WO2020043108A1 - Fm antenna circuit and terminal device - Google Patents

Abstract

Embodiments of the present application provide an FM antenna circuit and a terminal device. The FM antenna circuit comprises a mainboard unit, a first matching circuit, a second matching circuit, a third matching circuit, and an FM processing unit, wherein a power supply end of the mainboard unit is connected to a power supply end of the FM processing unit by means of the first matching circuit; a ground end of the mainboard unit is connected to a ground end of the FM processing unit by means of the second matching circuit; the ground end of the mainboard unit is connected to an input end of the FM processing unit; an output end of the FM processing unit is connected to a signal end of the mainboard unit by means of the third matching circuit; the mainboard unit receives and sends an FM antenna signal to the FM processing unit; and the FM processing unit performs signal processing on the FM antenna signal, and sends the processed FM antenna signal to the mainboard unit, so that the mainboard unit outputs the processed FM antenna signal. The embodiments of the present application implement zero-clearance demands of an FM antenna while the receiving performance of the FM antenna meets real-time requirements.

Description

FM antenna circuit and terminal equipment

This application claims priority from a Chinese patent application filed on August 31, 2018 with the State Intellectual Property Office of China, with the application number 201811014163.X, and the application name "FM Antenna Circuit and Terminal Equipment", the entire contents of which are incorporated herein by reference. In this application.

Technical field

The embodiments of the present application relate to the technical field of electronic terminals, and in particular, to a frequency modulation (Frequency Modulation, FM) antenna circuit and terminal equipment.

Background technique

Terminal equipment, such as mobile phones, are equipped with FM radios. FM antennas must be used in conjunction with FM radio functions. At present, the FM frequency band falls between 78MHZ-108MHZ, and the wavelength is about 3m. When the terminal equipment is provided with a 1 / 4-wavelength antenna with a length of FM antenna signal, about 75 cm, the terminal equipment can receive the FM antenna signal. Generally, the terminal equipment can use an external whip antenna or earphone as the FM antenna, can also use a built-in copper wire or ceramic antenna or a flexible printed circuit (Flexible Printed Circuit (FPC)) cable as the FM antenna.

However, when the user wants to listen to the FM radio, if the user does not carry a headset, the user cannot listen, causing inconvenience to the user, and the external headset is not convenient to carry. If the terminal equipment uses an external rod antenna or a built-in FM antenna, the headroom around the FM antenna needs to be between 2-3mm, and the FM antenna must be irrelevant to the battery, shield, and camera in the terminal equipment. The clearance between the parts is more than 5mm, otherwise it will affect the omnidirectional communication effect of the FM antenna, making the receiving performance of the FM antenna unable to meet the actual requirements.

Summary of the Invention

An embodiment of the present application provides an FM antenna circuit, which is used to implement the headroom-free claim of the FM antenna, so that the reception performance of the FM antenna meets actual requirements, and the omnidirectional communication effect of the FM antenna is guaranteed.

In a first aspect, an embodiment of the present application provides an FM antenna circuit, including: a main board unit, a first matching circuit, a second matching circuit, a third matching circuit, and an FM processing unit;

The power terminal of the main board unit is connected to the power terminal of the FM processing unit through the first matching circuit; the ground terminal of the main board unit is connected to the ground terminal of the FM processing unit through the second matching circuit. Connection; the ground terminal of the motherboard unit is connected to the input terminal of the FM processing unit; the output terminal of the FM processing unit is connected to the signal terminal of the motherboard unit through the third matching circuit;

The motherboard unit is configured to receive an FM antenna signal; and send the FM antenna signal to the FM processing unit;

The FM processing unit is configured to perform signal processing on the FM antenna signal and send the processed FM antenna signal to the motherboard unit;

The motherboard unit is further configured to output the processed FM antenna signal.

The FM antenna circuit provided in the first aspect isolates signals in the FM frequency band in all connection channels between the main board unit and the FM processing unit through the first matching circuit, the second matching circuit, and the third matching circuit to avoid electromagnetic interference. Therefore, the ground wire of the motherboard unit can be used as an FM antenna, and the FM processing unit can receive the FM antenna signal sent by the ground wire of the motherboard unit through the connection to the ground terminal of the motherboard unit. After the FM antenna signal is processed, it is output by the motherboard unit. . In the FM antenna circuit of the embodiment of the present application, the ground wire of the main board unit can be used as an FM antenna. While the receiving performance of the FM antenna meets actual requirements, the signals in the FM frequency band on all connection channels in the main board unit are isolated, thereby avoiding The electromagnetic wave interference makes the ground wire of the main board unit not limited by the clearance height of related components, realizes the requirement of zero clearance of the FM antenna, and has the characteristics of low cost and space saving.

In a possible design, the circuit further includes: an FM antenna;

The ground terminal of the motherboard unit is connected to the input terminal of the FM processing unit through the FM antenna;

The motherboard unit is configured to send the FM antenna signal to the FM processing unit through the FM antenna.

