CN104319473A - Ultra-wideband tri-trap antenna - Google Patents

Abstract

An ultra-wideband tri-trap antenna comprises a dielectric substrate. The upper surface and the lower surface of the dielectric substrate are respectively coated with a radiation patch and a conductive layer. The radiation patch comprises a patch front end in the diameter decreasing and a micro-strip feeder line connected to the tail of the patch front end. The conductive layer comprises a base plate with arc-shape edge and a split ring reflector arranged above the base plate with arc-shape edge. The arc-shaped edge of the base plate with arc-shape edge protrudes upwards. The base plate with arc-shape edge is provided with a U-shaped groove with a downward opening. The split ring reflector comprises an upper ring with a rectangular opening, a lower ring with a rectangular opening and symmetrical branches arranged outside the rings. According to the ultra-wideband tri-trap antenna, straight grooves in both inner side edges of the U-shaped groove and wave grooves outside the U-shaped groove are used for trapping the frequency band of a wireless local area network and the C-band respectively, and the non-base plate area at the bottom of the antenna is used for trapping the downlink band of the X-band through the split ring reflector with double openings and the branches. The ultra-wideband tri-trap antenna has the advantages of being novel in overall structure, small in size, high in trap quantity, good in trap form and the like.

Description

A UWB Triple-Notch Antenna

technical field

The invention relates to an ultra-wideband antenna, in particular to an ultra-wideband triple-notch antenna.

Background technique

The microstrip antenna has the advantages of small size, simple structure, and easy integration, so the microstrip antenna has a wide range of applications. In recent years, research on ultra-wideband (Ultra-Wideband) antennas has attracted more and more attention, especially after the FCC specified the 3.1-10.6GHz frequency band as a civilian frequency band in 2002, and developed ultra-wideband antennas for this frequency band. Subsequently, there is overlap with some existing frequency bands, such as wireless metropolitan area network (WiMax, 3.3-3.6GHz), C-band satellite communication (3.7-4.2GHz), wireless local area network (WLAN, 5.2-5.8GHz), X Band satellite communication (7.25-7.75GHz, 7.9-8.4GHz), etc., so the practicability of the ultra-wideband notch antenna is very strong.

Ultra-wideband notch antenna has achieved a lot of achievements in recent years, the technology is becoming more and more mature, and the existing theory has also been fully applied. However, there are relatively few applications after further optimization of existing theories. Ultra-wideband antenna frequency bandwidth, in which there are many overlapping defined and widely used frequency bands, so ultra-wideband multi-notch antennas have strong practical research significance, and can simultaneously trap C-band, wireless local area network (WLAN) and X-band downlink The antenna of the frequency band has a stronger practical significance. The miniaturization degree of an ultra-wideband antenna is one of the important indicators to measure the performance of the antenna. It will become the development trend of the future ultra-wideband antenna to achieve better multi-notch effect under the condition of smaller size.

Contents of the invention

The object of the present invention is to provide an ultra-wideband triple-notch antenna with small size, simple structure, wide impedance bandwidth and suppressing three waves at the same time.

In order to achieve the above object, the technical solution adopted by the present invention is: comprising a dielectric substrate, the upper and lower surfaces of the dielectric substrate are respectively covered with a radiation patch and a conductive layer; the radiation patch includes a front end of the patch whose diameter gradually decreases And the microstrip feeder connected to the front end of the patch; the conductive layer includes a curved edge floor and a split ring reflector arranged above the curved edge floor, the curved edge of the curved edge floor protrudes upwards, and the curved edge A U-shaped groove with a notch downward is arranged on the edge floor, and the split ring reflector includes two circular rings with rectangular notches at the upper and lower places and symmetrical branches arranged outside the circular ring.

The dielectric substrate is an FR4 dielectric substrate.

The radiation patch and the conductive layer are connected through SMA joints.

The front end of the patch is a gradient structure formed by successively cutting off the triangular part and the trapezoidal part from the front end of the rectangular patch with symmetrical left and right sides.

The microstrip feeder is a stepped rectangular structure.

The impedance of the input end of the microstrip feeder is 50 ohms.

The U-shaped grooves are two U-shaped grooves arranged in parallel on the arc-shaped edge floor.

The groove length of described U-shaped groove is determined by the following formula:

where _εeff is the effective permittivity, _εr is the relative permittivity of the substrate, L- _slot is the length of the inverted U-shaped slot, and f- _notch is the frequency that needs to be notched.

The outer layer of the U-shaped groove is provided with a wavy U-shaped groove in which the vertical grooves on both sides are wavy.

Two pairs of branches are arranged symmetrically on the outside of the ring of the split ring reflector, respectively including the first branch arranged horizontally, and the included angle between the first branch and the horizontal direction is 30° under the first branch, and the length is longer than the first branch. The second branch of a branch.

