A differential end-fire filter antenna based on multimode resonance

Abstract

This invention relates to a differential end-fire filter antenna based on multimode resonance, belonging to the field of 5G communication equipment. It includes a dielectric substrate, with a metal ground layer on the lower surface of the dielectric substrate; an inverter, a driver 1, a driver 2, a driver 3, a pair of U-shaped open resonators, and a director are sequentially arranged on the upper surface of the dielectric substrate; a circular groove is provided at each end of the metal ground layer, and a metal through hole is provided in each of the two circular grooves for penetrating the driver 1 and the dielectric substrate, and the two metal through holes are connected to differential feed excitation sources with equal amplitude and opposite phase.

Description

Technical Field

[0001] This invention belongs to the field of 5G communication equipment and relates to a differential end-fire filter antenna based on multimode resonance. Background Technology

[0002] With the rapid development of 5G technology and intelligent connected vehicles, the low latency of 5G will accelerate the popularization of industrial intelligence. Narrow-channel environments such as tunnels, mines, and underground parking lots require antennas with high directivity and small aperture. Intelligent connected vehicles also present the need for antennas to conform to the vehicle body. End-fire filter antennas, due to their parallel radiation characteristics with the substrate, naturally possess the advantage of conformal design. Furthermore, integrating the filter with the antenna design can effectively reduce system loss and size, thus end-fire filter antennas are receiving increasing attention.

[0003] Most readily available antennas currently use single-ended feeding. Before use, circuitry needs to be designed to cascade the differential signal from the RF chip onto a balun and filter to convert the differential signal into a single-ended signal. This inevitably leads to energy loss and an excessively large RF front-end circuit, making it unsuitable for integration into portable devices. Therefore, this invention proposes a differential end-fire filtering antenna, which can largely avoid the use of balun circuits and filters, thereby simplifying circuit design and reducing system losses.

[0004] Furthermore, existing Yagi segment antennas typically achieve filtering effects by adding bandpass or bandstop filters to the feed structure of traditional quasi-Yagi antennas. While this approach yields a good filtering response, it requires the introduction of complex filtering circuitry, increasing the antenna's design complexity and size. Additionally, the introduction of the filter degrades the gain curve, thus reducing antenna performance. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a differential end-fire filtering antenna based on multimode resonance.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A differential end-fire filter antenna based on multimode resonance includes a dielectric substrate, the lower surface of which is provided with a metal ground layer; the upper surface of the dielectric substrate is sequentially provided with an inverter, a driver 1, a driver 2, a driver 3, a pair of U-shaped open resonators and a director; each end of the metal ground layer is provided with a circular groove, and each of the two circular grooves is provided with a metal through hole for penetrating the driver 1 and the dielectric substrate, and the two metal through holes are connected to differential feed excitation sources with equal amplitude and opposite phase.

[0008] Furthermore, the driver 1 includes a U-shaped microstrip with a pair of oppositely arranged L-shaped open stubs inside the U-shaped microstrip. The metal through-holes are opened on both sides of the U-shaped microstrip and connected to the differential excitation source for power supply. The L-shaped open stubs extend along the +Z axis.

[0009] Furthermore, the inverter and the director are located on the two sides of the dielectric substrate, respectively, and the distance from the center of the dielectric substrate is approximately half a wavelength electrical length.

[0010] Furthermore, both the driver 2 and the driver 3 are rectangular bars, wherein the length of the driver 3 is half the wavelength electrical length.

[0011] Furthermore, the U-shaped open resonator is located between the driver 3 and the director, and its length is half the electrical wavelength.

[0012] Furthermore, the dielectric substrate has a relative permittivity ε of 2.55, a loss tangent of 0.0015, a thickness of 1.524 mm, and a thickness of half an ounce for the deposited copper metal.

[0013] Furthermore, the driver 1, driver 2, and L-row open-circuit stubs together constitute a dual-mode resonator.

[0014] Furthermore, the antenna operates at a center frequency of 3.91 GHz, with a bandwidth percentage of 13% (3.66-4.16 GHz), a maximum achievable gain of 6 dBi in the band, and a front-to-back ratio of over 16 dB for the end-fire antenna in the passband.

