JP2006217279A - Antenna switch circuit and radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently obtain a quantity of isolation between transmission and receiving in a desired frequency band, and to miniaturize a circuit and reduce a cost. <P>SOLUTION: A receiving terminal end switch 6 for terminating an receiving station 2 is mounted to the receiving station 2 side of a receiving switch 5 for turning on/off connection between an antenna terminal 3 and the accepting station 2. A resonance circuit connecting a capacitor 7 and an inductor 8 in series is connected to the receiving terminal end switch 6, and connected to a ground terminal 9. The receiving terminal end switch 6 has a role increasing a quantity of isolation between transmission and reception, by grounding a high-frequency signal passing through the receiving switch 5 in a noncontact state in the case of the transmission in a high frequency manner through the LC resonance circuit by the capacitor 7 and the inductor 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna switch circuit for switching between a radio circuit and an antenna, and a radio communication apparatus including the antenna switch circuit.

  Conventionally, a circuit as shown in FIG. 6 has been used as an antenna switch circuit used in a wireless communication device. FIG. 6 is a circuit diagram showing a configuration example of a conventional antenna switch circuit, and FIG. 7 is a characteristic diagram showing isolation characteristics between transmission and reception of the conventional antenna switch circuit. The operating principle of this antenna switch circuit will be briefly described.

  In FIG. 6, reference numeral 120 surrounded by a broken line indicates an antenna switch semiconductor integrated circuit. The antenna switch semiconductor integrated circuit 120 includes a transmission terminal 101, a reception terminal 102, an antenna terminal 103, a transmission switch 104 having one end connected to the transmission terminal 101 and the other end connected to the antenna terminal 103, and one end receiving terminal. 102, the other end of the receiving switch 105 is connected to the antenna terminal 103, the other end is connected to the receiving terminal 102 and the receiving switch 105, and the receiving terminal terminating switch 113 is connected to the other end of the receiving terminal terminating switch 113. The capacitor 114 has a ground terminal 109 connected to the capacitor 114, and the ground terminal 109 is grounded.

  In this antenna switch circuit, at the time of transmission, the transmission switch 104 is connected at a high frequency, the reception switch 105 is disconnected at a high frequency, and the reception terminal termination switch 113 is connected at a high frequency. As a result, the transmission terminal 101 and the antenna terminal 103 are connected at a high frequency, the reception terminal 102 and the antenna terminal 103 are disconnected at a high frequency, and the reception terminal 102 and the ground terminal 109 are connected at a high frequency.

  At the time of reception, the reception switch 105 is connected at a high frequency, the transmission switch 104 is disconnected at a high frequency, and the reception terminal termination switch 113 is disconnected at a high frequency. As a result, the receiving terminal 102 and the antenna terminal 103 are connected in high frequency, the transmitting terminal 101 and the antenna terminal 103 are disconnected in high frequency, and the receiving terminal 102 and the ground terminal 109 are disconnected in high frequency.

  A part of the high-frequency signal input from the transmission terminal 101 at the time of transmission has a capacitance value when the reception switch 105 is not connected in terms of high frequency, and therefore passes through the reception switch 105 and is output to the reception terminal 102. The power ratio between the high-frequency signal input to the transmission terminal 101 and the high-frequency signal output to the reception terminal 102 is referred to as the “transmission / reception isolation amount”. The amount of isolation between transmission and reception needs to be a predetermined value or more (for example, 20 decibels or more) in a desired frequency band. When the amount of isolation between transmission and reception is smaller than 20 dB, when the power of the high-frequency signal for transmission input to the transmission terminal 101 is large, the power of the high-frequency signal output from the reception terminal 102 becomes large, and the reception terminal 102 There is a risk that the receiving device connected to the will be destroyed by overpower input. Even when the power of the high-frequency signal input to the transmission terminal 101 during transmission is small, the high-frequency signal input from the transmission terminal 101 and output to the antenna terminal 103 is affected by the device connected to the reception terminal 102 or the microstrip line. As a result, the loss when passing through the antenna switch circuit increases.

  The reception terminal termination switch 113 has a function of increasing the amount of isolation between transmission and reception by grounding the high-frequency signal that has passed through the reception switch 105 at the time of transmission via the capacitor 114 and the ground terminal 109 in a high frequency manner. With this circuit configuration, as shown in FIG. 7, it is possible to obtain a transmission / reception isolation amount I of a desired value or more (for example, 20 decibels or more) in a desired frequency band, and satisfy the characteristic requirements as an antenna switch circuit. can do. As this type of antenna switch circuit, for example, the one shown in Patent Document 1 is known.

