CN114430110A - an antenna - Google Patents

Abstract

The invention relates to the field of millimeter wave detection, in particular to an antenna with bidirectional radiation capability, which comprises an end-fire antenna and a side-fire antenna, wherein the end-fire antenna and the side-fire antenna are arranged on the same PCB, and an included angle between the main polarization direction of the end-fire antenna and the main polarization direction of the side-fire antenna is 80-100 degrees. According to the invention, the end-fire antenna and the side-fire antenna are simultaneously arranged on the PCB, so that simultaneous transmission and reception in two directions are realized, a PCB and a set of control system are saved, and the manufacturing cost of the millimeter wave radar system for realizing bidirectional detection, particularly bidirectional detection in the orthogonal direction, is greatly saved.

Description

an antenna

technical field

The invention relates to the field of millimeter wave detection, in particular to an antenna with bidirectional radiation capability.

Background technique

Millimeter wave detection is a very promising new detection method. Compared with ultrasonic detection and infrared detection, it has the characteristics of high accuracy and is not easy to be blocked by obstacles. Millimeter wave radar, as the name suggests, is a radar technology that utilizes millimeter waves with a wavelength of 10mm to 1mm and a frequency of 30-300GHz. The radar spectrum is 60-64GHz for industrial applications and 76-81GHz for automotive applications. Since the wavelength of the signal at these frequencies is shorter, the size of the radar antenna is also smaller. The small size of radar, coupled with advanced antenna technologies such as Antenna-on-Package (AoP) and Antenna-on-PCB (AoPCB), enables mmWave radars to find widespread use in automotive navigation, building automation, healthcare, and industrial applications. Millimeter-wave (mmWave) radar emits electromagnetic waves, and anything in its path reflects the signal back. By capturing and processing reflected signals, radar systems can determine the distance, velocity and angle of objects. Millimeter-wave radar can provide millimeter-level accuracy in object distance detection, making it an ideal sensing technology for human biological signals. In addition, millimeter wave technology can also perform non-contact continuous monitoring of patients and ordinary users (such as the elderly who need monitoring), so it is more convenient for doctors, patients or ordinary users. In order to meet wider application requirements and achieve large-scale deployment, the current mainstream development trend of millimeter-wave radar is cost reduction.

Usually, the millimeter wave radar antenna is realized by PCB board, and the advantage is that the processing technology is mature and the quality is controllable. In the prior art, on the one hand, only one-way millimeter-wave radar antennas are usually involved, that is, a set of millimeter-wave radar systems are set on a PCB board to perform one-way detection; In the application of radar detection, those skilled in the art need to set up two sets of millimeter-wave radar systems using the existing technology, correspondingly need two PCB boards, two processors, especially two sets of millimeter-wave array antennas, for example, the publication number is CN209044871U's utility model "two-way multi-lane traffic monitoring device based on 77GHz millimeter-wave radar" patent uses forward millimeter-wave radar and reverse millimeter-wave radar. Since mmWave PCBs are expensive to manufacture, using existing technology will undoubtedly multiply the cost of the overall system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the problem of high cost of the millimeter-wave radar system in the application of millimeter-wave radar detection in two directions in the prior art, and to provide an antenna with bidirectional radiation capability.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

An antenna, including an end-fire antenna and a side-fire antenna, the end-fire antenna and the side-fire antenna are arranged on the same PCB board, and the main polarization direction of the end-fire antenna and the main polarization direction of the side-fire antenna are The included angle between them is 80° to 100°.

In the present invention, the end-fire antenna and the side-fire antenna are simultaneously arranged on a PCB board, and the main polarization directions of the end-fire antenna and the side-fire antenna are at an angle of 80° to 100°, so that the antenna of the present invention can pass through the same PCB board. It realizes the transmission and reception in the two directions of the side-fire direction and the end-fire direction, which saves a PCB board and a set of control systems, and greatly saves the manufacture of millimeter-wave radar systems that realize two-way detection, especially two-way detection in orthogonal directions. cost.

