CN103730721B - Based on the bow-tie slot of coplanar wave guide feedback - Google Patents

Abstract

The invention relates to a miniaturized broadband antenna, in particular to a butterfly slot antenna based on coplanar waveguide feeding, which includes a ground plate (1), a dielectric substrate (2), and the ground plate (1) etches a butterfly slot (3). The center of the dielectric substrate is the coordinate origin, and the two butterfly-shaped gaps are left-right symmetrical with respect to the X-axis. An asymmetrical coplanar waveguide is used for feeding, and a ring-shaped conduction band (7) is loaded inside the butterfly-shaped gap. By lengthening and bending one of the feeding slots, the impedance matching of the antenna is improved, and the bandwidth of the antenna is improved; a triangular annular conduction band is loaded inside the butterfly slot, which improves the low-frequency gain of the antenna and makes the antenna within the working frequency band The gain is flatter. The antenna works at 2.76-8.1GHz, the relative bandwidth reaches 150.84%, the gain in the working frequency band is greater than 1.5dBi, and the maximum gain can reach 5.53dBi. The invention is simple in design and easy to process, and is suitable for broadband wireless communication systems.

Description

Bowie Slot Antenna Based on Coplanar Waveguide Feeding

technical field

The invention relates to wireless communication technology, in particular to a miniaturized broadband antenna in a wireless communication system, in particular to a butterfly slot antenna based on coplanar waveguide feeding.

Background technique

With the rapid development of wireless communication, global positioning system, satellite communication, personal communication and other communication systems put forward higher requirements for the broadband and miniaturization of the antenna. The broadband antenna can cover multiple frequency bands, which can reduce the number of antennas required by the communication system, thereby reducing system cost and weight.

Butterfly-shaped slot antenna has received extensive attention due to its advantages of wider bandwidth and smaller size. The structure of a butterfly antenna fed by a traditional coplanar waveguide (CPW) is shown in Figure 1. The length and width of the slots on both sides of the central conduction band of the CPW are the same. Through the continuous efforts of many scholars, a variety of methods for widening the bandwidth have emerged. For example, combining the butterfly antenna with the array antenna can obtain a wide bandwidth of 10.32% (Gu Donghua et al., coplanar waveguide fed butterfly aperture dipole slot antenna, microwave Journal of the Chinese Academy of Sciences, 27(2007), 25-28); using a rectangular-sided butterfly slot, an impedance bandwidth of 67% was obtained (Su Xiaoen et al., Simulation Analysis and Design of Coplanar Waveguide-fed Broadband Rectangular-sided Butterfly Slot Antenna, Microwave Journal, 22(2006), 35-39). The impedance bandwidth achieved by the prior art is relatively small.

Contents of the invention

The object of the present invention is to provide a miniaturized, ultra-broadband, stable-gain butterfly-shaped slot antenna based on asymmetric coplanar waveguide feeding, which not only has good broadband impedance characteristics, but also has relatively flat gain characteristics, and the antenna area does not increase.

The idea of the present invention is as follows: the present invention is mainly composed of a butterfly-shaped slot and an asymmetric coplanar waveguide that feeds power to it. By adjusting the length of one of the slots in the coplanar waveguide, the asymmetric coplanar waveguide formed can adjust the antenna impedance and improve its Impedance matching allows multiple separated frequency bands to be connected together, resulting in an ultra-wideband antenna.

The present invention is realized by adopting the following technical solutions:

A butterfly-shaped slot antenna based on coplanar waveguide feeding, including a ground plane, a dielectric substrate, and a butterfly-shaped slot etched on the ground plane. The center of the dielectric substrate is selected as the coordinate origin. The waveguide feed, the coplanar waveguide feed is an asymmetric coplanar waveguide feed; the butterfly slot is loaded with a ring-shaped conductive tape.

The asymmetric coplanar waveguide is composed of a central guide strip, a first slot and a second slot, and the first slot is elongated and bent to form an asymmetric coplanar waveguide.

The annular guide belt is a triangular annular guide belt.

Compared with the prior art, the present invention has the following advantages: by adopting asymmetric coplanar waveguide feeding, the impedance characteristic of the antenna is improved, the bandwidth of the antenna is greatly improved, and the butterfly slot antenna can work at 2.76-8.1GHz, relatively The bandwidth reaches 150.84%. By loading the triangular circular conduction band in the butterfly slot, the gain characteristics of the antenna are improved, and the gain of the antenna in the working frequency band is flatter.

