Matching circuit of emergency help seeking terminal

Abstract

The utility model relates to the technical field of antennas, and particularly provides a matching circuit of an emergency help seeking terminal, which comprises a first transmitting circuit, a first receiving circuit, a second transmitting circuit, a duplexer, a radio frequency switch, a transceiving control circuit and an antenna, the first transmitting circuit and the first receiving circuit are respectively and electrically connected with the duplexer, the duplexer is electrically connected with the radio frequency switch, the transceiving control circuit is electrically connected with the radio frequency switch, and the radio frequency switch is connected with the antenna through the second inductor; the second transmitting circuit is connected with the antenna through a third inductor; a grounding inductor is electrically connected between the antenna and the second inductor and between the antenna and the third inductor, and the grounding inductor is a common inductor of the first transmitting circuit, the first receiving circuit and the second transmitting circuit and is used for adjusting resistance values of all frequency points to enable the frequency points to reach working standards. Therefore, three different frequency points of the second transmitting circuit (162MHz), the first transmitting circuit (240MHz) and the first receiving circuit (320MHz) share one antenna.

Description

Technical Field

[0001] This application relates to the field of antenna technology, and particularly to a matching circuit for an emergency rescue terminal. Background Art

[0002] Existing products of emergency rescue terminals based on the Tianqi low-earth orbit satellite constellation mainly include two communication methods: the AIS distress transmission path and the time-division duplex satellite communication path. The frequency of the AIS distress transmission path is 162 MHz, and its main function is to send distress signals to surrounding ships and shore-based receivers, but this system does not have satellite communication capabilities. On the other hand, the time-division duplex satellite communication path operates at a frequency of 400 MHz and achieves communication by transmitting and receiving data at different times on the same frequency. However, with the increasing tension of 400 MHz channel resources, the time-division duplex communication method faces challenges in channel selection and communication efficiency.

[0003] Therefore, in this context, how to design a matching circuit for an emergency rescue terminal to achieve qualified wireless signal gain at different frequency points with the same antenna is a technical problem to be solved. Summary of the Invention

[0004] In view of the above problems in the prior art, this application provides a matching circuit for an emergency rescue terminal, which realizes the sharing of a single antenna by three different frequency points: the second transmission circuit (162 MHz), the first transmission circuit (240 MHz), and the first reception circuit (320 MHz).

[0005] To achieve the above object, this application provides a matching circuit for an emergency rescue terminal, including: a first transmission circuit, a first reception circuit, a second transmission circuit, a duplexer, a radio frequency switch, a transceiver control circuit, and an antenna;

[0006] The first transmission circuit and the first reception circuit are respectively electrically connected to the duplexer, the duplexer is electrically connected to the radio frequency switch, the transceiver control circuit is electrically connected to the radio frequency switch, and the radio frequency switch is connected to the antenna through a second inductor;

[0007] The second transmission circuit is connected to the antenna through a third inductor;

[0008] A grounding inductor is electrically connected between the antenna and the second inductor, and between the antenna and the third inductor. The grounding inductor is a common inductor for the first transmission circuit, the first reception circuit, and the second transmission circuit, and is used to adjust the resistance values of all frequency points to meet the working standards.

[0009] As described above, in the present application, by introducing a frequency division duplex communication path, the problem of the tight number of 400 MHz channels is effectively solved. Frequency division duplex can transmit and receive simultaneously at different frequencies, improving the utilization efficiency of spectrum resources, avoiding channel congestion, and thus enhancing the stability and reliability of communication. Moreover, the matching circuit enables the same antenna to achieve qualified wireless signal gains at three different frequency points: the second transmitting circuit (162 MHz), the first transmitting circuit (240 MHz), and the first receiving circuit (320 MHz). Since multiple frequency points share one antenna, the number of antennas and the complexity of the overall structure are reduced, and the production cost and maintenance difficulty are also lowered.

[0010] As a possible implementation, the second transmitting circuit includes a transmitting circuit at a frequency of 162 MHz.

[0011] The first transmitting circuit includes a transmitting circuit at a frequency of 240 MHz.

[0012] The first receiving circuit includes a transmitting circuit at a frequency of 320 MHz.

[0013] As a possible implementation, it further includes: a first capacitor;

[0014] The first capacitor is provided between the duplexer and the RF switch.

