JP2015211288A - Antenna module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna module capable of reducing malfunction of an AGC circuit caused by a signal transmitted from a communication antenna.SOLUTION: An antenna module 100 includes: a substrate; a communication antenna 10 arranged along a part of an outer periphery of the substrate to transmit/receive a signal of a first frequency band; a first high frequency circuit section 20 mounted on the substrate and connected to the communication antenna 10 to process the signal of the first frequency band; and a second high frequency circuit section 30 mounted on the substrate 1 to process a signal of a second frequency band. The second high frequency circuit section 30 includes a variable gain amplifier 31 for amplifying the inputted signal of the second frequency band and a detection part 33 for detecting a level of an output signal from the variable gain amplifier 31 and outputting a control signal for varying an amplification factor of the variable gain amplifier 31 on the basis of the detected result to configure an AGC circuit, and a filter 32 for attenuating the signal of the first frequency band is connected between the variable gain amplifier 31 and the detection part 33.

Description

  The present invention relates to an antenna module, and more particularly to an antenna module including a broadcast receiving booster amplifier having an automatic gain control function.

  2. Description of the Related Art Conventionally, in-vehicle broadcast receivers, it is difficult to make a large space for installing a broadcast receiving antenna, and therefore a booster amplifier that supports broadcast reception such as AM broadcast, FM broadcast, or terrestrial digital broadcast has been widely used. It has been.

  In a radio receiver system 900 described in Patent Document 1 (conventional example), as shown in FIG. 3, a booster amplifier 920 connected to an antenna 910 and a radio receiver 930 connected to a subsequent stage of the booster amplifier 920 are provided. Consists of including.

  The booster amplifier 920 detects a change in impedance on the output signal line of the RF amplifier 922, a voltage-controlled attenuator 921 that receives the RF signal from the antenna 910, an RF amplifier 922 that amplifies the output signal from the attenuator 921 And a voltage control unit 924 for controlling the operation of the attenuator 921 based on the detection result of the impedance detector 923.

  The gain of the reception level from the antenna can be controlled using operation information of an AGC (Automatic Gain Control: hereinafter referred to as AGC) circuit in the radio receiver 930. Therefore, even when the reception strength of the desired station is lower than the reception strength of the non-desired station, a technology is disclosed that can obtain an audio output with good reception sensitivity without being destroyed by the reception strength of the desired station. Has been.

JP 2006-80602 A

  However, in the above-described conventional example, only suppression of sensitivity by an undesired station in the broadcast frequency band is considered. In recent years, with the spread of mobile phones and WLAN (Wireless Local Area Network: hereinafter referred to as WLAN), etc., especially in in-vehicle devices, there is a demand for an antenna module in which these communication antennas and booster amplifiers are integrated. Is growing. In an antenna module in which such a communication antenna and a booster amplifier are integrated, a signal transmitted from a communication antenna arranged near the booster amplifier directly enters the AGC circuit, causing the AGC circuit to malfunction. There has been a problem that the desired station may be suppressed and reception quality may deteriorate.

  The present invention solves the above-described problems, and an object thereof is to provide an antenna module that can reduce malfunction of an AGC circuit due to a signal transmitted from a communication antenna.

  In order to solve this problem, an antenna module of the present invention is configured on a substrate, a communication antenna that is arranged along a part of the outer periphery of the substrate, and that transmits and receives a signal in a first frequency band, and is formed on the substrate. And a first high-frequency circuit unit connected to the communication antenna and processing a signal in the first frequency band; and a second high-frequency circuit unit configured on the substrate and processing a signal in the second frequency band. A high-frequency circuit unit, wherein the second high-frequency circuit unit detects a level of an output signal of the variable gain amplifier and a variable gain amplifier that amplifies the input signal of the second frequency band. And a detection unit that configures an AGC circuit by outputting a control signal that varies the amplification degree of the variable gain amplifier based on the result, and between the variable gain amplifier and the detection unit, 1 frequency band signal Characterized by comprising a filter that Decay.

  According to this, since it is possible to prevent a signal transmitted from the communication antenna from being directly input to the detection unit, an antenna module capable of reducing malfunction of AGC due to a signal transmitted from the communication antenna. Can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the antenna module which can reduce the malfunctioning of the AGC circuit by the signal transmitted from a communication antenna can be provided.

It is a block diagram which shows the structure of the antenna module which concerns on this embodiment. It is a figure which shows the structure of the antenna module which concerns on this embodiment. It is a figure which shows the radio receiver system of a prior art.

[First Embodiment]
The antenna module 100 according to the first embodiment will be described below.

  First, the configuration of the antenna module 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the configuration of the antenna module 100. FIG. 2 is a schematic plan view showing an outline of the structure of the antenna module 100.

  As shown in FIG. 1, the antenna module 100 includes a communication antenna 10, a first high-frequency circuit unit 20, and a second high-frequency circuit unit 30. As shown in FIG. 2, the antenna module 100 includes a substrate 1, a communication antenna 10, a first high-frequency circuit unit 20, and a second high-frequency circuit unit 30 arranged on the substrate 1. Yes.

