CN104377417A - Spiral artificial surface plasma field intensity intensifier - Google Patents
Spiral artificial surface plasma field intensity intensifier Download PDFInfo
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- CN104377417A CN104377417A CN201410626252.5A CN201410626252A CN104377417A CN 104377417 A CN104377417 A CN 104377417A CN 201410626252 A CN201410626252 A CN 201410626252A CN 104377417 A CN104377417 A CN 104377417A
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Abstract
The invention provides a spiral artificial surface plasma field intensity intensifier which comprises a traditional coaxial waveguide, a transition waveguide from the coaxial waveguide to an artificial surface plasma waveguide, and the spiral artificial surface plasma waveguide. The transition waveguide includes the inner conductor transition and outer conductor transition. The inner conductor transition is achieved through a periodical spiral type groove array with the depth gradually decreased, and the outer conductor transition is achieved through a horn antenna with an opening gradually becoming larger. One part of the spiral artificial surface plasma waveguide is formed by the spiral groove array with the constant depth and width, the gradually decreased radius and the changed period, and the other part of the spiral artificial surface plasma waveguide is a conical top end and is composed of a spiral groove with the depth and the radius reduced at the same time and becoming zero at the top end of a conical point. The spiral artificial surface plasma field intensity intensifier is simple in structure, compact in size, efficient in broadband, high in field intensity intensifying factor, suitable for being used in cooperation with a traditional microwave or terahertz transmission circuit and capable of being widely applied in the fields of microwave or terahertz imaging, the high-resolution medical endoscope technology and the like.
Description
Technical field
The present invention relates to a kind of enhanced intensity device structure, particularly relate to a kind of spirality artificial surface plasma field intensity booster structure.
Background technology
Surface plasmons (Surface Plasmon Polaritons, be called for short SPPs) is the mixed activation state that there is a kind of electronics on metal and medium (normally air) interface and photon.SPPs is a kind of surface wave, can break through diffraction limit, and electromagnetic field is constrained within the scope of the sub-wavelength near metal and medium interface, has very strong field enhancement effect.Research for SPPs had once once been limited in optical band or higher frequency, due to the good characteristic of SPPs, if by the concept of surface plasmons to low-frequency range (microwave or terahertz wave band), contribute to the guided wave technology obtaining high binding microwave or terahertz signal, and it is highly integrated to realize the device size of low-frequency range to be reduced to sub-wavelength magnitude.But because the plasma frequency of metal is generally all in ultraviolet band, metal is very large at the dielectric constant of low-frequency range, make electromagnetic skin depth very little, so in low-frequency range, metal is similar to perfact conductor (Perfect Electric Conductor, PEC), thus make SPPs very poor in the field constraint of metal surface, effect spread cannot be realized on the metal surface, greatly limit the application of SPPs in low-frequency range.In recent years, someone proposes the method at metal surface borehole or cutting, electromagnetic field can not only be increased in intrametallic penetrating power, the sub-wavelength constraint of field can also be realized, and the equivalent plasma frequency of body structure surface is only relevant with the geometric parameter of surface texture, thus engineering design can be carried out at lower frequency to SPPs.This plasma frequency is called as artificial surface plasmon (Spoof Surface Plasmon Polaritons is called for short SSPPs) by the surface plasma that surface geometry controls.Its basic thought is the hole digging period profile in metal surface, and the size of hole and interval, all much smaller than wavelength, to strengthen electromagnetic osmosis, thus reduce the plasma frequency of metal surface by the means of effective medium.2005, the people such as Hibbins confirmed SSPPs phenomenon in microwave section, and subsequently, the people such as Williams also demonstrate the existence of SSPPs at terahertz wave band, for new page has been opened in the development of low frequency SPPs and application.SSPPs causes the great interest of researcher since then.
Metal wire smooth is at present considered to one of best terahertz waveguide.This guided wave has the advantage of low-loss and low dispersion, but retrains poor.Therefore, the people such as Maier have arrived the concept of SSPPs on the geometry position shape of metal wire, demonstrate the sub-wavelength ring groove carving periodic distribution on ideal wire along its length in theory, SSPPs can be transmitted, and realize the sub-wavelength constraint of field, thus realize the local enhancement effect of microwave or THz wave, for periodicity metal wire structure is at microwave or terahertz imaging, high-resolution medical endoscopes technology, biological detection, national security, food and agricultural product quality control, global environment detects and wide prospect has been opened up in the application in the field such as information and radar communication technology.