[0015] As a possible implementation, it further includes: a second capacitor;

[0016] The second capacitor is provided between the duplexer and the first transmitting circuit.

[0017] As a possible implementation, it further includes: a third capacitor;

[0018] The third capacitor is provided between the duplexer and the first receiving circuit.

[0019] As a possible implementation, the first capacitor, the second capacitor, and the third capacitor are all 1 nF.

[0020] As a possible implementation, the grounding inductor is 180 nH.

[0021] As a possible implementation, the second inductor is 43 nH.

[0022] As a possible implementation, the third inductor is 270 nH.

[0023] As a possible implementation, the antenna is a 195 mm tape measure antenna. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the working principle of a matching circuit for an emergency rescue terminal provided by this application;

[0025] It should be understood that in the above structure schematic diagram, the sizes and shapes of the respective block diagrams are for reference only and should not constitute an exclusive interpretation of the embodiments of the present invention. The relative positions and inclusion relationships between the respective block diagrams presented in the structure schematic diagram only schematically represent the structural associations between the block diagrams and do not limit the physical connection manners of the embodiments of the present invention. Specific Embodiments

[0026] The following takes embodiments in conjunction with the accompanying drawings to further illustrate the technical solutions provided by this application. It should be understood that the system structures and service scenarios provided in the embodiments of this application are mainly for illustrating possible implementation manners of the technical solutions of this application and should not be interpreted as the only limitation of the technical solutions of this application. Those of ordinary skill in the art know that with the evolution of the system structure and the emergence of new service scenarios, the technical solutions provided by this application are equally applicable to similar technical problems.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. In case of inconsistency, the meaning described in this specification or the meaning derived from the content recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application. In order to accurately describe the technical content in this application and to accurately understand the present invention, the following explanations or definitions of the terms used in this specification are given before the description of the specific embodiments.

[0028] Time-division duplex means: a technology for realizing duplex communication by transmitting uplink (transmission) and downlink (reception) data respectively within different time intervals on the same frequency channel.

[0029] Frequency-division duplex means: a technology for transmitting uplink and downlink data respectively on two different frequency channels.

[0030] Before introducing a matching circuit for an emergency rescue terminal provided by this application, the following content is first explained:

[0031] To solve the problem of the tightness of the 400 MHz channel quantity, the inventor improved the satellite communication path of the emergency rescue terminal to a frequency division duplex mode. Specifically, the transmitting frequency is 240 MHz and the receiving frequency is 320 MHz. However, due to the limitation of the product size, the emergency rescue terminal of this frequency division duplex mode still uses the 195 mm tape measure antenna used by the time division duplex terminal. The inventor found that the impedance value of this antenna performs well (50 Ω) at the original 400 MHz frequency point, but the impedance values at the three new frequency points of 162 MHz, 240 MHz, and 320 MHz are not ideal.

[0032] In order to ensure that the same antenna can work properly at different frequencies and meet the usage requirement that the reflection coefficient is less than -6 dB, therefore, the following matching circuit is designed for impedance matching.

[0033] The embodiment of the present application provides a matching circuit for an emergency rescue terminal, as Figure 1 shown, including: a first transmitting circuit 1, a first receiving circuit 2, a second transmitting circuit 3, a duplexer 4, a radio frequency switch 5, a transceiver control circuit 6, and an antenna 7;

[0034] The first transmitting circuit 1 and the first receiving circuit 2 are respectively electrically connected to the duplexer 4, the duplexer 4 is electrically connected to the radio frequency switch 5, the transceiver control circuit 6 is electrically connected to the radio frequency switch 5, and the radio frequency switch 5 is connected to the antenna 7 through a second inductor;

[0035] The second transmitting circuit 3 is connected to the antenna 7 through a third inductor;

[0036] A grounding inductor is electrically connected between the antenna 7 and the second inductor and between the antenna 7 and the third inductor. The grounding inductor is a common inductor for the first transmitting circuit 1, the first receiving circuit 2, and the second transmitting circuit 3, and is used to adjust the resistance values of all frequency points to meet the working standard.

[0037] Among them, the second transmitting circuit 3 includes a transmitting circuit at the 162 MHz frequency point; the first transmitting circuit 1 includes a transmitting circuit at the 240 MHz frequency point; the first receiving circuit 2 includes a transmitting circuit at the 320 MHz frequency point.