  The substrate 1 has a wiring pattern (not shown) formed of a metal foil such as copper on a base material made of an insulating resin material such as glass epoxy, and has a substantially rectangular shape as shown in FIG. A circuit is formed by appropriately mounting electronic components on the wiring pattern formed on the substrate 1, and the first high-frequency circuit unit 20 and the second high-frequency circuit unit 30 are configured.

  Next, the function and operation of each part constituting the antenna module 100 of the present embodiment will be described with reference to FIGS.

  The communication antenna 10 is configured by arranging an antenna element formed by a copper pattern along one side (Y1 side shown in FIG. 2) which is a part of the outer periphery of the substrate 1, and has a first frequency band. Send and receive signals. The first frequency band is a frequency band assigned to a mobile phone or the like, or a frequency band used in WLAN, and signals to be transmitted and received are communication signals performed using these frequencies.

  As shown in FIG. 1, the first high-frequency circuit unit 20 includes a matching circuit 21 and a first passband pass filter (denoted as first BPF in FIG. 1, hereinafter referred to as first BPF) 22. An output terminal 20a is provided.

  The matching circuit 21 has one end connected to the communication antenna 10 and the other end connected to one end of the first BPF 22 to perform impedance matching between the communication antenna 10 and the first BPF.

  The first BPF 22 has one end connected to the matching circuit 21 and the other end connected to the input / output terminal 20a. The first BPF 22 passes signals of the first frequency band and attenuates signals other than the first frequency band.

  The input / output terminal 20a is connected to a communication device that performs wireless communication in a first frequency band (not shown). The communication signal received by the communication antenna 10 is input to the communication device via the matching circuit 21 and the first BPF 22 via the input / output terminal 20a, and the communication signal output by the communication device communicates via the first BPF 22 and the matching circuit 21. It is radiated from the antenna 10 for use. As described above, the first high-frequency circuit unit 20 processes signals in the first frequency band.

  As shown in FIG. 1, the second high-frequency circuit unit 30 includes a variable gain amplifier 31, a filter 32, and a detection unit 33. The second high-frequency circuit unit 30 includes a second passband pass filter (denoted as second BPF in FIG. 1, hereinafter referred to as second BPF) 34 and a third passband pass filter (denoted as third BPF in FIG. 1). , Hereinafter, a third BPF) 35, an input terminal 30a, and an output terminal 30b. With the above configuration, the second high-frequency circuit unit 30 constitutes a booster amplifier having an AGC function for receiving broadcasts in the second frequency band.

  The input terminal 30a is connected to a receiving antenna that receives a second frequency band (not shown), and a signal in the second frequency band received by the receiving antenna is input to the input terminal 30a. The second frequency band is a frequency band such as an audio broadcast such as AM radio broadcast or FM radio broadcast, or a digital terrestrial television broadcast, and a received signal is a broadcast signal performed in these frequency bands. The input terminal 30a is connected to one end of the second BPF 34, and the broadcast signal in the second frequency band received by the receiving antenna is input to the second BPF 34 via the input terminal 30a.

  The second BPF 34 has one end connected to the input terminal 30a and the other end connected to the input of the variable gain amplifier 31. The second BPF 34 passes signals in the second frequency band and attenuates signals other than the second frequency band. .

  The variable gain amplifier 31 has the other end of the second BPF 34 connected to the input, one end of the filter 32 and one end of the third BPF 35 connected to the output, and the detection unit 33 connected to the control input. The variable gain amplifier 31 receives and amplifies the signal of the second frequency band that has passed through the second BPF 34 and outputs the amplified signal to one end of the filter 32 and one end of the third BPF 35. The amplification degree of the variable gain amplifier 31 is varied by a control signal input from the detection unit 33 to the control input.

  The filter 32 has one end connected to the output of the variable gain amplifier 31 and the other end connected to the detection unit 33. Therefore, the filter 32 is provided between the output of the variable gain amplifier 31 and the detection unit 33. It will be connected. The filter 32 passes the signal of the second frequency band and attenuates the signal of the first frequency band. For this reason, the signal of the first frequency band is attenuated and the signal of the second frequency band is input to the detection unit 33.

  The detection unit 33 has one end connected to the other end of the filter 32 and the other end connected to the control input of the variable gain amplifier 31. The detection unit 33 receives a signal obtained by attenuating the signal of the first frequency band by the filter 32 from the output signal of the variable gain amplifier 31. The level of this signal is detected, and a control signal is output based on the detected result. The control signal output from the detection unit 33 reduces the amplification factor of the variable gain amplifier 31 when the level of the signal input to the detection unit 33 is large, and when the level of the signal input to the detection unit 33 is small. A signal for increasing the amplification factor of the variable gain amplifier 31 is output. Specifically, a voltage signal or the like proportional to the signal input to the detection unit 33 is used as the output signal of the detection unit 33.

