CN205248439U - Two ring shape plane monopole antenna of ultra wide band - Google Patents

Abstract

The utility model discloses a two ring shape plane monopole antenna of ultra wide band, it comprises two rings shape radiating element, gradual change structure microstrip line, oval flute profile floor and coaxial joint. Two rings shape radiating element adopts the concentric semicircle ring integrated configuration that the internal diameter is the same and the external diameter is different, the wide antenna frequency band of exhibition, two rings shape radiating element intermediate formation circular port, adjust impedance match through changing the circular port radius, improve the omni -direction of antenna, through gradual change structure microstrip line to the radiating element feed, improve the standing wave characteristic of low -frequency range, be equipped with on the rectangle floor of medium back of the substrate lower extreme and use the radiating element center as the centre of a circle, the axial ratio is 1.3 oval recess, and be equipped with certain gap between the radiating element, be equivalent to a matching network, the impedance bandwidth of the wide antenna of further exhibition. This antenna has characteristics such as ultra wide band, miniaturization, simple structure, processing convenience, and the bandwidth of effectively working is 2.8-13.5GHz, and radiation characteristic is good, reaches the requirement of short distance ultra wide band communication application.

Description

The two annular planar monopole antennas of a kind of ultra broadband

Technical field

The utility model relates to a kind of antenna of wireless communication technology field, and particularly the two annular planar monopole antennas of a kind of ultra broadband, are applicable to short distance ultra-wideband communications.

Background technology

Along with the fast development of high-velocity electrons integrated circuit, for adapting to the demand of small integrated, ultra-wideband antenna is subject to extensive concern with advantages such as its low-power consumption, low cost, high security, High Data Rate and anti-multipath interference. 2002, FCC (FCC) ratified the application band using 3.1～10.6GHz frequency range as super-broadband tech, and this makes ultra-wideband printed monopole aerial become the focus of research. ultra-wideband antenna has high radiation efficiency in consistent group delay and linear phase shift, working band, stable directionality and antenna gain conventionally, and low section, miniaturization are the developing direction of current ultra-wideband antenna. printed antenna structure for ultra broadband mainly contains unipole antenna, dipole antenna, fractal structure, helical structure etc., and compared with other structure, printed monopole ultra-wide band antenna is the simplest, and has remarkable compact size and stable radiation characteristic. ultra-wideband printed unipole antenna is generally made up of the monopole patch and the conductor floor that overlay on medium substrate both sides or homonymy, realize broadband and the Miniaturization Design of antenna by matching network, reactance loading, structure optimization, increase distributing point etc., utilize microstrip line or the co-planar waveguide of floor central authorities to carry out feed, possess that volume is little, section is low, easily and the feature such as terminal device is integrated, by wireless communication system extensive use. the realization of printing monopole antenna ultra broadband characteristic is generally by optimizing radiating element, ground plane and feed structure are realized, with regard to radiating element, heart-shaped, U-shaped, circular, oval, the radiating elements such as interdigitated and floor can be equivalent to the electromagnetic even gradual change transmission line of transmission TEM mould, therefore there is broadband character in various degree, with regard to feed structure, mainly contain two kinds of micro-band and co-planar waveguides, coplanar waveguide structure is owing to having lower radiation loss and good dispersion characteristics, aspect increase bandwidth, there is advantage, but because the free degree increases, its structure optimization difficulty is larger, it is little that microstrip antenna has volume, lightweight, processing cost is low, easily with the advantage such as active device is integrated. in all kinds of ultra broadband printed monopole antennas, adopt microstrip-fed printing rectangular monopole antenna structure the simplest, other unipole antenna can be approximately its distortion or structure optimization. utilize feed structure to increase bandwidth, the most important thing is the adjustment in radiating element lower end and ground plane gap, the planar monopole antenna on a kind of rectangular channel floor, by ground plane otch, has been realized the impedance bandwidth of 4.8: 1. change feeding classification and also can effectively reduce the low frequency operation frequency of antenna, as use non-central feed or n-point feed etc., can reduce low frequency operation frequency. monopole patch is carried out stairstepping transition by a kind of rectangular patch printed monopole antenna, carries out feed by micro-band, the corresponding groove of opening rectangle on floor, be equivalent to increase a matching network between chip unit and floor, broadening the bandwidth of antenna, this antenna is of a size of 16 × 18mm, S₁₁Frequency coverage 3.1～11GHz of≤-10dB. A kind of circular patch printed monopole antenna uses circular monopole paster, utilizes microstrip-fedly, and impedance bandwidth exceedes 5.3: 1, S₁₁More than frequency coverage 2.27GHz～12GHz of≤-10dB. A kind of cannelure circular monopole antenna, by the outer circular monopole patch annulus that increases, is connected and feed by microstrip line, and the broadening beamwidth of antenna is opened a rectangular channel on circular patch, improves impedance matching, S by the angle of adjustment tank and X-axis₁₁Frequency coverage 2.127～12GHz of≤-10dB.