[0015] The beneficial effects of this invention are as follows: Three resonant modes are achieved on the Yagi structure through multi-stage coupling, thereby extending the antenna bandwidth; the driver 3 can generate new resonant modes and produce radiation nulls at the high-frequency edge of the gain curve passband, thus improving the out-of-band rejection level of the antenna at high frequencies; embedding a U-shaped resonator between the director and the driver 3 can obtain radiation nulls at the low-frequency edge of the gain curve, thereby improving the out-of-band selectivity of the antenna at low frequencies; the electrical dimensions of this antenna are: 0.48*0.50*0.02(λ). 3 This antenna boasts advantages such as low profile and small size; its operating center frequency is 3.91GHz, with a relative bandwidth of approximately 13% (3.66-4.16GHz), and an in-band gain of over 5dBi; this antenna can be cascaded with the differential signal output from the RF chip, avoiding the use of filters and balun circuits, thus achieving the goal of miniaturizing RF front-end devices and possessing certain engineering practical value.

[0016] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0018] Figure 1 This is a schematic diagram of the differential end-fire filter antenna based on multimode resonance described in this invention;

[0019] Figure 2 This is a schematic diagram showing the dimensions of the differential end-fire filter antenna based on multimode resonance described in this invention.

[0020] Figure 3 The S-type differential end-fire filter antenna based on multimode resonance described in this invention... cc11 S dd11 Parameters, Realized Gain;

[0021] Figure 4 This is the front-to-back comparison (FTBR) of the differential end-fire filter antenna based on multimode resonance described in this invention.

[0022] Figure 5 (a) shows the simulated E-plane radiation pattern when the antenna's center frequency is 3.91 GHz, and (b) shows the H-plane radiation pattern.

[0023] Figure reference numerals: Driver 1①, Driver 2②, Driver 3③, U-shaped open resonator ④, Inverter ⑤, Director ⑥, Rectangular substrate ⑦, Metal ground ⑧, Metallized via (differential excitation source feed port) ⑨. Detailed Implementation

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0026] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0027] See appendix Figure 1-4 This invention relates to a differential end-fire filtering antenna based on multimode resonance. The antenna includes a rectangular substrate ⑦ made of AD255C dielectric material. A metal ground layer ⑧ is connected to the lower surface of the rectangular substrate ⑦. An inverter ⑤, a driver 1 ①, a driver 2 ②, a driver 3 ③, a pair of U-shaped open resonators ④ arranged in opposite directions, and a director ⑥ are installed sequentially from left to right on the upper surface of the rectangular substrate ⑦. A circular slot is provided at each end of the metal ground layer ⑧. A metallized through-hole (differential excitation source feed port) ⑨ is provided in each of the two circular slots for penetrating the driver 1 ① and the rectangular substrate ⑦. The two metallized through-holes (differential excitation source feed ports) ⑨ are connected to differential excitation sources with equal amplitude and opposite phase.

[0028] The parameters of the antenna are detailed in Table 1: the unit is (mm).

[0029] Table 1

[0030]

[0031]

[0032] The dimensions of the rectangular substrate ⑦ are: 37*38.6*1.524mm. 3The copper layer is 0.5 ounces thick. Driver 1① includes a U-shaped microstrip and a pair of L-shaped open-circuit stubs. The U-shaped microstrip is fed by differential excitation sources on both sides, and the L-shaped open-circuit stubs extend along the +Z axis with a distance of 10 mm between them. Driver 2② includes a rectangular strip with a length of 26.4 mm. Driver 3③ is located in front of Driver 2② and has a length of 26.2 mm, which is half the electrical wavelength. Inverter 5 and director 6 are located on the two sides of the rectangular substrate 7, respectively, at a distance of approximately 1 / 2λ (λ is the wavelength) from the center of the rectangular substrate 7. Their lengths are 13.8 mm and 37 mm, respectively. U-shaped open-circuit resonator 4 is located between Driver 3③ and director 6 and has a length of approximately half the electrical wavelength. The differential-fed excitation source is fed through the bottom surface of the metallized vias ⑨ on both sides of the U-shaped microstrip line of driver 1①. The distance between the metallized vias ⑨ is 30.9 mm, the radius is 0.48 mm, and the height is 1.558 mm. The rectangular substrate ⑦ has a relative permittivity ε of 2.55, a loss tangent of 0.0015, and a thickness of 1.524 mm; the copper thickness is half an ounce. The antenna operates at a center frequency of 3.91 GHz, with a bandwidth percentage of approximately 13% (3.66-4.16 GHz). The maximum achievable gain within the band is approximately 6 dBi, and the front-to-back contrast of the end-fire antenna within the passband is greater than 16 dB.