All the time, space guided wave is extensively studied to the conversion of SPPs, as passed through prism-coupled or diffraction grating.But the research for how, space guided wave being converted efficiently to SSPPs is very few.2013, Southeast China University proposes and a kind ofly realizes the structure of guided wave to the efficient conversion of SSPPs at microwave frequency band, it is made up of traditional co-planar waveguide and " tooth type " ultra-thin periodic structure metal band plasma waveguide, devises the matching transition band of gash depth gradual change between the two.Matching transition part achieves wave vector coupling and the impedance matching of co-planar waveguide and plasma waveguide, the high efficiency of this structure microwave section achieves from guided wave to Spoof SPPs and wide-band conversion, for plasma function element and circuit have started application prospect the height of microwave section is integrated.But consider the difference of ultra-thin " tooth type " plasma waveguide and wire-form plasma waveguide transmission electromagnetic field pattern, such scheme will be no longer applicable.
Summary of the invention
In order to achieve the above object, technical scheme of the present invention is achieved in that
The method of carving the sub-wavelength ring groove of periodic distribution on the one hand on ideal wire along its length realizes SSPPs transmission, adopt space guided wave to the thought of the efficient conversion of SSPPs on the other hand, have devised a kind of spirality artificial surface plasma field intensity booster, it is characterized in that: comprise traditional coaxial waveguide and the coaxial waveguide transition waceguide to spirality artificial surface plasma waveguide, and spirality artificial surface plasma waveguide;
Wherein, transition waceguide comprises inner wire and outer conductor transition, and the periodic spin type groove array that inner conductor transition is increased progressively by the degree of depth realizes, and outer conductor transition becomes large horn antenna gradually by opening and realizes; Spirality plasma waveguide is made up of two parts, Part I is that the degree of depth and constant width, inside radius successively decrease, the spiral type groove array of mechanical periodicity, Part II is tapered tip, is reduced simultaneously and form at the spiral groove of cone point top vanishing by the degree of depth and radius.
Be tapered tip in the tip designs of structure, tapered tip be carved with the spiral type groove of inside radius gradual change to zero, make spiral type groove array have good transition to the top of structure.This structure not only makes full use of the stronger field effect of restraint of SSPPs, make use of the focus characteristics of pyramidal structure simultaneously, and then can realize efficient focusing function at the summit place of structure.
The present invention can regulate the physical dimension of transition waceguide and spirality plasma waveguide according to the type of coaxial waveguide and size, thus realize microwave section or the efficient and broadband conversion to SSPPs of terahertz wave band space guided wave, and then reach the effect of microwave or Terahertz frequency range enhanced intensity, realize artificial surface plasma Meta Materials and apply more widely.
The present invention has following beneficial effect:
1. the present invention mainly proposes a kind of spirality artificial surface plasma field intensity booster structure, comprises traditional coaxial waveguide and the coaxial waveguide transition waceguide to spirality artificial surface plasma waveguide, and spirality plasma wave guide structure.This structure uses for reference the design philosophy of co-planar waveguide to artificial surface plasma waveguide transferring structure on the one hand, the spiral type groove structure that inner wire utilizes the degree of depth to increase progressively is to realize the wave number coupling between coaxial waveguide and artificial surface plasma waveguide, the gradual change of the horn antenna of outer conductor employing simultaneously realizes the impedance matching between coaxial waveguide and artificial surface plasma waveguide, thus implementation space guided wave is to the Efficient Conversion of SSPPs; On the other hand, utilize the adjustable chromatic dispersion characteristic of artificial surface plasma waveguide, the spirality plasma waveguide proposing radius gradual change realizes the high order focusing ability of field intensity.This stereochemical structure can realize the efficient input of signal and the high order focusing of field intensity, and has greater flexibility in the design of microwave device and integrated circuit structure.
2. structure is simple: structure comprises traditional coaxial waveguide, coaxial waveguide to the transition waceguide of spirality artificial surface plasma waveguide, and spirality artificial surface plasma wave guide structure.Artificial surface plasma waveguide is the metal wire being carved with periodic spin type groove, simple structure, convenient processing, and not easy fracture.
