ring-type combined full-band terahertz even-order harmonic frequency multiplier according to claim 1, characterized in that, In the ring-type combined structure, the bandpass filter adopts a CMRC filter and a high- and low-impedance filter.

6. The ring-type combined full-band terahertz even-order harmonic frequency multiplier according to claim 1, characterized in that, The diode array consists of N Schottky diodes connected in series, where N ≥ 6.

7. The ring-type combined full-band terahertz even-order harmonic frequency multiplier according to claim 1, characterized in that, The input probe is an E-plane probe, and the output probe is an E-plane probe.

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