JP3434732B2 - Antenna switching device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna switching device which simplifies the structure for distributing a signal via a changeover switch, reduces loss due to distribution, facilitates circuit design, and improves efficiency.

[0002]

2. Description of the Related Art A conventional antenna switching device is used, for example, in a mobile phone terminal device. FIG. 4 is a circuit diagram showing a configuration of an antenna switching device used in a mobile phone terminal device. This antenna switching device includes a switch SW1, a switch SW2, a switch SW3, a switch SW4, and a switch SW5, and a switch control unit 100 that controls each of the switches, and a transmitting and receiving antenna AN.
T1, the external connection terminal OUT1, the antenna ANT2 for transmission and reception, and the connection between the external connection terminal OUT2 and the transmission unit 11 and the reception units 12 and 13 are switched.

The switch SW1 opens and closes the connection path between the antenna ANT1 and the external connection terminal OUT1 and the switch SW3. The switch SW1 has two switch circuits which are common connection contacts, one of which is commonly connected. These two switch circuits are
The other contact not commonly connected is the antenna AN.
The switch circuit is connected to T1 and the other contact not commonly connected is connected to the external connection terminal OUT1.

The switch SW2 is an antenna ANT2.
And a connection path between the external connection terminal OUT2 and the switch SW3. This switch SW2
Is a common connection contact in which one contact is commonly connected 2
A switch circuit having two switch circuits, the other contact not connected in common is connected to the antenna ANT2, and the other contact not connected in common is connected to the external connection terminal OUT2. Become.

The switch SW3 opens and closes a connection path between the switch SW1 and the switch SW2 and the switch SW4. The switch SW3 has two switch circuits, one contact being a common connection contact commonly connected, and the other non-common connection contact is a switch circuit connected to the common connection contact of the switch SW1. The other contact that is not commonly connected includes a switch circuit that is connected to the common connection contact of the switch SW2.

The switch SW4 has a switch Sw5 and a transmitter 11 having two switch circuits, one of which is a common connection contact, and a switch SW3.
It opens and closes the connection path between and. The switch SW4 has two switch circuits, one of which is a commonly connected contact, and the other not commonly connected is commonly connected to the switch circuit connected to the transmitter 11. The other contact which is not connected is composed of a switch circuit connected to the common connection contact of the switch SW5. The common connection contact of the switch SW4 is connected to the common connection contact of the switch SW3.

The switch SW5 opens and closes the connection path between the switch SW4 and the receivers 12 and 13. The contact not commonly connected in one of the switch circuits of the switch SW5 is connected to the receiving unit 12, and the contact of the other switch circuit not commonly connected is connected to the receiving unit 13.

Next, the operation will be described. In the present antenna switching device, the transmitting unit 11 and the antenna A are connected via an antenna switching unit including each switch SW1, switch SW2, switch SW3, switch SW4, and switch SW5.
When signals are input and output between the NT1 and the external connection terminal OUT1, three switches, that is, the switch SW4, the switch SW3, and the switch SW1 are inserted in the signal path.

When signals are input and output between the antenna ANT1 and the external connection terminal OUT1 and the receiving unit 12 or the receiving unit 13 via the antenna switching unit, the switch SW5, the switch SW4, and the switch SW3 are used. The four-stage switch of the switch SW1 is inserted in the signal path.

When signals are input and output between the receiving section 12 or the receiving section 13 and the antenna ANT2 or the external connection terminal OUT2 via the antenna switching section,
Four stages of switches SW5, SW4, SW3, and SW2 are inserted in the signal path.

[0011]

Since the conventional antenna switching device is configured as described above, the number of switches inserted in the signal path is large, so that the loss per switch circuit is small. However, there is a problem that the loss increases due to connection and distribution with multiple switches.

Therefore, an object of the present invention is to reduce the number of stages of switches inserted in the signal path, reduce the loss due to signal distribution by using multiple stages of switches, and also to simplify and improve the efficiency of circuit design. An object is to provide an antenna switching device. It is another object of the present invention to provide an antenna switching device capable of attenuating an input of an interference wave or the like having an unnecessary frequency when switching antennas and reducing the influence of the unnecessary interference wave.

