Broadband slot antenna based on slow wave structure

Abstract

A broadband slot antenna based on a slow wave structure disclosed by the present invention comprises a dielectric substrate, a radiation patch, a slow wave structure, an annular groove and an SIW cavity, the dielectric substrate and the radiation patch are circular, the radiation patch is attached to the upper surface of the dielectric substrate, the radius of the radiation patch is equal to the radius of the dielectric substrate, and the slow wave structure is arranged in the annular groove. The SIW cavity is formed by a plurality of metalized through holes which are uniformly distributed along a circle at intervals and vertically penetrate through the dielectric substrate and the radiation patch, the annular groove is formed in the radiation patch, vertically penetrates through the radiation patch and is coaxial with the radiation patch, the annular groove is located in an inner side space defined by the metalized through holes, and the metalized through holes are communicated with the annular groove. The slow wave structure is located on the inner side of the annular groove, the slow wave structure is achieved in the mode that a plurality of rectangular grooves which vertically penetrate through the radiation patch and are evenly distributed along a circle at intervals are formed in the radiation patch, and each rectangular groove extends in the radial direction of the radiation patch. The antenna has the advantages of simple structure, small size, large bandwidth and high gain.

Description

Technical Field

[0001] The present invention relates to a broadband slot antenna, and in particular to a broadband slot antenna based on a slow-wave structure. Background Art

[0002] In the contemporary field of wireless communication, as a key technology, the performance of an antenna directly affects the communication efficiency and reliability of the entire system. With the popularization of wireless communication and radar systems, broadband antennas have attracted extensive attention due to their high performance and become the focus of research.

[0003] At present, broadband antennas are widely used and can effectively radiate and receive signals within a relatively wide frequency range (usually several octaves). A broadband circular patch antenna was proposed in Document 1 "P. Liu, W. Jiang, W. Hu, S.-Y. Sun and S.-X. Gong, 'Wideband Multimode Filtering Circular Patch Antenna,' in IEEE Transactions on Antennas and Propagation, vol. 69, no. 11, pp. 7249-7259, Nov. 2021". This broadband circular patch antenna combines four resonance modes, namely quasi-TM01, quasi-TM02, quasi-TM03, and quasi-TM04, by cutting slots and adding short pins on the driven patch to obtain a wide passband. However, this broadband circular patch antenna has a complex structure, a large size, a relatively narrow relative bandwidth, and a low gain. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a broadband slot antenna based on a slow-wave structure with a simple structure, a small size, a large bandwidth, and a high gain.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows: A broadband slot antenna based on a slow-wave structure, comprising a dielectric substrate, a radiation patch, a slow-wave structure, an annular groove, and an SIW cavity. The dielectric substrate is a circular plate, and the radiation patch is a circular patch. The radiation patch is attached to the upper surface of the dielectric substrate. The radiation patch is coaxial with the dielectric substrate, and the radii of the radiation patch and the dielectric substrate are equal. The SIW cavity is formed by opening a plurality of metallized vias on the dielectric substrate and the radiation patch, which are evenly spaced along a circle and penetrate the dielectric substrate and the radiation patch up and down. The SIW cavity is used to guide electromagnetic waves to transmit in the inner space surrounded by its plurality of metallized vias, so that the energy is concentrated at the center of the broadband slot antenna based on the slow-wave structure, realizing the efficient radiation and reception of electromagnetic waves. The annular groove is opened on the radiation patch, penetrates the radiation patch up and down, and is coaxial with the radiation patch. The annular groove is located in the inner space surrounded by the plurality of metallized vias and has a spacing from the plurality of metallized vias. The annular groove is used to improve the impedance matching of the broadband slot antenna based on the slow-wave structure. The slow-wave structure is located inside the annular groove and does not contact the annular groove. The slow-wave structure is realized by opening a plurality of rectangular slots on the radiation patch that penetrate the radiation patch up and down and are evenly spaced along a circle. Each rectangular slot extends along the radial direction of the radiation patch. The slow-wave structure is used to introduce more frequency resonance points for the broadband slot antenna based on the slow-wave structure, thereby realizing broadband performance. At the same time, due to the realization of slotting, the broadband slot antenna based on the slow-wave structure can have a lower profile.

