CN107221746A - A kind of Broadband circularly polarized antenna based on V-type gap - Google Patents

Abstract

The invention discloses a broadband circularly polarized antenna based on a V-shaped slot, comprising a dielectric substrate, a Z-shaped microstrip feeder printed on the back of the dielectric substrate, the Z-shaped microstrip feeder connected to a stub, and a front side of the dielectric substrate The radiation patch is set, and the opening slit and the closing slit are etched on the radiating patch, and the opening slit and the closing slit are both V-shaped right-angled slits and are symmetrical about the vertical midline of the radiation patch. The broadband circularly polarized antenna of the present invention , has the characteristics of simple structure, small size, easy adjustment, and wide circular polarization bandwidth.

Description

A Broadband Circularly Polarized Antenna Based on V-shaped Slot

technical field

The invention relates to a wideband circularly polarized antenna, in particular to a wideband circularly polarized antenna based on a V-shaped slot.

Background technique

Due to the unique advantages of circularly polarized antennas in mobile communications, it has received great attention. Since the circularly polarized antenna is insensitive to the direction of rotation, it can avoid the problem of signal attenuation caused by the traditional linearly polarized antenna when the polarization is mismatched. Linearly polarized waves are prone to polarization deflection and attenuation in the transmission environment, while circularly polarized waves will reverse when encountering obstacles. Anti-interference ability and anti-rain and fog ability, and are widely used in civilian and military fields. Due to the unique anti-interference and anti-fading characteristics of circularly polarized antennas, they are widely used in communication systems such as GPS (Global Positioning System), RFID (Radio Frequency Identification), and WLAN (Wireless Metropolitan Area Network).

The difficulty in designing a wideband circularly polarized antenna lies in the impedance and axial ratio to achieve broadband characteristics while maintaining the miniaturization characteristics of the antenna. Common circular polarization techniques include the following: cutting the corners of the radiation patch, introducing perturbation units into square slots, crossed dipole antennas, and feed networks with 90° phase difference. However, these methods have the disadvantages of large size and narrow bandwidth. Conventional slot antennas are often half-wavelength in size, while open slot antennas are typically quarter-wavelength in size. Therefore, designing circularly polarized antennas with open slots can achieve broadband while maintaining a small size.

Contents of the invention

In order to overcome the shortcomings and deficiencies of the prior art, the present invention provides a broadband circularly polarized antenna based on a V-shaped slot. The circularly polarized antenna has the advantages of simple structure, easy fabrication, wide frequency band, and small size.

The present invention adopts following technical scheme:

A broadband circularly polarized antenna based on a V-shaped slot, comprising a dielectric substrate, a Z-shaped microstrip feeder is printed on the back of the dielectric substrate, the Z-shaped microstrip feeder is connected to a stub, and a radiation patch is arranged on the front of the dielectric substrate , the opening slit and the closing slit are etched on the radiation patch, and the opening slit and the closing slit are both V-shaped right-angled slits and symmetrical about the vertical midline of the radiation patch.

The Z-shaped microstrip feeder is composed of three microstrip lines, which are respectively the first microstrip line, the second microstrip line and the third microstrip line, and the first microstrip line and the third microstrip line are respectively vertical At both ends of the second microstrip line, the stub line is vertically connected to the second microstrip line.

The length of the opening slit is about 1/2 wavelength of the working frequency of the antenna.

The Z-shaped microstrip feeder couples and feeds the opening gap through the corresponding position on the side near the apex of the opening gap corresponding to the back side of the dielectric substrate.

The width of the open slit is greater than the width of the closed slit.

The size of the radiation patch is the same as that of the dielectric substrate.

Beneficial effects of the present invention:

A wide-band circularly polarized antenna based on a V-shaped slot disclosed in the present invention adopts the structure of an open slot, which effectively reduces the size of the antenna;

The present invention discloses a broadband circularly polarized antenna based on a V-shaped slot, in which stubs are added to the Z-shaped microstrip feeder to form multi-frequency resonance, effectively increasing the impedance bandwidth of the antenna;

The invention discloses a wideband circularly polarized antenna based on a V-shaped slot, which introduces a V-shaped closed slot into the patch, so that the orthogonal electric field can achieve a 90° phase difference on the broadband, forming a broadband circularly polarized.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a structural dimension diagram of the present invention, and the unit is millimeter;

Fig. 3 is the return loss figure of embodiment simulation among Fig. 1;

Fig. 4 is an axial ratio diagram of the simulation of the embodiment of the present invention.

detailed description

The present invention will be described in further detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example

As shown in Figure 1-Figure 2, a broadband circularly polarized antenna based on a V-shaped slot includes a dielectric substrate, and a Z-shaped microstrip feeder is printed on the back of the dielectric substrate, and the Z-shaped microstrip feeder is composed of three microstrips The lines are composed of the first microstrip line 1a, the second microstrip line 1b and the third microstrip line 1c, the first and the third microstrip lines are vertically connected to the second microstrip line respectively, and the stub Line 2 is connected to the second microstrip line, the first microstrip line is connected to the left edge of the dielectric substrate, and one side of the third microstrip line is connected to the upper edge of the dielectric substrate.