[0013]

An antenna switching device according to the present invention has only one stage inserted in each signal path between a receiving part or a transmitting part and a transmitting / receiving antenna or an external connection terminal, and is in an open state. And switch means controlled to a closed state, the receiving unit, the transmitting unit, the transmitting / receiving antenna, and external connection
Unwanted frequency signal appearing on the path of the signal connected to the terminal
Frequency signal suppressing means for suppressing the
Unnecessary circuits that open and close the connection between the signal suppressing means and the signal path.
Wave number signal suppression switch means, the switch means and the
Logical input terminal opening and closing of the unwanted frequency signal suppression switch means
Controlled by physical relationship , formation of each signal path and unnecessary
And a switch control means for suppressing a frequency signal .

In the antenna switching device of the present invention, only one stage of switch means controlled to be in the open state and the closed state is inserted in each signal path between the receiving section or the transmitting section and the transmitting / receiving antenna or the external connection terminal. So that the
No signal path is formed through the switch means
Therefore, the loss caused by the switching means on the signal path is increased.
Keep the addition low. In addition, unnecessary frequency signal suppression means and
It is not necessary to connect with the signal path.
Opening and closing according to the steps, the receiving unit, transmitting unit, transmission and reception
Need not appear on the path of the signal connected to the external connection terminal
Suppress frequency signals. Also, the switch at this time
Switch and the unnecessary frequency signal suppression switch means
The switch control means controls according to the logical relationship of the input terminals.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. The antenna switching device of the present embodiment is used in a mobile phone terminal device. FIG. 1 is a circuit diagram showing the configuration of the antenna switching device according to the present embodiment. This antenna switching device includes a switch (switch means) F1, a switch (switch means) F2, a switch (switch means) F3, a switch (switch means) F4, a switch (switch means) F5, and a switch (switch means) F.
6, switch (switch means) F7, switch (switch means) F7, switch (switch means) F8, switch (switch means) F9, switch (unnecessary frequency signal suppression switch means) F10, switch (unnecessary frequency signal suppression switch means) ) F11, switch (unnecessary frequency signal suppressing switch means) F12, switch (unnecessary frequency signal suppressing switch means) F13, switch (unnecessary frequency signal suppressing switch means) F14, and capacitor (unnecessary frequency signal suppressing means) for short-circuiting high frequency to ground ) C
1, a capacitor (unnecessary frequency signal suppressing means) C2, a capacitor (unnecessary frequency signal suppressing means) C3, a capacitor (unnecessary frequency signal suppressing means) C4, and a switch control unit (switch controlling means) 200 for controlling each switch. The antenna ANT1 for transmission / reception, the external connection terminal OUT1, the antenna ANT2 for transmission / reception, and the connection between the external connection terminal OUT2 and the transmitter 11 and the receivers 12 and 13 are switched.

The switch F1 includes a receiver 13 and an antenna A.
It is a switch for connecting to NT1, one contact is connected to the receiving unit 13, and the other contact is the antenna AN.
It is connected to T1 and switches F5 and F9.

The switch F2 is a switch for connecting the receiving unit 13 and the external connection terminal OUT1. One contact is connected to the receiving unit 13 and the other contact is the external connection terminal OUT1 and the switch F6. It is connected to the switch F10.

The switch F3 includes a receiver 13 and an antenna A.
A switch for connecting to NT2, one contact of which is connected to the receiver 13 and the other contact of which is an antenna AN.
It is connected to T2 and the switches F7 and F12.

The switch F4 is a switch for connecting the receiving unit 13 and the external connection terminal OUT2. One contact is connected to the receiving unit 13, and the other contact is the external connection terminal OUT2 and the switch F8 and It is connected to the switch F11.

Switch F1, switch F2, switch F
3. The contacts on one side of the switch F4 are commonly connected, and further connected to the switch F14 which is connected in series with the capacitor C1 whose one end is grounded.

The switch F5 includes a receiver 12 and an antenna A.
A switch for connecting to NT1, one contact is connected to the receiver 12, and the other contact is the antenna AN.
It is connected to T1 and the switches F1 and F9.

