An ultra-wideband high-gain terahertz antenna device that is easily integrated with a photodiode

Abstract

The present invention designs an ultra-wideband high-gain terahertz antenna device that is easy to integrate with a photodiode, comprising an antenna radiating arm, a dielectric substrate, an antenna feeding structure, and a dielectric lens; the antenna radiating arm is used to transmit traveling wave current and form electromagnetic radiation, thereby realizing wireless transmission of signals from the waveguide structure to free space; the middle layer of the dielectric substrate is used to support the antenna radiating arms on both sides, and the upper and lower dielectric substrates play a packaging and protection role. The feeding structure is used to achieve a broadband feeding effect, while making it easy for the antenna to form a planar integration with the terahertz photodiode. The dielectric lens is used to converge the antenna radiation energy, thereby making the antenna radiation pattern more directional and improving the overall gain of the antenna device. The terahertz antenna device proposed above adopts a transition feeding structure from a grounded coplanar waveguide to a microstrip line, which not only realizes a broadband design of the antenna, but also makes the planar structure easy to integrate with the photodiode at the transmitting front end of the optoelectronic terahertz communication system.

Description

Technical Field

[0001] The present application relates to the field of terahertz antennas and communication technologies, and in particular to an ultra-wideband high-gain terahertz antenna device that is easily integrated with a photodiode. Background Art

[0002] The surge in demand for communication data is placing higher demands on the capacity and speed of communication systems, making ultra-wideband terahertz communication a crucial technology for addressing this issue. As a key component in communication systems, the performance of terahertz antennas directly impacts the system's communication capacity and quality. Due to the wide bandwidth and high path loss associated with terahertz communication, the system places higher design requirements on antenna bandwidth and gain, making ultra-wideband, high-gain antenna performance crucial. Furthermore, with the increasing integration of communication systems, the integration of antennas with transceiver front-ends is inevitable. Therefore, ultra-wideband, high-gain, and easily integrated terahertz antenna structures are of paramount importance. Summary of the Invention

[0003] Based on the above background, this application discloses an ultra-wideband high-gain terahertz antenna device that is easily integrated with a photodiode. The antenna proposed in this invention is a novel planar antipodal Vivaldi antenna that operates in the terahertz frequency band and has ultra-wideband high-gain characteristics.

[0004] Specifically, the present invention first provides an ultra-wideband, high-gain terahertz antenna device that is easily integrated with a photodiode. The device comprises: an antenna radiating arm, an antenna feeding structure, a dielectric lens, and a three-layer dielectric substrate. The antenna radiating arm is divided into two parts, located on the upper and lower sides of the intermediate dielectric substrate, respectively. The antenna feeding structure is located on a side away from the antenna radiating arm forming an opening. The dielectric lens is placed at a certain distance from the antenna in the end-fire direction of the antenna.

[0005] The antenna radiating arm is used to transmit traveling wave current and generate electromagnetic radiation; the curved structure on both sides of the intermediate layer dielectric substrate forms a gradient slot shape, so that the current forms a radiation signal when it is conducted on the antenna;

[0006] The antenna feeding structure is used to achieve an ultra-wideband feeding effect, while integrating the antenna radiation arm and the photodiode of the photoelectric terahertz communication system transmission front end;

[0007] The dielectric lens is used to converge the antenna radiation energy, making the antenna radiation pattern more directional and improving the overall gain of the antenna device;

[0008] In the three-layer dielectric substrate, the middle dielectric substrate is used to fix the antenna radiation arm portion. The upper and lower dielectric substrates are made of the same material and are located on the upper and lower sides of the middle layer to play a packaging and protection role.

[0009] As a preferred embodiment of the present invention, the antenna radiating arm is composed of two metal patches located above and below the intermediate dielectric substrate, and the two metal patches are symmetrical about the central axis of the short side of the intermediate dielectric substrate;

[0010] The slot lines of the metal patch are exponentially gradient along the end-fire direction of the antenna; the exponential curve is used to achieve a gradient shape, and other curves that can achieve a gradient shape are also acceptable.

