Low-profile dual-band filtering patch antenna

• US 10,347,990 B2
• Filed: 05/23/2017
• Issued: 07/09/2019
• Est. Priority Date: 11/25/2016
• Status: Active Grant

• Current Assignee: South China University of Technology
• Original Assignee: South China University of Technology
• Inventors: Zhang, Xiu Yin, Zhang, Yao, Pan, Yong-Mei, Duan, Wen
• Primary Examiner(s): Mancuso, Huedung X
• Application Number:
  US15/602,116
• Publication Number:
  US 20180151955A1
• Time in Patent Office: 777 Days
• Field of Search: 343700 MS
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/521 reducing the coupling between adjacent antennas
• CPC Class Codes: H01Q 19/005 Patch antenna using one or more coplanar parasitic elements
• CPC Class Codes: H01Q 5/30 Arrangements for providing operation on different wavebands
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 9/0414 in a stacked or folded configuration
• CPC Class Codes: H01Q 9/045 with particular feeding means for circular polarisation H01Q9/0428
• CPC Class Codes: H01Q 9/0457 electromagnetically coupled to the feed line
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00
• CPC Class Codes: H04B 7/0413 MIMO systems

Abstract

A low-profile dual-band filtering patch antenna and its application to LTE MIMO system are disclosed. By using two embedded U-shaped radiating patches and a multi-stub microstrip feed-line, two operating bands and four radiation nulls can been generated and individually controlled, the design is thus very simple and flexible. Based on the proposed low-profile dual-band filtering patch antenna, a MIMO antenna with a very low profile, low mutual coupling and low ECCs has been presented.

Claims

1. A low-profile dual-band filtering patch antenna comprising a substrate, a ground on a bottom layer of the substrate, and a first U-shaped patch operating at upper frequency bands, a second U-shaped patch operating at lower frequency bands and a multi-stub microstrip line, the first U-shaped patch having a smaller size is embedded in the second U-shaped patch having a larger size;

wherein, when operating at the upper frequency bands, the multi-stub microstrip line forms a feeding structure, and when operating at the lower frequency bands, the multi-stub microstrip line and the first U-shaped patch form the feeding structure;

wherein the multi-stub microstrip line is arranged on a top layer of the substrate and comprises a main transmission line inserted into an opening of the first U-shaped patch, a first pair of open-ended stubs and a second pair of open-ended stubs loaded at both sides close to openings of the first U-shaped patch and the second U-shaped patch.

2. The low-profile dual-band filtering patch antenna according to claim 1, wherein the first U-shaped patch and the second U-shaped patch are arranged symmetrically relative to a central axis.

3. The low-profile dual-band filtering patch antenna according to claim 1, wherein the main transmission line is loaded along the central axis, the first pair of open-ended stubs and the second pair of open-ended stubs are loaded symmetrically on both sides of the main transmission line.

4. The low-profile dual-band filtering patch antenna according to claim 3, wherein the first pair of open-ended stubs having a shorter length and the second pair of open-ended stubs having a longer length are parallel to each other, the main transmission line crosses the first pair of open-ended stubs and reaches the second pair of open-ended stubs.

5. The low-profile dual-band filtering patch antenna according to claim 3, wherein a length of the first pair of open-ended stubs is shorter than a length of the first U-shaped patch, and a length of the second pair of open-ended stubs is longer than the length of the first U-shaped patch but shorter than a length of the second U-shaped patch.

6. A low-profile dual-band filtering patch antenna comprising a substrate, a ground on a bottom layer of the substrate, and a first U-shaped patch operating at upper frequency bands, a second U-shaped patch operating at lower frequency bands and a multi-stub microstrip line, the first U-shaped patch having a smaller size is embedded in the second U-shaped patch having a larger size;

wherein, when operating at the upper frequency bands, the multi-stub microstrip line forms a feeding structure, and when operating at the lower frequency bands, the multi-stub microstrip line and the first U-shaped patch form the feeding structure;

wherein the second U-shaped patch and the multi-stub microstrip line are arranged symmetrically relative to a central axis;

wherein the multi-stub microstrip line comprises a main transmission line inserted into an opening of the first U-shaped patch, a first pair of open-ended stubs and a second pair of open-ended stubs loaded at both sides close to openings of the first U-shaped patch and the second U-shaped patch;

wherein the main transmission line is loaded along the central axis, the first pair of open-ended stubs and the second pair of open-ended stubs are loaded symmetrically on both sides of the main transmission line, the first pair of open-ended stubs having a shorter length and the second pair of open-ended stubs having a longer length are parallel to each other, the main transmission line crosses the first pair of open-ended stubs and reaches the second pair of open-ended stubs.

