A compact broadband filter antenna and its mimo antenna based on cross-coupling structure

Abstract

The invention discloses a miniaturized broadband filter antenna based on a cross-coupling structure and a compact MIMO filter antenna composed of the cross-coupling structure, belonging to the technical field of microwave antennas. The filter antenna of the present invention includes a first dielectric substrate with the same size and closely attached, a metal floor, and a lower second dielectric substrate. A rectangular metal patch is arranged in the center of the upper surface of the first dielectric substrate and two surrounding A U-shaped parasitic patch around a rectangular metal patch, the upper surface of the second dielectric substrate is a metal floor with two gaps, and the lower surface of the dielectric substrate is a terminal bent open circuit with two transverse branches and shorting nails Microstrip feeding structure; the filter antenna is used as a unit to form a 2×2 MIMO antenna; the MIMO filter antenna of the present invention has a compact structure and has obvious advantages in bandwidth, size, and filter performance.

Description

technical field [0001] The invention belongs to the technical field of microwave antennas, and in particular relates to a miniaturized broadband filter antenna and a compact MIMO filter antenna based on a cross-coupling structure. Background technique [0002] The filter antenna integrates the filter and the antenna, which not only has radiation and filtering characteristics at the same time, but also has a compact structure. If it is applied to a massive MIMO system, not only the communication performance of the system can be improved, but also the miniaturization of the system can be better realized. [0003] In recent years, scholars at home and abroad have conducted research on filter antennas and their applications in MIMO systems. In 2017, X.Y. Zhang et al published a paper entitled "Low-Profile Dual-Band Filtering Patch Antenna and Its "Application to LTE MIMO System" article uses a microstrip antenna in series with a filter circuit to realize a dual-band antenna wi...

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Problems solved by technology

The edge spacing of the MIMO antenna elements composed of it is 0.15λ L (λ L is the wavelength corresponding to the center frequency of the low frequency band), and due to the large size of a single filter antenna, it is about 0.51λ L ×0.63λ L / 0.7λ H ×0.87λ H (λ H is the wavelength corresponding to the center frequency of the high frequency band), so the number of antennas that can be placed in a certain space is limited

[0004] In 2018, H.W.Deng et al published a paper titled "Closely spaced broadband MIMO differential filtering slotline antenna With CM suppression " article, using the gap on the floor as the radiation unit, while using the dual-mode resonator as the feed structure, to achieve a filter antenna with better out-of-band rejection, the antenna bandwidth is 25%, the gain is 3.3dBi, the antenna unit The edge distance is 0.05λ 0 (λ 0 is the wavelength corresponding to the center frequency), the isolation is 16dB, but the size of the filter antenna unit is still large, close to λ 0 ×λ 0

[0005] In 2019, J.F. Qian et al published a paper entitled "A wide stopband filtering patch antenna and its application in MIMO system " article, using parallel coupled lines as the feed structure, designed a filter antenna with high-order harmonic suppression, the gain is 2.59dBi, and the size of the filter antenna unit is about 0.4λ 0 ×0.4λ 0 , when the MIMO antenna element edge spacing is 0.098λ 0 , the isolation is 26.5dBi, but the working bandwidth of the antenna is only 3.2%

[0006] With the development of massive MIMO systems towards compactness and miniaturization, it is difficult for filter antennas based on the above technologies to meet the requirements of bandwidth and size at the same time

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