  The variable gain amplifier 31 is controlled by the control signal input from the detection unit 33 so that the amplification level decreases when the output level of the variable gain amplifier 31 is large, the output signal is lowered, and the output level is small. In this case, the output signal is increased by controlling the amplification degree to be increased. By performing control in this way, an AGC circuit is configured, and the output level of the variable gain amplifier 31 can be maintained within a certain range.

  The third BPF 35 has one end connected to the output of the variable gain amplifier 31 and the other end connected to the output terminal 30b. The third BPF 35 allows signals in the second frequency band to pass and attenuates signals other than the second frequency band. To do.

  The output terminal 30b is connected to a receiving device (not shown) that receives broadcasts in the second frequency band. The broadcast signal of the second frequency band received by the receiving antenna that receives the second frequency band passes through the second BPF 34, is amplified by the variable gain amplifier 31, and is again a signal other than the second frequency band by the third BPF 35. Is attenuated and output.

  As described above, the second high-frequency circuit unit 30 processes the signal in the second frequency band.

  Hereinafter, the effect by having set it as this embodiment is demonstrated.

  The antenna module 100 according to the present embodiment is configured on the substrate 1, the communication antenna 10 that is arranged along a part of the outer periphery of the substrate 1 and transmits / receives a signal in the first frequency band, and the substrate 1. A first high-frequency circuit unit 20 connected to the communication antenna 10 and processing a signal in the first frequency band, and a second high-frequency circuit unit configured on the substrate 1 and processing a signal in the second frequency band. 30, and the second high-frequency circuit unit 30 detects the level of the output signal of the variable gain amplifier 31 and the variable gain amplifier 31 that amplifies the input signal of the second frequency band, and the detection result And a detection unit 33 that constitutes an AGC circuit by outputting a control signal for varying the amplification degree of the variable gain amplifier 31 based on the first gain, and between the variable gain amplifier 31 and the detection unit 33, the first Attenuate frequency band signals And configured to include a filter 32.

  Thereby, since the filter 32 for attenuating the signal of the first frequency band is provided between the variable gain amplifier 31 and the detection unit 33, the signal of the first frequency band input to the detection unit 33 is attenuated. be able to. For this reason, even when the communication antenna 10 is arranged near the second high-frequency circuit unit 30 constituting the booster amplifier for broadcast reception, the signal transmitted from the communication antenna 10 is directly input to the detection unit 33. Can be prevented. Therefore, it is possible to provide an antenna module that can reduce malfunction of AGC due to a signal transmitted from the communication antenna 10.

  As described above, the antenna module 100 according to the embodiment of the present invention has been specifically described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. It is possible. For example, the present invention can be modified as follows, and these embodiments also belong to the technical scope of the present invention.

  (1) In this embodiment, the communication antenna 10 is described as being formed on the substrate 1 with a copper foil pattern. However, the communication antenna 10 is configured separately from the substrate and is modified to be mounted on the substrate. May be. Further, it may be configured not to be mounted on the substrate but to be arranged along the outer shape of the substrate and connected by a cable or the like.

  (2) In the present embodiment, the case where the communication antenna 10, the first high-frequency circuit unit 20, and the second high-frequency circuit unit 30 are each described as an example, but there are a plurality of each. Even a more complex antenna module can be configured similarly by configuring the filter 32 to attenuate the frequency band used for communication.

  (3) The filter 32 has been described without touching its specific configuration and characteristics, but is applicable to any filter that attenuates the signal in the first frequency band and passes the signal in the second frequency band. It is possible to select and use an appropriate filter according to the system. For example, when the first frequency band is a mobile phone using the 800 MHz band and the second frequency band is FM radio broadcasting, a low-pass filter that passes the frequency at which FM radio broadcasting is performed may be used. A notch filter that attenuates 800 MHz may be used. Furthermore, it is possible to carry out both filters in combination.

DESCRIPTION OF SYMBOLS 1 Board | substrate 10 Communication antenna 20 1st high frequency circuit part 20a Input / output terminal 21 Matching circuit 22 1st pass-band pass filter 30 2nd high frequency circuit part 30a Input / output terminal 30b Output terminal 31 Variable gain amplifier 32 Filter 33 Detection part 34 Second pass band pass filter 35 Third pass band pass filter 100 Antenna module

Claims (1)

A substrate,
A communication antenna disposed along a part of the outer periphery of the substrate for transmitting and receiving a signal in a first frequency band;
A first high-frequency circuit unit configured on the substrate and connected to the communication antenna and processing a signal in the first frequency band;
A second high-frequency circuit unit configured on the substrate and processing a signal in a second frequency band,
The second high-frequency circuit unit includes a variable gain amplifier that amplifies an input signal of the second frequency band;
An antenna module comprising: a detection unit configured to detect an output signal level of the variable gain amplifier and to output a control signal that varies an amplification degree of the variable gain amplifier based on a detection result; There,
An antenna module comprising a filter for attenuating a signal in the first frequency band between the variable gain amplifier and the detection unit.