JP 2000-68807 A

  However, in the above conventional configuration, in order to obtain a predetermined amount or more of the isolation between transmission and reception, it is necessary to reduce the resistance value of the receiving terminal termination switch to reduce the impedance of the ground path. For this reason, there is a problem that the semiconductor size of the reception terminal termination switch is increased, the shape of the antenna switch circuit is increased, and the cost is increased.

  The present invention has been made in view of the above circumstances, and can provide a sufficient amount of isolation between transmission and reception in a desired frequency band, and can reduce the size and cost of a circuit. An object is to provide a circuit and a wireless communication device.

  The antenna switch circuit of the present invention is provided between a transmission switch that switches the connection between the transmission terminal and the antenna terminal, a reception switch that switches the connection between the reception terminal and the antenna terminal, and the reception terminal and the reception switch, A receiving terminal termination switch for turning on / off a connection with a ground path for terminating the receiving terminal, and a resonance circuit provided in a ground path connected to the receiving terminal termination switch.

  In the above configuration, by providing a resonance circuit in the ground path for terminating the receiving terminal, it is possible to sufficiently secure the amount of isolation between transmission and reception in a desired frequency band. Further, when the receiving terminal termination switch is made of a semiconductor, the size of the semiconductor can be reduced by reducing the switch, so that the circuit can be reduced in size and cost.

  Further, the present invention provides the antenna switch circuit described above, wherein the reception switch connects the reception terminal and the antenna terminal during transmission in which the transmission terminal and the antenna terminal are connected by the transmission switch. The receiving terminal termination switch is in a disconnected state, and the receiving terminal and the ground path are connected when the receiving terminal and the antenna terminal are disconnected by the receiving switch.

  In the above configuration, when the transmission terminal and antenna terminal are connected and the reception terminal and antenna terminal are disconnected during transmission, the reception terminal termination switch is connected and the reception terminal is grounded via the resonance circuit. For example, when an antenna switch circuit is applied to a time division transmission / reception system such as TDMA, a sufficient amount of isolation between transmission and reception can be obtained in a desired frequency band, and the circuit can be reduced in size and cost. It becomes possible to plan.

  Further, the present invention is the antenna switch circuit described above, wherein the reception terminal termination switch is configured to transmit the reception terminal and the ground path during transmission in which the transmission terminal and the antenna terminal are connected by the transmission switch. Are connected.

  In the above configuration, when the transmission terminal and the antenna terminal are connected at the time of transmission, the reception terminal termination switch is in the connection state, and the reception terminal is grounded and terminated through the resonance circuit. For example, the antenna switch circuit Is applied to simultaneous transmission / reception systems such as CDMA and time-division transmission / reception systems such as TDMA, it is possible to obtain a sufficient amount of isolation between transmission and reception in a desired frequency band, and to reduce the size and cost of the circuit. It becomes.

  Also, the present invention is the antenna switch circuit described above, wherein the resonance circuit is configured by a series resonance circuit in which a capacitor and an inductor are connected in series.

  With the above configuration, the resonance circuit can be configured simply and compactly by the series resonance circuit, and a sufficient amount of isolation between transmission and reception can be obtained in a desired frequency band, and the circuit can be reduced in size and cost.

  Further, the present invention is the antenna switch circuit described above, and is configured by a semiconductor integrated circuit including the transmission switch, the reception switch, the reception terminal termination switch, and the resonance circuit.

  In the above configuration, by configuring an antenna switch circuit having a resonance circuit with a semiconductor integrated circuit, a sufficient amount of isolation between transmission and reception can be secured in a desired frequency band, and the reception terminal termination switch can be made small. Since the semiconductor size can be reduced, the circuit can be reduced in size and cost.

  According to another aspect of the present invention, there is provided the antenna switch circuit including a semiconductor integrated circuit including the transmission switch, the reception switch, and the reception terminal termination switch, and the resonance circuit connected to the semiconductor integrated circuit. Shall be.