The FM antenna circuit provided in the first aspect isolates signals in the FM frequency band in all connection channels between the main board unit and the FM processing unit through the first matching circuit, the second matching circuit, and the third matching circuit to avoid electromagnetic interference. . The FM antenna is separately connected to the ground wire of the motherboard unit and the FM processing unit, so that the FM processing unit can receive the FM antenna signal sent by the ground wire of the motherboard unit through the FM antenna. After the FM antenna signal is processed, it is then sent to the motherboard. Unit output. In the FM antenna circuit of the embodiment of the present application, by separately setting an FM antenna between the ground wire of the main board unit and the FM processing unit, the reception performance of the FM antenna signal is improved, and the FM frequency band on all connection channels in the main board unit is isolated. Signal, to avoid electromagnetic wave interference, so that the FM antenna will not be limited by the clearance height of related components, to achieve the FM antenna zero clearance requirements, and has the characteristics of low cost and space saving.

In a possible design, the FM antenna includes any one of a metal wire, a ceramic wire, and a flexible circuit board FPC cable.

In a possible design, the first matching circuit, the second matching circuit, and the third matching circuit are respectively: a band stop filter circuit, and the band stop filter circuit includes M inductors and The M capacitors are connected in parallel with N capacitors, the M inductors are connected in series, the N capacitors are connected in series, and M and N are positive integers.

In a possible design, the first matching circuit, the second matching circuit, and the third matching circuit are respectively: a band stop filter chip.

In a possible design, the FM processing unit includes: a signal amplification circuit and a signal processing circuit;

The power terminal of the motherboard unit is connected to the power terminal of the signal amplifier circuit through the first matching circuit; the ground terminal of the motherboard unit is connected to the ground terminal of the signal amplifier circuit through the second matching circuit. Connection; the ground terminal of the motherboard unit is connected to the input terminal of the signal amplifier circuit, the output terminal of the signal amplifier circuit is connected to the input terminal of the signal processing circuit, and the output terminal of the signal processing circuit passes through the A third matching circuit is connected to the signal end of the motherboard unit;

The signal amplifying circuit is configured to receive the FM antenna signal from the main board unit, amplify the FM antenna signal, and send the amplified FM antenna signal to the signal processing circuit;

The signal processing circuit is configured to process the amplified FM antenna signal, and send the processed FM antenna signal to the motherboard unit.

In a possible design, the motherboard unit includes: a baseband module;

The first input terminal of the baseband module is connected to the output terminal of the FM processing unit through the third matching circuit;

The baseband module is configured to receive the processed FM antenna signal from the FM processing unit, and output the processed FM antenna signal.

In a possible design, the motherboard unit further includes: a radio frequency module, a fourth matching circuit, a fifth matching circuit, and a sixth matching circuit;

The power terminal of the radio frequency module is connected to the power terminal of the baseband module through the fourth matching circuit; the ground terminal of the radio frequency module is connected to the ground terminal of the baseband module through the fifth matching circuit; The signal terminal of the radio frequency module is connected to the signal terminal of the baseband module through the sixth matching circuit, and the ground terminal of the radio frequency module is connected to the second input terminal of the baseband module;

The radio frequency module is configured to receive a high frequency antenna signal; and send the high frequency antenna signal to the baseband module;

The baseband module is configured to process the high-frequency antenna signal and output the processed high-frequency antenna signal.

The FM antenna circuit provided in the first aspect isolates signals in the high-frequency band in all connection channels between the RF module and the baseband module through the fourth matching circuit, the fifth matching circuit, and the sixth matching circuit to avoid electromagnetic wave interference. Therefore, the ground wire of the RF module can be used as a high-frequency antenna, and the baseband module can receive the high-frequency antenna signal sent by the ground wire of the radio-frequency module through the connection to the ground terminal of the radio-frequency module. Output. In the FM antenna circuit of the embodiment of the present application, the ground wire of the RF module can be used as a high-frequency antenna. While the receiving performance of the high-frequency antenna meets actual requirements, the signals in the high-frequency band on all the connection channels in the RF module are isolated. The electromagnetic wave interference is avoided, so that the ground wire of the RF module is not limited by the clearance height of related components, and the zero clearance of the high-frequency antenna is realized, and the characteristics of low cost and space saving are achieved.

In a possible design, the circuit further includes: a high-frequency antenna;

The ground terminal of the radio frequency module is connected to the second input terminal of the baseband module through the high frequency antenna;

The radio frequency module is configured to receive the high frequency antenna signal through the high frequency antenna.

The FM antenna circuit provided in the first aspect isolates signals in a high-frequency band in all connection channels between the RF module and the baseband module through a fourth matching circuit, a fifth matching circuit, and a sixth matching circuit, so as to avoid electromagnetic wave interference. Then separately connect the high-frequency antenna to the ground wire of the RF module and the baseband module, so that the baseband module can receive the high-frequency antenna signal sent by the ground wire of the radio-frequency module through the high-frequency antenna. After the high-frequency antenna signal is processed, Output by the baseband module. In the FM antenna circuit of the embodiment of the present application, a high-frequency antenna is separately provided between the ground wire of the radio-frequency module and the baseband module, thereby improving the reception performance of the high-frequency antenna signal. The signals in the frequency band avoid electromagnetic wave interference, so that the high-frequency antenna will not be restricted by the clearance height of related components, and the requirement of zero-headroom of the high-frequency antenna is realized, and it has the characteristics of low cost and space saving.

