A dual-band antenna

Abstract

The present application belongs to the field of antenna technology, and provides a dual-frequency antenna, comprising: a signal input end, a first radiation unit and a second radiation unit; the first radiation unit comprises a first input section, an input matching section, a first signal transmission section and an end folding section; wherein the first signal transmission section is in a "U" shape to form a first matching cavity, and a first gap section is formed between the input matching section and the end folding section; the second radiation unit comprises a second input section, an isolation section and a second signal transmission section; wherein the isolation section and the second signal transmission section form a closed annular cavity, and the closed annular cavity comprises a second matching cavity, a second gap section and a third gap section; thereby forming a hybrid structure antenna of a gap-coupled radiation and a special-shaped annular hybrid structure, and can realize dual-band operation in a smaller space, and has good impedance matching, thereby solving the problems of fewer frequency bands and poor impedance matching in existing antennas.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to a dual-frequency antenna. Background Art

[0002] With the rapid development of mobile communications and the improvement of people's material living standards, handheld mobile communication devices have become an indispensable tool in daily life. The penetration rate of various mobile terminal devices in society is increasing very fast. The Internet, radio and television networks, and data communication networks will be merged into one network. The rich network information resources can allow individuals to obtain the desired information through one network, and can also allow enterprises to provide a variety of forms of network access. Among them, the most convenient and fastest way is wireless access, because wireless access saves a lot of network laying costs, can be quickly planned, installed, and put into use, and maintenance is relatively simple.

[0003] However, as an important part of the entire communication system, the RF transceiver front end is also constantly developing with the updates of the entire communication field. However, the existing antennas have problems such as fewer frequency bands and poor impedance matching. Summary of the invention

[0004] The purpose of the present application is to provide a dual-frequency antenna, aiming to solve the problems of fewer frequency bands and poor impedance matching in existing antennas.

[0005] The embodiment of the present application provides a dual-frequency antenna, comprising: a signal input terminal; a first radiation unit and a second radiation unit respectively connected to the signal input terminal;

[0006] The first radiation unit comprises a first input section, an input matching section, a first signal transmission section and a terminal folding section connected in sequence; wherein the first signal transmission section is in a "U" shape to form a first matching cavity, and a first gap section is formed between the input matching section and the terminal folding section;

[0007] The second radiation unit includes a second input section, an isolation section and a second signal transmission section connected in sequence; wherein the isolation section and the second signal transmission section form a closed annular cavity, and the closed annular cavity includes a second matching cavity, a second gap section and a third gap section.

[0008] Optionally, the isolation segment and the first segment of the second signal transmission segment form the second matching cavity, and the shape of the second matching cavity is a triangle.

[0009] Optionally, the second gap segment is formed between the isolation segment and the second segment of the second signal transmission segment, and the second gap segment includes a plurality of gap structures with different widths.

[0010] Optionally, the third gap segment is formed between the isolation segment and the third segment of the second signal transmission segment, and the angle between the third gap segment and the second gap segment is 90 degrees.

[0011] Optionally, the second section and the third section of the second signal transmission section form a “U”-shaped structure.

[0012] Optionally, the second gap segment is in an “L” shape.

[0013] Optionally, the width of the isolation segment is greater than the width of the second signal transmission line.

[0014] Optionally, the first gap segment is in an “L” shape.

[0015] Optionally, the width of a first segment of the first signal transmission segment is greater than the width of a second segment.

[0016] Optionally, the width of the end folded section is greater than the width of the third section of the first signal transmission line.