  In the above configuration, an antenna switch circuit including a semiconductor integrated circuit including a receiving terminal termination switch and a resonant circuit connected to the semiconductor integrated circuit is configured to sufficiently secure a transmission / reception isolation amount in a desired frequency band. In addition, since the semiconductor terminal size can be reduced by reducing the receiving terminal termination switch, the circuit can be reduced in size and cost.

  In addition, the present invention is the antenna switch circuit described above, and includes resonance frequency variable means for changing the resonance frequency of the resonance circuit.

  In the above configuration, by changing the resonance frequency of the resonance circuit by the resonance frequency varying means, the frequency band for obtaining the necessary transmission / reception isolation amount is varied, and the transmission / reception isolation amount is sufficiently ensured in the desired frequency band. It becomes possible.

  The present invention also provides a wireless communication device comprising any one of the antenna switch circuits described above, and an antenna, a transmission circuit, and a reception circuit connected to the antenna switch circuit.

  With the wireless communication device provided with the antenna switch circuit of the present invention, a sufficient amount of isolation between transmission and reception can be obtained in a desired frequency band, and the size and cost of the device can be reduced.

  According to the present invention, it is possible to provide an antenna switch circuit and a wireless communication apparatus that can sufficiently obtain a transmission / reception isolation amount in a desired frequency band and that can reduce the size and cost of the circuit. .

  In this embodiment, a configuration example of an antenna switch circuit formed in a semiconductor integrated circuit is shown.

(First embodiment)
FIG. 1 is a circuit diagram showing a configuration of an antenna switch circuit according to a first embodiment of the present invention, and FIG. 2 is a characteristic diagram showing an isolation characteristic between transmission and reception of the antenna switch circuit according to the first embodiment. .

  In FIG. 1, reference numeral 20 surrounded by a broken line indicates an antenna switch semiconductor integrated circuit. The antenna switch semiconductor integrated circuit 20 includes a transmission terminal 1, a reception terminal 2, an antenna terminal 3, one end connected to the transmission terminal 1 and the other end connected to the antenna terminal 3. A transmission switch 4 for switching connection, one end connected to the receiving terminal 2 and the other end connected to the antenna terminal 3, respectively, a receiving switch 5 for switching connection between the receiving terminal 2 and the antenna terminal 3, and one end receiving terminal 2 and the reception terminal termination switch 6 connected to the reception switch 5, the capacitor 7 connected to the other end of the reception terminal termination switch 6, the inductor 8 connected to the other end of the capacitor 7, and the inductor 8. The ground terminal 9 is grounded.

  The reception terminal termination switch 6 is provided between the reception terminal 2 and the reception switch 5 and turns on and off the connection between the ground terminal 9 and the ground path for terminating the reception terminal 2. In this embodiment, in the antenna switch semiconductor integrated circuit, an LC resonance circuit including a capacitor 7 and an inductor 8 connected in series is provided on a ground path between the receiving terminal termination switch 6 and the ground terminal 9.

  In this antenna switch circuit, at the time of transmission, the transmission switch 4 is connected in high frequency, the reception switch 5 is disconnected in high frequency, and the reception terminal termination switch 6 is connected in high frequency. Thereby, the transmission terminal 1 and the antenna terminal 3 are connected in high frequency, the reception terminal 2 and the antenna terminal 3 are disconnected in high frequency, and the reception terminal 2 and the ground terminal 9 are connected in high frequency.

  At the time of reception, the reception switch 5 is connected at a high frequency, the transmission switch 4 is disconnected at a high frequency, and the reception terminal termination switch 6 is disconnected at a high frequency. Thereby, the receiving terminal 2 and the antenna terminal 3 are connected in high frequency, the transmitting terminal 1 and the antenna terminal 3 are disconnected in high frequency, and the receiving terminal 2 and the ground terminal 9 are disconnected in high frequency.

  A part of the high-frequency signal input from the transmission terminal 1 at the time of transmission has a capacitance value when the reception switch 5 is not connected in terms of high frequency, and thus passes through the reception switch 5 and is output to the reception terminal 2. The reception terminal termination switch 6 increases the isolation between transmission and reception by grounding the high frequency signal that has passed through the reception switch 5 at the time of transmission through the LC resonance circuit including the capacitor 7 and the inductor 8 at the ground terminal 9 in a high frequency manner. Have a role to play.