In a possible design, the high-frequency antenna is a metal plate.

In a possible design, the fourth matching circuit, the fifth matching circuit, and the sixth matching circuit are: a high-impedance filter circuit, and the high-impedance filter circuit includes: R connected in series A resistor and S capacitors, one end of each capacitor is connected to one end of any of the R resistors, the other end of each capacitor is grounded, and R and S are positive integers.

In a possible design, the fourth matching circuit, the fifth matching circuit, and the sixth matching circuit are respectively: a high-impedance filter chip.

In a second aspect, an embodiment of the present application provides a terminal device, including the FM antenna circuit according to the first aspect.

An FM antenna circuit and a terminal device provided in the embodiments of the present application are used to isolate signals in an FM frequency band in all connection channels between a motherboard unit and an FM processing unit through a first matching circuit, a second matching circuit, and a second matching circuit. The ground wire of the motherboard unit can be used as an FM antenna. Therefore, the FM processing unit can receive the FM antenna signal sent by the ground wire of the motherboard unit through connection with the ground terminal of the motherboard unit, and the FM antenna signal is processed and then output by the motherboard unit. In the FM antenna circuit of the embodiment of the present application, the ground wire of the main board unit can be used as an FM antenna. While the receiving performance of the FM antenna meets actual requirements, the ground wire based on the main board unit will not be limited by the clearance height of related components. The requirement of zero headroom of FM antenna is realized, and it has the characteristics of low cost and space saving.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application;

2 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application;

3 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application;

4 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application;

5 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

detailed description

The embodiment of the present application provides an FM antenna circuit and terminal equipment, which can realize the zero headroom requirement of the FM antenna, has the characteristics of low cost and space saving, can be applied to a full-duplex communication system, and can also be used as a multiple input output (Multipie input and Multiple Output (MIMO) antennas, and any other possible application scenarios.

In order to achieve the zero headroom requirement of the FM antenna, an embodiment of the present application provides an FM antenna circuit and a terminal device. All connections between the motherboard unit and the FM processing unit are performed through a first matching circuit, a second matching circuit, and a third matching circuit The signals in the FM band in the channel are isolated, and the ground wire of the motherboard unit can be used as an FM antenna. Therefore, the FM processing unit can receive the FM antenna signal sent by the ground wire of the motherboard unit through the connection to the ground terminal of the motherboard unit, and the FM antenna signal is processed and then output by the motherboard unit, so that the receiving performance of the FM antenna meets the actual requirements and realizes The requirement of zero headroom of the FM antenna.

The terminal device includes, but is not limited to, a mobile station (MS, Mobile Station), a mobile terminal (Mobile terminal), a mobile phone (Mobile phone), a mobile phone (handset), and a portable device (portable equipment). The device can communicate with one or more core networks via a radio access network (RAN, Radio Access Network). For example, the terminal device can be a mobile phone (or a "cellular" phone), a computer with wireless communication functions, etc. The terminal device may also be a portable, pocket-sized, handheld, computer-built or vehicle-mounted mobile device or device.

The technical solution of the FM antenna circuit in the embodiment of the present application will be described below with reference to the drawings in the embodiment of the present application.

FIG. 1 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application. As shown in FIG. 1, the FM antenna circuit 100 includes a main board unit 101, a first matching circuit 102, a second matching circuit 103, and a third matching circuit 104. And FM processing unit 105.

The power terminal of the main board unit 101 is connected to the power terminal of the FM processing unit 105 through the first matching circuit 102; the ground terminal of the main board unit 101 is connected to the ground terminal of the FM processing unit 105 through the second matching circuit 103; The ground terminal is connected to the input terminal of the FM processing unit 105; the output terminal of the FM processing unit 105 is connected to the signal terminal of the motherboard unit 101 through the third matching circuit 104.

The main board unit 101 is configured to receive an FM antenna signal; and send the FM antenna signal to the FM processing unit 105.

The FM processing unit 105 is configured to perform signal processing on the FM antenna signal and send the processed FM antenna signal to the main board unit 101.

The main board unit 101 is further configured to output a processed FM antenna signal.

Among them, for the convenience of explanation, as shown in FIG. 1, the power terminal, ground terminal, and signal terminal of the motherboard unit 101 are indicated by VCC, GND, and SIGNAL, respectively, and the power terminal, ground terminal, input terminal, and output terminal of the FM processing unit 105 are illustrated. VCC, GND, IN, and OUT are used for illustration.