Preferably, the isolation degree between the incident port of the end-fire antenna and the incident port of the side-fire antenna is set to be greater than 15 dB.

Preferably, the gain of the end-fire antenna in the side-fire direction is smaller than the gain of the side-fire antenna in the side-fire direction by a first difference X, and/or the gain of the side-fire antenna in the end-fire direction is set The gain of the end-fire antenna in the end-fire direction is smaller than the first difference value; the first difference value X≧5dB.

Preferably, the end-fire antenna transmits and/or receives in a direction parallel to the plane on which the PCB board is located, and the side-fire antenna transmits and/or receives in a direction perpendicular to the plane on which the PCB board is located.

Preferably, a plurality of end-fire antennas are connected in parallel to form an end-fire antenna array, and a plurality of side-fire antennas are connected in parallel to form a side-fire antenna array.

Preferably, the type of the end-fire antenna is a vivaldi antenna, a Yagi antenna, a quasi-Yagi antenna or a log-periodic antenna.

Preferably, the type of the side-emitting antenna is a loop slot antenna, a slot antenna, a loop antenna or a patch antenna.

Based on the same inventive concept, an antenna device is proposed, including a power divider and an antenna described in any one of the above, wherein the radio frequency signal input to the power divider is output to the end-fire antenna and the side-fire antenna respectively .

Preferably, the power divider is a Wilkinson power divider.

Based on the same inventive concept, an antenna device is proposed, including a radio frequency switch and an antenna according to any one of the above, wherein the incident port of the end-fire antenna and the incident port of the side-fire antenna are both connected to the and a radio frequency switch, which is used for switching the end-fire antenna and the side-fire antenna.

Compared with the prior art, the beneficial effects of the present invention:

1. In the present invention, an end-fire antenna and a side-fire antenna are simultaneously arranged on a PCB board, and the main polarization directions of the end-fire antenna and the side-fire antenna form an included angle of 80° to 100°, preferably 90°. The included angle enables the antenna of the present invention to achieve bidirectional transmission and reception in the side-fire direction and the end-fire direction through the same PCB board. Through the preferred embodiment, in the direction perpendicular to the plane of the PCB board (ie the side-fire direction) It transmits and receives at the same time in the direction parallel to the plane of the PCB board (ie the end-fire direction), saving a PCB board and a set of control systems, and greatly saving the millimeter-wave radar that realizes two-way detection, especially two-way detection in orthogonal directions. The manufacturing cost of the system.

2. The present invention realizes the functions of the end-fire antenna and the side-fire antenna on one PCB board, so that the space of the two-way millimeter-wave antenna can be made more flat, the manufacturing size of the millimeter-wave radar system can be made smaller, and the space can be saved.

Description of drawings

FIG. 1 is a schematic diagram of the principle of an orthogonal two-way millimeter-wave radar system in the prior art.

FIG. 2 is a schematic diagram of the principle of the antenna of the present invention.

FIG. 3 is a schematic diagram of the principle of the antenna of the present invention.

FIG. 4 is a schematic structural diagram of the antenna of Embodiment 1. FIG.

FIG. 5 is a schematic structural diagram of the antenna of Embodiment 1. FIG.

FIG. 6 is a schematic diagram of the connection between the antenna and the power divider or the radio frequency switch according to the first embodiment.

FIG. 7 is an antenna pattern of Embodiment 1. FIG.

FIG. 8 is an antenna gain diagram of Embodiment 1. FIG.

FIG. 9 is a schematic diagram of an implementation of adjusting isolation by using an active decoupling method.

FIG. 10 is a schematic diagram of an implementation of adjusting isolation using a high-resistance surface method.

FIG. 11 is a schematic diagram of an implementation of adjusting isolation by using the distance method.

FIG. 12 is a schematic diagram of an implementation of adjusting the antenna beam and gain by adding parasitic elements.