Compared with the prior art, the diameter of the front port of the radiation patch on the upper surface of the dielectric substrate of the present invention is gradually reduced from a large gradient, and combined with the microstrip feeder connected to its tail to form a wine glass-shaped structure, combined with an upwardly protruding arc The edge floor makes the antenna transition smoothly from one frequency resonance mode to another frequency resonance mode through the structural gradient, ensuring good impedance matching in a wider frequency band; in addition, the split ring reflector of the present invention has two upper and lower There are rectangular gaps respectively, which replace the inner and outer double-layer ring structure of the traditional split ring reflector. The notch effect can be well adjusted through the ring and the symmetrical branches arranged outside the ring, so that the final return loss is -5dB above. The invention has the advantages of simple structure, large bandwidth, large number of notches, good shape of notches, low cost and easy integration, etc., and can meet the requirements of the ultra-wideband communication system.

Further, the gradual change structure of the front end of the patch of the present invention is a gradual change structure left by cutting off the triangular part and the trapezoidal part from the rectangular patch end successively, which are symmetrical on the left and right sides. Compared with the traditional circular arc or oblique gradient, this structure The size of the cut-off part is adjustable, and the adjustment of the initial frequency point at the notch is obvious, which makes the antenna notch more accurate.

Furthermore, the microstrip feeder of the present invention has a stepped rectangular structure, and an impedance converter is formed by two sections of stepped rectangular microstrips with different widths, so that the small-area radiation patch can achieve impedance matching in the side-feed mode.

Further, the U-shaped grooves of the present invention are two U-shaped grooves arranged in parallel on the arc-shaped edge floor, and the two U-shaped straight grooves with the gap downwards generate wireless LAN frequency band traps, which are similar to the single U-shaped groove structure. ratio, which helps to improve the accuracy of the notch.

Further, in the present invention, the outer layer of the U-shaped groove is also provided with a wavy U-shaped groove in which the vertical grooves on both sides are wavy, so as to trap waves in the C-band. The wave groove makes full use of the length of the floor, which can better achieve the trapping effect and make the antenna miniaturized.

Further, two pairs of branches are arranged symmetrically on the outer side of the ring of the split ring reflector of the present invention, through the first branch arranged horizontally, and the included angle between the first branch and the horizontal direction is 30°, and the length is longer than the first branch. The second branch of one branch, combined with the upper and lower rings with rectangular notches respectively, produces a notch in the downlink frequency band of the X-band, which increases the return loss at this place and improves the notch effect.

Description of drawings

Fig. 1 is a schematic structural view of the upper patch of the present invention;

Fig. 2 is the cutting schematic diagram of the patch front end of the present invention;

Fig. 3 is a structural schematic diagram of the lower defective ground and the ring reflector with branch cracks of the present invention;

Fig. 4 is a schematic diagram of return loss simulation and actual measurement results of the present invention;

Fig. 5 is a schematic diagram of simulation and measured gain of an embodiment of the present invention;

In the attached drawings: 1. SMD front end; 2. Microstrip feeder; 3. Curved edge floor; 4. U-shaped groove; 5. Wave U-shaped groove; 6. Split ring reflector; 7. Rectangular notch; 8. The first branch; 9. The second branch.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, the patch antenna of the present invention is printed ^on an FR4 dielectric substrate with a size of 35×17×1.6mm, and the upper and lower surfaces of the dielectric substrate are respectively covered with a radiation patch on the upper surface and a conductive layer on the lower surface, and the material is silver . The radiation patch and the conductive layer are connected through SMA connectors; the radiation unit on the upper surface is a wine glass-shaped patch, and the radiation patch includes the front end 1 of the patch whose aperture decreases from a large gradient and a stepped rectangular microstrip connected to the tail of the front end 1 of the patch. The input impedance of the feeder 2 and the microstrip feeder 2 is 50 ohms, and the front end of the patch 1 is a gradient structure left by cutting the triangular part and the trapezoidal part from the front end of the rectangular patch symmetrically on both sides.

Referring to Fig. 2, the patch front end 1 of the present invention obtains a gradient structure by cutting off the uppermost triangle and the two lower trapezoids symmetrically on the left and right sides during the production process. The dotted line in the figure is the cutting line. The advantage of forming the gradient structure is that the size of the cut-off part can be adjusted, so that the accuracy of the notch can be improved.

Referring to Fig. 3, the bottom surface of the dielectric plate of the present invention has an arc-shaped edge floor 3 and a split ring reflector 6 with double openings with branches, the split ring reflector 6 is arranged above the arc-shaped edge floor 3, and the arc-shaped edge of the arc-shaped edge floor 3 Protruding upwards, the arc-shaped edge floor 3 is provided in parallel with two inner U-shaped grooves 4 with notches downward, and the outer layer of the U-shaped groove 4 is also provided with wavy U-shaped grooves with wavy vertical grooves on both sides 5. The split ring reflector 6 includes a circular ring with rectangular notches 7 at the upper and lower places and symmetrical branches arranged outside the circular ring, wherein the first branch 8 is arranged horizontally, and the second branch 9 is arranged on the first branch 8 The angle between the bottom and the horizontal direction is 30°, and the length is longer than the first branch 8.

