Miniaturized ultra-wideband circularly polarized antenna

Abstract

The invention relates to a miniaturized ultra-wideband circularly polarized antenna which comprises a cavity, an SMP connector is sintered at the bottom of the cavity, one end of a balun is welded in the cavity, and the other end of the balun is connected with a radiation PCB in a welding mode. A radiation slot is etched on the front surface of the radiation PCB, a solder mask is printed on the radiation slot, a resistor is mounted in the solder mask, and the resistor is connected with the radiation slot through soldering tin; when the antenna transmits signals, the SMP connector transmits the signals from the transmitter to the radiation PCB through the balun, the radiation PCB radiates the signals in the form of electromagnetic waves, when the antenna receives the signals, the radiation PCB receives the signals from the space, the signals are transmitted to the SMP connector through the balun, and the SMP connector transmits the signals to the receiver. The cross section of the antenna is low and is 6.25 mm, the size is small, meanwhile, the antenna has high gain, and the requirement of + / -60-degree airspace coverage can be met in a working frequency band.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-wideband antennas, and in particular to a miniaturized ultra-wideband circularly polarized antenna. Background Art

[0002] With the continuous development of science and technology, the application of electronic technology in the military field is becoming more and more extensive; although there are corresponding measures to counter the traditional interference and anti-interference methods, with the continuous emergence and development of new radar systems, electronic countermeasures have become a greater challenge. As the system bandwidth continues to increase, this requires that the bandwidth of the transmitting and receiving antennas must be continuously widened to adapt to the development of modern radars.

[0003] Ultra-wideband circularly polarized antennas usually use planar spiral antennas or conical spiral antennas. Conical spiral antennas have a high profile and are complex to process, and cannot meet the requirements of low profile. Planar spiral antennas are usually designed with a reflective back cavity when in use. Conventional planar spiral antennas have a high profile. In order to achieve ultra-wideband, there are usually two ways to achieve it: 1. Fill the back cavity with absorbing materials; 2. Make the back cavity into a cone or horn shape. However, these cannot meet the requirements of low profile and airspace coverage. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a miniaturized ultra-wideband circularly polarized antenna to solve the deficiencies of the prior art.

[0005] The object of the present invention is achieved by the following technical solutions: a miniaturized ultra-wideband circularly polarized antenna, which includes a cavity, an SMP connector sintered at the bottom of the cavity, one end of the balun is welded inside the cavity, and the other end is connected to the radiation PCB by welding; A radiation gap is etched on the front side of the radiation PCB, a solder mask is printed on the radiation gap, a resistor is installed inside the solder mask, and the resistor is connected to the radiation gap through solder; when the antenna transmits a signal, the SMP connector transmits the signal from the transmitter to the radiation PCB through the balun, and the radiation PCB then radiates the signal in the form of electromagnetic waves. When receiving a signal, the radiation PCB receives the signal from space, transmits it to the SMP connector through the balun, and the SMP connector then transmits the signal to the receiver.

[0006] The center of the radiation slot is an equiangular spiral, and the outer side is an Archimedean spiral, so as to increase the electrical length of the antenna at low frequency and improve the low frequency characteristics.

[0007] The solder resist is composed of two groups of square rings symmetrical with the central spiral of the radiating PCB. The solder resist is printed on the end of the Archimedean spiral gap outside the radiating gap. The resistor is installed in the square ring and connected to the radiating gap through the solder in the square ring. When the antenna is working, the resistor absorbs the terminal current, thereby reducing the lower limit of the operating frequency and expanding the operating bandwidth.

[0008] The antenna further comprises supporting foam, which is filled between the radiation PCB and the cavity to support the radiation PCB.

[0009] The radiation PCB is processed by using a substrate with a dielectric constant of 2.2, the balun is processed by using a substrate with a dielectric constant of 3.5, and the supporting foam is made of PMI foam with a low dielectric constant.

[0010] The present invention has the following advantages: a miniaturized ultra-wideband circularly polarized antenna with a low profile of 6.25 mm and a small volume, and at the same time has a high gain and can meet the requirements of ±60° airspace coverage within the working frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is an exploded schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the top view structure of the radiation PCB; Figure 3 Exploded schematic diagram of the radiation PCB structure In the figure: 1-radiation PCB, 2-balun, 3-support foam, 4-cavity, 5-SMP connector, 1-1-resistor, 1-2-solder mask, 1-3-radiation gap. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0013] like Figure 1-Figure 3As shown, the present invention specifically relates to a miniaturized ultra-wideband circularly polarized antenna to solve the problem in the prior art that the planar spiral antenna with a back cavity filled with absorbing materials has a low gain within the working frequency band. The antenna comprises a cavity 4, an SMP connector 5 is sintered at the bottom of the cavity 4, one end of a balun 2 is welded inside the cavity 4, and the other end is connected to a radiation PCB 1 by welding; Furthermore, a radiation gap 1-3 is etched on the front side of the radiation PCB 1, a solder resist 1-2 is printed on the radiation gap 1-3, a resistor 1-1 is installed inside the solder resist 1-2, and the resistor 1-1 is connected to the radiation gap 1-3 through solder.