In practice, the FM antenna is a standing wave antenna. The FM antenna signal is shielded by metal. Conductive metals can reflect, absorb, and cancel the FM antenna signal. Therefore, the FM antenna should be kept away from metal components. Isolate irrelevant parts such as battery, oscillator, shield, camera, etc., and leave a clear space (clearance) for the FM antenna. Generally, the clearance around the FM antenna should be between 2-3mm. It is necessary to ensure that the clearance between the FM antenna and the irrelevant parts such as the battery, shield, and camera in the terminal device is more than 5mm, so that the signal radiation intensity of the FM antenna in the 360 ° cross-section in all directions is the same, and the full range of the FM antenna is guaranteed. To the communication effect, to achieve the best communication effect of the terminal equipment, thereby avoiding electromagnetic wave interference from surrounding components. Among them, the electromagnetic wave interference may be conducted transmission electromagnetic wave interference, that is, there is a complete circuit connection between the interference source and the FM antenna, and the interference signal is transmitted to the FM antenna through this connection circuit. The transmission circuit may include a wire, a power source, a resistor, an inductor or Capacitors and other components.

In the embodiment of the present application, since the ground terminal of the motherboard unit 101 is connected to its own power terminal and signal terminal, and there is a connection relationship between the power terminal of the motherboard unit 101 and the power terminal of the FM processing unit 105, a power channel can be formed. . The ground terminal of the main board unit 101 and the ground terminal of the FM processing unit 105 have a connection relationship, and can form a ground connection channel. The signal terminal of the main board unit 101 and the output terminal of the FM processing unit 105 have a connection relationship, which can constitute a signal channel. Therefore, when the ground wire of the motherboard unit 101 is used as an FM antenna, the signals in the FM frequency band in all connection channels between the motherboard unit 101 and the FM processing unit 105 can be isolated to avoid electromagnetic wave interference on the motherboard unit. The impact of the FM antenna signal received by the 101 ground wire.

The signal in the FM frequency band is a signal in which the signal frequency band falls within the FM frequency band in all connection channels between the main board unit 101 and the FM processing unit 105. The FM antenna signal is the signal received by the main board unit 101 through its ground wire and falls in the FM Signals in the frequency band.

Specifically, a first matching circuit 102 may be provided on a power supply channel between the motherboard unit 101 and the FM processing unit 105, and a second matching circuit may be provided on a ground connection channel between the motherboard unit 101 and the FM processing unit 105. 103. A third matching circuit 104 may be provided on a signal path between the motherboard unit 101 and the FM processing unit 105. The settings of the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 may block the FM processing unit. The FM band signals on all the connection channels between 105 and the motherboard unit 101, so that the signal channel between the motherboard unit 101 and the FM processing unit 105 can only transmit signals in other frequency bands than the signals in the FM band. Eliminates electromagnetic interference from surrounding components to the FM antenna signal on the ground line of the motherboard unit 101. At this time, the ground line of the motherboard unit 101 will not be limited by the clearance height of related components such as batteries, shields, cameras, etc. Set the distance between the ground wire of the main board unit 101 and these components very small, so that the ground wire of the main board unit 101 can meet the FM antenna zero net It demands.

Furthermore, when the ground wire of the motherboard unit 101 receives the FM antenna signal, it can send the FM antenna signal to the FM processing unit 105 through its connection with the input end of the FM processing unit 105. The FM processing unit 105 then performs corresponding signal processing on the FM antenna signal, such as amplification, selective reception, and coding, to obtain a processed FM antenna signal. The processed FM antenna signal may include, but is not limited to, a voice signal. In addition, the FM processing unit 105 may send the processed FM antenna signal to the motherboard unit 101, and the motherboard unit 101 outputs the processed FM antenna signal, for example, the motherboard unit 101 plays the processed FM antenna signal.

The FM antenna circuit provided in the embodiment of the present application isolates signals in the FM frequency band in all connection channels between the main board unit and the FM processing unit through a first matching circuit, a second matching circuit, and a third matching circuit to avoid electromagnetic wave interference. Therefore, the ground wire of the motherboard unit can be used as an FM antenna, and the FM processing unit can receive the FM antenna signal sent by the ground wire of the motherboard unit through the connection to the ground terminal of the motherboard unit. After the FM antenna signal is processed, it is output by the motherboard unit. . In the FM antenna circuit of the embodiment of the present application, the ground wire of the main board unit can be used as an FM antenna. While the receiving performance of the FM antenna meets actual requirements, the signals in the FM frequency band on all connection channels in the main board unit are isolated, thereby avoiding The electromagnetic wave interference makes the ground wire of the main board unit not limited by the clearance height of related components, realizes the requirement of zero clearance of the FM antenna, and has the characteristics of low cost and space saving.

Exemplarily, on the basis of the embodiment shown in FIG. 1, an embodiment of the present application further provides an FM antenna circuit 100. FIG. 2 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application. As shown in FIG. 2, different from FIG. 1, the FM antenna circuit 100 in the embodiment of the present application further includes an FM antenna 106.

The ground terminal of the motherboard unit 101 is connected to the input terminal of the FM processing unit 105 through the FM antenna 106.

The motherboard unit 101 is configured to send an FM antenna signal to the FM processing unit 105 through the FM antenna 106.

In the embodiment of the present application, if the FM antenna 106 is introduced into the FM antenna circuit 100, the FM antenna 106 can receive the FM antenna signal from the ground line of the motherboard unit 101 through a connection with the ground terminal of the motherboard unit 101. The FM antenna 106 can then be connected to the input of the FM processing unit 105 to transmit the FM antenna signal to the FM processing unit 105, and the separate setting of the FM antenna 106 can improve the reception performance of the FM antenna signal. After the FM processing unit 105 processes the FM antenna signal, the processed FM antenna signal is transmitted to the motherboard unit 101, and the motherboard unit 101 outputs the processed FM antenna signal.