[0011] The metal patch is loaded with an elliptical patch edge on one side edge of the surface formed by the slotted curve.

[0012] As a preferred solution of the present invention, the antenna feeding structure is composed of a cascade of three parts: a grounded coplanar waveguide, a microstrip line, and a parallel double line;

[0013] The grounded coplanar waveguide structure is used to realize the integration of the photodiode at the emission front end of the optoelectronic terahertz communication system;

[0014] The microstrip line and the parallel double line form a gradient transmission line structure to achieve a broadband feeding effect.

[0015] As a preferred solution of the present invention, the shape of the dielectric lens is composed of a hemisphere and a section of a cylinder, and the lens is at a set distance from the antenna radiation aperture surface.

[0016] As a preferred solution of the present invention, the antenna device can be integrated with a photodiode. The material of the intermediate dielectric substrate is consistent with the growth substrate material of the terahertz photodiode. The upper and lower dielectric substrates serve to encapsulate and protect the intermediate layer and the antenna.

[0017] As a preferred solution of the present invention, in the antenna feeding structure, the grounded coplanar waveguide has holes opened on both sides.

[0018] As a preferred solution of the present invention, the height of the extended cylinder and the radius of the hemisphere in the dielectric lens are 0.36.

[0019] As a preferred solution of the present invention, the intermediate layer dielectric substrate is composed of a cuboid and a semi-elliptical guide structure that is coplanar with the cuboid and has the same thickness as the cuboid.

[0020] Compared with the prior art, the antenna device described in the present invention includes an antenna radiating arm portion, a dielectric substrate, a feeding structure, and a dielectric lens. The antenna radiating arm is divided into two parts, one on each side of the middle dielectric substrate; the radiating arm of the antipodal structure forms a gradient slot for transmitting traveling wave current and forming electromagnetic radiation, thereby realizing wireless transmission of signals from the waveguide structure to free space. The middle layer of the antenna dielectric substrate is used to support the antenna radiating arms located on both sides, and the middle dielectric layer is InP, which is consistent with the substrate material of the terahertz photodiode; the upper and lower dielectric substrates serve as packaging and protection. The antenna feeding structure is composed of a cascade of three parts: a grounded coplanar waveguide, a microstrip line, and a parallel double line, which is used to achieve a broadband feeding effect and facilitate the planar integration of the antenna and the terahertz photodiode. The dielectric lens is used to converge the antenna radiation energy, making the antenna radiation pattern more directional and improving the overall gain of the antenna device. The ultra-wideband terahertz antenna device proposed above adopts a transition feeding structure from grounded coplanar waveguide to microstrip line, which not only realizes the broadband design of the antenna, but also makes its structure easy to integrate with the transmitting front end of the optoelectronic terahertz communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of an ultra-wideband high-gain terahertz communication antenna device;

[0022] Figure 2 It is a schematic diagram of the antipodal antenna radiation arm of an ultra-wideband high-gain terahertz communication antenna device;

[0023] Figure 3 The figure is a schematic diagram of a segmented broadband feeding structure of an ultra-wideband high-gain terahertz communication antenna device; wherein (a) is the upper surface and (b) is the lower surface;

[0024] Figure 4 This is the S11 simulation result of an ultra-wideband high-gain terahertz communication antenna device without lens loading;

[0025] Figure 5 It is an ultra-wideband high-gain terahertz communication antenna device with or without an elliptical guiding structure when the lens is not loaded;

[0026] Figure 6 It is an ultra-wideband high-gain terahertz communication antenna device with radiation patterns at four frequencies of 220GHz, 240GHz, 260GHz, and 280GHz when no lens is loaded;

[0027] Figure 7 This is a schematic diagram of the antenna gain at 280 GHz when an ultra-wideband high-gain terahertz communication antenna device is loaded with a lens. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific technical solutions, but they are not intended to limit the present invention.