  Here, if the semiconductor size of the reception terminal termination switch 6 is reduced for downsizing and cost reduction, the resistance value of the reception terminal termination switch 6 increases. For this reason, there may be a case where it is not possible to obtain a transmission / reception isolation amount of a predetermined value or more (in this example, 20 decibels or more) in a desired frequency band with the capacitor alone, as in the transmission / reception isolation amount A shown in FIG. .

  On the other hand, in the present embodiment, a resonance circuit that performs series resonance at a desired frequency is configured by the reception terminal termination switch 6, the capacitor 7, and the inductor 8 so as to reduce the impedance in the desired frequency band from the reception switch 5 side. I have to. With this configuration, the amount of attenuation can be increased in the vicinity of a desired frequency, as in the amount of isolation B between transmission and reception shown in FIG. 2, and the isolation between transmission and reception is 20 dB or more, which is the desired amount of isolation between transmission and reception in a desired frequency band. Can be obtained. Therefore, the receiving terminal termination switch can be made small and the semiconductor size can be made small while ensuring the necessary amount of transmission / reception isolation, so that the antenna switch circuit can be reduced in size and cost.

  In the above embodiment, the inductor is configured in the semiconductor integrated circuit. However, the inductor may be configured by a wire connected to the semiconductor integrated circuit. For example, when a semiconductor chip that constitutes a semiconductor integrated circuit is housed in a package, a wire that connects the semiconductor chip and the package terminal can function as an inductor.

(Second Embodiment)
FIG. 3 is a circuit diagram showing a configuration of an antenna switch circuit according to the second embodiment of the present invention. The second embodiment is an example in which a resonant circuit composed of a capacitor and an inductor is connected to the outside of the semiconductor integrated circuit.

  The antenna switch semiconductor integrated circuit 30 includes a transmission terminal 1, a reception terminal 2, an antenna terminal 3, a transmission switch 4 having one end connected to the transmission terminal 1 and the other end connected to the antenna terminal 3, and one end receiving terminal 2. The other end of which is connected to the antenna terminal 3, the other end of which is connected to the receiving terminal 2 and the receiving switch 5, and the receiving terminal connected to the other end of the receiving terminal terminating switch 6. The terminal terminal 10 and the ground terminal 9 are provided, and the ground terminal 9 is grounded. A capacitor 11 and an inductor 12 are connected in series to the reception terminal 10, and the other end of the inductor 12 is grounded.

  In this antenna switch circuit, the operation of each switch at the time of transmission and reception is the same as that of the first embodiment described above. At the time of transmission, the transmission terminal 1 and the antenna terminal 3 are connected at a high frequency, the reception terminal 2 and the antenna terminal 3 are disconnected at a high frequency, and the reception terminal 2 and the reception termination terminal 10 are connected at a high frequency. In reception, the receiving terminal 2 and the antenna terminal 3 are connected in high frequency, the transmitting terminal 1 and the antenna terminal 3 are disconnected in high frequency, and the receiving terminal 2 and the receiving terminal 10 are disconnected in high frequency. .

  A part of the high-frequency signal input from the transmission terminal 1 at the time of transmission has a capacitance value when the reception switch 5 is not connected in terms of high frequency, and thus passes through the reception switch 5 and is output to the reception terminal 2. The receiving terminal termination switch 6 grounds the high-frequency signal that has passed through the receiving switch 5 at the time of transmission from the receiving termination terminal 10 to the ground in a high-frequency manner through the LC resonance circuit including the capacitor 11 and the inductor 12, thereby isolating between transmission and reception. Has the role of increasing the amount.

  That is, a resonance circuit that resonates in series at a desired frequency is formed by the capacitor 11 and the inductor 12 provided outside the semiconductor chip constituting the semiconductor integrated circuit, and the impedance in the desired frequency band from the receiving switch 5 side is reduced. As in the first embodiment, the attenuation amount can be increased in the vicinity of the desired frequency, and a transmission / reception isolation amount of 20 dB or more, which is a desired transmission / reception isolation amount, can be obtained in a desired frequency band. it can. Therefore, it is possible to reduce the semiconductor size of the receiving terminal termination switch while ensuring the necessary amount of transmission / reception isolation, and thus it is possible to reduce the size and cost of the antenna switch circuit.