The switch F6 is a switch for connecting the receiving section 12 and the external connection terminal OUT1. One contact is connected to the receiving section 12, and the other contact is the external connection terminal OUT1 and the switch F2 and It is connected to the switch F10.

The switch F7 includes a receiver 12 and an antenna A.
A switch for connecting to NT2, one contact of which is connected to the receiver 12 and the other contact of which is the antenna AN.
It is connected to T2 and the switches F3 and F12.

The switch F8 is a switch for connecting the receiving unit 12 and the external connection terminal OUT2. One contact is connected to the receiving unit 12, and the other contact is the external connection terminal OUT2 and the switch F4. It is connected to the switch F11.

Switch F5, switch F6, switch F
7. The contacts on one side of the switch F8 are connected in common, and further connected to the switch F13 connected in series with the capacitor C2 whose one end is grounded.

The switch F9 includes a transmitter 11 and an antenna A.
It is a switch for connecting to NT1, one contact is connected to the transmitter 11 and the switch F10, and the other contact is connected to the antenna ANT1 and the switch F1.

The switch F10 is a switch for connecting the transmitter 11 and the external connection terminal OUT1. One contact is connected to the transmitter 11 and the switch F9, and the other contact is the external connection terminal OUT1. It is connected to the switches F2 and F6.

The switch F11 has an external connection terminal OUT2.
And a switch for connecting the capacitor C4 and
One contact is connected to the external connection terminal OUT2 and the switches F4 and F8, and the other contact is connected to the capacitor C4 whose one end is grounded.

The switch F12 is a switch for connecting the antenna ANT2 and the capacitor C3. One contact is connected to the antenna ANT2, the switch F3 and the switch F7, and the other contact is grounded at one end.
Connected to 3.

The capacitors C1, C2, C3 and C4 are grounded at one end and inserted for the purpose of high frequency short circuit. Further, the respective switches are input terminals CTLA, CTLB, CTLC, CT of the switch control unit 200.
It is controlled by the logical relationship of LD.

Next, the operation will be described. The antenna switching device of the present embodiment is characterized in that the number of switches passing through at the time of signal distribution is reduced to only one so as to reduce the loss due to the distribution. In addition, for unused terminals, high-frequency shorts at specific frequencies are possible with built-in capacitors, so it is possible to attenuate input of undesired frequencies such as interfering waves and leakage of your own transmission signals. It is possible to reduce the troubles caused by various interference waves.

FIG. 2 is an explanatory diagram showing a control state of opening and closing of each switch by the switch control unit 200 of the antenna switching device of the present embodiment, and each switch F1
~ It has a form as a truth table for controlling the opening and closing of the switch F14, the opening and closing control of each switch based on this truth table, the input terminals CTLA, CTLB, CTLC of the switch control unit 200, It is realized by the logical relationship of CTLD.

First, the flow of signals until the transmission signal is output to the antenna ANT1 will be described. The transmission signal output from the transmission unit 11 is supplied to the antenna ANT1 when the switch F9 is turned on. At this time, the other switches (the switches F1 to F8 and the switch F10) are turned off and do not conduct. Also, switch F
Other switches from 11 to the switch F14 are turned on, high frequencies are short-circuited to the ground side by the capacitors C1, C2, C3 and C4, and symbols RF2, RF4 and
It is possible to prevent the transmission signal from leaking to the unused terminals indicated by RF5, RF6, and RF7.

In addition, the signal transmitted by the user is the antenna AN.
Although there is a case where a defect such as spurious occurs due to being input to T2, the terminal indicated by reference symbol RF2 is short-circuited to the ground side by the capacitor C3 due to the switch F12 being on, so the occurrence of the above defect is avoided. it can.

The flow of the transmission signal when the transmission signal is output to the external connection terminal OUT1 is also the same as that of the switch F.
10 is turned on, and the terminals indicated by reference signs RF3 and RF4 are connected. The other switches in this case act in the same manner as described above, and function to prevent leakage to each unused terminal.