[0029] like Figure 1-3 As shown, the present invention discloses an ultra-wideband high-gain terahertz antenna device that is easily integrated with a photodiode, comprising: an antenna radiating arm, an antenna feeding structure, a dielectric lens, and a three-layer dielectric substrate; the antenna radiating arm is divided into two parts, located on the upper and lower sides of the middle dielectric substrate, respectively; the antenna feeding structure is located on the side away from the antenna radiating arm forming an opening; and the dielectric lens is placed at a certain position away from the antenna in the end-fire direction of the antenna;

[0030] The antenna radiating arm is used to transmit traveling wave current and generate electromagnetic radiation; the curved structure on both sides of the intermediate layer dielectric substrate forms a gradient slot shape, so that the current forms a radiation signal when it is conducted on the antenna;

[0031] The antenna feeding structure is used to achieve an ultra-wideband feeding effect, while integrating the antenna radiation arm and the photodiode of the photoelectric terahertz communication system transmission front end;

[0032] The dielectric lens is used to converge the antenna radiation energy, making the antenna radiation pattern more directional and improving the overall gain of the antenna device;

[0033] In the three-layer dielectric substrate, the middle dielectric substrate is used to fix the antenna radiation arm portion. The upper and lower dielectric substrates are made of the same material and are located on the upper and lower sides of the middle layer to play a packaging and protection role.

[0034] The present invention has the following features: First, the feeding structure of grounded coplanar waveguide-microstrip line-parallel double lines makes the feeding structure broadband, and the antenna bandwidth is not limited by the feeding structure bandwidth. The introduction of the grounded coplanar waveguide facilitates the integration with the terahertz photodiode at the transmitting end; Second, in the radiating arm part of the antenna, the edges of the two radiating arms forming a gradient groove are loaded with a metal elliptical structure, which makes the current distribution more uniform and reduces the impedance mismatch caused by current reflection; Third, the addition of a semi-elliptical guiding structure to the intermediate dielectric layer further improves the antenna gain; In addition, because the intermediate dielectric layer is thin and difficult to process and protect, the upper and lower dielectric layers are introduced to play a packaging and protection role without affecting the antenna radiation characteristics. Fourth, in order to meet the high gain requirements of terahertz communication for antennas, the form and material of the dielectric lens are reasonably optimized so that the antenna plus lens can achieve better radiation characteristics.

[0035] In a specific embodiment, the design target is an ultra-wideband high-gain antipodal Vivaldi antenna used in a terahertz communication system. The operating frequency of the antenna is designed to be 220GHz-280GHz, meeting the frequency bandwidth requirements of terahertz communication. In this specific embodiment, the antenna device is as follows Figure 1 It includes an antenna radiation arm 1; the upper, middle and lower three-layer dielectric structures correspond to the figure marks 2, 3 and 4 respectively; a feeding structure composed of a grounded coplanar waveguide 5, a gradient microstrip line 6 and a parallel double line 7; a feeding port position 8; and an extended hemispherical lens 9. The overall size of the antenna substrate is 4.8mm*1.6mm*0.22mm, the upper and lower dielectric materials are Teflon, and the middle dielectric material is InP. In the extended hemispherical lens 9, the radius of the dielectric lens is 10mm, the extended cylindrical height is 4.2mm, and the lens dielectric material is Teflon. The antenna radiation arm 1 is as shown Figure 2 It is divided into two parts symmetrical about the short side center axis of the intermediate dielectric layer, and is located on the upper and lower sides of the intermediate dielectric layer 3 respectively. Figure 3 The antenna feeding structure is divided into three parts: grounded coplanar waveguide 5, gradient microstrip line 6, parallel double line 7. The substrate material used in these three parts is InP, and the structure is located in the middle dielectric layer 3. Figure 1 The upper and lower dielectric layers 2 and 4 are located above and below the middle dielectric layer 3, respectively, ultimately forming a three-layer dielectric structure. The middle dielectric layer 3 contains a semi-elliptical guide structure in the direction of the slot formed by the antenna radiating arm 1. The extended hemispherical lens 9 is located axially of the antenna's tapered slot, with the central axis of the antenna's narrow side passing through the center of the lens. The reference distance h from the dielectric lens to the antenna can be approximately calculated using the following formula:

[0036] Where r is the hemisphere radius and ε is the dielectric constant of the lens material.