Detailed ways

The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, it should not be construed that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

Example 1

In this embodiment, a bidirectional radiating antenna with one transmit and two receive is taken as an example, and it is necessary to perform transmit and receive detection in the direction perpendicular to the ground and in the direction parallel to the ground. As shown in FIG. 1 , according to the practice of the prior art, two sets of millimeter-wave radar systems are required, especially two sets of millimeter-wave array antennas are required, which need to be implemented by using two PCB boards.

This embodiment provides a one-transmit, two-receive, orthogonal two-way bidirectional radiating antenna, as shown in FIG. 2 , including an end-fire antenna and a side-fire antenna. The end-fire antenna and the side-fire antenna are arranged on the same PCB, and Both the incident port of the end-fire antenna and the incident port of the side-fire antenna are connected to the power divider, and the power divider is used for distributing electric power to the end-fire antenna and the side-fire antenna.

The orthogonal bidirectional means that the two directions of the bidirectional radiation form an included angle of 90°, as shown in FIG. 3 , namely the side-fire direction and the end-fire direction. In the present invention, the relationship between the direction of the radiation direction and the antenna can be It is divided into side-fire antenna array and end-fire antenna array. A side-firing antenna array is an antenna array whose maximum radiation direction points to the array axis or the vertical direction of the array. An end-fire antenna array is an antenna array with the maximum radiation direction pointing in the direction of the array axis. Antenna arrays whose maximum radiation direction points to other directions are neither sidefire nor endfire. Here, the antenna realized by the PCB board is used as an example to further illustrate the side-fire and end-fire directions. The side-fire direction is the direction perpendicular to the plane where the PCB board is located, that is, the direction parallel to the coordinate axis z-axis; the end-fire direction is the plane where the PCB board is located. The parallel direction, that is, the direction perpendicular to the z-axis.

Due to the influence of manufacturing process and other factors, or due to the needs of specific applications, the included angle between the side-fire direction and the end-fire direction of the present invention may not be the standard 90°, and the included angle may also range from 80° to 100° When the included angle ranges from 80° to 100°, the purpose of the present invention can be achieved, and two-way detection or communication can be achieved.

In this embodiment, by connecting the incident port of the side-fire antenna and the incident port of the end-fire antenna to the power divider, the transmitted signal is distributed to the end-fire transmit antenna and the side-fire transmit antenna at the same time through the power divider. Working at the same time, the transmitting antenna has the ability to radiate to the side-fire and end-fire directions at the same time. The working mode is a simultaneous working mode, and the efficiency is higher in this mode.

Compared with the prior art solution, the present invention saves a PCB board and a set of control systems by realizing the transmission and reception in the end-fire direction and the side-fire direction on the same PCB, and significantly reduces the manufacturing cost of the radar system.

Specifically, as shown in Figure 4 and Figure 5, it is a 24GHz single-transmit and dual-receive radar scheme. In this scheme, the antenna includes an end-fire antenna and a side-fire antenna, and a power divider is used to connect the incident port of the antenna; the end-fire antenna is selected Vivaldi antenna, WHEMS antenna is used for side-firing antenna. The end-fire antenna includes an end-fire transmitting unit and an end-fire receiving unit, and the side-fire antenna includes a side-fire transmitting unit and a side-fire receiving unit. The transmitting antenna composed of the two antennas, the end-fire transmitting unit and the side-fire transmitting unit, has the ability to transmit electromagnetic waves in the end-fire direction and the side-fire direction at the same time; the two antennas, the end-fire receiving unit and the side-fire receiving unit, respectively receive the end-fire transmission The reflected echoes of the two antennas, the unit and the side-fire transmitting unit, in the end-fire direction and the side-fire direction.

The electromagnetic wave sent by the end-fire transmitting unit in the direction of end-fire is reflected by obstacles and received by the end-fire receiving unit (Vivaldi antenna); the electromagnetic wave sent by the side-fire transmitting unit in the direction of side-fire is reflected by obstacles and passes through the side-fire receiving unit ( WHEMS antenna) received. In this way, the radar detection function in two orthogonal directions is realized on a single PCB board.