[0017] In the dual-frequency antenna provided in the present application, the dual-frequency antenna includes: a signal input end; a first radiation unit and a second radiation unit respectively connected to the signal input end; the first radiation unit includes a first input section, an input matching section, a first signal transmission section and an end folding section connected in sequence; wherein the first signal transmission section is in a "U" shape to form a first matching cavity for impedance matching, and a first gap section is formed between the input matching section and the end folding section; the second radiation unit includes a second input section, an isolation section and a second signal transmission section connected in sequence; wherein the isolation section and the second signal transmission section form a closed annular cavity, and the closed annular cavity includes a second matching cavity for impedance matching, and a second gap section for generating a second frequency band resonant signal and a third gap section for generating a third frequency band resonant signal; thereby forming a hybrid structure antenna of a gap-coupled radiation and a special-shaped annular hybrid structure, and can realize dual-band operation in a smaller space, and has good impedance matching, which solves the problem of fewer frequency bands and poor impedance matching in existing antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a dual-band antenna provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0021] The present application embodiment provides a dual-frequency antenna. Figure 1 As shown, the dual-frequency antenna in this embodiment includes: a signal input terminal 100; a first radiation unit and a second radiation unit respectively connected to the signal input terminal 100; the first radiation unit includes a first input section 60, an input matching section 61, a first signal transmission section and an end folding section 63 connected in sequence; wherein the first signal transmission section is in a "U" shape to form a first matching cavity 20, and a first gap section 10 connected to the first matching cavity 20 is formed between the input matching section 61 and the end folding section 63; the second radiation unit includes a second input section 70, an isolation section 71 and a second signal transmission section connected in sequence; wherein the isolation section 71 and the second signal transmission section form a closed annular cavity, and the closed annular cavity includes a second matching cavity 30, a second gap section 40 and a third gap section 50 connected in sequence.

[0022] In this embodiment, the first radiation unit and the second radiation unit constitute the antenna body of the dual-band antenna and are separated into two independent parts by the signal input end. Each radiation unit corresponds to a frequency band, thereby forming a radiation body for multi-band radiation. By combining the first radiation unit with the second radiation unit, a hybrid structure antenna of slot-coupled radiation and special-shaped ring hybrid structure is formed. The hybrid structure antenna can realize dual-band operation in a smaller space and has good impedance matching, which solves the problem of fewer frequency bands and poor impedance matching in existing antennas.

[0023] Specifically, in this embodiment, the first signal transmission section is composed of a front section, a middle section and a terminal section. The three sections are the first section 621, the second section 622 and the third section 623. The first section 621, the second section 622 and the third section 623 are connected in sequence and are in a "U" shape to form a first matching cavity 20. The first matching cavity 20 is used for impedance matching. A first slot section 10 is formed between the terminal folding section 63 and the input matching section 61. The first slot section 10 is a coupling slot structure for generating a resonant signal in the first frequency band. The resonant frequency of the first radiation unit is adjusted by adjusting the length or width of the coupling slot. For example, a radiation mechanism similar to a semi-open waveguide cavity is adopted to form an edge radiation mode. The first slot section 10 is connected to the first matching cavity 20 as a whole. The length of the first slot section 10 and the first matching cavity 20 corresponds to the first frequency band. The range of the first frequency band can be 2.4 GHz-2.5 GHz.

[0024] In this embodiment, the radiation frequency range of the second radiation unit is a broadband resonant frequency, and the radiation is performed through a three-part resonant cavity. The second signal transmission section is composed of a three-section structure of a front section, a middle section, and a terminal section. The three-section structures are respectively a first section 721, a second section 722, and a third section 723. The first section 721, the second section 722, and the third section 723 are connected in sequence, wherein the isolation section 71 and the second signal transmission section form a closed annular cavity, and the closed annular cavity includes a second matching cavity 30, a second slot section 40, and a third slot section 50. Among them, the second matching cavity 30, the second slot section 40, and the third slot section 50 form a complete inner ring, and the second slot section 40 and the third slot section 50 in the second radiation unit resonate in two adjacent frequency bands, respectively, thereby forming a complete radiation frequency band together. For example, the second slot section 40 generates a second frequency band resonant signal, and the third slot section 50 generates a third frequency band resonant signal, and the second frequency band is adjacent to the third frequency band.