Next, the flow of received signals between the antenna ANT1 and the receiving section 12 or the receiving section 13 will be described. The reception signal input from the antenna ANT1 is supplied to the reception unit 12 or the reception unit 13 when the switch F5 (or the switch F1) is turned on. At this time, the other unnecessary terminals denoted by reference signs RF2, RF3, RF4, and RF5 are high-frequency shorted switches F12 and F as in the above.
11 is turned on, and acts to prevent leakage to other terminals or input of unwanted interference signals from the other terminals to the receivers 12 and 13.

Even when an input signal is input from the antenna ANT2, the external connection terminal OUT1, and the external connection terminal OUT2 to the reception units 12 and 13, respectively, the respective switches operate and are connected in the same manner as described above, so that the reception unit is connected. 12,
A signal can be supplied to 13. As for the unused terminal, each switch that short-circuits that terminal to the ground at high frequency is turned on, and the high frequency such as the interference wave is grounded through the capacitor to prevent the input of unnecessary interference waves. do.

As described above, in the present embodiment, the number of switches inserted in the signal path can be reduced to one, and the antennas ANT1 and ANT2 can be turned on / off by turning on / off each switch. Since it is possible to switch the connection relationship between the external connection terminal OUT1 and the external connection terminal OUT2 and the transmission unit 11, the reception unit 12, and the reception unit 13, it is possible to suppress an increase in loss caused by using the switch in multiple stages. Further, there is an effect that the circuit design is facilitated and an antenna switching device that can improve the efficiency of the circuit design can be provided.

In particular, since there is no unnecessary distribution to unused terminals, the loss due to distribution can be minimized. Further, since the terminals to be supplied to the receiving section have two terminals as indicated by reference signs RF6 and RF7, the reception frequency band can be narrowed, impedance matching can be easily achieved, and loss due to impedance mismatching can be achieved. Can be reduced.

Further, since the loss of the antenna switching section can be reduced as compared with the conventional case, the output power of the power amplifier module can be reduced in the transmitting section circuit, and the current consumption can be reduced. In the receiver circuit, the reception sensitivity is improved, and the effect that the callable distance is extended is also obtained.

Further, since the band of only the necessary frequency can be limited by narrowing the band of the receiving terminal to be used, it is possible to effectively attenuate the input of the interference wave of the unnecessary frequency and the like. There is also an effect that defects can be reduced.

Furthermore, since the unused terminals are short-circuited at high frequencies by the built-in capacitors, it is possible to attenuate the input of undesired interfering waves of the pass characteristics and the leakage of the transmission signal of the user, thus preventing the undesired operation. It also has the effect of reducing various problems caused by waves.

In the above description, a capacitor whose one end is grounded is used for high frequency short circuit. For example, a band filter circuit whose one end is grounded is used to short-circuit the unnecessary frequency band to the ground side. It may be configured. Alternatively, it is also possible to insert a band-pass filter circuit in series in the signal path to attenuate signals other than necessary signals and to limit the input / output band. Furthermore, adding measures such as adequate shielding for each signal path is also effective for inputting unnecessary frequency interference waves, attenuating leakage of own transmission signals, and reducing various problems caused by interference waves. Is.

Next, an antenna switching device according to another embodiment of the present invention will be described. The antenna switching device according to the present embodiment has the same basic configuration as that of the above-mentioned embodiment, but is further devised as a countermeasure against a problem caused by an interference wave. FIG. 3 is a circuit diagram showing the configuration of the antenna switching device according to the present embodiment. It should be noted that the same or corresponding portions as those in FIG.

In the antenna switching device of the present embodiment, the terminals denoted by reference symbols RF1, RF3 and RF4 are
Further, capacitors (unnecessary frequency signal suppressing means) C5, C6, C7 and switches (unnecessary frequency signal suppressing switch means) F15, F16, F17 for high frequency short circuit are added.

Regarding the roles of the capacitors C5, C6 and C7, as described above, reference numerals RF1, RF3 and RF are used.
Switch F1 when the terminal shown by 4 is not used
5, F16 and F17 are turned on and the terminals are short-circuited at a high frequency to prevent unwanted interference waves from leaking or the leakage of own transmission signal to the terminals.