In addition, since the ground wire of the motherboard unit 101 is not limited by the clearance height of related components such as batteries, shields, cameras, etc., the FM antenna 106 is also not limited by the clearance height of these components. The distance between these parts is set very small, which achieves the zero headroom requirement of the FM antenna 106.

Wherein, optionally, the FM antenna 106 includes any one of a metal wire, a ceramic wire, and a flexible circuit board (Flexible Printed Circuit (FPC)) cable. Specifically, the FPC cable is usually set to 75 cm.

The FM antenna circuit provided in the embodiment of the present application isolates signals in the FM frequency band in all connection channels between the main board unit and the FM processing unit through a first matching circuit, a second matching circuit, and a third matching circuit to avoid electromagnetic wave interference. . The FM antenna is separately connected to the ground wire of the motherboard unit and the FM processing unit, so that the FM processing unit can receive the FM antenna signal sent by the ground wire of the motherboard unit through the FM antenna. Motherboard unit output. In the FM antenna circuit of the embodiment of the present application, by separately setting an FM antenna between the ground wire of the main board unit and the FM processing unit, the reception performance of the FM antenna signal is improved, and the FM frequency band on all connection channels in the main board unit is isolated. Signal, to avoid electromagnetic wave interference, so that the FM antenna will not be limited by the clearance height of related components, to achieve the FM antenna zero clearance requirements, and has the characteristics of low cost and space saving.

Exemplarily, based on the embodiment shown in FIG. 1 or FIG. 2, the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 may include multiple implementation forms. The following uses two feasible implementation forms to describe the detailed structures of the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 in detail.

In a feasible implementation form, optionally, the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 are respectively: a band stop filter circuit, and the band stop filter circuit includes M inductors and M N capacitors connected in parallel with inductors, M inductors connected in series, N capacitors connected in series, and M and N are positive integers.

The number of inductors and capacitors included in the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 may be the same or different, which is not limited.

In another feasible implementation form, optionally, the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 are respectively: a band stop filter chip.

The number and type of the band stop filter chips used by the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 may be the same or different, which is not limited.

It should be noted that no matter which implementation form the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 sample, as long as the impedance set in the FM frequency band (such as 70MHZ-120MHZ) is large, the impedance set at other frequency points It can be small. In this way, the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 can block the FM antenna signal between the motherboard unit 101 and the FM processing unit 105.

Exemplarily, on the basis of the embodiment shown in FIG. 1 or FIG. 2, an embodiment of the present application provides an FM antenna circuit 100. FIG. 3 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application. As shown in FIG. 3, the FM processing unit 105 may specifically include: a signal amplification circuit 1051 and a signal processing circuit 1052.

The power terminal of the motherboard unit 101 is connected to the power terminal of the signal amplifier circuit 1051 through the first matching circuit 102; the ground terminal of the motherboard unit 101 is connected to the ground terminal of the signal amplifier circuit 1051 through the second matching circuit 103; The ground terminal is connected to the input terminal of the signal amplification circuit 1051, the output terminal of the signal amplification circuit 1051 is connected to the input terminal of the signal processing circuit 1052, and the output terminal of the signal processing circuit 1052 is connected to the signal terminal of the motherboard unit 101 through the third matching circuit 104. .

The signal amplifying circuit 1051 is configured to receive the FM antenna signal from the main board unit 101, and amplify the FM antenna signal; and send the amplified FM antenna signal to the signal processing circuit 1052.

The signal processing circuit 1052 is configured to process the amplified FM antenna signal and send the processed FM antenna signal to the motherboard unit 101.

In the embodiment of the present application, a first matching circuit 102 is provided on a power supply channel between the motherboard unit 101 and the signal processing circuit 1052, and a second matching is provided on a ground connection channel between the motherboard unit 101 and the signal processing circuit 1052. The circuit 103 is provided with a third matching circuit 104 on a signal path between the motherboard unit 101 and the signal processing circuit 1052, so that the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 block the signal processing circuit 1052. Transmission of FM antenna signals with the motherboard unit 101. Accordingly, the main board unit 101 can transmit an FM antenna signal to the signal processing circuit 1052.

Further, the signal amplification circuit 1051 (such as a low-noise amplifier (LNA)) can firstly amplify the FM antenna signal through connection with the ground of the motherboard unit 101 to obtain an amplified FM antenna with high gain and low noise Signal to compensate for the loss caused by the FM antenna signal during transmission.

Further, the signal processing circuit 1052 can smoothly receive the amplified FM antenna signal, and it is convenient to select the FM antenna signal that falls in the FM frequency band from the amplified FM antenna signal, and encode and process the FM antenna signal. Get the processed FM antenna signal.

Exemplarily, on the basis of the embodiment shown in FIG. 1 or FIG. 2, an embodiment of the present application provides an FM antenna circuit 100. Continuing to combine with FIG. 3, the motherboard unit 101 may specifically include a baseband module 1011.