[0025] The coupled slot antenna in this embodiment has the unique advantages of simple structure, low manufacturing cost, high radiation efficiency, etc. According to the edge radiation principle of the open waveguide cavity of the electromagnetic field, the slot length is determined according to the principle of 1 / 2*λ. The radiation impedance Rr of the ideal half-wave slot antenna is (60л) 2 / 73.1=500Ω, which is quite different from the transmission impedance of the communication coaxial RF cable. Therefore, impedance matching design is required to avoid compressing the effective matching frequency band width.

[0026] Furthermore, in one embodiment, the shape of the first signal transmission segment is a "U"-shaped structure, thereby forming a first matching cavity 20 with an impedance matching effect. The first matching cavity 20 is connected to the first slot segment 10. The first segment 621, the second segment 622 and the third segment 623 in the first signal transmission segment can form an impedance matching segment to achieve transitional matching between the impedance of the RF circuit and the impedance of the slot antenna. Specifically, by adjusting the width and length of the impedance matching segment, a smooth conversion of the input impedance from 50Ω (or 75Ω) to the characteristic impedance of the slot antenna (500Ω) can be achieved. The impedance matching segment can extend to the signal feeding point, which can be the signal input terminal 100.

[0027] In one embodiment, the total length of the first signal transmission segment in the first radiation unit is 1 / 4 wavelength of the first frequency segment, thereby generating a resonant signal, and forming efficient radiation through the gap coupling current generated by the first gap segment 10 formed between the end folding segment 63 and the input matching section 61. The front section of the first signal transmission segment also forms transmission impedance matching by changing the width adjustment of the first matching cavity 20.

[0028] In one embodiment, the input matching section 61 can eliminate the inductive capacitance Cr and the inductive inductance Lr generated when the signal of the signal input terminal 100 is transmitted in the first section 621 of the first signal transmission section, so as to obtain good signal transmission characteristics.

[0029] In one embodiment, the isolation segment 71 and the first segment 721 of the second signal transmission segment form the second matching cavity 30 , and the shape of the second matching cavity 30 is a triangle.

[0030] In this embodiment, by setting the second matching cavity 30 to be triangular, a good impedance change rate can be achieved in the entire operating frequency range. At the same time, this structure also makes it easy to leave space for the optimal width design required by the isolation section 71.

[0031] In one embodiment, the triangular design of the second matching cavity 30 can gradually convert the impedance of 50Ω (or 75Ω) of the signal input end 100 into the characteristics of a loop antenna. By setting the second matching cavity 30 to a triangle, a good impedance change rate can be achieved in the entire operating frequency range, thereby adapting to the wider operating frequency (5.15GHz-5.85GHz) and higher bandwidth ratio of the second radiation unit.

[0032] Furthermore, in this embodiment, the second matching cavity 30 is also configured as a main impedance matching loop within the entire radiation frequency range corresponding to the second radiation unit.

[0033] In one embodiment, the second gap section 40 is formed between the isolation section 71 and the second section 722 of the second signal transmission section, and the second gap section 40 includes a plurality of gap structures with different widths.

[0034] In one embodiment, the third gap section 50 is formed between the isolation section 71 and the third section 723 of the second signal transmission section, and the angle between the third gap section 50 and the second gap section 40 is 90 degrees.

[0035] In one embodiment, the second section 722 and the third section 723 of the second signal transmission section form a "U"-shaped structure. In this embodiment, by compressing the second signal transmission section into an irregular curved long strip, for example, an irregular "U"-shaped structure, the gap width of the entire long strip is very small, and a strong coupling current can be formed on both sides of the cavity, wherein the gap length at the end of the long strip (i.e., the third gap section 50) corresponds to 1 / 4 wavelength of the high frequency of the second operating frequency, and the gap in the middle section of the long strip (i.e., the second gap section 40) corresponds to 1 / 4 wavelength of the low frequency of the second operating frequency, thereby synthesizing a wide-band operating characteristic.