[0006] Compared with the prior art, the advantages of the present invention are as follows: a broadband slot antenna is formed by a dielectric substrate, a radiation patch, a slow-wave structure, an annular slot and an SIW cavity. The dielectric substrate is a circular plate, and the radiation patch is a circular patch. The radiation patch is attached to the upper surface of the dielectric substrate. The radiation patch is coaxial with the dielectric substrate, and the radii of the radiation patch and the dielectric substrate are equal. The SIW cavity is formed by opening a plurality of metallized vias that are evenly spaced along a circle and penetrate the dielectric substrate and the radiation patch up and down. The annular slot is opened on the radiation patch, penetrates the radiation patch up and down, and is coaxial with the radiation patch. The annular slot is located in the inner space surrounded by the plurality of metallized vias and has a spacing from the plurality of metallized vias. The slow-wave structure is located inside the annular slot and does not contact the annular slot. The slow-wave structure is realized by opening a plurality of rectangular slots that penetrate the radiation patch up and down and are evenly spaced along a circle on the radiation patch. Each rectangular slot extends along the radial direction of the radiation patch. Among them, the SIW cavity is used to guide electromagnetic waves to transmit in the inner space surrounded by its plurality of metallized vias, so that the energy is concentrated at the center of the broadband slot antenna based on the slow-wave structure, realizing the efficient radiation and reception of electromagnetic waves. The annular slot is used to improve the impedance matching of the broadband slot antenna based on the slow-wave structure. The slow-wave structure is used to introduce more frequency resonance points for the broadband slot antenna based on the slow-wave structure, thereby realizing broadband performance. At the same time, due to the realization of slotting, the broadband slot antenna based on the slow-wave structure can have a lower profile. Therefore, the structure of the present invention is simple, the size is small, and the bandwidth is large and the gain is high.

[0007] Further, the dielectric substrate is made of 5880 substrate, with a radius of 20 mm and a thickness of 1.575 mm. The thickness of the radiation patch is 0.035 mm. The inner radius of the annular slot is 12.15 mm and the outer radius is 13 mm. The number of metallized vias included in the SIW cavity is 60. The radius of each metallized via is 0.5 mm, and the distance from the central axis of each metallized via to the central axis of the dielectric substrate is 17.7 mm. In the slow-wave structure, the number of rectangular slots is 12. The length direction of each rectangular slot is defined as the radial extension direction of the dielectric substrate. The length of each rectangular slot is 11.2 mm and the width is 0.45 mm.

[0008] Further, for the broadband slot antenna based on a slow-wave structure, a coaxial cable is used for feeding. The coaxial cable vertically penetrates the dielectric substrate and the radiation patch up and down, and its top is in the same plane as the upper end face of the radiation patch. The coaxial cable is located between two adjacent rectangular slots and does not contact either of the two adjacent rectangular slots. The distance between the center line of the coaxial cable and the center of the radiation patch is 4.37 mm. The angle between the line connecting the center of the top of the coaxial cable and the center of the upper end face of the radiation patch and the line extending backward from the center of the upper end face of the radiation patch in the direction perpendicular to the rear end face of the dielectric substrate is 70.21°. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 FIG. is a top view of the broadband slot antenna based on a slow-wave structure of the present invention;

[0010] Figure 2 FIG. is a side view of the broadband slot antenna based on a slow-wave structure of the present invention;

[0011] Figure 3 FIG. is the |S11| curve graph of the broadband slot antenna based on a slow-wave structure of the present invention;

[0012] Figure 4 FIG. is the gain curve graph of the broadband slot antenna based on a slow-wave structure of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] The present invention will be further described in detail below in conjunction with the embodiments of the drawings.

