CN110829038A - Broadband quasi-yagi antenna based on dielectric resonator - Google Patents

Abstract

The invention discloses a broadband quasi-yagi antenna based on a dielectric resonator, and belongs to the technical field of antennas. The microwave dielectric substrate comprises a substrate, wherein the substrate comprises an upper layer and a lower layer which are formed by microwave dielectric substrates; the dielectric resonator is characterized by also comprising a reflector, a dielectric resonator, a top layer director, a bottom layer director, a differential microstrip pair and a coplanar strip line; the reflector is printed on the lower layer of the substrate; the dielectric resonator is adhered to the upper surface of the substrate; the differential microstrip pair and the coplanar strip line are printed on the upper layer of the substrate; the differential microstrip pair is connected with the coplanar strip line; the coplanar strip line is connected with a metal bonding pad on the dielectric resonator to excite two resonance modes of the dielectric resonator, and the two resonance modes provide two resonance points of the antenna; the top layer director is printed on the upper layer of the substrate; the bottom layer director is printed on the lower layer of the substrate; the top layer director and the bottom layer director partially overlap; two resonance points of the dielectric resonator and the additional two resonance points provided by the bottom layer director and the top layer director form a broadband response of the antenna.

Description

A Broadband Quasi-Yagi Antenna Based on Dielectric Resonators

technical field

The invention specifically relates to a broadband quasi-Yagi antenna based on a dielectric resonator, which belongs to the technical field of antennas.

Background technique

With the development of wireless systems, end-fire antennas have received extensive attention due to their specific applications, such as point-to-point communication systems and radar imaging systems. To date, various types of end-fire antennas have been researched and developed around the world, including log-periodic antennas, horn antennas, surface wave antennas, and quasi-Yagi antennas. The log-periodic antenna has an ultra-wide bandwidth for end-fire radiation, but its end-fire gain is limited due to part of the radiation characteristics. The traditional metal horn antenna has high gain and large bandwidth, but it is bulky and heavy. In order to reduce the weight of the horn antenna, the researchers proposed a substrate-integrated waveguide horn antenna. However, since the open end of the substrate-integrated horn antenna is too thin, its working frequency band is narrow. Vivaldi antennas also have broadband characteristics, but cross-polarization and side lobes deteriorate rapidly as the operating frequency increases. Quasi-Yagi antenna is a typical parasitic element antenna, which has the advantages of simple structure, light weight, good directivity, and easy array formation, etc., and has a strong attraction. With the development of modern wireless communication systems, low-frequency spectrum resources are increasingly scarce, and high-frequency spectrum has abundant spectrum resources. As the transmitter and receiver of the wireless communication system, the working frequency of the antenna is rising. Traditional antennas using metal strips as radiating elements are limited by the skin effect and have more losses when operating at high frequencies. Because there is no surface current in the dielectric resonator, the loss of the antenna using the dielectric resonator as the radiating element will be relatively small at high frequencies. In the existing Yagi antenna based on dielectric resonators, only one main mode is excited in the radiating element formed by the dielectric resonator, so its working bandwidth is narrow and cannot meet the broadband and multi-frequency working requirements in modern wireless communication systems. Therefore, dielectric resonator-based quasi-Yagi antennas with broadband responses are urgently needed in modern wireless communication systems.

SUMMARY OF THE INVENTION

Aiming at the deficiencies in the prior art, the present invention proposes a dielectric resonator-based broadband quasi-Yagi antenna with high gain and stable gain in the passband.

In order to realize the above-mentioned purpose of the invention, the technical scheme adopted by the present invention is as follows:

A broadband quasi-Yagi antenna based on a dielectric resonator, comprising a substrate, the substrate comprising an upper layer and a lower layer formed by a microwave dielectric substrate; and a reflector, a dielectric resonator, a top layer director, a bottom layer director, a differential micrometer Strip pair and coplanar strip line; the reflector is printed on the lower layer of the substrate; the dielectric resonator is pasted on the upper surface of the substrate; the differential microstrip pair and the coplanar strip line are printed on the bottom layer of the substrate upper layer; the differential microstrip pair is connected to a coplanar stripline; the coplanar stripline is connected to a metal pad on the dielectric resonator to excite two resonance modes of the dielectric resonator; the two resonance modes provide the Two resonance points; the top layer director is printed on the upper layer of the substrate; the bottom layer director is printed on the lower layer of the substrate; the top layer director and the bottom layer director are partially overlapped ; The two resonance points of the dielectric resonator, the additional resonance point introduced by the bottom layer director and the additional resonance point introduced by the top layer director form an antenna broadband response.