(Third embodiment)
FIG. 4 is a circuit diagram showing a configuration of an antenna switch circuit according to a third embodiment of the present invention, and FIG. 5 is a characteristic diagram showing isolation characteristics between the transmission and reception of the antenna switch circuit according to the third embodiment. . The third embodiment is a configuration example in which resonance frequency variable means for changing a resonance frequency of a resonance circuit including a capacitor and an inductor is provided, and a frequency band for obtaining a desired amount of isolation between transmission and reception is variable.

  In addition to the configuration of the first embodiment shown in FIG. 1, the antenna switch semiconductor integrated circuit 40 includes a resonance circuit switch 15 and a capacitor 16 corresponding to an example of a resonance frequency varying means connected in parallel with the capacitor 7. Composed. Other components of the antenna switch semiconductor integrated circuit 40 and operations at the time of transmission and reception are the same as those in the first embodiment described above.

  The resonance circuit switch 15 changes the resonance frequency by selecting whether to use only the capacitor 7 or the parallel connection of the capacitor 7 and the capacitor 16 as the capacitance component of the resonance circuit by turning on and off the connection of the capacitor 16. Have a role to play. The reception terminal termination switch 6 transmits a high-frequency signal that has passed through the reception switch 5 during transmission at the ground terminal 9 via an LC resonance circuit including the capacitor 7 and the inductor 8 or an LC resonance circuit including the capacitor 7, the capacitor 16, and the inductor 8. It has the role of increasing the amount of isolation between transmission and reception by grounding at high frequency.

  In the third embodiment, by turning on and off the resonance circuit switch 15, the resonance frequency can be changed by switching the capacitance component of the resonance circuit to only the capacitor 7 or the parallel connection of the capacitor 7 and the capacitor 16. . Thus, it is possible to change the frequency band in which a desired large transmission / reception isolation amount can be obtained by switching the frequency characteristic of the transmission / reception isolation amount as shown in FIG. 5 between the transmission / reception isolation amounts B1 and B2. It becomes. Therefore, in addition to the effects of the first and second embodiments, the frequency characteristic of the transmission / reception isolation amount is changed in accordance with the target frequency band to obtain the desired transmission / reception isolation amount in the desired frequency band. Can do.

  Instead of adding the resonant circuit switch 15 and the capacitor 16, a variable capacitor may be provided instead of the capacitor 7 so that the resonant frequency of the resonant circuit can be changed.

  The antenna switch circuits of the first to third embodiments described above are used in an antenna switching unit of a wireless communication device such as a mobile phone terminal. In this case, an antenna switch circuit including the antenna switch semiconductor integrated circuits 20, 30, and 40 is mounted on the antenna switching unit, the transmission circuit is connected to the transmission terminal 1, the reception circuit is connected to the reception terminal 2, and the antenna is connected to the antenna terminal 3. To do. With the antenna switch circuit of this embodiment, the wireless communication device can be configured in a small size and at low cost.

  In the first to third embodiments, the antenna switch circuit is configured in a semiconductor integrated circuit. However, the same effect can be obtained by using individual components. The same effect can be obtained by using a mechanical switch such as MEMS instead of using a semiconductor integrated circuit.

  In the above embodiment, one resonance circuit is configured to increase the amount of isolation between transmission and reception in one frequency band. However, two or more resonance circuits are configured to have one or more frequency bands. It is also possible to increase the amount of isolation between transmission and reception. This configuration is useful for a wireless communication apparatus that performs transmission and reception using a plurality of frequency bands.

  In the above embodiment, a configuration is shown in which either the transmission switch or the reception switch is connected to switch between the transmission terminal and the reception terminal at the time of transmission and at the time of reception, and the antenna switch circuit is time-shared such as TDMA. The example applied to the transmission / reception system has been described. However, the present embodiment can also be applied to a simultaneous transmission / reception system such as CDMA when the frequency of the transmission signal and the frequency of the reception signal are separated so as not to be affected by the resonance circuit.

  In the above embodiment, the antenna switch semiconductor integrated circuit has a single reception terminal. However, the antenna switch semiconductor integrated circuit has a plurality of reception terminals, a reception terminal termination switch corresponding to each reception terminal, a capacitor, and an inductor. The same effect can be obtained even when the antenna switch circuit is configured.

  In the above embodiment, the antenna switch semiconductor integrated circuit is configured to have one transmission terminal and one antenna terminal. However, the same effect can be obtained when the antenna switch semiconductor integrated circuit includes a plurality of transmission terminals and antenna terminals. . In the case of a configuration having a plurality of reception terminals, transmission terminals, and antenna terminals, a resonance circuit may be shared for a plurality of connection paths to be formed.