Description of drawings

Figure 1 is a schematic diagram of the traditional coplanar waveguide fed butterfly slot antenna structure

Fig. 2 is a structural schematic diagram of a bowtie slot antenna fed by an asymmetric coplanar waveguide according to the present invention

In the figure: 1-ground plate, 2-dielectric substrate, 3-butterfly slot, 4-, 5-the first slot and the second slot of the asymmetric coplanar waveguide, 6-the center conduction band of the asymmetric coplanar waveguide, 7- Triangular ring guide

Fig. 3 is S ₁₁ of the broadband antenna of the present invention

Fig. 4 is the impedance characteristic of broadband antenna of the present invention

Fig. 5 is the gain of broadband antenna described in the present invention

Fig. 6 is the pattern of broadband antenna described in the present invention at 4GHz and 6GHz

detailed description

Below in conjunction with accompanying drawing, the embodiment of the present invention is described in detail:

As shown in Figure 2, the bowtie slot antenna fed by an asymmetric coplanar waveguide according to the present invention includes a ground plate 1 and a dielectric substrate 2, the center of the dielectric substrate is selected as the coordinate origin, and the ground plate 1 is etched as The butterfly slot 3 of the radiating unit and the asymmetric coplanar waveguide that feeds the butterfly slot, the butterfly slot 3 is symmetrical about the X axis, in order to improve the low frequency gain, a triangular annular conduction band 7 is loaded in the butterfly slot; The symmetric coplanar waveguide is composed of a central conductive strip 6 and slots 4 and 5 on both sides, wherein the slot 4 on the right is bent and increased in length, forming an asymmetric coplanar waveguide with unequal lengths of the slots on both sides.

Accompanying drawing 3 has shown the frequency characteristics (curve 2 among the figure) of the bowtie slot antenna S ₁₁ that adopts asymmetric coplanar waveguide feeding, wherein the abscissa represents the frequency variable, and the unit is GHz, and the ordinate represents the amplitude variable, and the unit is dB. For the convenience of comparison, the figure also shows the S ₁₁ of the antenna fed by the traditional coplanar waveguide (curve 1 in the figure). It can be seen that for the traditional antenna fed by the coplanar waveguide, there are three resonant frequencies f ₁ =3.28 GHz, f ₂ =7.0 GHz, f ₃ =10.66 GHz. The three working frequency bands are separated from each other to form three separate frequency bands. When feeding with asymmetric coplanar waveguide, the lengthening of the feeding slot improves the impedance matching of the antenna. The three frequency bands are connected together to make the antenna's working frequency band It is 2.76～8.1GHz, the absolute bandwidth is 5.34GHz, and the relative bandwidth is 150.84%, which is greatly widened.

Accompanying drawing 4 shows the impedance characteristics of the bowtie slot antenna fed by an asymmetric coplanar waveguide (curve 2 in the figure), and compares it with the result when fed by a traditional coplanar waveguide (curve 1 in the figure). In the figure, the abscissa represents the frequency variable, and the unit is GHz, and the ordinate represents impedance, and the unit is ohm. When the traditional coplanar waveguide is used for feeding, except for the resonance point, the impedance of the antenna is high at other frequencies, up to 146Ω. After the slot (4) on the right is lengthened, the impedance of the antenna is reduced to within the range of 2.76-8.1GHz. Near 50 ohms, so that the impedance matching of this working range is improved.

Accompanying drawing 5 shows the gain characteristics of the butterfly slot antenna fed by traditional coplanar waveguide and asymmetric coplanar waveguide (respectively curves 1 and 2 in the figure), and the results after loading the triangular annular guide band (Curve 3 in the figure) for comparison. In the figure, the abscissa represents the frequency variable, and the unit is GHz, and the ordinate represents the gain, and the unit is dBi. It can be seen that before loading the triangular annular conduction strip, compared with the antenna fed by the traditional coplanar waveguide, the gain of the antenna at other frequencies except for 4-5.7 GHz after using the asymmetric coplanar waveguide feed The gain has been reduced. After loading the loop guide band, the gain in the 2-7GHz frequency band has been improved, especially at 3GHz, the antenna gain has been increased from 0.8dBi to 2.4dBi, so that the gain in the entire working frequency band is more flat.

Accompanying drawing 6 shows the directivity pattern of the bowtie-shaped slot antenna that adopts asymmetric coplanar waveguide feeding, wherein figure (a) is the directivity pattern at 4GHz, and figure (b) is the directivity pattern at 6GHz, among the figure, curve 1 is the H-plane main polarization, curve 2 is the H-plane cross polarization, curve 3 is the E-plane main polarization, and curve 4 is the E-plane cross polarization. It can be seen that the main polarization pattern of the E plane is in the shape of "8", which has a certain directionality, and the cross polarization is relatively large. The radiation of the main polarization pattern of the H plane is better at 0°~180°, and the cross polarization is larger. As the frequency increases, the main polarization pattern of the antenna is basically undistorted.

Claims (3)

1. the bow-tie slot based on coplanar wave guide feedback, comprise ground plate (1), medium substrate (2), ground plate (1) etching butterfly gap (3), medium substrate center is selected to be the origin of coordinates, butterfly gap is symmetrical about X-axis, adopt coplanar wave guide feedback, it is characterized in that:

Described coplanar wave guide feedback is asymmetrical coplanar wave guide feedback;

Inside, described butterfly gap is loaded with annular conduction band (7).

2. a kind of bow-tie slot based on coplanar wave guide feedback as claimed in claim 1, it is characterized in that, described asymmetric coplanar wave-guides is made up of center conduction band (6) and the first gap (4) and the second gap (5), and the first gap (4) lengthen and bend.

3. a kind of bow-tie slot based on coplanar wave guide feedback as claimed in claim 1, is characterized in that, described annular conduction band (7) is triangle annular conduction band.