Orthogonal oscillator based on metamaterial waveguide

Abstract

The invention provides a quadrature oscillator based on super-structure waveguides, the whole oscillator is formed by sequentially connecting three parallel super-structure waveguides (1.1) and a crossed super-structure waveguide (1.2) end to end, an inner square resonant ring and an outer square resonant ring are formed, and the corner connecting positions of the resonant rings are connected through corner connecting structures (1.3). And a negative resistance unit (1.4) is arranged between the two parallel microstrip lines (2.1) of the corner connecting structure. Through the dispersion regulation and control function of the metamaterial waveguide, the problem of index tradeoff between quadrature phase precision and phase noise of a traditional quadrature oscillator is solved, and high phase precision and low phase noise indexes are achieved at the same time. The invention has the advantages of simple processing and simple structure, and has very high application scenarios in orthogonal amplitude modulation and multiple-input-output radar systems.

Description

Technical Field

[0001] The present invention relates to a technology of an orthogonal oscillator based on a metawaveguide for generating high-frequency orthogonal oscillation signals, belonging to the fields of integrated circuits and novel artificial electromagnetic materials. Background Art

[0002] With the increasing demand of integrated systems for high-phase-precision and high-quality-factor orthogonal signals, traditional orthogonal oscillators are difficult to meet the strict requirements of both high quality factor and high phase precision simultaneously. In traditional designs, orthogonal LC oscillators are often used to generate orthogonal signals due to their high-quality-factor resonant structures. However, their coupling structures and phase adjustment mechanisms usually lead to deteriorated phase noise, increased power consumption, and enlarged physical area. Specifically, the greater the coupling strength of the coupling structure, the greater the control over the signal orthogonality and the higher the orthogonal phase precision. However, this will result in a larger offset frequency, which in turn leads to deteriorated phase noise. On the contrary, the smaller the coupling strength of the coupling structure, the mismatch between the two oscillators causes the oscillation frequencies of the two oscillators to be different, thus destroying the orthogonal relationship between the output oscillation signals and resulting in a large orthogonal phase error.

[0003] A metawaveguide is an artificial structure composed of a periodic or aperiodic arrangement of sub-wavelength units, and can flexibly manipulate electromagnetic waves by designing the structural units and their arrangements. As a type of metawaveguide, artificial surface plasmons utilize periodically arranged metal structural units designed artificially to simulate the physical characteristics of surface plasmons in the optical frequency band in the microwave band, generate surface plasmon modes similar to those in the optical wave frequency band, and can adjust the electromagnetic waves by adjusting the metal structure size, having advantages such as adjustable dispersion characteristics, strong field confinement, and slow-wave characteristics. In short, the metawaveguide provides a practical solution for controlling dispersion characteristics through structural design and a direct means for designing the transmission behavior of electromagnetic waves. Summary of the Invention

[0004] Technical Problem: To solve the deficiencies of the prior art, the present invention proposes an orthogonal oscillator based on a metawaveguide, which solves the problem of the trade-off between high-quality-factor and high-phase-precision indicators caused by the insufficient design freedom of traditional orthogonal oscillators, and solves the problem that the prior art requires an additional phase adjustment structure, which increases power consumption and system complexity. The present invention utilizes the dispersion regulation function of the metawaveguide to overcome the problem of the trade-off between orthogonal phase precision and phase noise in traditional orthogonal oscillators. By adjusting the waveguide structure, precise matching of the electrical lengths of the inner and outer resonant rings is achieved, and high-phase-precision and low-phase-noise indicators are obtained.

[0005] Technical solution: An orthogonal oscillator based on a metawaveguide according to the present invention is integrally formed by sequentially connecting three parallel metawaveguides and a cross metawaveguide end to end, forming a square resonance ring with an inner and an outer circle. The corner joints of the resonance ring are connected by a corner connection structure, and a negative resistance unit is provided between two parallel microstrip lines of the corner connection structure.

[0006] The parallel metawaveguide is composed of two parallel microstrip lines and folded open-circuit line stubs symmetrically arranged on both outer sides of the two parallel microstrip lines. Each side of the microstrip line is composed of two folded open-circuit line stubs connected in parallel.

[0007] The folded open-circuit line stub is a comb-like structure, and each comb-like structure is composed of a first continuous zigzag metal strip.

[0008] The cross metawaveguide is composed of two cross microstrip lines that cross in the middle and folded open-circuit line stubs located on both outer sides of the cross microstrip lines. Each side of the cross microstrip line is composed of two symmetric folded open-circuit line stubs connected in parallel; a cross structure is provided at the middle position of the cross microstrip lines.