7. The low-profile dual-band filtering patch antenna according to claim 6, wherein a length of the first pair of open-ended stubs is shorter than a length of the first U-shaped patch, and a length of the second pair of open-ended stubs is longer than the length of the first U-shaped patch but shorter than a length of the second U-shaped patch, and an input port connecting to the main transmission line.

8. A LET MIMO system, comprising a substrate, a ground on a bottom layer of the substrate, and at least one low-profile dual-band filtering patch antenna unit arranged on the substrate, wherein the low-profile dual-band filtering patch antenna unit comprises a first U-shaped patch operating at upper frequency bands, a second U-shaped patch operating at lower frequency bands and a multi-stub microstrip line on a top layer of the substrate, the first U-shaped patch having a smaller size is embedded in the second U-shaped patch having a larger size;

wherein, when operating at the upper frequency bands, the multi-stub microstrip line forms a feeding structure, and when operating at the lower frequency bands, the multi-stub microstrip line and the first U-shaped patch form the feeding structure;

the multi-stub microstrip line comprises a main transmission line inserted into an opening of the first U-shaped patch, a first pair of open-ended stubs and a second pair of open-ended stubs loaded at both sides close to openings of the first U-shaped patch and the second U-shaped patch.

9. The LET MIMO system according to claim 8, wherein comprising at least two low-profile dual-band filtering patch antenna units arranged at two sides of a substrate central axis of one substrate.

10. The LET MIMO system according to claim 8, wherein comprising at least four low-profile dual-band filtering patch antenna units arranged at four angles of one rectangular substrate.

11. The LET MIMO system according to claim 9, wherein each two low-profile dual-band filtering patch antenna units are arranged parallelly and close to each other, and isolated by a decoupling network.

12. The LET MIMO system according to claim 11, wherein the decoupling network comprising at least three interdigital short-ended lines with a length of about a quarter-wavelength at the lower frequency bands.

13. The LET MIMO system according to claim 8, wherein the first U-shaped patch and the second U-shaped patch are arranged symmetrically relative to a central axis.

14. The LET MIMO system according to claim 8, wherein the main transmission line is loaded along the central axis, the first pair of open-ended stubs and the second pair of open-ended stubs are loaded symmetrically on both sides of the main transmission line.

15. The LET MIMO system according to claim 14, wherein the first pair of open-ended stubs having a shorter length and the second pair of open-ended stubs having a longer length are parallel to each other, the main transmission line crosses the first pair of open-ended stubs and reaches the second pair of open-ended stubs.

16. The LET MIMO system according to claim 14, wherein a length of the first pair of open-ended stubs is shorter than a length of the first U-shaped patch, and a length of the second pair of open-ended stubs is longer than the length of the first U-shaped patch but shorter than a length of the second U-shaped patch.

17. The LET MIMO system according to claim 11, wherein the first U-shaped patch and the second U-shaped patch are arranged symmetrically relative to a central axis;

the multi-stub microstrip line comprises a main transmission line inserted into an opening of the first U-shaped patch, a first pair of open-ended stubs and a second pair of open-ended stubs loaded at both sides close to openings of the first U-shaped patch and the second U-shaped patch;

the main transmission line is loaded along the central axis, the first pair of open-ended stubs and the second pair of open-ended stubs are loaded symmetrically on both sides of the main transmission line;

the first pair of open-ended stubs having a shorter length and the second pair of open-ended stubs having a longer length are parallel to each other, the main transmission line crosses the first pair of open-ended stubs and reaches the second pair of open-ended stubs;

a length of the first pair of open-ended stubs is shorter than a length of the first U-shaped patch, and a length of the second pair of open-ended stubs is longer than the length of the first U-shaped patch but shorter than a length of the second U-shaped patch.

18. The LET MIMO system according to claim 12, wherein the first U-shaped patch and the second U-shaped patch are arranged symmetrically relative to a central axis;

the multi-stub microstrip line comprises a main transmission line inserted into an opening of the first U-shaped patch, a first pair of open-ended stubs and a second pair of open-ended stubs loaded at both sides close to openings of the first U-shaped patch and the second U-shaped patch;

the main transmission line is loaded along the central axis, the first pair of open-ended stubs and the second pair of open-ended stubs are loaded symmetrically on both sides of the main transmission line;

the first pair of open-ended stubs having a shorter length and the second pair of open-ended stubs having a longer length are parallel to each other, the main transmission line crosses the first pair of open-ended stubs and reaches the second pair of open-ended stubs.