Utility model content

The purpose of this utility model be to provide a kind of size little, with roomy, simple in structure, return loss is lower and have wider impedance bandwidth and the two annular planar monopole antennas of the ultra broadband of good omnidirectional radiation characteristic.

The technical solution of the utility model is, on FR4 medium substrate, be printed on two circular ring-shaped radiation unit (1), the oval flute profile floor in grading structure microstrip line (2) and the back side (3), external coaxial fitting (4), two circular ring-shaped radiation unit (1) adopt the concentric semicircles ring combining structure that internal diameter is identical and external diameter is different, in the middle of two circular ring-shaped radiation unit, form a circular port, grading structure microstrip line (2) lower end is connected with coaxial fitting (4) inner wire, be convenient to external coaxial cable, on the rectangle floor of lower end, the medium substrate back side, be provided with taking radiating element center as the center of circle, axial ratio is 1.3 oval recess, form oval flute profile floor (3), and between radiating element, be provided with certain gap.

Effect of the present utility model is: this antenna have ultra broadband, size little, simple in structure, be convenient to the features such as processing, by adjusting upper and lower annulus external diameter, Circularhole diameter, oval flute profile radius, broadening impedance bandwidth, utilize gradual change microstrip line as feed, can improve the stationary wave characteristic of low-frequency range, increase low frequency effective current path. This antenna has ultra broadband characteristic, and effectively bandwidth of operation covers 2.8～13.5GHz, and radiation characteristic is good, and gain stabilization reaches the requirement of short distance ultra-wideband communications application.

Brief description of the drawings

Fig. 1 is the structural representation of the utility model example xoy direction.

Fig. 2 is the structural representation of the utility model example zoy direction.

Fig. 3 is the structural representation of the utility model example xoz direction.

Fig. 4 is utility model example reflectance factor S₁₁With parameter r₁、r₂Change curve.

Fig. 5 the utility model example reflectance factor S₁₁With parameter r₃Change curve.

Fig. 6 the utility model example reflectance factor S₁₁With parameter r₄Change curve.

The impedance frequency characteristic of Fig. 7 the utility model example.

Fig. 8 the utility model example actual measurement reflectance factor S₁₁Curve and simulation result comparison.

To be the utility model example be 3,6 in frequency to Fig. 9, E face gain pattern when 9GHz.

To be the utility model example be 3,6 in frequency to Figure 10, H side gains directional diagram when 9GHz.