3. strong innovation, technology is perspective good: the present invention achieves electromagnetic high order focusing and high efficiency of transmission, strong innovation at microwave or Terahertz frequency range, has no this class formation both at home and abroad; It can well and traditional microwave transmission line with the use of, be convenient to be integrated in microwave circuit, expanded the range of application of artificial surface plasma device, there is good technology perspective.
4. large, the bandwidth of enhanced intensity coefficient: the present invention finally can realize the high order focusing of the terminal field intensity of artificial surface plasma field intensity booster.Within the scope of 10GHz ~ 35GHz, more than 30 times of signal source entry port place field intensity can be reached in the field intensity at the summit place of conical plasmon structures.
5, have wide range of applications: the present invention can at microwave or terahertz imaging, and high-resolution medical endoscopes technology, biological detection, national security, food and agricultural product quality control, global environment detects and the field such as information and radar communication technology realizes extensive use.
Accompanying drawing illustrates:
Fig. 1 is the front view of embodiment one;
Fig. 2 (a) is the left view of the coaxial waveguide part of embodiment two;
Fig. 2 (b) is the inner and outer conductor figure of the transition portion of embodiment two;
Fig. 2 (c) be embodiment two spirality artificial surface plasma waveguide region III structure chart;
Fig. 2 (d) be embodiment two spirality artificial surface plasma waveguide region IV structure chart;
Fig. 3 is that the change of the depth of groove of embodiment two transition waceguide spiral type groove array is to the influence curve figure of its dispersion characteristics;
Fig. 4 is that the change of the radius of embodiment two plasma wave driving screw type groove array is to the influence curve figure of its dispersion characteristics;
Fig. 5 is that the given viewpoint amplitude of field strength of embodiment two is with frequency variation curve figure;
Fig. 6 is that the amplitude of field strength ratio of point of observation 2 and point of observation 1 is with frequency variation curve figure.
Specific embodiments:
Be described in further detail below in conjunction with the enforcement of accompanying drawing to technical scheme:
Embodiment one
As shown in Figure 1, enhanced intensity device is made up of three parts.Part I (region I) is traditional coaxial waveguide, signal input; Part II (region II) is transition waceguide, comprises inner wire and outer conductor transition, and the periodic spin type groove array that inner conductor transition is increased progressively by the degree of depth realizes, and the horn antenna that outer conductor transition is magnified gradually by opening realizes; Part III (region III and region IV), spirality artificial surface plasma waveguide: region III is the Part I of spirality artificial surface plasma waveguide, that the degree of depth and constant width, inside radius successively decrease, the spiral type groove array of mechanical periodicity, region IV is the Part II of spirality artificial surface plasma waveguide, is the tapered tip being reduced by the degree of depth and inside radius simultaneously and form at the spiral groove of cone point top vanishing.The parameters of structural dimension of transition waceguide and the waveguide of spirality ion can regulate according to the type of coaxial waveguide and size, matches with coaxial waveguide parameter (as waveguide type, waveguide length, waveguide cross-section size etc.).
Embodiment two
For structure shown in such as Fig. 2 (a), region I is traditional coaxial waveguide, single overall length L
1=10 millimeters, waveguide inner conductor outer diameter 2R
1=7 millimeters, outer conductor internal diameter 2R
2=16 millimeters, wall thickness t=1 millimeter.Coaxial waveguide is as the input of guided wave signals.
Transition waceguide is connected with coaxial waveguide, plays effect space wave being converted into efficiently SSPPs signal.As shown in Fig. 2 (b), transition waceguide region II comprises inner wire and outer conductor transition.The gradual change degree of depth of inner conductor transition spiral type groove array is from h
1=0 millimeter is evenly increased to h
2=1 millimeter, the remainder of spiral type groove array keeps the ultimate depth h of gradual change
2, the external diameter of inner conductor transition spiral type groove array keeps 2R
1constant, be used for realizing the wave number coupling between coaxial waveguide and artificial surface plasma waveguide, the change of the ring groove degree of depth on the impact of its dispersion characteristics as shown in Figure 3.The horn antenna gradual change internal diameter of outer conductor is from 2R
2=16 millimeters increase progressively by cone angle a=10 °, the total length place arriving transition waceguide terminates, thickness is t=1 millimeter, be used for realizing the impedance matching between coaxial waveguide and artificial surface plasma waveguide, the horizontal cycle spacing p=3 millimeter of adjacent two spiral type grooves in transition waceguide, recess width is a=1.5 millimeter, and the total length of transition waceguide is L
2=30 millimeters.