[0009] The folded open-circuit line stub is a comb-like structure, and each comb-like structure is composed of a second continuous zigzag metal strip.

[0010] In the parallel metawaveguide described above, the widths of the folded first stubs are w 1 = 19um, w 2 = 14.3um, the slot width s 1 = 2um, and the width of the first continuous zigzag metal strip and the width of the parallel microstrip line w 0 = 2um.

[0011] In the cross metawaveguide described above, the widths of the folded first stubs are w 3 = 16.6um, w 4 = 11.9um, w 5 = 11.4um, w 6 = 11.9um, the slot width s 2 = 2um.

[0012] In the cross metawaveguide described above, the width of the second continuous zigzag metal strip and the width of the cross microstrip line w 0 = 2um.

[0013] The negative resistance unit is composed of two cross-coupled inverters.

[0014] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0015] The present invention utilizes the dispersion regulation function of the metawaveguide to overcome the problem of index trade-off between the quadrature phase accuracy and phase noise of traditional quadrature oscillators. By adjusting the waveguide structure, precise matching of the electrical lengths of the inner and outer resonant loops is achieved, and high phase accuracy and low phase noise indices are obtained.

[0016] The present invention realizes high-precision phase output through artificial surface plasmons, without the need for an additional phase adjustment mechanism, simplifies the design, and reduces the volume.

[0017] Under the process limitation of 65-nanometer CMOS, the present invention can achieve performance comparable to that of more advanced processes and has high application scenarios in practice. Description of the Drawings

[0018] Figure 1 is a quadrature oscillator based on a metawaveguide; it includes: parallel metawaveguide 1.1, cross metawaveguide 1.2, corner connection structure 1.3, and negative resistance unit 1.4.

[0019] Figure 2 is a parallel metawaveguide; it includes: microstrip line 2.1, overlapping open-circuit stub 2.2, and first continuous zigzag metal strip (2.2.1).

[0020] Figure 3 is a cross metawaveguide; it includes: cross microstrip line 3.1, cross structure 3.1.1, folded open-circuit stub 3.2, and second continuous zigzag metal strip 3.2.1.

[0021] Figure 4 is a negative resistance unit; it includes: inverter 4.1.

[0022] Figure 5 is the phase shift curves of metawaveguides and microstrip lines with different lengths. Detailed Embodiment

[0023] The technical solutions of the present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0024] The present invention proposes a quadrature oscillator based on a metawaveguide. The overall structure is composed of a head-to-tail connected resonant loop formed by metawaveguides and uniformly distributed negative resistance units. Each metawaveguide is composed of a microstrip line structure and symmetrically parallel folded open-circuit stubs. The symmetrically parallel folded open-circuit stubs are in a comb-like structure, and each comb-like structure includes a continuous zigzag metal strip. The metawaveguide is twisted into a Möbius loop to form an oscillation feedback closed loop. The loss is compensated by the negative resistance unit, and the wave can propagate continuously in the resonant loop. In addition, the negative resistance unit can maintain the odd-mode state of the inner and outer rings of the resonant loop. The typical structure of the negative resistance unit is as Figure 4As shown, it is composed of two cross-coupled inverters. Each inverter is composed of an NMOS transistor and a PMOS transistor in series. When it works, the phase of the wave propagating on the transmission line is a periodic function related to the position of the transmission line, while the amplitude remains constant. Therefore, orthogonal signals can be extracted from different positions.

[0025] The present invention is implemented using a 65-nanometer CMOS process. Without any additional phase adjustment structure, it can significantly improve the orthogonality accuracy and quality factor of the output signal. Through the dispersion regulation function of the metasurface waveguide, the present invention overcomes the trade-off problem between the orthogonality phase accuracy and phase noise of traditional orthogonal oscillators, and simultaneously achieves a high phase accuracy of about 0.21° error and a low phase noise of 112.72 dBc@1MHz; specifically:

[0026] The oscillator is composed of a parallel metasurface waveguide and a cross metasurface waveguide, connected end to end to form a square resonant ring with two inner and outer circles. The resonant ring corner connection structure includes a negative resistance unit.

[0027] The parallel metasurface waveguide is composed of two parallel microstrip lines and symmetrically parallel folded open-circuit line stubs.

[0028] The folded open-circuit line stub is a comb-like structure located on both the inner and outer sides of the microstrip line. Each comb-like structure includes a continuous zigzag metal strip.

[0029] The cross metasurface waveguide is composed of cross microstrip lines and symmetrically parallel folded open-circuit line stubs.