In this configuration, each of the capacitors for high frequency short circuit may be another short circuit circuit such as a bandpass filter circuit.

Further, in the present embodiment as well, the capacitor is used for high frequency short circuit, but other circuits such as a bandpass filter circuit are used in series with each of the terminals to attenuate signals other than necessary signals to limit the band for input and output. It is also possible to have it, or to provide sufficient shielding for each signal path to suppress the input of undesired interference waves etc. and attenuate the leakage of the own transmission signal, and reduce various problems caused by other interference waves. .

Furthermore, in the present embodiment, the receiving section has a two-terminal configuration. However, by using a plurality of terminal configurations, it is possible to obtain the same narrow band effect as in the above-described embodiments. Needless to say. Further, the terminals other than the receiving section can be similarly configured with a plurality of terminals.

[0050]

As described above, according to the present invention, each signal path between the receiving section or the transmitting section and the transmitting / receiving antenna or the external connection terminal can be switched through the switching means having only one stage. Since it was configured to be formed,
There is an effect that the loss in the switch means in each of the formed signal paths can be minimized. Further, also in the circuit design, the loss due to the switch means in the signal path only needs to consider the loss of only one stage, which has the effect of facilitating the circuit design and improving the efficiency.

Further, the receiving section, the transmitting section, the transmitting / receiving antenna,
Unwanted frequency appearing on the path of the signal connected to the external connection terminal
Unnecessary frequency signal suppressing means for suppressing a number of signals, and the unnecessary frequency signal suppressing means
Opens or closes the connection between the frequency signal suppressing means and the signal path.
Unnecessary frequency signal suppression switch means, switch means ,
Input terminal for opening and closing the unnecessary frequency signal suppression switch means
Controlled by logical relationships, said forming and said signal paths
Since the switch control means for suppressing the signal of the unnecessary frequency is provided, when switching the antenna, the receiving section, the transmitting section, which is cut off from the path of another signal by the switch means,
This has the effect of attenuating the undesired interference waves that may be on the path of the signal connected to the transmission / reception antenna and the external connection terminal, and can reduce the effects of unnecessary interference waves.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an antenna switching device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a control state for opening and closing each switch of the antenna switching device according to the embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of an antenna switching device according to another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a conventional antenna switching device.

[Explanation of symbols]

11 ... Transmission unit, 12, 13 ... Reception unit, 200 ... Switch control unit (switch control means), F1, F2, F
3, F4, F5, F6, F7, F8, F9 ... Switch (switch means), F10, F11, F12, F13,
F14, F15, F16, F17 ... Switch (unnecessary frequency signal suppression switch means), C1, C2, C3, C
4, C5, C6, C7 ... Capacitor (unnecessary frequency signal suppressing means), OUT1, OUT2 ... External connection terminals, A
NT1, ANT2 ... Antenna (transmission / reception antenna).

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01Q 21/30 H01Q 3/24

Claims (2)

(57) [Claims] 1. An antenna switching device for switching a signal path between a plurality of receiving units or transmitting units having different receiving frequency bands and a plurality of transmitting / receiving antennas or a plurality of external connection terminals, the receiving unit or the transmitting unit. A switch means that is inserted into each signal path between the transmitting / receiving antenna or the external connection terminal and is controlled to an open state and a closed state; and the receiving section, transmitting section, transmitting / receiving antenna, and external With connection terminal
Suppress unwanted frequency signals that appear on the path of connected signals
And an unnecessary frequency signal suppressing means for connecting the unnecessary frequency signal suppressing means and the signal path.
Unnecessary frequency signal suppression switch means for opening and closing, and the switch means and the unnecessary frequency signal suppression switch hand
Controlled by the logic relation between the input terminal opening and closing stages, antenna switching, characterized by comprising a Sui <br/> pitch control means for the suppression of the signal formation and the unwanted frequency of each signal path apparatus. 2. A pre-Symbol switch control means, said receiving portion which is cut off a path for all the other signal by said switching means is controlled to the open state, the transmitting unit, receiving antenna or signals connected to an external connection terminal, 2. The antenna switching device according to claim 1, wherein the unnecessary frequency signal suppression switch means is controlled to be closed for the path.