[0037] The antenna device in this embodiment satisfies the ultra-wideband characteristic, such as Figure 4 The S11 curve of the antenna has an impedance bandwidth of approximately 100 GHz. The radiation characteristics of the antenna device are as follows: Figure 5-Figure 7 ,in Figure 5 Comparing the antenna gain with and without the guiding structure, the guiding device increased the antenna gain by 2-3dB and achieved a gain bandwidth of 80GHz when the gain was greater than 10dBi. Figure 6 The end-fire pattern of the antenna shown has good consistency in the wideband range of 220GHz-280GHz, with no obvious distortion. Figure 7 The overall gain of the antenna is as high as 30dBi, achieving high gain characteristics. In summary, this embodiment achieves the design and application goals of ultra-wideband high-gain antennas in terahertz communications.

[0038] The above are only preferred embodiments of the present invention, and do not limit the implementation methods and protection scope of the present invention. For those skilled in the art, it should be aware that the solutions obtained by using the present invention and the illustrations to make equivalent substitutions and obvious changes should all be included in the protection scope of the present invention.

Claims

1. An ultra-wideband high-gain terahertz antenna device that is easily integrated with a photodiode, characterized in that: include: Antenna radiation arm, antenna feeding structure, dielectric lens, and dielectric substrate with three-layer structure; The antenna radiating arm is divided into two parts, located on the upper and lower sides of the intermediate layer dielectric substrate respectively. The antenna feeding structure is located on the side away from the opening formed by the antenna radiating arm. The dielectric lens is placed at a certain position away from the antenna in the end-fire direction of the antenna. The antenna radiation arm is used to transmit traveling wave current and generate electromagnetic radiation; The curved structures on both sides of the intermediate dielectric substrate form a gradient slot shape, which enables the current to form a radiation signal when it is conducted on the antenna; The antenna feeding structure is used to achieve an ultra-wideband feeding effect, while integrating the antenna radiation arm and the photodiode of the photoelectric terahertz communication system transmission front end; The dielectric lens is used to converge the antenna radiation energy, making the antenna radiation pattern more directional and improving the overall gain of the antenna device; The shape of the dielectric lens is composed of a hemisphere and a section of a cylinder. The lens is at a set distance from the antenna radiation aperture surface. The ratio of the height of the extended cylinder to the radius of the hemisphere in the dielectric lens is 0.

36. In the three-layer dielectric substrate, the middle dielectric substrate is used to fix the antenna radiation arm part. The upper and lower dielectric substrates are made of the same material and are located on the upper and lower sides of the middle layer to play a packaging and protection role. The antenna device can be integrated with a photodiode, and the material of the intermediate dielectric substrate is consistent with the growth substrate material of the terahertz photodiode; the intermediate dielectric substrate consists of a cuboid and a semi-elliptical guiding structure that is coplanar with the cuboid and has the same thickness as the cuboid.

2. The antenna device according to claim 1, wherein The antenna radiating arm is composed of two metal patches located above and below the middle dielectric substrate. The two metal patches are symmetrical about the central axis of the short side of the middle dielectric substrate. The slot lines of the metal patch show an exponential gradient along the end-fire direction of the antenna; The metal patch is loaded with an elliptical patch edge on one side edge of the surface formed by the slotted curve.

3. The antenna device according to claim 1, wherein The antenna feeding structure is composed of a cascade of three parts: a grounded coplanar waveguide, a microstrip line, and a parallel double line; The grounded coplanar waveguide structure is used to realize the integration of the photodiode at the emission front end of the optoelectronic terahertz communication system; The microstrip line and the parallel double line form a gradient transmission line structure to achieve a broadband feeding effect.

4. The antenna device according to claim 3, wherein: In the antenna feeding structure, the grounded coplanar waveguide has holes on both sides.

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