As shown in FIG. 6( a ) and FIG. 6( b ), in another embodiment, the power divider can be replaced with a radio frequency switch, and the incident port of the end-fire antenna and the incident port of the side-fire antenna are both Connected to the RF switch, the RF switch is used to switch the end-fire antenna and the side-fire antenna to realize time-division multiplexing of the end-fire antenna and the side-fire antenna. This mode is time-sharing operation. model. In the time-sharing working mode, the transmit signal passes through the RF switch and is distributed to the end-fire transmit antenna and the side-fire transmit antenna at different times. In this mode, the gain of a single path is higher.

At the same time, the working mode is suitable for millimeter-wave radar systems with large link margin and high efficiency requirements; the time-sharing working mode is suitable for millimeter-wave radar applications with tight link margins.

In order to make the bidirectional antenna of the present invention achieve the best effect in the radar system, the present invention provides the following preferred design parameters:

When devices such as power dividers or RF switches are not connected, the isolation between the incident port of the end-fire antenna and the incident port of the side-fire antenna is greater than 15dB; the reason for setting the isolation greater than 15dB is that in order to make The end-fire antenna and the side-fire antenna are independent of each other to reduce coupling, otherwise the radio frequency switch cannot play the role of switching the radiation direction normally; the power divider cannot play the role of normal power distribution. Antenna port isolation greater than 15dB usually requires the distance between the two antennas to be greater than twice the wavelength. Other methods can also be used to improve the antenna isolation to meet the requirements of greater than 15dB, such as high resistance surface method, active decoupling method, etc. The vivaldi antenna in this embodiment achieves port isolation by increasing the distance, and the WHEMS antenna achieves high port isolation through surface wave self-suppression technology.

When devices such as a power splitter or a radio frequency switch are not connected, the gain of the end-fire antenna in the side-fire direction is smaller than the gain of the side-fire antenna in the side-fire direction by a first difference X, and/or the The gain of the side-fire antenna in the end-fire direction is smaller than the gain of the end-fire antenna in the end-fire direction by a first difference, and the first difference X≧5dB. Setting according to this condition can increase the recognition degree of the orthogonal two-way radar in the orthogonal two-way, otherwise the two-way orthogonality cannot play its due role. A working side-fire/end-fire antenna will not interfere with a non-working end-fire/side-fire antenna. In order to meet this condition, changing the beam and gain of the antenna can be realized by adding a director, adding a parasitic unit, adding a reflector and other methods.

In other embodiments, the type of end-fire antenna may be a vivaldi antenna, a Yagi antenna, a quasi-Yagi antenna, or a log-periodic antenna.

In other embodiments the type of side emitting antenna may be a loop slot antenna, slot antenna, loop antenna or patch antenna.

The power divider has a filtering function, and is preferably a Wilkinson power divider.

As shown in Fig. 7 and Fig. 8, it can be seen from the transmitting antenna pattern and gain results that the orthogonal bidirectional radar antenna of the one-transmit, dual-receive hybrid side-fire end-fire in this embodiment has good bidirectional performance in both end-fire and side-fire directions. Radiation properties.

The present invention provides a specific implementation method among multiple implementation methods for the above-mentioned active decoupling method, high-resistance surface method, distance method, and adding parasitic units:

The active decoupling method, as shown in Figure 9, is a method for realizing the isolation between the end-fire part and the side-fire part of the orthogonal dual-polarized transmitting antenna by using the active decoupling method. Part of the connection is constructed with a 180-degree phase difference to achieve the cancellation of coupled interference signals, thereby achieving high isolation.

The distance method, as shown in Figure 10, is a method for realizing the isolation between the end-fire part and the side-fire part of the orthogonal dual-polarized transmitting antenna by increasing the distance. It is well known that electromagnetic waves decay rapidly with increasing distance. This method achieves high isolation by increasing the distance between the end-fire portion and the side-fire portion.