[0014] Furthermore, the radiation PCB 1 is processed by using a substrate with a dielectric constant of 2.2, and radiation slots 1-3 are etched on the front of the radiation PCB 1. The center of the radiation slots 1-3 is an equiangular spiral, and the outer side is an Archimedean spiral.

[0015] Furthermore, the solder resist 1-2 is composed of two groups of square rings that are rotationally symmetrical about the center of the radiation PCB 1. The material of the solder resist is green oil, which is printed at the end of the Archimedean spiral gap of the radiation gap 1-3. When installing the resistor 1-1, solder is first applied to the radiation PCB 1. The solder is located on the radiation gap 1-3, specifically at the metal area inside the square ring of the solder resist 1-2, and the resistor 1-1 is also installed at this position. The resistor 1-1 is connected to the radiation gap 1-3 through solder, and the solder resist 1-2 can limit the range of solder flow, thereby fixing the position of the resistor.

[0016] Furthermore, the balun 2 is processed with a substrate having a dielectric constant of 3.5, and the supporting foam 3 is made of PMI foam with a low dielectric constant, which plays a role in supporting the radiation PCB 1. During installation, the SMP connector 5 is first sintered on the cavity 4, the balun 2 is welded inside the cavity 4, and then the supporting foam is installed in the cavity 4, and the radiation PCB 1 is connected to the balun 2 by welding.

[0017] The present invention designs the center of the radiation slot 1-3 into an equiangular spiral, which overcomes the shortcomings of the Archimedean spiral antenna with long arms and large transmission loss; the outer side is designed into an Archimedean spiral, which increases the electrical length of the antenna at low frequency, improves the low-frequency characteristics and reduces the size of the antenna. This design can also reduce the input impedance of the antenna. The input impedance of a conventional planar spiral antenna is 188 ohms, while the input impedance of the antenna of the present invention is 110 ohms, which can effectively reduce the length of the balun 2, thereby reducing the antenna profile. The balun 2 transmits signals between the SMP connector 5 and the radiation PCB 1, and also plays the role of unbalanced-balanced conversion and impedance transformation.

[0018] The antenna of the present invention can transmit and receive 8GHz-18GHz radio frequency signals. When the antenna transmits a signal, the SMP connector 5 transmits the signal from the transmitter to the radiation PCB1 through the balun, and the radiation PCB1 then radiates the signal in the form of electromagnetic waves; when receiving a signal, the radiation PCB1 receives the 8GHz-18GHz signal in space, transmits it to the SMP connector 5 through the balun 2, and the SMP connector 5 then transmits the signal to the receiver. When the antenna is working, the resistor 1-1 absorbs the terminal current, thereby reducing the lower limit of the operating frequency, expanding the operating bandwidth, and improving the antenna's directional pattern.

[0019] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used for various other combinations, modifications and improvements, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A miniaturized ultra-wideband circularly polarized antenna, characterized in that: It comprises a cavity (4), an SMP connector (5) is sintered at the bottom of the cavity (4), one end of the balun (2) is welded inside the cavity (4), and the other end is connected to the radiation PCB (1) by welding; A radiation gap (1-3) is etched on the front side of the radiation PCB (1), a solder mask (1-2) is printed on the radiation gap (1-3), a resistor (1-1) is installed inside the solder mask (1-2), and the resistor (1-1) is connected to the radiation gap (1-3) through solder; when the antenna transmits a signal, the SMP connector (5) transmits the signal from the transmitter to the radiation PCB (1) through the balun (2), and the radiation PCB (1) then radiates the signal in the form of electromagnetic waves; when receiving a signal, the radiation PCB (1) receives the signal from space and transmits it to the SMP connector (5) through the balun (2), and the SMP connector (5) then transmits the signal to the receiver.

2. A miniaturized ultra-wideband circularly polarized antenna according to claim 1, characterized in that: The center of the radiation slot (1-3) is an equiangular spiral, and the outer side is an Archimedean spiral, so as to increase the electrical length of the antenna at low frequency and improve the low-frequency characteristics.

3. The miniaturized ultra-wideband circularly polarized antenna according to claim 2, characterized in that: The solder resist (1-2) is composed of two groups of square rings symmetrically arranged about the central spiral of the radiating PCB (1). The solder resist (1-2) is printed at the end of the Archimedean spiral gap outside the radiating gap (1-3). The resistor (1-1) is installed in the square ring and connected to the radiating gap (1-3) through the solder in the square ring. When the antenna is working, the resistor (1-1) absorbs the terminal current, thereby reducing the lower limit of the operating frequency and expanding the operating bandwidth.

4. A miniaturized ultra-wideband circularly polarized antenna according to any one of claims 1 to 3, characterized in that: The antenna further comprises supporting foam (3), wherein the supporting foam (3) is filled between the radiating PCB (1) and the cavity (4) and plays a role in supporting the radiating PCB (1).

5. The miniaturized ultra-wideband circularly polarized antenna according to claim 3, characterized in that: The radiation PCB (1) is processed using a substrate with a dielectric constant of 2.2, the balun (2) is processed using a substrate with a dielectric constant of 3.5, and the support foam (3) is made of PMI foam with a low dielectric constant.

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