The first input terminal (not shown in FIG. 3) of the baseband module 1011 is connected to the output terminal of the FM processing unit 105 through the third matching circuit 104.

The baseband module 1011 is configured to receive a processed FM antenna signal from the FM processing unit 105 and output the processed FM antenna signal.

In the embodiment of the present application, the FM processing unit 105 generally processes the FM antenna signal into a baseband signal. When the processed FM antenna signal is a baseband signal, the baseband module 1011 can decode the baseband signal received from the FM processing unit 105. To obtain a voice signal and output it through a voice playback device (such as a speaker).

Among them, a voice transmission interface is usually provided between the baseband module 1011 and the FM processing unit 105. The voice transmission interface includes, but is not limited to, a Pulse Coded Modulation (PCM) interface, an I2S (Inter-IC Sound Bus) interface, and a serial interface. Peripheral interface (Serial, Peripheral, Interface), linear input (Line) interface.

Exemplarily, on the basis of the embodiment shown in FIG. 3, an embodiment of the present application further provides an FM antenna circuit 100. FIG. 4 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application. As shown in FIG. 4, different from FIG. 3, the motherboard unit 101 further includes a radio frequency module 1012, a fourth matching circuit 1013, a fifth matching circuit 1014, and a sixth matching circuit 1015.

The power terminal of the RF module 1012 is connected to the power terminal of the baseband module 1011 through the fourth matching circuit 1013; the ground terminal of the RF module 1012 is connected to the ground terminal of the baseband module 1011 through the fifth matching circuit 1014; the signal terminal of the RF module 1012 The sixth matching circuit 1015 is connected to the signal terminal of the baseband module 1011, and the ground terminal of the radio frequency module 1012 is connected to the second input terminal of the baseband module 1011.

The radio frequency module 1012 is configured to receive a high frequency antenna signal; and send a high frequency antenna signal to the baseband module 1011.

The baseband module 1011 is configured to process a high-frequency antenna signal and output the processed high-frequency antenna signal.

Among them, for convenience of explanation, as shown in FIG. 4, the power terminal, the ground terminal, and the signal terminal of the RF module 1012 are indicated by VCC, GND, and SIGNAL, respectively. The power terminal, the ground terminal, the signal terminal, and the second input of the baseband module 1011 are illustrated. The terminals are indicated by VCC, GND, SIGNAL, and IN, respectively.

In the embodiment of the present application, since the ground terminal of the RF module 1012 has a connection relationship with its own power terminal and signal terminal, and there is a connection relationship between the power terminal of the RF module 1012 and the power terminal of the baseband module 1011, a power channel can be formed. The ground terminal of the radio frequency module 1012 has a connection relationship with the ground terminal of the baseband module 1011, and can form a ground connection channel. The signal end of the radio frequency module 1012 has a connection relationship with the output end of the baseband module 1011, and can form a signal channel. Therefore, when the ground wire of the RF module 1012 is used as a high-frequency antenna, signals in the high-frequency band in all connection channels between the baseband module 1011 and the RF module 1012 can be isolated, thereby avoiding grounding of the RF module 1012 by electromagnetic interference. The effect of the high-frequency antenna signal received by the line.

The signals in the high-frequency band are signals in which the signal band falls within the high-frequency band in all connection channels between the baseband module 1011 and the radio-frequency module 1012, and the high-frequency antenna signals are received by the radio-frequency module 1012 through the ground wire and fall. For signals in the high-frequency band, any frequency in the high-frequency band is usually higher than the maximum frequency of the FM band.

Specifically, a fourth matching circuit 1013 may be provided on the power channel between the baseband module 1011 and the radio frequency module 1012, and a fifth matching circuit 1014 may be provided on the ground channel between the baseband module 1011 and the radio frequency module 1012. A sixth matching circuit 1015 is provided on all signal channels between the baseband module 1011 and the radio frequency module 1012. The settings of the fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 can block the baseband module 1011 and the radio frequency module. Transmission of signals in the high-frequency band on all connection channels between 1012. In this way, electromagnetic interference from surrounding components to the high-frequency antenna signals on the ground line of the RF module 1012 is reduced or eliminated. At this time, the ground of the RF module 1012 The cable will not be restricted by the clearance height of related components such as batteries, shields, cameras, etc. The distance between the ground of the RF module 1012 and these components can be set very small, so that the ground of the RF module 1012 can be Meet the requirements of zero headroom for high-frequency antennas.

Furthermore, when the ground wire of the radio frequency module 1012 receives a high-frequency antenna signal, it can send the high-frequency antenna signal to the baseband module 1011 through its connection with the input end of the baseband module 1011. The baseband module 1011 performs processing such as filtering, encoding, etc. on the high-frequency antenna signal, and outputs the processed high-frequency antenna signal. The high-frequency antenna signal may include, but is not limited to, a communication signal of a terminal device.