Spirality plasma waveguide strengthens the carrier of transmission as SSPPs signal.As shown in Fig. 2 (c), the spirality plasma waveguide of Part I (region III), conductor inside radius is from r
1=2.5 millimeters are evenly reduced to r
2=0.2 millimeter, r
1for the inside radius of transition waceguide destination county inner conductor transition spiral type groove; The horizontal cycle distance value of adjacent two spiral type grooves is p=3 millimeter, and recess width is a=1.5 millimeter, and the degree of depth is h
2=1 millimeter, all remain unchanged, length L
3=63 millimeters.As shown in Fig. 2 (d), Part II (region IV) is tapered tip, by the degree of depth from h
2, inside radius is from r
2reduce simultaneously and form at the spiral groove of cone point top vanishing, length L
4=10 millimeters.The change of spiral type groove radius on the impact of its dispersion characteristics as shown in Figure 4.This embodiment enhanced intensity device total length is 113 millimeters.
According to embodiment two, utilize the enhanced intensity usefulness that electromagnetic simulation software can obtain as shown in Figure 5, within the scope of 10GHz ~ 35GHz, more than 30 times of coaxial line entry port place (point of observation 1) field intensity can be reached, as shown in Figure 6 in the field intensity at the summit place (point of observation 2) of spirality artificial surface plasmon structures.
Claims (4)
1. a spirality artificial surface plasma field intensity booster, is characterized in that: comprise traditional coaxial waveguide and the coaxial waveguide transition waceguide to artificial surface plasma waveguide, and spirality artificial surface plasma waveguide;
Wherein, transition waceguide comprises inner wire and outer conductor transition, and the periodic spin type groove array that inner conductor transition is increased progressively by the degree of depth realizes, and outer conductor transition becomes large horn antenna gradually by opening and realizes; Spirality plasma waveguide is made up of two parts, Part I is that the degree of depth and constant width, inside radius successively decrease, the spiral type groove array of mechanical periodicity, Part II is tapered tip, is reduced simultaneously and form at the spiral groove of cone point top vanishing by the degree of depth and radius.
2. a kind of spirality artificial surface plasma field intensity booster according to claim 1, is characterized in that: in transition waceguide, and the spiral type groove array gradual change of inner conductor transition adopts the degree of depth from h
1start uniform increments to h
2, the horizontal cycle distance of adjacent two grooves of spiral type groove array is p, and recess width is a; The horn antenna gradual change of outer conductor transition adopts internal diameter from 2R
2smoothly increase progressively according to cone angle a, the total length place arriving transition waceguide terminates, and thickness is that t remains unchanged, and the single total length of transition waceguide is L
2, parameter h
1, h
2, p, a, R
2, t, a, L
2with coaxial waveguide match parameters.
3. a kind of spirality artificial surface plasma field intensity booster according to claim 1, is characterized in that: the Part I of spirality plasma waveguide is that conductor inside radius is from r
1evenly r is decremented to gradually through period spin type groove
2, the horizontal cycle distance of adjacent two spiral type grooves is p, recess width is a, the degree of depth is h
2, all remain unchanged, total length is L
3; Part II is length is L
4tapered tip, be carved with the degree of depth above from h
2, inside radius is from r
2be decremented to the spiral type groove of zero, parameter r
1, r
2, p, a, h, L
3, L
4with coaxial waveguide match parameters.
4., according to the arbitrary described a kind of spirality artificial surface plasma field intensity booster of claim 1-3, it is characterized in that: coaxial waveguide is as the input of guided wave signals.
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Cited By (3)
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| CN105703048A (en) * | 2016-01-13 | 2016-06-22 | 北京大学 | Ultra wide band terahertz class surface plasmon coupler and coupling method |
| CN108844914A (en) * | 2018-05-28 | 2018-11-20 | 南开大学 | A kind of Terahertz super-resolution imaging device and imaging method based on metal probe |
| CN113671629A (en) * | 2021-08-26 | 2021-11-19 | 桂林电子科技大学 | New method for constructing plasma wave interferometer in optical fiber core |
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| CN113671629A (en) * | 2021-08-26 | 2021-11-19 | 桂林电子科技大学 | New method for constructing plasma wave interferometer in optical fiber core |
| CN113671629B (en) * | 2021-08-26 | 2022-07-29 | 桂林电子科技大学 | New method for constructing plasma wave interferometer in optical fiber core |
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