Detailed description of the invention

Detailed description of the invention of the present utility model is: as shown in Figure 1, 2, 3, the two annular planar monopole antennas of a kind of ultra broadband are to be made up of the two circular ring-shaped radiation unit (1), grading structure microstrip line (2), oval flute profile floor, the back side (3) and the external coaxial fitting (4) that are printed on medium substrate. two circular ring-shaped radiation unit (1) adopt the concentric semicircles ring combining structure that internal diameter is identical and external diameter is different, broadening antenna frequency band, in the middle of two circular ring-shaped radiation unit, form a circular port, by adjusting circle hole radius, change radiating element Surface current distribution, reduce required bandwidth standing internal wave ratio, thereby adjusting impedance matching, improve the omni-directional of antenna, by grading structure microstrip line (2) to radiating element feed, in optimizing impedance matching, reduce radiation loss, improve the stationary wave characteristic of low-frequency range, increase low frequency effective current path, the lower end of grading structure microstrip line (2) is connected with coaxial fitting (4) inner wire, so that external coaxial line, on the rectangle floor of lower end, the medium substrate back side, be provided with taking radiating element center as the center of circle, axial ratio is 1.3 oval recess, form oval flute profile floor (3), and between radiating element, be provided with certain gap, be equivalent to a matching network, the further impedance bandwidth of broadening antenna, and realize omni-directional radiation.

Select DIELECTRIC CONSTANTS_r=3.0 FR4 type double-side copper-applying medium substrate, thickness h=1mm, dielectric loss is 0.001. Medium substrate l=40mm, wide w=40mm. Microstrip antenna has that volume is little, lightweight, processing cost is low, easily with the advantage such as active device is integrated. Realize the ultra broadband characteristic of two annulus unipole antennas and should adjust w₁、w₂, make it produce additional reactance characteristic, further to compensate the Reactance with change of frequency, thus Bandwidth. For reaching compact in size, microstrip line height l₂Be desirablely slightly larger than 1/4 effective wavelength, and the mean breadth of microstrip line is 1/2 corresponding wavelength. The parameters of antenna all can affect the bandwidth of antenna, and according to bandwidth requirement, the initial configuration of antenna is sized to: r₁＝12mm，r₂＝9mm，r₃＝5mm，r₄＝16mm，l₁＝21mm，l₂＝16.5mm，w₁＝2.3mm，w₂=4.2mm, as shown in Figure 1.

Use HFSS simulation software to be analyzed antenna performance, to first annulus external diameter of major parameter r₁, second annulus external diameter r₂, coupling aperture r₃, oval recess radius r₄Analyze, by regulating these parameters to improve impedance matching.

To upper and lower semicircular ring external diameter r₁、r₂Analyze r₁、r₂The reflectance factor S obtaining while getting different values₁₁Curve as shown in Figure 4. As can be seen from the figure, upper and lower semicircular ring external diameter r₁、r₂Impedance matching on antenna and resonance point have all produced certain impact, as first annulus external diameter r₁When increase, reflectance factor S₁₁The degree of depth is deepened, and impedance matching is become better and better, and resonance point is with second annulus external diameter r₂Diminish and certain deviation occurs to the right. Work as r₁＝13mm、r₂When=9mm, can obtain good impedance matching and bandwidth, S₁₁The impedance bandwidth of≤-10dB covers 2.7GHz～13.6GHz, meets design requirement.

To coupling aperture r₃Analyze r₃The reflectance factor S obtaining while getting different values₁₁Curve as shown in Figure 5. As can be seen from the figure, the coupling aperture forming in the middle of two annulus radiating elements can change radiating element surface current direction, causes the skew of each resonance point, improves the bandwidth of operation of antenna. Along with r₃Increase, the Frequency point of antenna increases, reflectance factor S₁₁The curve degree of sinking reduces, impedance matching variation, and resonance point is also along with r₃Increase certain deviation has occurred left. Work as r₃When=4mm, can obtain good bandwidth and impedance matching, S₁₁The impedance bandwidth of≤-10dB covers 2.6GHz～13.4GHz.

To oval recess radius r₄Analyze r₄The reflectance factor S obtaining while getting different values₁₁Curve as shown in Figure 6. As can be seen from the figure, oval recess radius r₄Variation larger on impedance bandwidth impact, along with r₄Increase, reflectance factor S₁₁The curve heighten degree that sink, the bandwidth of low frequency end increases, and there is certain deviation to the right in front end resonance point, works as r₄When=18mm, front end produces mismatch phenomenon, and bandwidth is produced to certain influence, works as r₄When=16mm, can obtain good impedance bandwidth, S₁₁The impedance bandwidth of≤-10dB covers 2.4GHz～13.7GHz.