Further as a preferred technical solution of the present invention, the length a of the dielectric resonator is about one third of the air wavelength corresponding to the center frequency of the antenna; the distance L1 between the dielectric resonator and the reflector is _about the center of the antenna. The frequency corresponds to a quarter of the wavelength of air.

As a further preferred technical solution of the present invention, the ratio a/b of the length a to the width b of the dielectric resonator is greater than 2, so as to obtain two resonance modes with close resonance frequencies.

As a further preferred technical solution of the present invention, the dielectric resonator is a rectangular dielectric resonator, which is made of a ceramic material with a relative permittivity greater than 45.

As a further preferred technical solution of the present invention, the length of the top layer director and the length of the bottom layer director are both slightly shorter than the length a of the dielectric resonator.

As a further preferred technical solution of the present invention, the relative permittivity of the substrate is less than 10.

As a further preferred technical solution of the present invention, the reflector is a metal ground; the metal ground, as the reflector of the antenna, also serves as the ground of the differential microstrip pair.

As a further preferred technical solution of the present invention, the center frequency of the antenna is 10.45 GHz, and the relative bandwidth is greater than 20%, that is, the reflection coefficient is less than -10 dB.

The broadband quasi-Yagi antenna based on the dielectric resonator according to the present invention adopts the above technical solution compared with the prior art, and has the following technical effects:

The present invention forms a broadband Yagi antenna with high gain and stable gain in the passband by combining the respective resonant frequencies of the dielectric resonator and the two directors. The two resonance points of the dielectric resonator and the resonance points of the two directors are composed of A broadband response that meets the multi-frequency operation requirements of modern wireless communications.

Description of drawings

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

Fig. 2 is the structural representation two of the present invention;

3 is a comparison diagram of simulation and actual measurement of the E surface of the present invention at a frequency of 9.48 GHz;

FIG. 4 is a comparison diagram of the simulation and actual measurement of the H plane of the present invention at a frequency of 9.48 GHz;

5 is a comparison diagram of simulation and actual measurement of the E surface of the present invention at a frequency of 10.34 GHz;

FIG. 6 is a comparison diagram of the simulation and actual measurement of the H plane of the present invention at a frequency of 10.34 GHz;

7 is a comparison diagram of simulation and actual measurement of the E surface of the present invention at a frequency of 11.42 GHz;

FIG. 8 is a comparison diagram of the simulation and actual measurement of the H surface of the present invention at a frequency of 11.42 GHz;

Fig. 9 is the simulation and actual measurement comparison diagram of return loss and actual gain of the present invention;

In the drawings, 1-area where the dielectric resonator is located; 2-area where the upper layer of the substrate is located; 3-area where the lower layer of the substrate is located; 11-reflector; 12-dielectric resonator; 13-top layer director; 14-bottom layer director ; 15 - differential microstrip pair; 16 - coplanar strip line.

Detailed ways

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

As shown in FIG. 1 and FIG. 2, a broadband quasi-Yagi antenna based on dielectric resonators includes a substrate, the substrate includes an upper layer and a lower layer composed of a microwave dielectric substrate; it also includes a reflector 11, a dielectric resonator 12, a top layer guide 13, bottom director 14, differential microstrip pair 15, coplanar strip line 16; reflector 11 is printed on the lower layer of the substrate; dielectric resonator 12 is pasted on the upper surface of the substrate; differential microstrip pair 15, coplanar The striplines 16 are all printed on the upper layer of the substrate; the differential microstrip pair 15 is connected to the coplanar stripline 16; the coplanar stripline 16 is connected to the metal pad of the dielectric resonator 12 to excite the two resonance modes of the dielectric resonator 12; The two resonance modes provide two resonance points of the antenna; the top layer director 13 is printed on the upper layer of the substrate; the bottom layer director 14 is printed on the lower layer of the substrate; the top layer director 13 and the bottom layer director 14 are partially overlapped; The two resonance points of the dielectric resonator 12 and the additional two resonance points provided by the bottom and top layer directors constitute the broadband response of the antenna.