The FM antenna circuit provided in the embodiment of the present application isolates signals in a high-frequency band in all connection channels between a radio frequency module and a baseband module through a fourth matching circuit, a fifth matching circuit, and a sixth matching circuit, so as to avoid electromagnetic interference, Therefore, the ground wire of the RF module can be used as a high-frequency antenna, and the baseband module can receive the high-frequency antenna signal sent by the ground wire of the radio-frequency module through the connection to the ground terminal of the radio-frequency module. Output. In the FM antenna circuit of the embodiment of the present application, the ground wire of the RF module can be used as a high-frequency antenna. While the receiving performance of the high-frequency antenna meets actual requirements, the signals in the high-frequency band on all the connection channels in the RF module are isolated. The electromagnetic wave interference is avoided, so that the ground wire of the RF module is not limited by the clearance height of related components, and the zero clearance of the high-frequency antenna is realized, and the characteristics of low cost and space saving are achieved.

Exemplarily, on the basis of the embodiment shown in FIG. 4, an embodiment of the present application further provides an FM antenna circuit 100. FIG. 5 is a schematic structural diagram of an FM antenna circuit according to an embodiment of the present application. As shown in FIG. 5, different from FIG. 4, the FM antenna circuit 100 further includes a high-frequency antenna 1016.

The ground terminal of the radio frequency module 1012 is connected to the second input terminal of the baseband module 1011 through a high frequency antenna 1016.

The radio frequency module 1012 is configured to receive a high frequency antenna signal through a high frequency antenna 1016.

In the embodiment of the present application, if a high-frequency antenna 1016 is introduced into the FM antenna circuit 100, the high-frequency antenna 1016 can receive a high-frequency antenna signal from the ground of the radio-frequency module 1012 through a connection with the ground terminal of the radio-frequency module 1012. The high-frequency antenna 1016 can transmit the high-frequency antenna signal to the baseband module 1011 by connecting with the input end of the baseband module 1011, and the separate setting of the high-frequency antenna 1016 can improve the receiving performance of the high-frequency antenna signal. After the baseband module 1011 processes the high-frequency antenna signal, it outputs the processed high-frequency antenna signal.

In addition, since the ground wire of the RF module 1012 is not limited by the clearance height of related components such as batteries, shields, cameras, etc., the high-frequency antenna 1016 is also not limited by the clearance height of these components. The distance between 1016 and these parts is set very small, which achieves the zero headroom requirement of the high-frequency antenna 1016.

Wherein, optionally, the high-frequency antenna 1016 is a metal plate. For example, when the terminal device is a mobile phone, the front case metal plate in the mobile phone usually plays a role of heat dissipation and isolation. In the embodiment of the present application, the front case metal plate can be used as the high-frequency antenna 1016 to receive high-frequency antenna signals, saving the mobile phone. Of space.

The FM antenna circuit provided in the embodiment of the present application isolates signals in a high-frequency band in all connection channels between a radio frequency module and a baseband module through a fourth matching circuit, a fifth matching circuit, and a sixth matching circuit to avoid interference from electromagnetic waves. Then separately connect the high-frequency antenna to the ground wire of the RF module and the baseband module, so that the baseband module can receive the high-frequency antenna signal sent by the ground wire of the radio-frequency module through the high-frequency antenna. After the high-frequency antenna signal is processed, Output by the baseband module. In the FM antenna circuit of the embodiment of the present application, a high-frequency antenna is separately provided between the ground wire of the radio-frequency module and the baseband module, thereby improving the reception performance of the high-frequency antenna signal. The signals in the frequency band avoid electromagnetic wave interference, so that the high-frequency antenna will not be restricted by the clearance height of related components, and the requirement of zero-headroom of the high-frequency antenna is realized, and it has the characteristics of low cost and space saving.

Exemplarily, based on the embodiment shown in FIG. 4 or FIG. 5, the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 may include multiple implementation forms. The following uses two feasible implementation forms to describe the detailed structures of the first matching circuit 102, the second matching circuit 103, and the third matching circuit 104 in detail.

In the embodiment of the present application, the fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 achieve high-frequency antenna signal blocking by setting impedances higher than the FM frequency band and lower impedances at other frequency points. . The fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 are implemented in various forms.

In a feasible implementation form, optionally, the fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 are respectively: a high-impedance filter circuit, and the high-impedance filter circuit includes: R resistors connected in series And S capacitors, one end of each capacitor is connected to one end of any of the R resistors, the other end of each capacitor is grounded, and R and S are positive integers.

The number of inductors and capacitors included in the fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 may be the same or different, which is not limited.

In another feasible implementation form, optionally, the fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 are respectively: a high-impedance filter chip.

The number and types of high-impedance filter chips used by the fourth matching circuit 1013, the fifth matching circuit 1014, and the sixth matching circuit 1015 may be the same or different, which is not limited.

Exemplarily, on the basis of the embodiments shown in FIG. 1 to FIG. 5, an embodiment of the present application further provides a terminal device 10. FIG. 6 is a schematic structural diagram of a terminal device according to an embodiment of the present application. As shown in FIG. 6, the terminal device 10 in the embodiment of the present application may include: an FM antenna circuit 100.

For the structure of the FM antenna circuit 100, reference may be made to the description in the foregoing embodiment, and details are not described herein again.

The terminal device 10 provided in this embodiment may be a communication terminal such as a data card, a wireless internet card, a wireless router, a mobile phone, a wearable device, glasses, or a media device.