Referring to FIG. 4 , the antenna with the structure of the present invention has a bandwidth greater than 3.1-10.6 GHz with return loss ≤ -10 dB after actual measurement, and realizes notches at three places: 3.7-4.2 GHz, 5.15-5.825 GHz and 7.25-7.75 GHz.

Referring to Fig. 5, after the actual measurement of the structure antenna of the present invention, the antenna maintains a relatively stable gain within the entire working frequency band, and the gain is between 2-4dBi, while near the center frequency of the three notches, the antenna gain drops significantly to -4dBi Left and right, the interference of the three-segment wave is effectively suppressed.

The lower floor of the present invention forms a defect structure by opening a pair of parallel U-shaped straight grooves and a pair of parallel U-shaped wave grooves on its outer layer, respectively trapping WLAN (5.2 to 5.8GHz) and C-band (3.7 to 4.2GHz) , the double U-shaped slot is better than the single-slot notch. Compared with the straight slot, the effective slot length ratio of the wave U-shaped slot is 1.57:1, which is convenient to reduce the size of the antenna; a non-floor area at the bottom of the antenna is designed with a Dual split-ring reflectors trapping the X-band downlink (7.25 to 7.75GHz). The double-opening structure replaces the complex structure of double-layer openings inside and outside the traditional split ring reflector, and the two pairs of branches can improve the trapping effect in this band. The antenna of the present invention has the advantages of simple overall structure, low cost, small size, large number of wave notches, good shape of wave notches, and the like.

Claims (10)

1. An ultra-wideband tri-notch antenna, comprising: the radiation patch comprises a dielectric substrate, wherein the upper surface and the lower surface of the dielectric substrate are respectively covered with a radiation patch and a conducting layer; the radiating patch comprises a patch front end (1) with the caliber gradually reduced from large to small and a microstrip feeder line (2) connected to the tail part of the patch front end (1); the conducting layer include arc edge floor (3) and set up split ring reflector (6) in arc edge floor (3) top, the arc edge on arc edge floor (3) upwards protrudes, is provided with U type groove (4) that the breach is decurrent on arc edge floor (3), split ring reflector (6) are including two upper and lower punishment do not seted up the ring of rectangle breach (7) and set up the symmetry minor matters in the ring outside.

2. The ultra-wideband tri-notch antenna of claim 1, wherein: the dielectric substrate is FR4 dielectric substrate.

3. The ultra-wideband tri-notch antenna of claim 1, wherein: the radiation patch is connected with the conducting layer through the SMA connector.

4. The ultra-wideband tri-notch antenna of claim 1, wherein: the patch front end (1) is a gradually-changed structure which is left by sequentially cutting off a triangular part and a trapezoidal part from the front end of the rectangular patch and is symmetrical on the left side and the right side.

5. The ultra-wideband tri-notch antenna of claim 1, wherein: the microstrip feeder line (2) is of a step variable-pitch structure.

6. The ultra-wideband tri-notch antenna of claim 1 or 5, wherein: the impedance of the input end of the microstrip feeder line (2) is 50 ohms.

7. The ultra-wideband tri-notch antenna of claim 1, wherein: the U-shaped grooves (4) are two U-shaped grooves which are arranged on the arc-shaped edge floor (3) in parallel.

8. The ultra-wideband tri-notch antenna of claim 1 or 7, wherein: the slotting length of the U-shaped slot (4) is determined by the following formula:

<math> <mrow> <msub> <mi>&epsiv;</mi> <mi>eff</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>&epsiv;</mi> <mi>r</mi> </msub> <mo>+</mo> <mn>1</mn> </mrow> <mn>2</mn> </mfrac> </mrow> </math>

wherein,_effis the effective dielectric constant of the dielectric material,_ris the relative dielectric constant, L, of the substrate_TroughIs the length of the inverted U-shaped groove, f_{Trapped wave}Is the frequency of the desired notch.

9. The ultra-wideband tri-notch antenna of claim 8, wherein: the outer layer of the U-shaped groove (4) is provided with a wave U-shaped groove (5) with vertical grooves at two side edges being wavy.

10. The ultra-wideband tri-notch antenna of claim 1, wherein: two pairs of branches are symmetrically arranged on the outer side of the circular ring of the split ring reflector (6), and respectively comprise a first branch (8) which is horizontally arranged, and a second branch (9) which is arranged below the first branch (8) and has an included angle of 30 degrees with the horizontal direction, and the length of the second branch is larger than that of the first branch (8).