[0038] Thus, in the present application, by introducing a frequency-division duplex communication path, the problem of the tight number of original 400 MHz channels is effectively solved. Frequency-division duplex can simultaneously transmit and receive on different frequencies, improving the utilization efficiency of spectrum resources, avoiding channel congestion, and thus enhancing the stability and reliability of communication. Moreover, this matching circuit enables the same antenna 7 to achieve qualified wireless signal gain at three different frequency points: the second transmitting circuit 3 (162 MHz), the first transmitting circuit 1 (240 MHz), and the first receiving circuit 2 (320 MHz). Since multiple frequency points share one antenna 7, the number of antennas 7 and the complexity of the overall structure are reduced, and the production cost and maintenance difficulty are lowered.

[0039] In an embodiment of the present application, it further includes: a first capacitor (1 nF);

[0040] The first capacitor is arranged between the duplexer 4 and the RF switch 5.

[0041] In an embodiment of the present application, it further includes: a second capacitor (1 nF);

[0042] The second capacitor is arranged between the duplexer 4 and the first transmitting circuit 1.

[0043] In an embodiment of the present application, it further includes: a third capacitor (1 nF);

[0044] The third capacitor is arranged between the duplexer 4 and the first receiving circuit 2.

[0045] The functions of the first capacitor C1, the second capacitor C2, and the third capacitor C3 will be specifically described below.

[0046] The first capacitor C1 (1 nF): Its main purpose is to act as a decoupling capacitor to isolate the noise or interference that the RF switch 5 may introduce, ensuring the purity of the signal. This helps protect the subsequent circuits from the transient effects generated when the RF switch 5 switches.

[0047] The second capacitor C2 (1 nF) and the third capacitor C3 (1 nF): Their main purpose is also to act as decoupling capacitors, but mainly to isolate the potential interference between the duplexer 4 and the first transmitting circuit 1, and the first receiving circuit 2 respectively. Since the duplexer 4 is responsible for separating the transmitting signal and the receiving signal at different frequencies, the second capacitor C2 and the third capacitor C3 help ensure that the signals do not interfere with each other during transmission and improve the overall stability of the system.

[0048] In summary, the arrangement of the first capacitor C1, the second capacitor C2, and the third capacitor C3 is to achieve better signal isolation and decoupling in the circuit to reduce the influence of noise and interference.

[0049] In an embodiment of the present application, the grounding inductor is 180 nH.

[0050] In an embodiment of the present application, the second inductor is 43 nH.

[0051] In an embodiment of the present application, the third inductor is 270 nH.

[0052] In an embodiment of the present application, the antenna 7 is a 195 mm tape measure antenna.

[0053] The working principle of the embodiment of the present application is as follows:

[0054] For the second transmitting circuit 3 (162 MHz frequency point), the antenna 7 is connected through the grounding inductor L1 and the third inductor L3 to achieve matching.

[0055] For the first transmitting circuit 1 (240 MHz frequency point) and the first receiving circuit 2 (320 MHz frequency point), the antenna 7 is first connected through the grounding inductor L1 and the second inductor L2, and then through the RF switch 5 and the duplexer 4. These two frequency points share a matching path, and the matching requirements of the two frequency points are simultaneously satisfied by adjusting the value of the second inductor L2;

[0056] It should be noted that the grounding inductor L1, as the common inductor for the three frequency points, adjusts the resistance value of the antenna 7 at the three frequency points by parallel grounding. Since the resistance values of the antenna 7 at the three frequency points of 162 MHz, 240 MHz, and 320 MHz are all small, the introduction of L1 effectively increases the resistance value, providing a basis for the subsequent adjustment of the reactance value.

[0057] Specifically, when the antenna 7 transmits at the 162 MHz frequency point, the RF switch 5 switches to the RF1 (floating) state, and the antenna 7 is connected through the grounding inductor L1 and the third inductor L3 to achieve impedance matching at this frequency point.

[0058] Matching effect: Through the inductance matching of L1 and L3, the impedance value of the antenna 7 at 162 MHz is adjusted to an appropriate range, and the reflection coefficient is less than -6 dB, meeting the emission requirements.