The substrate adopts a substrate with a relative dielectric constant less than 10. Specifically, a Rogers 4003C substrate with a dielectric constant of 3.38 and a loss tangent of 0.0027 was used. The substrate includes an area 1 where the dielectric resonator is located, an area 2 where the upper layer of the substrate is located, and an area 3 where the lower layer of the substrate is located. The reflector 11 is a metal ground; the metal ground serves as the reflector 11 of the antenna and also serves as the ground for the differential microstrip pair 15 . In front of the dielectric resonator 12 are two metal directors, namely the bottom director 14 and the top director 13 . The differential microstrip pair 15 is connected to the coplanar stripline 16, the differential signal on the differential microstrip pair 15 is converted into a differential signal on the coplanar stripline 16, and the coplanar stripline 16 is connected to the metal pad of the dielectric resonator 12, The two resonance modes of the dielectric resonator are excited, providing the two resonance points of the antenna. The broadband quasi-Yagi antenna based on the dielectric resonator of the embodiment of the present invention uses a dielectric resonator 12 to replace the traditional metal driver, and then prints two directors on the upper and lower layers of the substrate at the same time, and the director is also closer to the dielectric resonance. The director 12 can make the dielectric resonator 12 excite the mode of the director, and the upper and lower directors can respectively provide two resonance points. The two resonance points of the dielectric resonator 12 and the resonance points of the two directors form a broadband response.

The center frequency of the antenna is f ₀ , and the air wavelength λ=cf ₀ (c is 3×108 m/s). The length a of the dielectric resonator 12 is about one third of the air wavelength corresponding to the antenna center frequency; the distance _l1 between the dielectric resonator 12 and the reflector 11 is about one quarter air wavelength corresponding to the antenna center frequency. The length of the top layer director 13 and the length of the bottom layer director 14 are both slightly shorter than the length a of the dielectric resonator 12 . The dielectric resonator 12 is a rectangular dielectric resonator, and is made of a ceramic material with a relative permittivity greater than 45. The realization of antenna impedance matching can be realized by adjusting the width w ₂ and length l ₂ of the broadband portion of the coplanar strip line 16 .

The ratio a/b of the length a to the width b of the dielectric resonator 12 is greater than 2, so as to obtain two resonance modes with close resonance frequencies. The frequencies of the two resonance points of the dielectric resonator 12 can be closer to each other.

In specific implementation, the parameters are as follows: the relative permittivity of the dielectric resonator 12 is 69, the length a of the dielectric resonator 12 is 11.5 mm, the width b of the dielectric resonator 12 is 3.3 mm, and the thickness c of the dielectric resonator 12 is 1mm, the distance _l1 of the dielectric resonator 12 and the reflector 11 is 8mm, the broadband length _l2 of the coplanar strip line 16 is 6mm, the length dl2 of the top layer director ₁₃ is 7.8mm, and the width of the top layer director 13 is 7.8mm. dw ₂ is 4mm, the distance g ₃ of the top layer director 13 and the dielectric resonator 12 near the director end is 3mm, the length dl ₁ of the bottom layer director 14 is 7.8mm, and the width dw ₁ of the bottom layer director 14 is 2.8 mm, the distance g ₂ between the bottom director 14 and the dielectric resonator 12 near the end of the director is 3.5 mm, the distance g ₁ between the two microstrip lines of the differential microstrip pair 15 is 1.5 mm, and the coplanar strip line 16 has a narrow band width w ₁ is 1 mm, the width w ₂ of the coplanar strip line 16 is 1.6 mm, the width w ₃ of the metal pad on the dielectric resonator 12 is equal to w ₁ , the height of the metal pad on the dielectric resonator 12 is equal to c, and the width of the metal pad on the dielectric resonator 12 is equal to c. The length sl was 34 mm, and the width sw of the substrate was 30 mm.