[0036] In this embodiment, each resonance in the second radiation unit can utilize the entire volume, so there are three resonance modes, namely 1 / 2λ, 1*λ, and 3 / 2λ, so that it can be applied to broadband communication antennas or multi-frequency antennas. The radiation impedance value of the loop antenna is Rr=31171*(A 4 / λ 4 ), where A is the area enclosed by the loop antenna, in meters, and λ is the wavelength of the working signal, in meters. It can be calculated from this formula that the size of Rr is in the milliohm range, so there is a very large deviation between its radiation impedance value and the transmission impedance of the coaxial RF cable used for communication (usually 75Ω or 50Ω). The second section 722 and the third section 723 of the second signal transmission section form a "U"-shaped structure, thereby forming the second matching cavity 30, the second slot section 40 and the third slot section 50 in sequence, which can achieve good transmission impedance matching.

[0037] In one embodiment, the width of the second slot segment 40 gradually decreases along the direction of the third slot segment 50, wherein the coupling length of the third slot segment 50 corresponds to a resonant signal with a resonant frequency in the third frequency segment, and the resonant frequency range may be 5.55 GHz-5.85 GHz, and the coupling length of the second slot segment 40 corresponds to a resonant signal with a resonant frequency in the second frequency segment, and the resonant frequency range may be 5.15 GHz-5.55 GHz.

[0038] In one embodiment, the second slot segment 40 is in an "L" shape. In this embodiment, the second slot segment 40 has two widths, wherein the slot of the shorter width is longer, and the slot of the longer width is shorter, thereby forming an "L"-shaped structure, which can further realize the transition between different resonant frequencies.

[0039] In one embodiment, the width of the isolation segment 71 is greater than the width of the second signal transmission line. In this embodiment, the isolation segment 71 can fully isolate the coupling current between the signal input segment 100 and the three-part structure of the second signal transmission segment. The larger width of the isolation segment 71 forms sufficient isolation, which can eliminate the high-order mode surface current formed on the surface of the transmission line by the signal at the operating frequency (e.g., 5.15GHz-5.85GHz), thereby avoiding reducing the radiation efficiency of the second radiation unit. Furthermore, the width of the isolation segment 71 can also be used to form a second matching cavity 30, so that the second matching cavity 30 generates an impedance gradient network, thereby generating a good impedance match in a wide band.

[0040] In one embodiment, the first radiation element may serve as a finite ground for the second radiation element, thereby serving as a reference ground for a radiation antenna in the second radiation element to form radiation.

[0041] In one embodiment, the first slot segment 10 is in an “L” shape. In this embodiment, the first slot segment 10 is connected to the first matching cavity 20 by folding, which can further improve the impedance matching effect of the first matching cavity 20.

[0042] In one embodiment, the width of the first section 621 of the first signal transmission section is greater than the width of the second section 622. In this embodiment, by making the width of the first section 621 in the first signal transmission section greater than the width of the second section 622, a smooth conversion of the input impedance from 50Ω (or 75Ω) to the characteristic impedance of the slot antenna (500Ω) is achieved. Furthermore, the first section 621 is closer to the signal input terminal 100 than the second section 622, and the first section 621 has a larger width to form sufficient isolation to fully isolate the coupling current in the signal input section 100 and the first signal transmission section, thereby avoiding reducing the radiation efficiency of the first radiating unit.

[0043] In one embodiment, the width of the terminal folded section 63 is greater than the width of the third section 623 of the first signal transmission line. In this embodiment, by designing the width of the terminal folded section 63 to be wider, the high-order mode surface current derived from the terminal radiation current can be eliminated, avoiding the reduction of radiation efficiency, thereby improving the radiation efficiency of the first radiation unit.

[0044] In one embodiment, the antenna body of the dual-frequency antenna in this embodiment can be manufactured by PCB printing, and the antenna can be installed alone on the casing of the whole machine.

[0045] In one embodiment, in the dual-band antenna of this embodiment, the first radiating unit can serve as a limited ground for the second radiating unit, and the input end of the first radiating unit serves as a grounding point and a signal input end 100 (ie, a signal feeding point) connected to the RF system through a coaxial cable.