  In the above embodiment, an example of 20 dB or more is shown as the amount of isolation between transmission and reception necessary in a desired frequency band, but even when the amount is less than 20 dB, by applying the configuration of this embodiment, The same effect of increasing the amount of isolation between transmission and reception in a desired frequency band can be obtained. Further, when the amount of isolation between transmission and reception is insufficient in a desired frequency band and a further amount of isolation between transmission and reception is desired with respect to the current characteristics, the configuration of the present embodiment is applied and the ground path of the reception terminal is applied. By providing a resonance circuit, a larger amount of isolation between transmission and reception can be obtained.

  According to the antenna switch circuit of the present embodiment described above, a desired amount of isolation between transmission and reception can be sufficiently obtained in a desired frequency band, and the switch element can be reduced in size, so that the antenna switch circuit can be reduced in size. Moreover, cost reduction can be realized. For this reason, for example, when used in a mobile phone terminal, the mobile phone terminal can be made small and low-cost.

  The present invention has an effect that a sufficient amount of isolation between transmission and reception can be obtained in a desired frequency band, and the circuit can be reduced in size and cost, and switching between a radio circuit and an antenna can be achieved. The present invention is useful for an antenna switch circuit to be performed and a wireless communication apparatus including the antenna switch circuit.

1 is a circuit diagram showing a configuration of an antenna switch circuit according to a first embodiment of the present invention; The characteristic view which shows the transmission / reception isolation characteristic of the antenna switch circuit which concerns on 1st Embodiment A circuit diagram showing composition of an antenna switch circuit concerning a 2nd embodiment of the present invention. A circuit diagram showing composition of an antenna switch circuit concerning a 3rd embodiment of the present invention. The characteristic view which shows the transmission / reception isolation characteristic of the antenna switch circuit which concerns on 3rd Embodiment Circuit diagram showing a configuration example of a conventional antenna switch circuit Characteristic diagram showing isolation characteristics between transmission and reception of a conventional antenna switch circuit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission terminal 2 Reception terminal 3 Antenna terminal 4 Transmission switch 5 Reception switch 6 Reception terminal termination switch 7, 11, 16 Capacitor 8, 12 Inductor 9 Ground terminal 10 Reception termination terminal 15 Resonance circuit switch 20, 30, 40 Antenna switch semiconductor integrated circuit

Claims (8)

A transmission switch for switching the connection between the transmission terminal and the antenna terminal;
A receiving switch for switching the connection between the receiving terminal and the antenna terminal;
A reception terminal termination switch that is provided between the reception terminal and the reception switch, and that turns on or off a connection between a ground path for terminating the reception terminal;
An antenna switch circuit comprising: a resonance circuit provided in a ground path connected to the reception terminal termination switch. The antenna switch circuit according to claim 1,
The reception switch is in a disconnected state between the reception terminal and the antenna terminal at the time of transmission in which the transmission terminal and the antenna terminal are connected by the transmission switch,
The reception terminal termination switch is an antenna switch circuit that connects the reception terminal and the ground path when the reception terminal and the antenna terminal are not connected by the reception switch. The antenna switch circuit according to claim 1,
The reception terminal termination switch is an antenna switch circuit that connects the reception terminal and the ground path during transmission in which the transmission terminal and the antenna terminal are connected by the transmission switch. An antenna switch circuit according to any one of claims 1 to 3,
The resonance circuit is an antenna switch circuit configured by a series resonance circuit in which a capacitor and an inductor are connected in series. An antenna switch circuit according to any one of claims 1 to 4,
An antenna switch circuit configured by a semiconductor integrated circuit including the transmission switch, the reception switch, the reception terminal termination switch, and the resonance circuit. An antenna switch circuit according to any one of claims 1 to 4,
An antenna switch circuit comprising: a semiconductor integrated circuit including the transmission switch, the reception switch, and the reception terminal termination switch; and the resonance circuit connected to the semiconductor integrated circuit. The antenna switch circuit according to any one of claims 1 to 6,
An antenna switch circuit comprising resonance frequency variable means for changing the resonance frequency of the resonance circuit.   A wireless communication apparatus comprising: the antenna switch circuit according to claim 1; and an antenna connected to the antenna switch circuit, a transmission circuit, and a reception circuit.

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