Use the software HFSS, Agilent E5230C network analyzer and microwave anechoic chamber to simulate and measure the broadband quasi-Yagi antenna based on dielectric resonators of the present invention. The center frequency of the broadband quasi-Yagi antenna of the device is 10.45GHz, and the relative bandwidth FBW is greater than 20%. Among them, the specific relative bandwidth FBW is 21.7%, that is, the reflection coefficient is less than -10dB, and the maximum value of the cross-polarization level on the E-plane and the H-plane is -18dB and -17dB, respectively. Therefore, the embodiment of the present invention is based on dielectric resonance. The broadband quasi-Yagi antenna of the device not only has a wide bandwidth but also has good radiation performance.

Compared with the traditional metal quasi-Yagi antenna, the broadband quasi-Yagi antenna based on the dielectric resonator of the present invention can obtain wider bandwidth and higher gain.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in further detail. It should be understood that the above-mentioned specific embodiments are only specific embodiments of the present invention and are not intended to limit the present invention. the scope of the present invention, any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall belong to the protection scope of the present invention.

Claims (8)

1. a broadband quasi-Yagi antenna based on a dielectric resonator, comprises a substrate, and the substrate comprises an upper layer and a lower layer formed by a microwave dielectric substrate; it is characterized in that, also comprise reflector (11), dielectric resonator (12), a top layer director (13), a bottom layer director (14), a differential microstrip pair (15), a coplanar stripline (16); the reflector (11) is printed on the lower layer of the substrate; the The dielectric resonator (12) is pasted on the upper surface of the substrate; the differential microstrip pair (15) and the coplanar strip line (16) are both printed on the upper layer of the substrate; the differential microstrip pair (15) and the coplanar strip a line (16) is connected; the coplanar strip line (16) is connected to a metal pad on the dielectric resonator (12), and excites two resonant modes of the dielectric resonator (12); the two resonant modes provide an antenna The top layer director (13) is printed on the upper layer of the substrate; the bottom layer director (14) is printed on the lower layer of the substrate; the top layer director (13) ) and the bottom layer director (14) partially overlap; the two resonance points of the dielectric resonator (12) and the additional resonance point introduced by the bottom layer director (14), the top layer director (13) The additional resonance points constitute an antenna broadband response. 2. The broadband quasi-Yagi antenna based on a dielectric resonator according to claim 1, wherein the length a of the dielectric resonator (12) is about one third of the air wavelength corresponding to the center frequency of the antenna; the The distance _l1 between the dielectric resonator (12) and the reflector (11) is about a quarter of the air wavelength corresponding to the center frequency of the antenna. 3. The broadband quasi-Yagi antenna based on a dielectric resonator according to claim 1, wherein the ratio a/b of the length a and the width b of the dielectric resonator (12) is greater than 2, so as to obtain a resonant frequency close to of the two resonance modes. 4 . The broadband quasi-Yagi antenna based on a dielectric resonator according to claim 1 , wherein the dielectric resonator ( 12 ) is a rectangular dielectric resonator and is made of a ceramic material with a relative permittivity greater than 45. 5 . 5. The broadband quasi-Yagi antenna based on a dielectric resonator according to claim 1, wherein the length of the top layer director (13) and the length of the bottom layer director (14) are both slightly shorter than the dielectric resonance The length a of the device (12). 6 . The broadband quasi-Yagi antenna based on a dielectric resonator according to claim 1 , wherein the relative permittivity of the substrate is less than 10. 7 . 7. The broadband quasi-Yagi antenna based on a dielectric resonator according to claim 1, characterized in that, the reflector (11) is a metal ground; the metal ground, as the reflector (11) of the antenna, is also as the ground for the differential microstrip pair (15). 8. The broadband quasi-Yagi antenna based on a dielectric resonator according to any one of claims 1 to 7, wherein the center frequency of the antenna is 10.45 GHz, and the relative bandwidth is greater than 20%, that is, the reflection coefficient is less than -10 dB part.

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