[0046] In one embodiment, the antenna body (i.e., the first radiation unit and the second radiation unit) is printed on a PCB board, and can be made into a PCB antenna alone, or printed on a system mainboard to be made into an onboard antenna. The grounding point and the signal feeding point on the antenna body are connected to the RF system via a 50-ohm coaxial cable. That is, the antenna installation method is assembly, and the antenna body is printed on a PCB board, and can be made into a PCB antenna alone and installed on the inner wall of the casing, or printed on the system mainboard to be made into an onboard antenna. Both installation methods can be fed by a 50-ohm coaxial cable, and connected to the RF system of the Netcom terminal device via a coaxial cable to work. Compared with the traditional PCB printed dipole antenna, this antenna can be used in a smaller space in the casing, ensuring efficiency and gain, achieving ultra-wideband dual-band and simple structure.

[0047] In the dual-frequency antenna provided in the present application, the dual-frequency antenna includes: a signal input end; a first radiation unit and a second radiation unit respectively connected to the signal input end; the first radiation unit includes a first input section, an input matching section, a first signal transmission section and an end folding section connected in sequence; wherein the first signal transmission section is in a "U" shape to form a first matching cavity, and a first gap section is formed between the input matching section and the end folding section; the second radiation unit includes a second input section, an isolation section and a second signal transmission section connected in sequence; wherein the isolation section and the second signal transmission section form a closed annular cavity, and the closed annular cavity includes a second matching cavity, a second gap section and a third gap section; thereby forming a hybrid structure antenna of a slot-coupled radiation and a special-shaped annular hybrid structure, and can realize dual-band operation in a smaller space, and has good impedance matching, which solves the problems of fewer frequency bands and poor impedance matching in existing antennas.

[0048] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A dual-frequency antenna, characterized in that: include: A signal input end, and a first radiation unit and a second radiation unit respectively connected to the signal input end; The first radiation unit comprises a first input section, an input matching section, a first signal transmission section and a terminal folding section connected in sequence; wherein the first signal transmission section is composed of a first section, a second section and a third section connected in sequence, the first signal transmission section is in a "U" shape to form a first matching cavity for impedance matching, and a first gap section is formed between the input matching section and the terminal folding section, which is connected to the first matching cavity and is used to generate a resonant signal in a first frequency band; The second radiation unit comprises a second input section, an isolation section and a second signal transmission section connected in sequence; wherein the isolation section and the second signal transmission section form a closed annular cavity, and the closed annular cavity comprises a second matching cavity for impedance matching, and a second slot section for generating a second frequency band resonant signal and a third slot section for generating a third frequency band resonant signal; The signal input end is located between the first radiation unit and the second radiation unit; the first radiation unit corresponds to a first frequency band, and the total length of the first signal transmission segment in the first radiation unit is 1 / 4 wavelength of the first frequency band.

2. The dual-band antenna according to claim 1, characterized in that: The isolation section and the first section of the second signal transmission section form the second matching cavity, and the shape of the second matching cavity is a triangle.

3. The dual-band antenna according to claim 1, wherein: The second gap section is formed between the isolation section and the second section of the second signal transmission section, and the second gap section includes a plurality of gap structures with different widths.

4. The dual-band antenna according to claim 3, characterized in that: The third gap section is formed between the isolation section and the third section of the second signal transmission section, and the angle between the third gap section and the second gap section is 90°.

5. The dual-band antenna according to claim 4, characterized in that: The second section and the third section of the second signal transmission section form a "U"-shaped structure.

6. The dual-band antenna according to claim 1, characterized in that: The second gap section is in an "L" shape.

7. The dual-band antenna according to claim 1, characterized in that: The width of the isolation segment is greater than the width of the second signal transmission segment.

8. The dual-band antenna according to claim 1, wherein: The first gap section is in an "L" shape.

9. The dual-band antenna according to claim 1, wherein: The width of a first section of the first signal transmission section is greater than the width of a second section.

10. The dual-band antenna according to claim 1, wherein: The width of the terminal folded section is greater than the width of the third section of the first signal transmission section.

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