[0033] See attached document Figure 2 , Figure 2 The detailed values ​​of the antenna parameters marked in the figure are listed in Table 1. These parameters were optimized using HFSS2022. The inverter length and the metal ground length are not marked in the figure.

[0034] Figure 3 S obtained from the simulation of this invention cc11 S dd11 The figure shows the parameters and the curves of realized gain versus frequency. As shown in the figure, the simulation results indicate that S... dd11 The impedance bandwidth below -10dB is approximately 13%; the center frequency is 3.91GHz, and the operating frequency band is from 3.26 to 4.16GHz; the simulated achievable gain curves show that the maximum achievable gain in the band is approximately 6dBi, and the gain response is flat in the passband. In addition, there is a radiation null at 3.48GHz and 4.25GHz, which improves the antenna's filtering performance.

[0035] Figure 4 This is a graph showing the before-and-after ratio (FTBR) as a function of frequency, obtained from simulations of the present invention. The graph shows that the before-and-after ratio of the differential end-fire filter antenna based on multimode resonance involved in this invention is greater than 16 dB in the passband, and can reach a maximum of 24 dB.

[0036] Figure 5(a) shows the simulated E-plane radiation pattern of the antenna at its center frequency of 3.91 GHz, and (b) shows the H-plane radiation pattern. As shown in the figure, the solid line represents the main polarization curve, and the dotted line represents the cross-polarization curve. It can be seen from the figure that the antenna has good end-fire radiation characteristics.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-mode resonant based differentially end-fire filtered antenna, characterized by: The antenna comprises a dielectric substrate, a metal ground layer is arranged on the lower surface of the dielectric substrate, a reverser, a driver 1, a driver 2, a driver 3, a pair of U-shaped open resonators and a director are sequentially arranged on the upper surface of the dielectric substrate, two circular grooves are arranged at two ends of the metal ground layer respectively, a metal through hole for penetrating the driver 1 and the dielectric substrate is arranged in each of the two circular grooves, and two metal through holes are connected with a differential feeding excitation source with equal amplitude and opposite phase. The driver 1 comprises a U-shaped microstrip, a pair of oppositely arranged L-shaped open stubs are arranged in the U-shaped microstrip, and the metal through holes are arranged on both sides of the U-shaped microstrip and connected with the differential excitation source. The reverser and the director are respectively located at the two side edges of the dielectric substrate, and the distance from the center of the dielectric substrate is substantially half of the wavelength electrical length. The driver 2 and the driver 3 are both rectangular strips, and the length of the driver 3 is half of the wavelength electrical length. The U-shaped open resonator is located between the driver 3 and the director, and the length of the U-shaped open resonator is half of the wavelength electrical length. The driver 1, the driver 2 and the L-shaped open stubs constitute a dual-mode resonator.

2. The multi-mode resonant based differential end-fire filtered antenna of claim 1, wherein: The relative dielectric constant of the medium substrate The center frequency of the antenna is 3.91 GHz, the bandwidth percentage is 13%, the maximum gain in the band can reach 6dBi, and the front-to-back ratio of the end-fire antenna in the passband is more than 16dB. 2.55, the loss tangent is 0.0015, the thickness is 1.524 mm, and the thickness of the deposited metal copper is half ounce.

3. The multi-mode resonant based differential end-fire filtered antenna of claim 1, wherein: ​

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