The radiation patch 6 is printed on the front of the dielectric substrate. The size of the radiation patch is the same as that of the dielectric substrate. The radiation patch is etched with an opening gap 4 and a closing gap 5, and the two gaps are V-shaped right angles. Slit, in this embodiment, the length and width of the V-shaped opening slit are greater than the length and width of the V-shaped closed slit, the opening direction of the opening slit and the closed slit are the same, both open upward, and are symmetrical about the vertical midline of the radiation patch. The two sides of the V-shaped opening slit and the V-shaped closed slit are parallel to each other. In the embodiment, the closed slit is located below the opening slit, and its vertices are on the same straight line. The length of the opening slit is 1/2 wavelength of the operating frequency of the antenna.

The position on the left side of the apex of the opening gap is the specific feeding position of the opening gap, and the Z-shaped microstrip feeder is printed on the corresponding position on the back of the dielectric substrate to couple and feed the opening gap, which can initially stimulate low-frequency resonance and circular poles. change.

The first is to achieve low-frequency resonance and obtain preliminary circular polarization. The opening slit 4 is etched on the radiation patch 6, and the Z-shaped microstrip feeder passes through the specific position 3 of the V-shaped opening slit on the back of the dielectric substrate to couple and feed the slit. Low-frequency resonance and circular polarization can be initially excited.

The Z-shaped microstrip feeder is composed of three microstrip lines, which are respectively the first microstrip line, the second microstrip line and the third microstrip line, and the first microstrip line and the third microstrip line are respectively vertical At both ends of the second microstrip line, the stub line is vertically connected to the second microstrip line, as shown in Figure 1, the second microstrip line is located at the back of the dielectric substrate corresponding to the opening gap, and the stub line perpendicular to the second microstrip line.

Secondly, multi-frequency resonance is introduced to widen the impedance bandwidth, and the stub 2 is connected to the Z-shaped microstrip feeder, thereby introducing multi-frequency resonance and effectively increasing the impedance bandwidth.

Finally, the circular polarization characteristics of the entire frequency band are realized. The V-shaped closed slit is etched on the radiation patch 6, so that the mutually orthogonal electric fields on the patch achieve a 90° phase difference, so that the axial ratio in the entire frequency band is less than 3dB, that is, circular polarization is achieved.

In order to verify the effectiveness of this scheme, a specific example is given below to illustrate.

In this example, an FR4 dielectric substrate with a relative permittivity of 4.4, a loss tangent of 0.02, and a thickness of 0.8mm is selected, and the plane size of the dielectric substrate is 44×42mm. The length of the stub is 5.6mm, the width of the V-shaped opening gap is 7.2mm, the width of the closed gap is 3mm, and the length is 16.5mm. The inner conductor of the coaxial line is connected to the microstrip feeder, and the outer conductor is connected to the radiation patch. The specific dimensions are shown in Table 1, in mm:

Table 1

L W h L1 L2 L3 L4 L5 42 44 0.8 12.6 7.4 16.5 14 5.5 L6 L7 L8 L9 L10 W1 W2 W3 23.2 6.3 5.6 11.8 19 twenty two 7.2 3 W4 W5 W6 W7 W8 2.9 4.2 2.3 2 3.6

The simulated return loss and axial ratio results of the circularly polarized antenna fabricated with the dimensions shown in Figure 2 above are shown in Figure 3 and Figure 4, respectively. As can be seen from the figure, the circularly polarized antenna has a return loss of less than -10dB within 2.19-4.6GHz, an axial ratio of less than 3dB, and a relative bandwidth of 71%. The broadband circularly polarized antenna of the present invention has simple structure, small size, Easy to adjust, wide circular polarization bandwidth, etc., suitable for high-speed data communication scenarios such as RFID, WLAN, and WIMAX.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the embodiment, and any other changes, modifications, substitutions and combinations made without departing from the spirit and principle of the present invention , simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims (6)

1. a kind of Broadband circularly polarized antenna based on V-type gap, it is characterised in that including medium substrate, the medium substrate back of the body Z-type microstrip feed line is printed in face, and the Z-type microstrip feed line connects stub, and the medium substrate front sets radiation patch, described In radiation patch etch aperture slots and closure gap, the aperture slots and closure gap be V-type right angle gap and on The vertical center line of radiation patch is symmetrical.

2. Broadband circularly polarized antenna according to claim 1, it is characterised in that the Z-type microstrip feed line is by three micro-strips Line is constituted, respectively the first microstrip line, the second microstrip line and the 3rd microstrip line, the first microstrip line and the 3rd the microstrip line difference Perpendicular to the two ends of the second microstrip line, the stub is vertical with the second microstrip line to be connected.

3. Broadband circularly polarized antenna according to claim 1, it is characterised in that the length of the aperture slots is antenna work / 2nd wavelength of working frequency.

4. Broadband circularly polarized antenna according to claim 1, it is characterised in that the Z-type microstrip feed line is opened described in Mouth gap carries out couple feed close to summit side correspondence medium substrate back side opposite position to aperture slots.

5. Broadband circularly polarized antenna according to claim 1, it is characterised in that the width of aperture slots is more than closure gap Width.

6. Broadband circularly polarized antenna according to claim 1, it is characterised in that the size of the radiation patch and medium base The size of plate is identical.