The high-resistance surface method, as shown in FIG. 11 , is a method for realizing the isolation between the end-fire part and the side-fire part of the orthogonal dual-polarized transmitting antenna by using the high-resistance surface method. The method achieves high isolation by adding a high-resistance surface between the end-fire part and the side-fire part to suppress attenuating coupled signals.

Adding parasitic elements, as shown in Figure 12, is a method of adjusting the antenna beam and gain by adding parasitic elements. This method adjusts the beam and gain of the antenna by adding metal or dielectric parasitic elements around the antenna to meet the end-fire requirements. The condition that the gain of the antenna in the side-fire direction is at least 5dB lower than that of the side-fire antenna in the side-fire direction, or the gain of the side-fire antenna in the end-fire direction is less than that of the end-fire antenna by at least 5dB.

Example 2

The difference between this embodiment and Embodiment 1 is that the number of end-fire antennas is set to multiple, and multiple end-fire antennas are connected in parallel to form an end-fire antenna array; the number of side-fire antennas is multiple, and multiple side-fire antennas The antennas are connected in parallel to form a side-emitting antenna array, thereby realizing the function of multiple transmissions and multiple receptions on one PCB board, so as to flexibly adapt to the needs of different application environments and improve the performance of the antenna system.

Example 3

This embodiment provides a communication device, including the bidirectional radiating antenna described in Embodiment 1, where the orthogonal bidirectional radar antenna is used for transmitting and receiving detection in a direction perpendicular to the ground and in a direction parallel to the ground Make transmit and/or receive probes.

This embodiment also provides an auxiliary monitoring device, including the above communication device, and the applicable frequency ranges include 24 GHz and 30 GHz to 300 GHz.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. The antenna is characterized by comprising an end-fire antenna and a side-fire antenna, wherein the end-fire antenna and the side-fire antenna are arranged on the same PCB, and an included angle between a main polarization direction of the end-fire antenna and a main polarization direction of the side-fire antenna is 80-100 degrees.

2. An antenna according to claim 1, wherein the isolation between the incident port of the endfire antenna and the incident port of the broadside antenna is set to be greater than 15 dB.

3. An antenna according to claim 1, characterized in that the gain of the endfire antenna in the broadside direction is smaller than the gain of the endfire antenna in the broadside direction by a first difference X and/or the gain of the endfire antenna in the endfire direction is smaller than the gain of the endfire antenna in the endfire direction by a first difference X; the first difference value X is larger than or equal to 5 dB.

4. An antenna according to claim 1, wherein the endfire antenna transmits and/or receives in a direction parallel to the plane of the PCB and the broadside antenna transmits and/or receives in a direction perpendicular to the plane of the PCB.

5. An antenna according to claim 1, wherein a plurality of end-fire antennas are connected in parallel to form an end-fire antenna array, and a plurality of side-fire antennas are connected in parallel to form a side-fire antenna array.

6. An antenna as claimed in any one of claims 1 to 5, wherein the endfire antenna is of the type vivaldi antenna, yagi antenna, quasi-yagi antenna or log periodic antenna.

7. An antenna according to claim 6, wherein the side-radiating antenna is of the type loop slot antenna, loop antenna or patch antenna.

8. An antenna device, comprising a power divider and an antenna according to any one of claims 1 to 7, wherein the rf signals input to the power divider are output to the endfire antenna and the broadside antenna, respectively.

9. The antenna apparatus of claim 8, wherein the power divider is a Wilkinson power divider.

10. An antenna arrangement comprising a radio frequency switch and an antenna according to any of claims 1 to 7, wherein the incident port of the endfire antenna and the incident port of the broadside antenna are both connected to the radio frequency switch, and wherein the radio frequency switch is configured to switch between the endfire antenna and the broadside antenna.

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