[0059] For the transmission at 240 MHz and the reception at 320 MHz, these two frequency points share a matching path. The antenna 7 is first connected through the grounding inductor L1 and the second inductor L2, and then the RF switch 5 switches to RF2 and is connected to the duplexer 4. The duplexer 4 is then connected to the 240 MHz transmitter and the 320 MHz receiver respectively to achieve the frequency division duplex working mode.

[0060] Matching adjustment: Since these two frequency points need to share a matching path, it is necessary to adjust the value of the second inductor L2 to meet the impedance matching requirements of both frequency points simultaneously. Through optimization design, the impedance values of antenna 7 at 240 MHz and 320 MHz both reach the qualified range, and the reflection coefficients are both less than -6 dB.

[0061] The terms "first", "second", "third", etc. or terms such as module A, module B, module C, etc. in the specification and claims are only used to distinguish similar objects and do not represent a specific order for the objects. Understandably, the specific order or sequence can be interchanged under the permitted circumstances so that the embodiments of the present application described here can be implemented in an order other than that illustrated or described here.

[0062] The term "comprising" used in the specification and claims should not be construed as being limited to the content listed thereafter; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned features, wholes, steps or components, but does not exclude the presence or addition of one or more other features, wholes, steps or components and their groups. Therefore, the expression "a device comprising device A and B" should not be limited to a device consisting only of components A and B.

[0063] The "one embodiment" or "embodiment" mentioned in this specification means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment of the present application. Therefore, the phrases "in one embodiment" or "in an embodiment" that appear throughout this specification do not necessarily all refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the various specific features, structures or characteristics can be combined in any appropriate manner, as will be apparent to those of ordinary skill in the art from this disclosure.

[0064] Note that the above is only the preferred embodiment of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described here, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments. Without departing from the concept of the present application, more other equivalent embodiments can be included, all of which fall within the protection scope of the present application.

Claims

1. A matching circuit for an emergency distress terminal, characterized in that, Comprising: A first transmitting circuit (1), a first receiving circuit (2), a second transmitting circuit (3), a duplexer (4), a radio frequency switch (5), a transceiver control circuit (6), and an antenna (7); The first transmitting circuit (1) and the first receiving circuit (2) are respectively electrically connected to the duplexer (4), the duplexer (4) is electrically connected to the radio frequency switch (5), the transceiver control circuit (6) is electrically connected to the radio frequency switch (5), and the radio frequency switch (5) is connected to the antenna (7) through a second inductor; The second transmitting circuit (3) is connected to the antenna (7) through a third inductor; A grounding inductor is electrically connected between the antenna (7) and the second inductor, and between the antenna (7) and the third inductor. The grounding inductor is a common inductor for the first transmitting circuit (1), the first receiving circuit (2), and the second transmitting circuit (3), and is used to adjust the resistance values of all frequency points to meet the working standards.

2. The matching circuit according to claim 1, wherein The second transmitting circuit (3) includes a transmitting circuit at a frequency point of 162 MHz; The first transmitting circuit (1) includes a transmitting circuit at a frequency point of 240 MHz; The first receiving circuit (2) includes a transmitting circuit at a frequency point of 320 MHz.

3. The matching circuit according to claim 1, wherein Further comprising: A first capacitor; The first capacitor is arranged between the duplexer (4) and the radio frequency switch (5).

4. The matching circuit according to claim 1, characterized in that Further comprising: A second capacitor; The second capacitor is arranged between the duplexer (4) and the first transmitting circuit (1).

5. The matching circuit according to claim 1, wherein Further comprising: A third capacitor; The third capacitor is arranged between the duplexer (4) and the first receiving circuit (2).

6. The matching circuit according to claim 1, wherein Further comprising: a first capacitor, a second capacitor, and a third capacitor; The first capacitor is arranged between the duplexer (4) and the radio frequency switch (5); The second capacitor is arranged between the duplexer (4) and the first transmitting circuit (1); The third capacitor is arranged between the duplexer (4) and the first receiving circuit (2); The first capacitor, the second capacitor, and the third capacitor are all 1 nF.

7. The matching circuit according to claim 1, wherein The grounding inductor is 180 nH.

8. The matching circuit according to claim 1, characterized in that, The second inductor is 43 nH.

9. The matching circuit according to claim 1, wherein The third inductor is 270 nH.

10. The matching circuit according to claim 1, characterized in that, The antenna (7) is a 195 - mm tape measure antenna.

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