[0030] The folded open-circuit line stub is a comb-like structure located on both the inner and outer sides of the cross microstrip line. Each comb-like structure includes a continuous zigzag metal strip.

[0031] The cross structure is located in the middle of the cross microstrip line, and the cross structure is composed of two non-overlapping upper and lower layers.

[0032] The corner connection structure is formed by the microstrip line and the cross microstrip line extending and connecting at 45 degrees.

[0033] As Figure 1 shown, it is the overall schematic diagram of the oscillator.

[0034] The parallel metasurface waveguide is Figure 1 part of module 1, and the specific structure is as Figure 2 shown, where the widths of the folded first stubs are w 1 =19um, w 2 =14.3um, the slot width s 1 =2um, and the widths of the metal strip and the microstrip line w 0 =2um.

[0035] The cross-metamaterial waveguide is Figure 1 part of Module 2, which is composed of two cross-coupled inverters. The specific structure is as shown in Figure 3 . Among them, the widths of the folded first stubs are w 3 = 16.6um, w 4 = 11.9um, w 5 = 11.4um, w 6 = 11.9um, the slit width s 2 = 2um, the width of the metal strip and the width of the microstrip line w 0 = 2um.

[0036] The negative resistance unit is Figure 1 part of Module 1.4, and the specific structure is as shown in Figure 4 . Among them, the two inverters are connected in a cross-coupled manner.

[0037] The phase shift curves of each section of the metamaterial waveguide are as shown in Figure 5 . It can be seen from the figure that for metamaterial waveguides with different lengths, they all have exactly the same phase shift situation, indicating that this structure has the ability to decouple the physical length and the electrical length, and has high practical value. The orthogonal oscillator based on the metamaterial waveguide can achieve a high phase accuracy of about 0.21° error and a low phase noise of 112.72dBc@1MHz.

Claims

1. An orthogonal oscillator based on a meta-waveguide, characterized in that: The oscillator as a whole is composed of three parallel metastructure waveguides (1.1) and a cross metastructure waveguide (1.2) connected end to end in sequence to form a square resonance ring with two inner and outer circles. The corner connection of the resonance ring is connected by a corner connection structure (1.3), and a negative resistance unit (1.4) is provided between two parallel microstrip lines (2.1) of the corner connection structure (1.3).

2. The orthogonal oscillator based on metawaveguide according to claim 1, characterized in that: The parallel metastructure waveguide (1.1) is composed of two parallel microstrip lines (2.1) and folded open line branches (2.2) symmetrically arranged on the two outer sides of the two parallel microstrip lines (2.1), and each side of the microstrip line (2.1) is composed of two folded open line branches (2.2) connected in parallel.

3. The orthogonal oscillator based on metawaveguide according to claim 2, characterized in that: The folded open-circuit branch nodes (2.2) are comb-tooth structures, and each comb-tooth structure is composed of a first continuous wavy metal strip (2.2.1).

4. The orthogonal oscillator based on meta-waveguide according to claim 1, characterized in that: The cross metastructure waveguide (1.2) is composed of two cross microstrip lines (3.1) that cross in the middle and folded open line branches (3.2) located on both outsides of the cross microstrip lines (3.1); each side of the cross microstrip line (3.1) is composed of two symmetrical folded open line branches (3.2) connected in parallel; and a cross structure (3.1.1) is provided in the middle of the cross microstrip line (3.1).

5. The orthogonal oscillator based on meta-waveguide according to claim 4, characterized in that: The folded open-circuit branch nodes (3.2) are comb-tooth structures, and each comb-tooth structure is composed of a second continuous wavy metal strip (3.2.1).

6. The metamaterial-based rotating traveling wave orthogonal oscillator according to claim 1, characterized in that: In the parallel metawaveguide (1.1), the widths of the folded first branches are w1=19um, w2=14.3um, the slit width is s1=2um, the width of the first continuous wavy metal strip (2.2.1) and the width of the parallel microstrip line (2.1) are w0=2um.

7. The orthogonal oscillator based on meta-waveguide according to claim 1, characterized in that: In the cross-metastructure waveguide (1.2), the widths of the folded first branches are w3=16.6um, w4=11.9um, w5=11.4um, w6=11.9um, and the slot width is s2=2um.

8. The orthogonal oscillator based on meta-waveguide according to claim 1, characterized in that: In the cross-metawaveguide (1.2), the width of the second continuous wavy metal strip (3.2.1) and the width of the cross-microstrip line (3.1) w0=2um.

9. The orthogonal oscillator based on meta-waveguide according to claim 1, characterized in that: The negative resistance unit (1.4) is composed of two cross-coupled inverters (4.1).

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