[0014] Embodiment 1: As shown in Figure 1 and Figure 2As shown in the figure, a broadband slot antenna based on a slow-wave structure includes a dielectric substrate 1, a radiation patch 2, a slow-wave structure, an annular slot 3, and a SIW cavity. The dielectric substrate 1 is a circular plate, and the radiation patch 2 is a circular patch. The radiation patch 2 is attached to the upper surface of the dielectric substrate 1. The radiation patch 2 is coaxial with the dielectric substrate 1, and the radii of the radiation patch 2 and the dielectric substrate 1 are equal. The SIW cavity is formed by opening a plurality of metallized vias 4 on the dielectric substrate 1 and the radiation patch 2, which are evenly spaced along a circle and penetrate through the dielectric substrate 1 and the radiation patch 2 up and down. The SIW cavity is used to guide electromagnetic waves to transmit in the inner space surrounded by its plurality of metallized vias 4, so as to concentrate the energy at the center of the broadband slot antenna based on the slow-wave structure, realizing the efficient radiation and reception of electromagnetic waves. The annular slot 3 is opened on the radiation patch 2. The annular slot 3 penetrates through the radiation patch 2 up and down and is coaxial with the radiation patch 2. The annular slot 3 is located in the inner space surrounded by the plurality of metallized vias 4 and has a spacing from the plurality of metallized vias 4. The annular slot 3 is used to improve the impedance matching of the broadband slot antenna based on the slow-wave structure. The slow-wave structure is located inside the annular slot 3 and does not contact the annular slot 3. The slow-wave structure is realized by opening a plurality of rectangular slots 5 on the radiation patch 2, which penetrate through the radiation patch 2 up and down and are evenly spaced along a circle. Each rectangular slot 5 extends along the radial direction of the radiation patch 2. The slow-wave structure is used to introduce more frequency resonance points for the broadband slot antenna based on the slow-wave structure, so as to realize the broadband performance. At the same time, due to the realization of slotting, the broadband slot antenna based on the slow-wave structure can have a lower profile.

[0015] In this embodiment, when the broadband slot antenna based on the slow-wave structure emits a signal, the high-frequency current generated by the signal source is transmitted to the radiation patch 2. The radiation patch 2 converts the current energy into an electromagnetic field and radiates it into space in the form of electromagnetic waves. In this process, the SIW cavity concentrates the energy transmitted to the radiation patch 2 at the center of the radiation patch 2. The annular slot 3 improves the impedance matching between the coaxial cable 6 and the broadband slot antenna, minimizing the energy loss. The slow-wave structure greatly improves the broadband performance of the broadband slot antenna.

[0016] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, the dielectric substrate 1 is a 5880 substrate with a radius of 20 mm and a thickness of 1.575 mm. The thickness of the radiation patch 2 is 0.035 mm. The inner radius of the annular slot 3 is 12.15 mm, and the outer radius is 13 mm. The number of metallized vias 4 included in the SIW cavity is 60. The radius of each metallized via 4 is 0.5 mm, and the distance from the central axis of each metallized via 4 to the central axis of the dielectric substrate 1 is 17.7 mm. In the slow-wave structure, the number of rectangular slots 5 is 12. The length direction of each rectangular slot 5 is defined as the radial extension direction of the dielectric substrate 1. The length of each rectangular slot 5 is 11.2 mm, and the width is 0.45 mm.

[0017] Embodiment 3: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, a coaxial cable 6 is used for feeding. The coaxial cable 6 vertically penetrates the dielectric substrate 1 and the radiation patch 2 up and down, and its top is in the same plane as the upper end face of the radiation patch 2. The coaxial cable 6 is located between two adjacent rectangular slots 5 and does not contact either of the two adjacent rectangular slots 5. The distance between the center line of the coaxial cable 6 and the center of the radiation patch 2 is 4.37 mm. The angle between the line connecting the center of the top of the coaxial cable 6 and the center of the upper end face of the radiation patch 2 and the line extending backward from the center of the upper end face of the radiation patch 2 in the direction perpendicular to the rear end face of the dielectric substrate 1 is 70.21°.