Fig. 7 is the impedance frequency characteristic simulation result of this antenna, as can be seen from the figure, in wider frequency range interval, the input impedance of antenna is near match point, when low frequency, present induction reactance characteristic, mainly that oval recess plays capacitive reactance effect with the reactance that gap and two ends, the floor bossing of two annulus radiating elements are introduced during due to low frequency, and the reactive component of two annulus radiating elements is changed between capacitive reactance and induction reactance, need oval recess to have contrary Changing Pattern with the reactive component that gap and two ends, the ground projection of radiating element are risen with change of frequency. Therefore, introduce oval concave floorboard radiating element is increased with the vertical and parallel relation of ground plane, be equal to the increase of electric capacity variable and inductance variable, be more conducive to the reactive component compensation of antenna.

By above analysis, draw the main structure parameters of this antenna: r₁＝13mm，r₂＝9mm，r₃＝4mm，r₄＝16mm，l₁＝21mm，l₂＝16.5mm，w₁＝2.3mm，w₂＝4.2mm。

Test at microwave dark room, use the reflectance factor S of vector network analyzer test antenna₁₁Curve, the S of actual measurement antenna₁₁Curve and simulation result contrast as shown in Figure 8, variation tendency from the impedance of antenna with frequency, measured value and simulation value have kept good uniformity, substantially conform to simulation value at low frequency end measured value, along with the increase of frequency, there is certain deviation in measured value and simulation value, and there is fluctuation, resonance point departs from simulation value, mainly because effective wavelength corresponding to front end diminishes, manual welding feed part is introduced certain error, has reduced the standing-wave ratio of input port, causes some key parameter generation minor variations. The frequency range measured result of be less than-10dB of reflectance factor is 2.8GHz～13.5GHz, and antenna has broadband character, and resonance characteristic is comparatively obvious, and resonance power or the adjustment resonance location of the adjacent resonance point of balance can increase bandwidth.

Antenna is 3,6 in frequency, gain pattern when 9GHz as shown in Figure 9, Figure 10, the antenna pattern of antenna is better, E surface radiation directional diagram is approximately " ∞ ", shape is irregular slightly a bit, H surface radiation directional diagram is similar to omnidirectional, along with the rising of frequency, directional change is little, the size of antenna becomes large with respect to wavelength, CURRENT DISTRIBUTION is approximately the aerial array of multiple miniature antenna compositions, causes that radiation field stack occurs and produces secondary lobe, in the time of high frequency f=9GHz, E surface radiation directional diagram produces secondary lobe, and H surface radiation directional diagram keeps omnidirectional radiation characteristic substantially.

Experimental result shows, can improve the impedance bandwidth of antenna by the size of adjusting two annulus radiating elements, grading structure microstrip line, oval flute profile floor. Radiating element is carried out to two annulus modular design, adjust feed structure, adopt oval recess structure simultaneously in ground plane upper end, adjust the gap of oval recess and radiant body, significantly broadening antenna impedance bandwidth, antenna impedance bandwidth covers 2.8～13.5GHz and reaches 4.82: 1, and actual measurement and simulation result coincide good, its return loss is lower, radiation characteristic is stable, has wider impedance bandwidth, simple in structure, easy to process, be applicable to short distance super broad band radio communication.

Claims (1)

1. the two annular planar monopole antennas of ultra broadband, by two circular ring-shaped radiation unit (1), grading structure microstrip line (2), oval flute profile floor, the back side (3) and coaxial fitting (4) form, it is characterized in that: two circular ring-shaped radiation unit (1) adopt the concentric semicircles ring combining structure that internal diameter is identical and external diameter is different, in the middle of two circular ring-shaped radiation unit, form a circular port, grading structure microstrip line (2) lower end is connected with coaxial fitting (4) inner wire, be convenient to external coaxial cable, on the rectangle floor of lower end, the medium substrate back side, be provided with taking radiating element center as the center of circle, axial ratio is 1.3 oval recess, form oval flute profile floor (3), and between radiating element, be provided with certain gap.