The above embodiments, structural schematic diagrams, or simulation diagrams are merely illustrative of the technical solutions of the present application, and the dimensional ratios and simulation values do not limit the scope of protection of the technical solutions. Anything in the spirit and principles of the above embodiments Modifications, equivalent replacements, and improvements made within the scope shall be included in the protection scope of this technical solution.

Claims (13)

1. A frequency-modulated FM antenna circuit, comprising: a main board unit, a first matching circuit, a second matching circuit, a third matching circuit, and an FM processing unit;

   The power terminal of the main board unit is connected to the power terminal of the FM processing unit through the first matching circuit; the ground terminal of the main board unit is connected to the ground terminal of the FM processing unit through the second matching circuit. Connection; the ground terminal of the motherboard unit is connected to the input terminal of the FM processing unit; the output terminal of the FM processing unit is connected to the signal terminal of the motherboard unit through the third matching circuit;

   The motherboard unit is configured to receive an FM antenna signal; and send the FM antenna signal to the FM processing unit;

   The FM processing unit is configured to perform signal processing on the FM antenna signal and send the processed FM antenna signal to the motherboard unit;

   The motherboard unit is further configured to output the processed FM antenna signal.
2. The circuit according to claim 1, further comprising: an FM antenna;

   The ground terminal of the motherboard unit is connected to the input terminal of the FM processing unit through the FM antenna;

   The motherboard unit is configured to send the FM antenna signal to the FM processing unit through the FM antenna.
3. The circuit according to claim 2, wherein the FM antenna comprises any one of a metal wire, a ceramic wire, and a flexible circuit board FPC cable.
4. The circuit according to any one of claims 1-3, wherein the first matching circuit, the second matching circuit, and the third matching circuit are: a band-stop filter circuit, and the band-stop The filter circuit includes M inductors and N capacitors connected in parallel with the M inductors, the M inductors are connected in series, the N capacitors are connected in series, and M and N are positive integers.
5. The circuit according to any one of claims 1-3, wherein the first matching circuit, the second matching circuit, and the third matching circuit are: a band-stop filter chip.
6. The circuit according to any one of claims 1-5, wherein the FM processing unit comprises: a signal amplification circuit and a signal processing circuit;

   The power terminal of the motherboard unit is connected to the power terminal of the signal amplifier circuit through the first matching circuit; the ground terminal of the motherboard unit is connected to the ground terminal of the signal amplifier circuit through the second matching circuit. Connection; the ground terminal of the motherboard unit is connected to the input terminal of the signal amplifier circuit, the output terminal of the signal amplifier circuit is connected to the input terminal of the signal processing circuit, and the output terminal of the signal processing circuit passes through the A third matching circuit is connected to the signal end of the motherboard unit;

   The signal amplifying circuit is configured to receive the FM antenna signal from the main board unit, amplify the FM antenna signal, and send the amplified FM antenna signal to the signal processing circuit;

   The signal processing circuit is configured to process the amplified FM antenna signal, and send the processed FM antenna signal to the motherboard unit.
7. The circuit according to any one of claims 1-6, wherein the motherboard unit comprises: a baseband module;

   The first input terminal of the baseband module is connected to the output terminal of the FM processing unit through the third matching circuit;

   The baseband module is configured to receive the processed FM antenna signal from the FM processing unit, and output the processed FM antenna signal.
8. The circuit according to claim 7, wherein the motherboard unit further comprises: a radio frequency module, a fourth matching circuit, a fifth matching circuit, and a sixth matching circuit;

   The power terminal of the radio frequency module is connected to the power terminal of the baseband module through the fourth matching circuit; the ground terminal of the radio frequency module is connected to the ground terminal of the baseband module through the fifth matching circuit; The signal terminal of the radio frequency module is connected to the signal terminal of the baseband module through the sixth matching circuit, and the ground terminal of the radio frequency module is connected to the second input terminal of the baseband module;

   The radio frequency module is configured to receive a high frequency antenna signal; and send the high frequency antenna signal to the baseband module;

   The baseband module is configured to process the high-frequency antenna signal and output the processed high-frequency antenna signal.
9. The circuit according to claim 8, further comprising: a high-frequency antenna;

   The ground terminal of the radio frequency module is connected to the second input terminal of the baseband module through the high frequency antenna;

   The radio frequency module is configured to receive the high frequency antenna signal through the high frequency antenna.
10. The circuit according to claim 9, wherein the high-frequency antenna is a metal plate.
11. The circuit according to any one of claims 8 to 10, wherein the fourth matching circuit, the fifth matching circuit, and the sixth matching circuit are: a high-impedance filter circuit, and the high-impedance circuit. The filter circuit includes: R resistors and S capacitors connected in series, one end of each capacitor is connected to one end of any of the R resistors, the other end of each capacitor is grounded, and R and S are positive integers.
12. The circuit according to any one of claims 8 to 10, wherein the fourth matching circuit, the fifth matching circuit, and the sixth matching circuit are: a high-impedance filter chip.
13. A terminal device, comprising: the FM antenna circuit according to any one of claims 1-12.

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