[0018] To verify the performance of the broadband slot antenna based on the slow-wave structure of the present invention, the broadband slot antenna based on the slow-wave structure in Embodiment 3 of the present invention is simulated. The |S11| curve graph of the broadband slot antenna based on the slow-wave structure of the present invention is as Figure 3 shown; the gain curve graph of the broadband slot antenna based on the slow-wave structure of the present invention is as Figure 4 shown. Analysis Figure 3 shows that the -10 dB impedance bandwidth of the broadband slot antenna based on the slow-wave structure of the present invention is 7.34 - 10.14 GHz, the relative bandwidth is 32%, and there are a total of five resonance points, which are 7.64 GHz, 8.00 GHz, 8.92 GHz, 9.70 GHz, and 10.04 GHz, respectively. It has a wide bandwidth and realizes a multi-frequency mode. Analysis Figure 4 shows that the maximum in-band gain of the broadband slot antenna based on the slow-wave structure of the present invention is 8.7 dBi, and the 3 dB bandwidth is 7.87 - 9.04 GHz (13.8%), which has a high gain.

[0019] The profile, relative bandwidth, and gain of the broadband slot antenna based on the slow-wave structure of the present invention are compared with the antennas disclosed in 7 existing documents. The comparison data is shown in Table 1:

[0020] Table 1

[0021]

[0022] Among them, Document [1] is P. Liu, W. Jiang, W. Hu, S.-Y. Sun and S.-X. Gong, "Wideband Multimode Filtering Circular Patch Antenna," in IEEE Transactions on Antennas and Propagation, vol. 69, no. 11, pp. 7249-7259, Nov. 2021; Document [2] is Y.-M. Cai, S. Gao, Y. Yin, W. Li and Q. Luo, "Compact-Size Low-Profile Wideband Circularly Polarized Omnidirectional Patch Antenna With Reconfigurable Polarizations," in IEEE Transactions on Antennas and Propagation, vol. 64, no. 5, pp. 2016-2021, May 2016; Document [3] is X. Ding, Z. Zhao, Y. Yang, Z. Nie and Q.H. Liu, "A Low-Profile and Stacked Patch Antenna for Pattern-Reconfigurable Applications," in IEEE Transactions on Antennas and Propagation, vol. 67, no. 7, pp. 4830-4835, July 2019; Document [4] is H.-P. Liao, Y.-T. Tsai and S.-Y. Chen, "A Lightweight Broadband Circularly Polarized Stacked Patch Antenna Formed by Meshed Aluminum Disks for Inter-Satellite Communication," in IEEE Antennas and Wireless Propagation Letters, vol. 23, no. 4, pp. 1326-1330, April 2024; Document [5] is C. Zhang and Y.Ou, "A Design Methodology of Broadband Millimeter-Wave Conical Radiating Antenna Based on Ring-Shaped Microstrip Line," in IEEE Antennas and Wireless Propagation Letters, vol. 23, no. 7, pp. 2239-2243, July 2024; Reference [6] is Q. Liu, L. Zhu, J. Wang and W. Wu, "A Wideband Patch and SIW Cavity Hybrid Antenna With Filtering Response," in IEEE Antennas and Wireless Propagation Letters, vol. 19, no. 5, pp. 836-840, May 2020; Reference [7] is L. Wang, Z. Zhu and Y. En, "Performance Enhancement of Broadband Circularly Polarized Slot–Microstrip Antenna Using Parasitic Elements," in IEEE Antennas and Wireless Propagation Letters, vol. 20, no. 12, pp. 2255-2259, Dec. 2021.

[0023] Analysis of the data in Table 1 shows that the relative bandwidth of 32% of the broadband slot antenna based on the slow-wave structure of the present invention is better than that of the antennas disclosed in References [1], [2], [3], [5], [6], and [7], and is slightly worse than that of the antenna disclosed in Reference [4]. However, the antenna in Reference [4] has a very high profile and uses four dielectric substrates. The size of the broadband slot antenna based on the slow-wave structure of the present invention is smaller than that of the antennas disclosed in References [1], [5], and [7]. Although the sizes of the antennas disclosed in References [2], [3], [4], and [6] are relatively slightly smaller, their bandwidths are relatively narrow. The maximum in-band gain of the broadband slot antenna based on the slow-wave structure of the present invention is 8.7 dBi, which is better than that of the antennas disclosed in References [1], [2], [3], [6], and [7]. The maximum in-band gains of the antennas disclosed in References [4] and [5] are slightly higher, but their profiles are too high or their bandwidths are too narrow. It can be seen that the broadband slot antenna based on the slow-wave structure of the present invention has the best comprehensive performance in terms of profile, relative bandwidth, and gain.

Claims

1. A broadband slot antenna based on a slow-wave structure, characterized in that The invention comprises a dielectric substrate, a radiation patch, a slow-wave structure, an annular groove and a SIW cavity. The dielectric substrate is a circular plate, the radiation patch is a circular patch, the radiation patch is attached to the upper surface of the dielectric substrate, the radiation patch is coaxial with the dielectric substrate, and the radius of the radiation patch is equal to that of the dielectric substrate. The SIW cavity is formed by opening a plurality of metallized through holes evenly spaced along a circle and penetrating the dielectric substrate and the radiation patch from top to bottom on the dielectric substrate and the radiation patch. The SIW cavity is used to guide electromagnetic waves to transmit in the inner space surrounded by the plurality of metallized through holes, so that energy is concentrated at the center of the broadband slot antenna based on the slow-wave structure, so as to realize efficient radiation and reception of electromagnetic waves. The annular groove is opened on the radiation patch, and the The annular groove passes through the radiation patch up and down and is coaxial with the radiation patch. The annular groove is located in the inner space surrounded by multiple metallized through holes and has a spacing between the multiple metallized through holes. The annular groove is used to improve the impedance matching of the broadband slot antenna based on the slow-wave structure. The slow-wave structure is located on the inner side of the annular groove and does not contact the annular groove. The slow-wave structure is realized by opening multiple rectangular grooves in the radiation patch that pass through the radiation patch up and down and are evenly spaced along a circle. Each rectangular groove extends radially along the radiation patch. The slow-wave structure is used to introduce more frequency resonance points for the broadband slot antenna based on the slow-wave structure, thereby achieving broadband performance. At the same time, because of the slotting, the broadband slot antenna based on the slow-wave structure can have a lower profile.

2. A broadband slot antenna based on a slow-wave structure according to claim 1, characterized in that The dielectric substrate adopts a 5880 substrate with a radius of 20 mm and a thickness of 1.575 mm. The thickness of the radiation patch is 0.035 mm. The inner circle radius of the annular groove is 12.15 mm and the outer circle radius is 13 mm. The SIW cavity includes 60 metallized through holes, each of which has a radius of 0.5 mm, and the distance between the central axis of each metallized through hole and the central axis of the dielectric substrate is 17.7 mm. In the slow-wave structure, the number of rectangular grooves is 12, and the length direction of each rectangular groove is defined as the radial extension direction along the dielectric substrate. The length of each rectangular groove is 11.2 mm and the width is 0.45 mm.

3. The broadband slot antenna based on a slow-wave structure according to claim 2, characterized in that A coaxial cable is used for feeding. The coaxial cable vertically penetrates the dielectric substrate and the radiation patch from top to bottom, and the top of the coaxial cable is located in the same plane as the upper end surface of the radiation patch. The coaxial cable is located between two adjacent rectangular grooves and does not contact the two adjacent rectangular grooves. The distance between the center line of the coaxial cable and the center of the radiation patch is 4.37 mm. The angle between the line connecting the top center of the coaxial cable and the center of the upper end surface of the radiation patch and the line extending backward from the center of the upper end surface of the radiation patch in a direction perpendicular to the rear end surface of the dielectric substrate is 70.21°.

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